Do Smart Thermostats Save Money? Calculator
If you're wondering "do smart thermostats save money," this free calculator gives you an honest estimate: enter your monthly heating and cooling bill, pick an expected savings percentage, and add the device and install cost to see your estimated monthly and yearly savings, your payback period, and your 5-year net savings — instantly.
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How to use this calculator
Start with your average monthly heating and cooling bill — not your whole electric bill, just the portion that goes to heating and cooling. If you only know the total, check your utility bill's seasonal breakdown or your utility's online dashboard, which often splits usage by category.
Next, set the estimated savings percentage with the slider. The default of 10% matches typical manufacturer and ENERGY STAR claims; use a lower value if you already keep a tight schedule, or a higher one if your home is drafty or the thermostat runs all day with nobody home.
Enter the thermostat's price and, if you'll hire someone, the install cost. Your estimated savings, payback period, and 5-year net savings update instantly as you type or drag.
How it works
The math is simple and transparent. Estimated monthly savings = monthly bill × savings percentage ÷ 100. Estimated yearly savings = monthly savings × 12. Total upfront cost = device cost + install cost. Payback period = total upfront cost ÷ monthly savings, in months. Estimated 5-year net savings = (yearly savings × 5) − total upfront cost. Every savings figure on this page is an estimate.
Assumptions: your bill stays roughly constant, energy prices don't change, and you actually use the thermostat's scheduling and away features — a smart thermostat saves nothing if it runs the same schedule as the old one. We don't model equipment efficiency upgrades, rate plan changes, or demand charges.
Disclaimer: actual savings vary widely with climate, home insulation and air sealing, your thermostat habits, and local energy prices. Mild-climate homes may save less than the 8–12% commonly cited; drafty homes in extreme climates may save more. Use these results for planning, not as a guarantee.
Frequently asked questions
Do smart thermostats actually save money?
They can, but only if they reduce how long your heating and cooling equipment runs. The savings come from schedules, automatic setbacks when you are away, and features like geofencing and occupancy sensing. Manufacturers and ENERGY STAR studies commonly cite around 8 to 12 percent savings on the heating and cooling portion of an energy bill. Your actual result depends on your climate, insulation, and habits.
How much can a smart thermostat save per month?
Take your average monthly heating and cooling bill and multiply it by your expected savings percentage. For example, a $200 monthly bill with an estimated 10 percent savings equals about $20 per month, or $240 per year. That is an estimate, not a guarantee. Homes with old equipment, poor insulation, or aggressive setback schedules may save more, while mild-climate homes may save less.
How long does it take a smart thermostat to pay for itself?
Divide the total upfront cost (device plus any installation) by your estimated monthly savings. A $250 device saving an estimated $20 per month has a 12.5-month payback period. Many owners break even in one to two years; higher energy prices or larger homes usually pay back faster.
Do I need professional installation for a smart thermostat?
Not always. Most smart thermostats are designed for DIY installation and take 30 to 60 minutes if your wiring is compatible. However, homes with a C-wire problem, high-voltage baseboard heat, or multi-zone systems often need a professional, which adds roughly $75 to $150 in install cost. Add that to the calculator so your payback period stays honest.
Why do savings vary so much from home to home?
Savings depend on your climate (extreme hot or cold regions have more to save), your home's insulation and air sealing, your current thermostat habits, and how aggressively you use scheduling and away modes. A smart thermostat cannot save much if you already keep the thermostat set efficiently around the clock. Treat every figure on this page as an estimate for planning, not a promise.