Air Fryer
A countertop cooking appliance that circulates very hot air around food using a fan and a heating element, producing results similar to deep frying with little or no oil. Air fryers typically draw 1,200 to 1,800 watts but cook in shorter sessions than a full-size oven, making them more energy-efficient for small portions.
Air Handler Blower
The fan unit inside a central air conditioning or heating system that circulates conditioned air through the ductwork and into living spaces. The blower runs whenever the system is operating, but it consumes far less power than the outdoor compressor — typically 300 to 500 watts for a residential unit. Its electricity cost is often overlooked when estimating total AC operating expense.
Air Infiltration
The uncontrolled flow of outdoor air into a home through gaps, cracks, and openings in the building shell — around doors, windows, electrical outlets, and pipe penetrations. It forces heating and cooling systems to work harder because conditioned air escapes at the same time unconditioned outside air enters. The EIA estimates air infiltration accounts for 25–40 percent of a typical home's heating and cooling energy use.
Common fixes include weatherstripping on exterior doors and caulking around window frames, both of which cost under $50 per opening and can be done without a contractor.
All-Electric Home
A residence that uses electricity as the sole energy source for every major end use — space heating, cooling, water heating, and cooking — with no natural gas or propane appliances. Because electricity carries loads that gas-supplied homes split across two fuel sources, all-electric homes show higher average monthly kWh consumption and are more sensitive to electricity rate changes.
Ambient Temperature Effect
The influence of the air temperature surrounding an appliance on how hard that appliance must work to maintain its set temperature. For refrigerators and freezers, higher ambient temperatures — such as those in an unconditioned garage in summer — force the compressor to run more frequently, increasing electricity consumption.
Studies have found that ambient temperatures above 90°F can raise freezer energy consumption by 30 to 50 percent compared to operation at 70°F.
Ampere A
An ampere, or amp, measures how much electric current is flowing through a wire. It's the volume of electricity moving, where voltage is the pressure behind it. Your home's breaker panel is rated in amps, often 100 or 200.
Each breaker in your panel trips at a set amperage to keep a circuit from overheating. Volts times amps gives you watts, the actual power being used.
Related: Volt , Watt
Appliance-Level Measurement
The practice of measuring the electricity consumption of a single appliance or device in isolation, rather than tracking whole-home usage. This is typically done with a plug-in energy monitor or a smart plug with energy-monitoring capability. It allows a household to calculate the exact monthly cost of operating a specific device.
Auto Defrost
A freezer or refrigerator feature that automatically melts accumulated frost on interior coils using a built-in heating element on a timed cycle. This prevents frost buildup without manual intervention but consumes additional electricity each time the defrost cycle runs.
Automatic Transfer Switch ATS
An electrical device installed between the utility line and a home's main panel that detects when grid power is lost, disconnects the home from the grid, and switches it to a backup generator — all without manual intervention. It reverses the process when grid power returns, preventing the generator and utility power from being connected at the same time, which would be dangerous.
Average Monthly Usage
The average Texas home uses roughly 1,000 kilowatt-hours a month, though summer cooling can push it well past 2,000. This number matters because electricity plans advertise their rate at 500, 1,000, and 2,000 kWh, and the price can change a lot depending on which usage level you actually hit.
A plan that looks cheap at 1,000 kWh can cost much more at 500 kWh because of hidden minimum-usage fees or bill credits. Check your past 12 months of bills to find your real average before you compare.
Related: Electricity Usage , Kilowatt-Hour , Electricity Facts Label
Source: Power to Choose (PUCT)
Baseload
Baseload is the steady, around-the-clock level of electricity demand that never goes away, even at 3 a.m. when most of Texas is asleep. Power plants that run constantly, like nuclear and large natural gas units, cover this baseline, while other sources ramp up to meet the daytime peaks.
Picture a chart of daily electricity use: baseload is the flat floor everything sits on top of, and peak demand is the tall spike in the afternoon.
Related: Peak Demand , Load , Megawatt
Source: ERCOT
Blower Door Test
A diagnostic procedure in which a large calibrated fan is temporarily mounted in a home's doorframe to depressurize the house. The resulting pressure difference draws outside air through any gaps or cracks, making air leakage points detectable by touch, smoke pencil, or infrared camera. The test produces a quantitative measurement of the home's total air infiltration rate.
Results are typically expressed in CFM50 (cubic feet per minute at 50 Pascals of pressure) and can be compared against building-code thresholds or efficiency program standards.
Source: ENERGY STAR
BPI Certified Building Analyst BPI
A professional credential issued by the Building Performance Institute that demonstrates competency in whole-house diagnostic methodology, including blower door testing, combustion safety analysis, and energy improvement planning. BPI-certified analysts are trained to treat a home as an interconnected system rather than evaluating components in isolation.
Source: Building Performance Institute
BTU BTU
British Thermal Unit — the standard measure of heat energy used to rate the cooling or heating capacity of air conditioners and other HVAC equipment. One BTU is the amount of energy needed to raise one pound of water by one degree Fahrenheit. Air conditioners are commonly rated in BTUs per hour, with larger numbers indicating more cooling power.
A window unit rated at 12,000 BTU per hour can remove roughly twice as much heat from a space as a 6,000 BTU unit in the same amount of time.
Source: U.S. Energy Information Administration
Building Envelope
The set of physical components that separate a home's conditioned interior from the outdoors, including walls, roof, windows, doors, and foundation slab or crawl space. A tighter, well-insulated envelope reduces the temperature difference the HVAC system must overcome, directly cutting the cooling and heating electricity a home requires.
Older homes with minimal attic insulation and single-pane windows can have envelope losses severe enough to double electricity use compared to a same-size newer home — making envelope quality as important as square footage when estimating expected bills.
Source: U.S. Department of Energy
C-Wire C-wire
A dedicated low-voltage wire in a home's thermostat wiring that provides continuous 24-volt power to a thermostat. Most smart thermostats require a C-wire to operate reliably; without one, the device may lose power or behave erratically.
Homes built before roughly 2000 often lack a C-wire at the thermostat location, requiring either an adapter kit or a short electrical upgrade before a smart thermostat can be installed.
