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Do smart plugs and smart thermostats actually save money?

The honest answer on smart home energy savings, using US Department of Energy and ENERGY STAR figures, plus how to get savings in practice.

By the Plugged-In Home editors · Updated

Researched, not lab-tested · We may earn a commission from links on this page. How we choose

Quick answer

They can, but only if you use them to switch things off or turn the heating down when you don’t need it. ENERGY STAR estimates certified smart thermostats save about 8% on heating and cooling bills. The US Department of Energy puts standby power at 5 to 10% of home energy use, which smart plugs can cut.

Which one fits you
Key takeaways
  • A smart thermostat saves money by setting back the temperature while you’re out or asleep.
  • Smart plugs save by cutting standby power, not by existing.
  • Energy-monitoring plugs show you where power goes, so you know what to cut.
  • Savings vary with climate, habits and equipment.

Thermostats: the bigger lever

Heating and cooling are nearly half of a typical US household’s energy bill, according to ENERGY STAR, and certified smart thermostats save about 8% of that on average. The savings come from not heating or cooling an empty home. A learning thermostat like the Nest Learning Thermostat does this automatically.

What we like
  • Learns your schedule automatically
  • Matter brings it to Apple Home and Alexa
  • Remote temperature sensor included
Watch out for
  • One of the most expensive thermostats
  • The remote sensor doesn’t appear in Apple Home or Matter

Skip it if you rent, or your heating system isn’t compatible. Check Google’s compatibility tool before buying.

Smart plugs: find the vampires first

The Department of Energy says standby power, the electricity devices draw while ‘off’, accounts for 5 to 10% of home energy use. An energy-monitoring plug shows you which devices are worst. Move it around for a few days at a time: TV and games setups, older appliances, and chargers are common culprits.

Best overall smart plug
Kasa Matter Smart Plug KP125M (2-pack)
9.2/10
What we like
  • Matter setup works in every major home app
  • Energy tracking with cost estimates
  • Slim, doesn’t block the second outlet
Watch out for
  • 2.4 GHz Wi-Fi only
  • Apple Home remote control needs a HomePod or Apple TV

Skip it if you only use Alexa and never care about energy data. The Amazon Smart Plug is simpler and usually cheaper.

Five habits that make the savings real

Buying the device is the easy part. These habits do the saving:

  1. 1Let the thermostat use eco or away temperatures. Don’t override them daily.
  2. 2Schedule entertainment setups to switch off overnight.
  3. 3Turn off always-on devices you forgot existed, like old speakers and set-top boxes.
  4. 4Use sunset schedules for lamps rather than leaving them on ‘just in case’.
  5. 5Check the energy graphs after a month and adjust.

Side by side

Product
Google Nest Learning Thermostat (4th Gen)
Kasa Matter Smart Plug KP125M (2-pack)
Our score8.9/109.2/10
Best forBest smart thermostatBest overall smart plug
MatterYesYes, certified
PriceUsually under $300Usually under $50 for two
Where to buyCheck price for Google Nest Learning Thermostat (4th Gen) (opens in a new tab)Check price for Kasa Matter Smart Plug KP125M (2-pack) (opens in a new tab)

Frequently asked questions

How long until a smart thermostat pays for itself?

It depends on your bills and climate. With ENERGY STAR’s average saving of about 8% on heating and cooling, high-bill homes recover the cost faster.

Do smart plugs use power themselves?

A little, to stay connected to Wi-Fi. It’s small compared with the standby power of most devices they switch off.

Filed under: Energy saving · Smart thermostats · Smart plugs

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