Smart home energy savings calculator
Enter your bill and the devices you have or want, and see how much a smart thermostat, plugs, and lighting could realistically save you each year, plus how long they take to pay for themselves. Conservative, sourced numbers, not vendor hype. No signup.
Figures last verified June 2026.
We assume about 45% of a typical bill is heating and cooling and about 7% is standby load, per US DOE. The thermostat saving scales with your bill.
Devices you have or plan to add
Prefilled from typical 2026 prices for the devices you picked. Edit it for your own gear.
Estimates only, in US dollars, and deliberately conservative. The thermostat figure uses the ENERGY STAR average (about 8% of heating and cooling, roughly $50 a year on a typical bill); standby savings use US DOE and NRDC figures. Real savings depend on your climate, rates, and habits. We earn no commission and send you to no installer.
How this calculator works
We start from your monthly bill and assume the documented shares for the big slices: about 45 percent goes to heating and cooling and about 7 percent to standby load, per US DOE. The thermostat saving is 8 percent of your heating and cooling cost (the ENERGY STAR average, roughly $50 a year on a typical bill), with the up-to-10 percent DOE figure shown as the upper range. Smart plugs claw back a slice of standby power, lighting and a power strip add small amounts, and the optional water-heater line trims part of the water-heating share. Payback is your upfront device cost divided by the annual savings.
The honest takeaway most calculators skip: the thermostat does most of the work, and the rest is modest. For the full reasoning, see our guide on how home automation saves energy. To see what a setup costs upfront, use the smart home budget calculator, and to pick hardware, our smart thermostat and smart plug guides.
What each device saves
The conservative figures behind the calculator, with their sources.
Smart thermostat
- Saving
- ~8% of heating/cooling (~$50/yr), up to 10%
- Basis
- ENERGY STAR; US DOE
Smart plugs (standby)
- Saving
- Modest per plug; ~$165/yr is the whole-home idle load
- Basis
- NRDC; US DOE
Smart lighting
- Saving
- Small, depends on habits
- Basis
- US DOE / ENERGY STAR
Water-heater scheduling
- Saving
- A slice of the ~18% water-heating share
- Basis
- US DOE Energy Saver
Frequently asked questions
How much does a smart thermostat actually save?
About 8 percent of your heating and cooling cost, or roughly $50 a year on a typical bill, per ENERGY STAR. The US Department of Energy puts the ceiling around 10 percent with a well-set schedule. Vendor claims of 20 to 30 percent are best-case marketing, so this calculator leads with the conservative figure and shows the realistic upper range.
Do smart plugs really save money?
A little, by cutting standby or 'vampire' power, the electricity devices draw while idle. The NRDC found home idle load wastes about $165 a year for an average US household, and smart plugs let you switch off the worst offenders on a schedule. The savings are modest per plug, not transformational, which is why we keep the estimate small and honest.
Is a smart home worth it just for energy savings?
On energy alone, the payback can take a few years, and the thermostat does most of the work. Most people buy smart-home gear for convenience and control, with energy savings as a bonus. Use the payback figure here to see whether the math works for your bill before you buy.
How is this calculated?
We take your monthly bill, assume the documented shares for heating/cooling (about 45 percent) and standby load (about 7 percent) per US DOE, then apply conservative per-device savings rates from ENERGY STAR, DOE, and NRDC. Payback is your upfront device cost divided by the annual savings. Every figure is shown with its source, and the numbers match our energy-savings guide.
Sources
- ENERGY STAR: smart thermostats (8%, ~$50/yr)
- US DOE: thermostats (up to 10%)
- NRDC: home idle load (~$165/yr standby)
- US DOE Energy Saver (water heating ~18%)
Figures change. We recheck and update them; this set was last verified in June 2026.