Source: U.S. Department of Energy – Energy Saver
Carbon Monoxide Poisoning CO Poisoning
A life-threatening medical emergency caused by inhaling carbon monoxide gas, which is produced by burning fuel — such as gas, charcoal, or propane — in an enclosed or poorly ventilated space. During power outages, CO poisoning risk rises sharply when people use gas ovens, grills, or portable generators indoors as improvised heat sources.
Source: Texas Department of State Health Services
Ceiling Fan
A ceiling-mounted electric fan that circulates air in a room, drawing typically 15 to 75 watts — a fraction of the electricity consumed by an air conditioner. By creating a wind-chill effect, a ceiling fan can make a room feel 3 to 4 degrees cooler, allowing occupants to raise the thermostat setpoint and reduce HVAC runtime without sacrificing comfort. Ceiling fans do not lower air temperature; they only affect perceived comfort, so they waste energy if left running in empty rooms.
Source: U.S. Department of Energy – Energy Saver
Chest Freezer
A standalone freezer with a lid that opens from the top rather than a front-mounted door. Because cold air is denser than warm air and sinks, chest freezers retain cold more effectively when opened, making them generally more energy-efficient per cubic foot than upright models.
Circuit-Level Monitoring
A feature of some whole-home energy monitors that measures electricity consumption on individual branch circuits in your electrical panel, rather than only the total draw of the whole house. It requires additional current-sensor clamps installed on specific circuit breakers and lets you attribute usage to a particular room, appliance, or system.
For example, a circuit-level monitor might show that your master bedroom's mini-split is drawing 900 watts while your kitchen circuit is nearly idle.
Clamp-Style Current Transformer CT
A sensor that clips around an electrical wire and measures the current flowing through it without breaking the circuit. It works by detecting the magnetic field the current produces, so no direct electrical contact is needed. Electricians and homeowners use clamp meters to measure power on 240-volt circuits — such as central air conditioners, electric dryers, or water heaters — that standard plug-in monitors cannot reach.
For example, clamping a CT around the wire feeding your central AC breaker lets you record exactly how many kilowatt-hours that system uses over a week without hiring an electrician or rewiring anything.
Source: U.S. Department of Energy
Coefficient of Performance (COP) COP
A measure of how efficiently a heat pump converts electricity into usable heat, expressed as the ratio of heat energy delivered to electrical energy consumed. A COP of 2.5 means the system delivers 2.5 units of heat for every 1 unit of electricity used, making it far more efficient than resistance heating, which has a COP of exactly 1.
Compressor Cycle
The on-off pattern of a refrigerator's compressor motor as it works to maintain the interior temperature. The compressor runs until the target temperature is reached, then shuts off until heat leaks back in. Longer or more frequent cycles — caused by a hot environment, a failing door seal, or an aging compressor — increase the appliance's overall energy consumption.
Compressor Draw
The amount of electrical power, measured in watts, that an air conditioner's compressor consumes while actively running. Compressor draw is the dominant load of a central AC or heat pump system and is distinct from the lower power used by the indoor air handler blower. Knowing the compressor draw is essential for estimating the operating cost of a cooling system.
Condenser Coils
A set of heat-exchanging coils, typically located at the back or underneath a refrigerator, that release the heat removed from the cabinet into the surrounding room. When coils are clogged with dust or debris, heat dissipation is reduced, forcing the compressor to run longer and use more electricity.
Convection Mode
A setting on an electric oven that runs a fan to circulate hot air around food. Because heat reaches food more evenly and efficiently, convection mode typically reduces cooking time by about 25 percent and allows a lower oven temperature compared with standard bake, cutting total electricity used per meal.
For example, a dish that takes 60 minutes at 350°F in standard mode may finish in 45 minutes at 325°F in convection mode, using noticeably fewer kWh.
Cooking Power
The amount of energy a microwave's magnetron actually delivers to food, as printed on the appliance's door label or specification sheet. This figure is lower than the appliance's total wall draw because it excludes power consumed by the control panel, turntable motor, and interior light.
A microwave labeled '1,100 watts cooking power' typically draws 1,200 to 1,300 watts from the wall outlet during active use.
Cooling Load
The amount of heat energy an air conditioning system must remove from a building to maintain a desired indoor temperature. Cooling load increases as outdoor temperatures rise, as more heat enters through windows and walls, or as internal sources like appliances and occupants add heat. It is typically measured in British Thermal Units (BTUs) per hour or in tons of cooling capacity.
Cooling Setpoint
The target indoor temperature at which an air conditioning system is programmed to activate. When the indoor temperature rises above the setpoint, the AC compressor turns on to bring the temperature back down. Raising the setpoint reduces how often the compressor runs and directly lowers electricity consumption.
Cost per Mile
The total fuel or electricity expense to drive one mile, calculated by dividing the cost of the fuel or energy source by the vehicle's efficiency rating. For electric vehicles, it equals kWh per mile multiplied by the electricity rate. For gasoline vehicles, it equals the price per gallon divided by miles per gallon.
Because electricity rates and gas prices vary, cost per mile is a more apples-to-apples way to compare fueling costs across different vehicle types than looking at price per gallon or price per kWh alone.
Countertop Toaster Oven
A compact electric oven that sits on a countertop and heats a much smaller cavity than a full-size range oven. Drawing roughly 1,200 to 1,800 watts, it can cook a single serving or small dish using approximately half the electricity a full-size oven would use for the same task.
Demand Shifting
The practice of moving discretionary electricity consumption—such as running a dishwasher, doing laundry, or charging an electric vehicle—away from high-price or high-demand periods toward times when electricity is cheaper or grid conditions are less stressed. Demand shifting is the primary strategy households use to reduce costs on time-of-use or indexed electricity plans.
Distribution Infrastructure
The lower-voltage power lines, poles, transformers, and related equipment that carry electricity from transmission substations to individual homes and businesses. This infrastructure is owned and operated by transmission and distribution utilities, not by retail electricity providers or grid operators.
Source: U.S. Energy Information Administration
Door Gasket
The flexible magnetic seal that runs along the edge of a refrigerator or freezer door, creating an airtight closure when shut. A worn or cracked gasket allows cold air to escape continuously, increasing compressor run time and energy use. Gaskets can typically be replaced without professional service.
