Smart Thermostat Savings Calculator — Nest & Ecobee 2026
Calculate how much a smart thermostat saves per year in 2026. Nest, Ecobee and Honeywell ROI based on your HVAC cost and savings percentage.
How to use this calculator
- Enter your total annual HVAC energy cost — find this by adding up all utility bills for a full year, or check your utility's annual summary.
- Set the heating percentage of your HVAC bill (typically 50–70% in cold climates, 30–50% in warm climates).
- Set expected savings percentage. Google Nest reports 10–12% on heating and 15% on cooling; Ecobee reports 23% on average.
- Enter the thermostat cost including installation (typically $150–$350 for the device; $50–$150 for professional install).
- Annual savings, payback period and 5-year ROI appear instantly.
Understanding your results
How smart thermostats save energy: Smart thermostats learn your schedule and adjust temperatures automatically — lowering heat when you leave and pre-heating before you return. They also detect occupancy, integrate with weather forecasts to optimise heating/cooling, and allow remote control so you never heat or cool an empty home.
Verified savings data: Google (Nest) reports average savings of 10–12% on heating and 15% on cooling from its own customer data, translating to roughly $131–$145/year for the average US home. Ecobee’s internal study found 23% average savings. The EPA’s ENERGY STAR program estimates programmable thermostats save about $180/year when used properly.
Setback savings rule of thumb: The DOE estimates you can save about 1% on heating for each degree you setback your thermostat for 8 hours. Setting your thermostat from 70°F to 62°F for 8 hours at work saves about 8% on heating — roughly $80–$150/year depending on your heating cost and climate.
IRA 25C tax credit: Smart thermostats meeting ENERGY STAR certification qualify for the Energy Efficient Home Improvement Credit (25C) — 30% of cost up to $150 credit per year. A $250 smart thermostat generates a $75 tax credit.
Best candidates for smart thermostats: Homes where occupants are away 8+ hours on weekdays, homes with older setpoint thermostats (not already programmable), homes in climates with significant heating or cooling seasons, and homes with older HVAC systems that run inefficiently under manual control.
Frequently asked questions
Direct answers for US homeowners.