EPA's ENERGY STAR program, which certifies smart thermostats against field data, puts the average saving at about 8 percent of a household's heating and cooling bills, or roughly $50 a year, and notes savings can run higher depending on climate, occupancy, and HVAC equipment. Manufacturers advertise considerably more on their own product pages, so treat those numbers as a ceiling rather than a forecast. For a cooling-dominated Texas home on an aggressively programmed summer schedule, 8 percent to the low teens is a defensible planning range, and only if the device is programmed correctly and paired with the right electricity plan. For a home spending $200 a month on electricity in July, where cooling is roughly half the bill, that is roughly $8 to $13 back per month, a real dent in the hardware cost over a single summer. For homes on the wrong rate structure, the savings shrink considerably or disappear.
This article explains the real mechanics behind those savings, what each degree of setpoint costs, how Nest and ecobee compare, and when a smart thermostat is not the right tool for the job.
Why Texas Is the Right Climate for This Technology
Texas cooling loads are among the highest in the country. ERCOT describes residential air conditioning as the dominant driver of peak demand on August afternoons, the period when grid stress is highest and, under time-of-use plans, electricity is most expensive. A device that automatically lifts the setpoint during those hours and pre-cools the house in the morning, when rates are lower, captures real arbitrage value.
The underlying physics matter here. Every degree you raise your thermostat setpoint reduces AC runtime. The Department of Energy's rule of thumb is a saving of as much as 1 percent for each degree when the setback period runs at least eight hours, a figure it frames around heating setback and says is larger in milder climates than in severe ones. That figure is not dramatic in isolation, but it compounds: a household that programs a 78-degree daytime setpoint instead of 72 degrees is running roughly 6 percent less cooling, before accounting for any time-of-use benefit.
The Cost Per Degree: Putting a Number on It
To make this concrete, consider a home with an older 13- to 14-SEER 3-ton central AC unit drawing about 3.5 kilowatts when running, compressor and air handler together. At 14.9 cents per kWh (the median advertised rate in our own ChooseMyPower plan snapshot of August 25, 2026, a little below the mid-2026 Texas residential average reported by EIA) one hour of full AC runtime costs approximately 52 cents. Wattage guides put a 3-ton system anywhere from about 2,400 to 3,500 watts depending on efficiency, so a newer high-efficiency SEER2 unit sits nearer the bottom of that band and would trim every dollar figure in this section by roughly 15 to 25 percent.
If tightening the schedule reduces runtime by two hours on a peak afternoon, that is about $1.04 saved that day. Over 90 peak days in a Texas summer, that is roughly $94. A Nest Thermostat retails for around $130. A Nest Learning Thermostat or ecobee Smart Thermostat Premium lists at $260 to $280. The payback window is one to two summers for the entry-level device, two to three summers for the premium models, assuming the scheduling is used.
The 1 percent per degree estimate applies across the setpoint range, but the savings are not linear in dollar terms. The higher the ambient outdoor temperature, the larger the temperature differential your AC must overcome, and the more runtime each additional degree of setpoint demands. A setpoint of 78 degrees on a 105-degree day costs more per hour than the same setpoint on an 85-degree day, simply because the system runs harder.
Nest vs. ecobee: What the Difference Is
Both Nest (Google) and ecobee are ENERGY STAR certified smart thermostats that support scheduling, remote control via app, and integration with most Texas utility demand-response programs. The practical differences come down to three things: sensor strategy, data reporting, and home compatibility.
The ecobee Smart Thermostat Premium ships with a remote room sensor. For a two-story Texas home where the upstairs runs 5 to 8 degrees hotter than the downstairs, this matters. The thermostat averages sensor readings and adjusts accordingly, reducing the tendency to either freeze the downstairs or leave the upstairs uncomfortable. The Nest Learning Thermostat now includes one Nest Temperature Sensor in the box, with additional sensors sold separately at about $40 each; the entry-level Nest Thermostat does not support them.
Nest's primary differentiator is its learning algorithm. Over the first week of use, the device builds a schedule based on observed occupancy and manual adjustments. For households with irregular schedules, this can be genuinely useful. For households with predictable routines, a manually programmed schedule on either device performs just as well and gives the homeowner more direct control.