Dual-Hose Portable AC
A portable air conditioner design that uses one hose to draw outdoor air over the condenser and a second hose to exhaust that air back outside. Because it does not depressurize the room, it avoids the hot-air re-infiltration problem common to single-hose models and typically operates more efficiently.
Duct Leakage
The unintended escape of conditioned air from holes, gaps, or poorly connected joints in a home's heating and cooling ductwork before that air reaches the intended room. ENERGY STAR estimates duct leakage accounts for 20–30 percent of cooling energy loss in many homes. Sealing ducts is a utility-rebated improvement offered by several Texas TDUs.
Source: ENERGY STAR
Duct Pressurization Test
A diagnostic measurement that uses a calibrated fan to pressurize a home's duct system and quantify how much conditioned air escapes through leaks before reaching living spaces. Results are typically expressed as a percentage of total system airflow or as cubic feet per minute. The test helps auditors determine whether duct sealing is cost-effective.
Ducts running through unconditioned attics or crawl spaces often show the highest leakage rates because joints and seams degrade over time in extreme temperatures.
Duct Test and Seal
A diagnostic and repair service in which a certified technician measures how much conditioned air escapes from a home's ductwork — typically using a pressurization device called a duct blower — and then seals identified leaks with mastic, metal tape, or aerosol sealant. Because leaky ducts in Texas can waste 20 to 40 percent of cooled or heated air before it reaches living spaces, sealing them reduces compressor run time and lowers electricity bills without any change to the AC unit itself.
Duty Cycle
The percentage of time a cycling appliance — such as a refrigerator compressor or air conditioner — is actually running within a given period. A 40 percent duty cycle means the compressor runs roughly 40 percent of each hour. Duty cycle, multiplied by running wattage, determines real energy consumption more accurately than rated wattage alone.
A refrigerator rated at 150 watts with a 40 percent duty cycle effectively consumes energy as though it were a continuous 60-watt device.
Electric Pressure Cooker
A sealed countertop appliance that cooks food under elevated pressure using an electric heating element, dramatically reducing cooking time compared to conventional methods. After the pressure-building phase, the element cycles to a low-power hold, so total energy consumption per meal is typically modest relative to cooking time.
Electric Strip Heat
A heating method that converts electricity directly into heat using resistance coils — the same principle as a toaster or space heater scaled to a whole home. Strip heat consumes roughly two to three times more electricity per unit of heat delivered than a heat pump, making it the primary driver of high winter electricity bills in all-electric homes.
A home relying on strip heat may see its January kWh total rival or exceed its July air-conditioning bill.
Electric Water Heater
A tank-style appliance that heats and stores a supply of hot water — typically 40 to 80 gallons — using one or two resistance heating elements rated at 4,000 to 5,500 watts each. The elements cycle on and off to maintain a set water temperature, and total monthly consumption commonly ranges from 380 to 500 kWh, making water heating one of the largest electricity loads in an all-electric home. Consumption rises with household size, tank temperature setting, and hot-water usage habits.
At the Texas median rate of roughly 14.7 cents per kWh, a typical electric water heater can add $56 to $74 to a monthly electricity bill.
Source: U.S. Department of Energy – Energy Saver
Electricity Usage
Your electricity usage is the total amount of energy your home consumed during the billing period, measured in kilowatt-hours. It's the single biggest factor in what you pay, and it's the number you plug in when comparing plans on a site like Power to Choose.
Your smart meter records usage and sends it to your TDU, who passes it to your retail provider for billing. Heating and cooling drive most of the swing from month to month in Texas.
Related: Kilowatt-Hour , Average Monthly Usage , Load , Smart Meter
Source: Power to Choose (PUCT)
Energy Efficiency Ratio EER
A measure of a cooling appliance's efficiency calculated by dividing its cooling output in BTUs by its electrical input in watts, both measured at a fixed set of conditions. A higher EER means more cooling delivered per watt of electricity consumed. Unlike SEER, which averages performance across a full season, EER reflects efficiency at a single peak-condition snapshot.
A window AC with an EER of 12 delivers 12 BTUs of cooling per watt, making it noticeably cheaper to run than a portable unit with an EER of 7 drawing the same rated BTUs.
Source: U.S. Department of Energy – Energy Saver
ENERGY STAR
A voluntary certification program run by the U.S. Environmental Protection Agency (EPA) that identifies appliances, electronics, and building products meeting defined energy-efficiency thresholds. Products carrying the ENERGY STAR label have been independently tested and use meaningfully less electricity than standard models for the same function.
Source: U.S. EPA ENERGY STAR
EnergyGuide Label
A federally required bright-yellow label displayed on most major home appliances that shows the model's estimated annual energy consumption in kilowatt-hours and its estimated yearly operating cost compared to similar models. The label is produced under the FTC's Appliance Labeling Rule and uses a national average electricity rate for its cost estimate, which may differ from local rates.
Source: Federal Trade Commission
EV Home Charging
The practice of recharging an electric vehicle's battery using electricity from a residential service connection, typically overnight. Home charging adds kilowatt-hours to a household's monthly electricity bill, and the rate paid per kWh on the household's electricity plan directly determines the per-mile fueling cost.
Federal Appliance Efficiency Standards
Minimum energy performance requirements set by the U.S. Department of Energy for household appliances including refrigerators, dishwashers, and water heaters. These standards are periodically tightened, meaning newer appliances are legally required to consume less energy than older models. Appliances already in use are not subject to the new limits; only newly manufactured units must comply.
Source: U.S. Department of Energy
Fuel Stabilizer
A chemical additive mixed into stored gasoline to slow oxidation and varnish buildup, extending the fuel's usable shelf life from about 30 days to 12 months or longer. Generators fueled with degraded, unstabilized gasoline can suffer carburetor damage or fail to start, which is a critical risk for storm-preparedness stockpiles.
Heat Pump
A vapor-compression system that moves heat rather than generating it: in winter it extracts warmth from outdoor air to heat the home; in summer it reverses to act as an air conditioner. A heat pump delivers two to four units of heating or cooling for every unit of electricity consumed, making it far more efficient than electric strip heat and a significant factor in comparing winter electricity usage across home types.
