Best Energy-Saving Smart Devices

The problem this solves

Smart devices are sold on convenience, and convenience can cost energy. The ones worth buying for your bill do one of two things: they show you where power goes, or they switch heating, cooling and standby devices off when you do not need them.

Try this before you buy anything

1. Find out what costs the most. Heating and cooling dwarf everything else in most homes. What uses the most electricity at home? explains the order.
2. Work out the sums. Watts × hours ÷ 1,000 × your rate. What do your appliances cost to run? shows how.
3. Turn things down by hand. A lower thermostat setting and switching the TV corner off at the wall cost nothing.

What to look for

• Energy monitoring, so you can see the effect.
• Schedules, so savings happen without you remembering.
• Your heating system. In the US, many apartments have their own thermostat. In the UK, many flats have gas central heating with radiator valves, which suits smart radiator valves.

Our picks at a glance

The picks in detail

Energy-monitoring smart plug

The cheapest way to see what standby costs, and to cut it on a schedule. Smart plugs for beginners covers setup.

Smart thermostat (with your landlord's agreement)

ENERGY STAR-certified models are reported to cut heating and cooling bills by more than 8% a year. It replaces a wired control, so it needs permission and must suit your system.

Smart radiator valves (common in UK flats)

These replace the heads on radiator valves so each room heats on its own schedule. Keep the original heads to refit when you move.

A plain energy monitor

No app and no Wi-Fi: plug it in, read the number, move it to the next appliance.

How we chose

These are research-based recommendations: we compared published specifications, maker documentation and the features that matter in a small home. We have not tested them hands-on. Most picks are types of product rather than single models, so the buttons open the retailer's results; compare a few listings before you buy, in your own country's store.

Mistakes to avoid

• Expecting a smart plug to save money by itself. It uses a little power to stay connected. The saving comes from what you switch off.
• Putting a heater on a smart plug. Only if both makers say it is suitable, the load is within the plug's rating, and never on a schedule that starts it while nobody is home.
• Over-heating with a smart system. Smart controls help only if the set temperatures are sensible.
• Buying for features you will not use. Every extra device is another thing drawing standby power.

Where the numbers come from

Use the electricity cost calculator with the readings from an energy monitor. A device on standby at 10 watts all day uses about 88 kWh a year: roughly $16 in the US at 18.2 cents per kWh, or £23 in the UK at 26.32p.

Measure before you buy

A smart plug with energy monitoring, or a simple plug-in meter, shows what each appliance really uses. Spend a week measuring before buying anything else; you may find the biggest saving is a habit, not a device.

What saves the most

Heating usually dominates energy bills, so controls that cut heating waste matter most: a smart thermostat if the landlord allows it, or timers and thermostatic radiator valves used well. ENERGY STAR says certified smart thermostats save more than 8% on heating and cooling for the average user. After heating, standby on the TV corner and computer setup is the easiest win for a renter.

The bottom line

Measure first with a plug or monitor, then schedule the things you find. Heating and cooling are where the real money is, so a thermostat or radiator valves come next if your home and lease allow them.