On data reporting, ecobee provides monthly energy reports that break down runtime by hour. This is useful for households trying to understand their consumption patterns or diagnose an aging AC system. Nest's reports are less granular in the base app.
For compatibility, neither device requires a common wire (C-wire) on most installations. Roughly 30 to 40 percent of Texas homes built before 2000 lack a C-wire at the thermostat location. ecobee includes its Power Extender Kit with every model except the Smart Thermostat Essential and Lite. Nest offers a workaround called Power Connector. Either way, a homeowner without a C-wire should budget an additional $50 to $100 for a professional installation if they are not comfortable running low-voltage wiring.
Programming a Schedule for Texas Summer
The default schedules on both devices are calibrated for moderate climates and will underperform in Texas without adjustment. A schedule built for Texas conditions looks roughly like this:
From midnight to 6 a.m., hold at 76 to 78 degrees. The house retains cool from the prior day and outdoor temperatures are lower, so the AC runs less.
From 6 a.m. to 9 a.m., pre-cool to 74 degrees if the household is on a time-of-use plan that charges peak rates from 3 p.m. to 8 p.m. This stores thermal mass in the house before expensive hours begin.
From 9 a.m. to 3 p.m., allow the setpoint to drift to 78 to 80 degrees, or enable away mode if the home is unoccupied. This is where the bulk of the runtime savings accumulate.
From 3 p.m. to 8 p.m., hold at 78 to 80 degrees on a time-of-use plan, or at whatever the household finds comfortable on a flat-rate plan. The pre-cooling from the morning means the house stays comfortable at the higher setpoint during the first one to two hours of the peak window.
From 8 p.m. onward, allow a gradual cool-down to sleeping temperature, typically 72 to 74 degrees.
This schedule can be programmed manually on both Nest and ecobee in under ten minutes. Nest's learning mode will eventually approximate something similar if the homeowner adjusts the device consistently for a week.
When a Smart Thermostat Is Not Worth It
Three situations argue against the purchase.
First, if the household is already on a flat-rate plan priced well below the market median, the dollar value of each unit of runtime saved is lower. On a genuinely flat plan near 7 cents per kWh, roughly the floor of what Texas marketplaces advertise, the same two hours of avoided afternoon runtime saves about 49 cents rather than $1.04. Payback extends to three or more summers.
Second, if the AC system is oversized for the home, short-cycling is already a problem, and smart scheduling may not reduce runtime as much as the standard estimates suggest. An HVAC contractor can assess this.
Third, if the household's schedule is genuinely random and the residents are unwilling to spend the time to program or verify the learned schedule, the device may increase bills by letting the house drift warm during unscheduled occupancy and then running the AC hard to recover.
The Rate Plan Connection
Smart thermostat savings scale with rate. Households on time-of-use plans, where afternoon electricity can cost 25 cents per kWh or more, extract the most value from pre-cooling and peak avoidance. As of August 25, 2026, the median listed rate across the 122 plans in our own ChooseMyPower marketplace snapshot is 14.9 cents per kWh at 1,000 kWh monthly usage. That is a one-day picture of advertised offers, not a statewide average, and it moves as plans come and go; EIA data reported for mid-2026 puts the average Texas residential price, delivery included, closer to 16.4 cents per kWh. That median reflects a wide spread: the cheapest listed plans advertise rates in the 6- to 7-cent range and some plans push past 20 cents. Treat those headline lows with suspicion: rates advertised far below the competitive 12-to-15-cent band are almost always bill-credit or usage-threshold products whose displayed price only holds inside a narrow usage window, so check the Electricity Facts Label at your own usage level before assuming the number applies to you.
Before purchasing a smart thermostat, the more valuable step may be auditing the current electricity plan. A household paying 18 cents per kWh who switches to a 12-cent plan saves about $60 in the first month at 1,000 kWh, most of what a smart thermostat saves in a full summer, and it repeats every month of the year. The thermostat and the rate plan are complementary tools, not substitutes. Address the plan first, then add the hardware.