Heat Pump Dryer
An electric clothes dryer that uses a refrigerant-based heat pump to recirculate and reuse warm air rather than exhausting it, requiring roughly 40–50% less electricity than a conventional resistance-element dryer. Because it operates at lower temperatures, it is gentler on fabrics. It typically costs more upfront but pays back the difference through lower monthly electricity bills.
A household switching from a conventional 5,000-watt electric dryer to a heat pump dryer might reduce dryer-related electricity use from roughly 50 kWh per month to 25–30 kWh per month.
Source: U.S. Department of Energy – Energy Saver
Heat-Pump Water Heater HPWH
A water heater that uses a refrigerant cycle to move heat from surrounding air into the water tank rather than generating heat directly from electric resistance coils. Heat-pump water heaters typically use 60 to 70 percent less electricity than a conventional electric storage water heater for equivalent hot-water output. They require adequate space with ambient temperatures above roughly 40°F to operate efficiently.
A Texas household replacing a standard 4,500-watt electric storage water heater with a heat-pump model can reduce water-heating consumption from roughly 270 kWh per month to under 100 kWh.
Heated Dry Cycle
A dishwasher setting that uses an electric heating element to evaporate moisture from dishes after the wash cycle ends. It adds roughly 0.5 to 1.0 kWh per cycle on top of the wash load, making it the largest single variable in a dishwasher's total electricity consumption.
Switching to an air-dry or fan-only setting instead of heated dry typically reduces a dishwasher's per-cycle kWh use by 30 to 40 percent.
Heating Element Duty Cycle
The fraction of time a heating element is actively drawing full power during a cook period. A slow cooker set to Low does not run its element continuously; instead, the element switches on and off to hold the target temperature, so actual average wattage is lower than the nameplate maximum.
A 200-watt crock pot with a 70% duty cycle draws an average of 140 watts over a full cook session, not 200 watts.
HERS Rating HERS
A standardized numerical score produced by the Residential Energy Services Network (RESNET) that benchmarks a home's energy efficiency against a reference house built to code. A score of 100 represents the reference house; lower scores indicate greater efficiency. New homes in many states must achieve a minimum HERS score to qualify for certain financing or incentive programs.
A home scoring 70 is estimated to use 30 percent less energy than the reference house; a net-zero home scores 0.
Source: RESNET
Home Battery Storage
A rechargeable battery system installed at a residence that stores electricity — from the grid, rooftop solar, or both — and discharges it to power the home when the grid is unavailable. Capacity is measured in kilowatt-hours (kWh), and the system is managed by an inverter that converts stored DC power to the AC power household appliances use.
A single residential battery unit typically holds 10 to 15 kWh of usable capacity, which can cover essential loads for 12 to 24 hours but falls short of whole-home use during a multi-day outage without solar recharging.
Source: U.S. Department of Energy – Energy Saver
Home Energy Audit
A systematic inspection of a home to identify where energy is being wasted and which improvements would reduce consumption. Auditors typically examine insulation, air sealing, appliances, HVAC equipment, and windows, and may use tools such as a blower door test or thermal camera.
In Texas, some utilities and assistance programs offer subsidized or free audits; a professional audit typically costs $200–$400 when paid out of pocket.
Source: U.S. Department of Energy
Horsepower hp
A unit of mechanical power used to rate electric motors, including pool pump motors. One horsepower equals 746 watts of electrical power at 100 percent efficiency; real-world motors draw more due to efficiency losses, so a 1 hp pool pump motor typically pulls around 1.2 kilowatts from the grid. Motor horsepower and daily run time together determine how much electricity the pump consumes each month.
Source: U.S. Energy Information Administration
HVAC HVAC
Acronym for Heating, Ventilation, and Air Conditioning — the equipment systems that control a building's indoor temperature, humidity, and air quality. In Texas, the air conditioning component dominates residential electricity use, typically accounting for 60–70 percent of a home's total consumption during peak summer months.
IECC Climate Zone
A geographic classification defined by the International Energy Conservation Code (IECC) that groups regions with similar heating and cooling demands together. Most of Texas falls in zones 2 and 3, which are warm and mixed-humid climates. The classification determines the minimum insulation levels, window performance, and air-sealing standards required by building codes for new and renovated homes.
Source: U.S. Department of Energy — Energy Codes
Induction Cooktop
A cooking surface that uses electromagnetic fields to heat cookware directly rather than heating a burner or coil that then heats the pot. Because heat is generated in the pan itself, less energy is lost to the surrounding air, making induction faster and more efficient than traditional electric coil or gas cooking.
For example, an induction burner rated at 1,800 watts may boil water in roughly half the time of a comparable electric coil burner, reducing actual kWh consumed per cooking session even though the nameplate wattage is similar.
International Energy Conservation Code IECC
A model building code developed by the International Code Council that sets minimum energy efficiency standards for new residential and commercial construction, including insulation levels, window performance, duct sealing, and mechanical equipment. Individual states adopt and sometimes amend the IECC; Texas uses its own adopted version to govern new construction statewide.
Source: U.S. Department of Energy — Building Energy Codes Program
Inverter-Driven Compressor
A type of air conditioner or heat pump compressor that continuously varies its motor speed to match the exact cooling or heating demand, rather than simply turning on at full power and cycling off. Because it avoids the energy spike of repeated full-power startups and runs at partial load most of the time, it consumes less electricity and maintains more even indoor temperatures than a single-speed compressor.
Mini-split systems almost always use inverter-driven compressors, which is why a 12,000 BTU mini-split typically draws fewer watts than a similarly sized window unit with a single-speed compressor.
Kill A Watt Meter
A brand-name plug-in energy monitor that displays real-time wattage and cumulative kilowatt-hours for any device plugged into it. It is widely used as a generic term for plug-in energy monitors in consumer contexts, though the name belongs to P3 International.
Kilowatt kW
A kilowatt is 1,000 watts. It measures how fast you're using electricity at a given moment, not how much you use over time. Think of it like speed: kilowatts are the speedometer, kilowatt-hours are the miles.
A central air conditioner might pull 3 to 5 kilowatts while it's running. Run 5 kW for two hours and you've used 10 kilowatt-hours.
Related: Kilowatt-Hour , Watt , Load , Peak Demand
Kilowatt-Hour kWh
A kilowatt-hour is the unit your electricity is measured and priced in. It's how much energy you use by running 1,000 watts for one hour. Every charge on your Texas electric bill traces back to how many kilowatt-hours you used that month.
Ten 100-watt bulbs left on for an hour burn one kilowatt-hour. A typical Texas home uses around 1,000 kWh a month, and your energy rate is quoted in cents per kWh.
Related: Kilowatt , Watt , Average Monthly Usage , Electricity Usage
Source: Public Utility Commission of Texas
kWh per 100 Miles kWh/100 mi
The EPA's standard measure of how much electricity an electric vehicle consumes to travel 100 miles. A lower number means the vehicle is more efficient. The figure is published for every model year on fueleconomy.gov and is used to calculate fueling cost per mile.
For example, a vehicle rated at 25 kWh/100 mi will consume 0.25 kWh for every mile driven — multiply that by your electricity rate to get cost per mile.
Source: U.S. Department of Energy — fueleconomy.gov
Lawrence Berkeley National Laboratory LBNL
A U.S. Department of Energy research facility that conducts scientific studies on energy efficiency, electricity use, and building science. Its publicly available data on appliance energy consumption and standby power is widely cited in consumer and regulatory contexts.
Source: Lawrence Berkeley National Laboratory
Level 2 EV Charging
A method of charging a plug-in electric vehicle using a 240-volt circuit — the same voltage as a large home appliance — that delivers roughly 7 to 11 kilowatts per hour of charge, significantly faster than a standard 120-volt outlet. Because a Level 2 session draws substantial power for several hours, scheduling it during off-peak electricity hours can produce notable savings on a time-of-use plan.
Liquefied Natural Gas LNG
Natural gas that has been cooled to a liquid state for easier storage and export by ship. When U.S. producers export large volumes of LNG, domestic natural gas supply tightens, which can push up the price of gas used to generate electricity and, in turn, raise wholesale electricity prices.
Source: U.S. Energy Information Administration
Load
Load is the amount of electricity a home, building, or the whole grid is drawing at a given moment, measured in kilowatts or megawatts. The more devices running at once, the higher the load. It's the demand side of the equation that ERCOT has to keep matched with supply, second by second.
Your home's load spikes when the AC, oven, and dryer all run together. Across Texas, total load climbs every summer afternoon as millions of air conditioners kick on at the same time.
Related: Peak Demand , Kilowatt , Megawatt , Baseload
Source: ERCOT
Load Shape
The pattern of a household's or facility's electricity consumption over time, typically shown as usage plotted hour by hour or day by day. Load shape reveals when consumption is highest and lowest, which determines how well different rate plan structures — such as time-of-use or flat-rate plans — will fit a given customer.
A household that concentrates most of its usage on weekend mornings has a very different load shape from one that runs appliances in the late afternoon, and the two households may pay very different amounts under the same time-of-use plan.
Manual Defrost
A freezer design that does not automatically remove frost buildup from interior walls. The owner must periodically turn off the unit and allow accumulated frost to melt, typically when frost exceeds a quarter-inch thickness. Frost buildup acts as insulation and forces the compressor to work harder, raising energy consumption.
Manual-defrost chest freezers generally use less electricity than auto-defrost models of the same size because they lack the heating element that auto-defrost units cycle on to melt frost automatically.
Megawatt MW
A megawatt is one million watts, or 1,000 kilowatts. It's the unit used to measure big power, like a power plant's output or how much electricity all of Texas is using at once. You won't see it on your bill, but you'll hear it whenever ERCOT talks about the grid.
One megawatt powers roughly 200 Texas homes during a summer afternoon. ERCOT set its all-time peak demand record on August 20, 2024, when statewide demand topped 85,500 megawatts.
Related: Kilowatt , Watt , Peak Demand , Baseload
Source: ERCOT
Megawatt-Hour MWh
A unit of electrical energy equal to 1,000 kilowatt-hours. Wholesale electricity is priced and traded in megawatt-hours, while retail bills report household consumption in kilowatt-hours.
A household that uses 1,000 kWh in a month has consumed exactly 1 MWh; a provider paying $50 per MWh wholesale translates that to roughly 5 cents per kWh before adding delivery charges and margin.
Miles per Gallon MPG
The EPA's standard measure of how far a gasoline-powered vehicle travels on one gallon of fuel. A higher number means better fuel economy. The EPA publishes combined city/highway MPG figures for every model year, which are used to calculate the per-mile cost of driving on gasoline.
Source: U.S. Department of Energy — fueleconomy.gov
Mini-Split
A ductless heating and cooling system pairing an outdoor compressor with one or more indoor air handlers to condition individual rooms or zones, with no central ductwork required. Mini-splits are common in apartments, home additions, and older homes that lack duct systems, and their per-zone operation can significantly affect monthly kWh totals compared to a whole-home central system.
Motorized Treadmill
A motorized treadmill is a fitness appliance with an electric motor that powers the running belt, drawing between roughly 300 watts at slow walking speeds and up to 1,500 watts or more on high-end commercial units at full speed. Actual electricity consumption depends on incline setting, belt speed, and the user's weight. Unlike ellipticals or stationary bikes without powered resistance, motorized treadmills have a continuous electrical draw whenever the motor is running.
A typical home user running at moderate pace for 45 minutes daily consumes roughly 13–14 kWh per month, costing around $2 at the Texas median rate.
Nameplate Rating
The energy consumption or power output figure printed on an appliance's label, representing performance under standardized test conditions. Real-world consumption can differ from the nameplate rating depending on environmental factors such as ambient temperature, how full the appliance is kept, and how often it is opened.
Natural Release
The period after a pressure cooker finishes its active cook cycle during which internal pressure drops on its own without venting, adding time to the total session but drawing little to no electricity. This phase is distinct from the active pressurized cook time and affects how total energy per meal is calculated.
Negative Pressure Infiltration
A condition in which a room or building has lower air pressure than the outside, causing unconditioned outdoor air to be pulled in through cracks, gaps, and unsealed openings. In the context of cooling, this raises the load on the air conditioner because warm outside air continuously enters to replace the air exhausted by a single-hose unit.
Overnight Baseline Draw
The minimum level of electricity a home consumes during overnight hours when occupants are asleep and most active appliances are off. It reflects the combined standby and continuous loads of devices such as refrigerators, modems, routers, set-top boxes, and clocks. Reviewing interval data from a smart meter reveals this figure clearly.
A surprisingly high overnight baseline — say, 500 watts or more — often signals energy-wasting standby loads worth investigating.
Package Terminal Air Conditioner PTAC
A self-contained heating and cooling unit installed directly through an exterior wall, common in hotels, older apartment buildings, and multifamily housing. Unlike a window unit, a PTAC is permanently built into the wall sleeve and typically cannot be removed by the tenant. It serves only the room or suite in which it is installed.
Payback Period
The length of time it takes for the energy savings from a more efficient appliance or home improvement to equal the extra upfront cost paid compared with a less efficient alternative. It is calculated by dividing the price premium of the efficient option by the annual dollar savings it produces. A shorter payback period means the investment recovers its cost faster.
In Texas, upgrading from a 14 SEER to an 18 SEER2 central air conditioner often yields a payback period of four to seven years, after which the owner captures pure savings for the remaining life of the equipment.
Peak Demand
Peak demand is the highest amount of electricity being used across the grid at one time, usually a hot summer afternoon between 3 and 7 p.m. when air conditioners run hardest. ERCOT watches peak demand closely because that's when the grid is stretched thinnest and prices climb.
Texas hits its yearly peak in July or August. The state's all-time record was about 85,500 megawatts, set August 20, 2024. Some time-of-use plans charge more during these peak hours to nudge you to shift usage to cheaper times.
Related: Load , Baseload , Megawatt
Source: ERCOT
Peak Draw
The maximum wattage an appliance pulls from the electrical circuit at any instant during operation, often occurring at startup or during the most demanding part of a cycle. Peak draw is frequently higher than the appliance's average consumption and is not, by itself, a reliable indicator of total electricity cost.
A blender may show a peak draw of 1,200 watts on its label, but if it runs for only 90 seconds per day, the actual kWh consumed is a fraction of what that number suggests.
Phantom Load
Electricity consumed by appliances and devices when they are switched off or in standby mode but still plugged in. Common sources include older refrigerators, pool pumps, and electric water heaters running on incorrect schedules. Phantom loads appear as a baseline of consumption during hours when no one is actively using anything in the home.
On a Smart Meter Texas interval chart, a consistently elevated reading between midnight and 5 a.m. is a practical indicator that phantom loads may be significant.
Pool Filtration Turnover
The volume of water that a pool pump circulates through the filter over a set period, typically expressed as the number of full pool-volume cycles completed per day. Adequate turnover is the practical goal of running a pump; once the required daily volume has passed through the filter, additional run time does not meaningfully improve water quality and only adds electricity cost. Turnover requirements vary by pool volume, bather load, and ambient temperature.
A properly maintained pool under 15,000 gallons often achieves adequate turnover in six hours rather than the commonly assumed eight, reducing monthly pump electricity use by roughly 25 percent.
Power Factor
A number between 0 and 1 that describes how efficiently an electrical device converts the power drawn from the outlet into useful work. A power factor of 1 means all drawn power is doing useful work; a lower number means some power is drawn but wasted as heat or returned unused to the grid. Motors, compressors, and fluorescent lighting typically have power factors below 1, while simple resistive devices like toasters or incandescent bulbs have a power factor very close to 1.
Residential customers are billed on kilowatt-hours of real power consumed, so power factor affects your bill indirectly by influencing how hard your equipment works and how much heat it generates, rather than appearing as a separate line item.
Power Outage
An interruption in electrical service caused by a fault, equipment failure, or physical damage on the TDU's distribution or transmission network. In Texas's deregulated market, outages are always reported to and resolved by the TDU—not the retail electric provider—because the TDU owns and operates the physical wires regardless of which REP is billing the customer.
Switching providers does not change the outage reporting process; the same TDU emergency number applies before and after a switch.
Pre-Cooling
A demand-shifting strategy in which a home's air conditioning system is run more intensively before an on-peak pricing window begins, cooling the indoor space to a lower temperature so the system can run less — or not at all — during the more expensive peak hours. Pre-cooling works best when paired with a programmable or smart thermostat and a well-insulated building envelope.
A household on a TOU plan might pre-cool to 70°F before 3 p.m. and allow the temperature to drift to 76°F by 8 p.m., reducing expensive on-peak air-conditioning runtime.
Programmable Thermostat
A thermostat that lets you set different temperature targets for different times of day or days of the week, so heating and cooling adjustments happen automatically without manual changes. Unlike a basic thermostat, it follows a schedule you program once — for example, raising the cooling setpoint while you are at work and lowering it before you return home.
A smart thermostat is a type of programmable thermostat that also connects to Wi-Fi, learns your preferences, and can receive signals from a utility or retail electric provider during demand response events.
R-Value
A measure of how well a building material resists heat flow — the higher the number, the better the insulation. In Texas, the recommended attic insulation level is R-38 to R-60 depending on climate zone. Homes built before 1990 often have R-11 or less, meaning a significant amount of heat moves through the ceiling and into the living space during summer.
Adding blown-in insulation to bring an attic from R-11 to R-38 typically costs $1,500–$2,500 for a 1,500-square-foot attic and can cut cooling costs by 15–20 percent.
Source: ENERGY STAR
Refrigerant
A chemical fluid that circulates through an air conditioner or heat pump, absorbing heat indoors and releasing it outside. When the refrigerant level is low — often due to a leak — the system must run longer to cool a space, increasing electricity consumption significantly.
A technician who finds a low refrigerant charge will typically locate and repair the leak before recharging the system, since simply topping it off without fixing the leak is both wasteful and, for many modern refrigerants, regulated.
Remote Room Sensor
A small, battery-powered sensor placed in a room away from the main thermostat that reports local temperature and sometimes occupancy data back to the thermostat. The thermostat can then average readings across multiple sensors or prioritize occupied rooms when setting the cooling target.
In a two-story Texas home where upper floors run several degrees hotter than the main floor, a remote room sensor on the upper level allows the thermostat to account for that difference rather than relying solely on a reading from one location.
Residential Energy Consumption Survey RECS
A periodic national survey conducted by the U.S. Energy Information Administration (EIA) that collects data on how American households use energy. It covers appliance ownership, home characteristics, fuel types, and energy expenditures, and is widely cited as the authoritative source for residential electricity consumption patterns.
Source: U.S. Energy Information Administration
Resistance Heating
A method of generating heat by passing electricity through a resistive element, which converts electrical energy to heat at a 1-to-1 ratio. Unlike a heat pump, it does not move heat from outside air but creates it directly, making it significantly less efficient and more expensive to operate per unit of heat delivered.
Resistance heating is common in older Texas homes and many apartments, and it is often the backup heating mode on heat-pump systems during very cold weather — a key reason winter electricity bills can spike sharply.
Resistive Heating Element
A wire or coil that generates heat by resisting the flow of electrical current, converting nearly all consumed electricity directly into heat. Resistive heating elements are used in appliances such as air fryers, toaster ovens, electric ranges, and space heaters, and they typically draw high, consistent wattage throughout operation.
Running Wattage
The steady amount of power, measured in watts, that an appliance consumes after it has started up and is operating normally. This figure is lower than the startup surge and is the correct input for calculating how many kilowatt-hours a device uses over time.
A refrigerator compressor may surge to 1,800 W at startup but settle to 150–200 W while running — using the startup figure to estimate monthly kWh would dramatically overstate the bill.
Source: U.S. Energy Information Administration
Running Watts
The steady power draw of an appliance once it has fully started and is operating normally, distinct from the higher surge it briefly draws at startup. Running watts are the figure used to calculate ongoing electricity consumption and monthly costs.
SEER Rating SEER
A standardized measure of air conditioner efficiency, calculated as total cooling output over a typical season divided by total electrical energy consumed. Higher SEER values mean less electricity is used to move the same amount of heat — a 20-SEER unit costs less to run than a 14-SEER unit doing identical work. Federal minimum standards require 14 SEER for new central air conditioners installed in the South.
A system below SEER 14 consumes noticeably more electricity per degree of cooling, which shows up directly in summer bills even if usage habits and rates stay constant.
Source: U.S. Department of Energy
SEER2 SEER2
An updated federal efficiency standard for air conditioners and heat pumps, measured as the ratio of cooling output (in BTUs) to electrical energy consumed (in watt-hours) over a typical cooling season. SEER2 uses a revised test procedure that more closely mimics real-world static pressure in duct systems, making ratings slightly lower than the older SEER scale. Since January 2023, new central air conditioners sold in the South and Southwest must meet a minimum of 15 SEER2.
A unit rated 18 SEER2 delivers the same cooling as a 14 SEER unit while consuming roughly 20–25% less electricity, directly reducing monthly operating cost.
Source: U.S. Department of Energy
Self-Clean Cycle
An oven function that burns off food residue by heating the oven cavity to approximately 900°F or higher for two to three hours. Because it sustains extreme temperatures for an extended period, a single self-clean cycle typically consumes 4 to 6 kWh — as much electricity as three or four standard baking sessions.
Setpoint
The target indoor temperature programmed into a thermostat, at which the heating or cooling system turns off. The system runs whenever the measured indoor temperature diverges from this target by more than a small margin.
Raising a cooling setpoint from 72°F to 78°F reduces how often the air conditioner runs, which directly lowers electricity consumption during the hours the higher setpoint is active.
Source: U.S. Department of Energy – Energy Saver
Short-Cycling
A condition in which an air conditioner or heat pump turns on and off in rapid, abnormally brief cycles rather than running for sustained periods. It typically indicates the system is oversized for the space it serves, and it reduces efficiency, increases wear on equipment, and can leave humidity poorly controlled.
Single-Hose Portable AC
A portable air conditioner design that uses one flexible duct to exhaust hot air from the condenser outside the room. Because it expels indoor air, it creates negative pressure in the space, drawing warm unconditioned air in through gaps and cracks in the building envelope, which reduces overall cooling efficiency.
Single-Speed Pool Pump
A pool circulation pump that runs at one fixed motor speed, typically full power, regardless of the filtration task at hand. Because it cannot slow down for lighter-duty cycles, it consumes substantially more electricity than variable-speed alternatives and is a notable contributor to high summer bills in Texas homes with pools.
Replacing a single-speed pump with a variable-speed model is one of the higher-return efficiency upgrades available to Texas pool owners, often saving 70–80% of the pump's prior energy use.
Smart Thermostat
A thermostat that connects to a home network and can automatically adjust heating and cooling setpoints based on a programmed schedule, occupancy sensors, or remote commands from a smartphone app. Unlike a basic programmable thermostat, a smart thermostat can learn household patterns and respond to utility demand-response signals. Studies by device manufacturers report average cooling savings of 10–15 percent compared to homes without scheduled setbacks.
Many smart thermostats qualify for a federal tax credit and utility rebates, reducing the effective upfront cost of a $150–$250 device.
Standby Draw
The small but continuous amount of electricity an appliance consumes while plugged in but not actively in use — typically to maintain a digital clock, display, or remote-ready circuit. Standby draw is measured in watts and accumulates into kilowatt-hours over days and months.
A microwave drawing 5 watts in standby for a full year consumes roughly 43.8 kWh, costing about $6.50 at median Texas electricity rates.
Standby Generator
A permanently wired backup power system, typically fueled by natural gas or propane, that detects a grid outage and starts automatically within seconds. Unlike a portable generator, a standby unit connects directly to the home's electrical panel through an automatic transfer switch and can run indefinitely as long as fuel supply continues.
A whole-home standby generator sized for a typical Texas house generally ranges from 10 to 22 kilowatts and requires an annual maintenance inspection to stay reliable.
Standby Mode Draw
The small but continuous amount of electricity an appliance or device consumes while it is switched off or in a low-power idle state, keeping its display, remote receiver, or internal circuits energized. Standby draw is measured in watts and accumulates quietly around the clock. It is closely related to the broader concept of phantom or vampire load but specifically refers to the manufacturer-designed low-power state rather than unintended leakage.
A treadmill console left in standby at 10 watts continuously consumes about 7.2 kWh per month — a modest but avoidable cost.
Standby Power
The small but continuous amount of electricity a plugged-in device consumes when it is switched off or in sleep mode, typically to maintain remote-control readiness, clocks, or network connections. Across many devices, standby power can add a meaningful amount to a monthly electricity bill.
The Lawrence Berkeley National Laboratory estimates standby loads account for 5 to 10 percent of residential electricity use in the United States.
Source: Lawrence Berkeley National Laboratory Standby Power
Startup Surge
The brief spike in power draw that occurs when a motor-driven appliance — such as a refrigerator compressor or air conditioner — first switches on. The surge typically lasts less than a second and can reach two to three times the appliance's normal running wattage. It matters for sizing generators and circuit protection but has negligible effect on monthly electricity bills.
Temperature Setback
A deliberate increase in the cooling setpoint — or decrease in the heating setpoint — during periods when full comfort conditioning is not needed, such as when occupants are away or asleep. Each degree of setback reduces the runtime of the heating or cooling equipment and lowers the associated electricity use.
For example, raising a thermostat from 78°F to 85°F while the house is unoccupied is a 7-degree cooling setback.
Thermal Mass
The ability of a building's materials — walls, floors, furniture, and contents — to absorb, store, and slowly release heat. A home with high thermal mass stays warmer longer after the heating system stops running, which is relevant during power outages in cold weather.
Pre-warming a home to 70–72°F before a forecasted outage takes advantage of thermal mass, potentially keeping interior temperatures above dangerous thresholds for several hours without any active heating.
Ton (Cooling Capacity)
A unit expressing the cooling output of an air conditioner or heat pump; one ton equals 12,000 British thermal units (BTUs) of heat removed per hour. Residential central AC systems in Texas are commonly sized between 2 and 5 tons. A higher ton rating generally means greater electricity draw, which is why central AC is the largest single contributor to monthly kWh consumption in most Texas households.
A 3-ton central air conditioner removes 36,000 BTUs of heat per hour and typically draws 3,000 to 3,600 watts of electricity while running.
Upright Freezer
A standalone freezer with a front-hinged door, similar in shape to a standard refrigerator. Because cold air spills out through the front when the door is opened, upright freezers typically lose more cold air per door-opening than chest freezers of comparable size, which can increase energy consumption.
Vampire Load
Electricity consumed by devices that remain plugged in but are not actively in use — such as televisions, game consoles, cable boxes, and phone chargers in standby mode. The Lawrence Berkeley National Laboratory estimates vampire loads account for 5–10 percent of a typical home's electricity use. Smart power strips can eliminate most of this waste automatically.
Variable-Speed Pump VSP
A pool pump that uses a permanent-magnet motor capable of operating at a range of speeds rather than one fixed speed. Because electrical power consumption falls sharply as motor speed decreases, a VSP can complete the same daily water filtration as a single-speed pump while using 50–75 percent less electricity. Owners set the speed to the lowest level that achieves adequate daily water turnover.
A VSP running at half speed to filter the same daily volume as a 1.5 hp single-speed pump typically draws 200–300 kWh per month instead of 400–500 kWh.
Volt V
A volt measures the electrical pressure that pushes current through your wires. Standard outlets in Texas homes run at about 120 volts; large appliances like a dryer or electric range use 240 volts.
Voltage is the push, current (measured in amps) is the flow, and power (watts) is what you get when you multiply them together.
Related: Watt , Ampere
Wall Draw
The total wattage an appliance pulls from a wall outlet during operation, including all internal components — not just the primary function (such as heating or cooking). Wall draw is always equal to or higher than an appliance's rated or advertised power output.
An air fryer rated at 1,500 watts has a wall draw of approximately 1,500 watts because its resistive heating coil and fan consume power simultaneously with no significant conversion loss.
Warming Plate
A low-wattage heating element, typically built into drip coffee makers, that keeps brewed coffee warm after brewing is complete. Because it operates continuously until the appliance is turned off, it can consume more electricity over time than the brewing cycle itself.
Watt W
A watt is the basic unit of electric power. It tells you how much electricity a device draws while it's on. The higher the wattage, the more energy a device burns and the more it adds to your bill.
An LED bulb might use 9 watts; an old incandescent used 60. A thousand watts equals one kilowatt, the size used to price your electricity.
Related: Kilowatt , Kilowatt-Hour , Electricity Usage
Watt-Hours per Session
The actual amount of electrical energy an appliance consumes during a single, defined period of use, calculated by multiplying the appliance's wattage by the number of hours it runs. This figure, rather than wattage alone, determines the electricity cost of any individual use.
A 1,500-watt air fryer running for 20 minutes consumes 0.5 watt-hours × 1,000 = 500 watt-hours, or 0.5 kWh per session.
Weatherstripping
Flexible sealing material applied around the edges of doors and windows to block drafts and prevent conditioned air from escaping. Reducing air infiltration lowers the amount of work a heating or cooling system must do, directly cutting electricity consumption.
Weatherstripping an exterior door typically costs $10–$30 in materials and is one of the highest-return, lowest-cost efficiency upgrades available to renters and homeowners alike.
Window Air Conditioner
A self-contained air conditioning appliance designed to fit in a standard window opening, cooling a single room by drawing 500 to 1,440 watts depending on its rated capacity. Unlike a central air system, it conditions only the space it serves, making it a lower-cost option for supplemental cooling but an inefficient choice if used across multiple rooms simultaneously. Its electricity draw is governed by its BTU rating and the ambient conditions it must overcome.
Source: U.S. Department of Energy – Energy Saver
Window Kit Seal
The panel and foam assembly that fills the window opening around a portable air conditioner's exhaust duct. An improperly sealed window kit allows hot outside air to leak back into the cooled space, reducing efficiency. Supplementing the manufacturer-supplied foam with additional weatherstripping or rigid foam board significantly reduces this leakage.