Best Energy-Monitoring Smart Plugs 2026

This article contains affiliate links: if you buy through them we may earn a commission, at no extra cost to you. Learn more.

It’s late, the house is quiet, and the TV corner is still glowing: the console’s little light, the soundbar, the streaming box, the router. “They’re off,” everyone says. An energy-monitoring smart plug settles the argument in a minute. Plug the power strip into it, open the app, and you see the watts those “off” devices pull, and what they add up to over a year. Then you can set them to switch off at midnight and forget about it.

The best energy-monitoring smart plug for most homes is the Kasa Smart Plug Slim KP125M: it shows live and past power use, estimates the bill (even with time-of-use rates), handles 15 A, and is Matter certified, so it works with Apple Home, Alexa and Google Home. If you want no cloud account at all, choose the Eve Energy.

Below: five plugs and meters, plus the step up to a whole-home monitor, with real specs from the makers and the safety rules for what not to plug in. We researched and compared them from maker spec pages and manuals; we did not test them.

Prices change often. The prices below are what we saw at the maker or a major retailer in October 2026; check the current price before you buy.

Our top picks

Energy-monitoring smart plugs compared

Plug	Max load	Works with	Energy data	Listing	About (Oct 2026)
Kasa KP125M	15 A / 1,800 W	Matter (Apple Home, Alexa, Google, SmartThings)	Live, history, bill estimate	UL	Not on maker page
Kasa EP25	15 A / 1.8 kW	Apple HomeKit, Alexa, Google, SmartThings	Live, daily, weekly, monthly	UL	Not on maker page
Eve Energy	15 A / 1,800 W	Thread + Matter (needs a hub)	Use + cost projection	UL, TÜV	Not on maker page
Emporia Smart Plug	10 A continuous, 15 A peak	Alexa, Google, Emporia Vue	Live, in Emporia app	ETL	$34.99 sale
Kill A Watt P4400	15 A / 1,875 VA	Nothing (LCD)	Live + running kWh total	Not stated	$32.99

What an energy-monitoring smart plug does

A regular smart plug just switches power on and off from your phone. An energy-monitoring smart plug also measures the power flowing through it, so the app shows watts right now and kilowatt-hours over days and months. That turns two vague questions into numbers: “What does this thing cost me?” and “Is it using power when I think it’s off?”

Always-on devices are the usual surprise. A 2015 NRDC study with Berkeley Lab, using smart meter data from 70,000 Northern California homes, found an average always-on load of 164 watts, nearly 23% of those homes’ electricity use. A plug that measures, schedules and switches off is the simplest tool to find and cut your share.

The best energy-monitoring smart plugs

1. Kasa Smart Plug Slim KP125M: best overall

The KP125M shows real-time and historical power use in the Kasa app, with charts, and estimates your bill from a single rate or time-of-use rates, so you can see what moving a load to off-peak hours would do. It can switch off automatically when power goes above a limit you set, run schedules, and fake occupancy with away mode. It’s Matter certified, so it works with Apple Home, Alexa, Google Home and SmartThings. It’s slim (2.6 x 1.5 x 1.6 in) and leaves the second outlet free. Rated 15 A, 1,800 W for resistive loads, 1/6 HP for motors; UL listed.

• Good: the most useful energy features here (history, bill estimate, time-of-use, power-limit auto-off); Matter means you’re not locked to one assistant.
• Watch out: the detailed energy data is in the Kasa app, not in every smart-home app; TP-Link’s page shows no price or warranty length.
• Best for: most homes, and anyone on a time-of-use plan.

Check the Kasa KP125M price on Amazon

2. Kasa Smart Plug Mini EP25: best for Apple HomeKit on Wi-Fi

The EP25 is the same size as the KP125M and tracks real-time use plus daily, weekly and monthly totals in the Kasa app. It works with Apple HomeKit, Alexa, Google Assistant and SmartThings over 2.4 GHz Wi-Fi, with schedules, timers, away mode and overheat protection. Rated 15 A, 1.8 kW at 120 V; UL and FCC certified, with a two-year limited warranty listed by TP-Link.

• Good: two-year warranty; native HomeKit without a Thread hub; sold in 2- and 4-packs.
• Watch out: TP-Link lists HomeKit rather than Matter for this model; the energy numbers are in the Kasa app (reviewers say Apple Home doesn’t show them); no price on the maker page.
• Best for: Apple households that want Wi-Fi plugs with energy tracking.

Check the Kasa EP25 price on Amazon

3. Eve Energy: best for privacy

Eve Energy tracks the power use of whatever is plugged in and projects the cost once you enter your electricity rate. It talks over Thread and Matter and is controlled locally through your home hub; Eve says “no subscription, no registration.” It works with Apple Home, Alexa, Google Home, SmartThings, Home Assistant and Homey, and it acts as a Thread router, which strengthens the network for your other Thread devices. The US version is rated 15 A, 1,800 W, and carries UL and TÜV certification.

• Good: no cloud account; keeps working on your home network; broad smart-home support.
• Watch out: you need a hub that is a Matter controller and Thread border router (for example a recent Apple TV or HomePod, or a compatible Google or Amazon hub); Eve’s page shows no price.
• Best for: Apple Home and Home Assistant users, and anyone who wants data to stay at home.

Check the Eve Energy price on Amazon

4. Emporia Energy Monitoring Smart Plug: best with an Emporia Vue

Emporia’s plug shows real-time use in the Emporia app, runs schedules and works with Alexa and Google Home. Its real strength is pairing with Emporia’s Vue panel monitor: the Vue measures a whole circuit, the plug splits out the one device on it, all in one app. It’s ETL certified, uses about 1 W itself according to Emporia, and comes in 1-, 2- and 4-packs with a one-year warranty. Its rating is lower than the others: 10 A continuous, 15 A peak for up to an hour a day, 1,800 W max.

• Good: about $34.99 on sale, $47.99 regular (Emporia, October 2026); one app with the Vue and Emporia EV chargers.
• Watch out: Emporia says not to use it for refrigerators, freezers, medical equipment, pet heat equipment or critical network devices; 10 A continuous rules out heaters and other big loads.
• Best for: Vue owners; electronics and small appliances.

Check the Emporia Smart Plug price on Amazon

5. P3 Kill A Watt P4400: best without an app

Not a smart plug, but often the better tool for a quick check. Plug it in, plug the appliance into it, and the LCD shows watts, volts, amps, hertz, VA and cumulative kilowatt-hours. P3’s manual rates it within 0.2% for voltage, 0.3% for current and 0.5% for watts. It handles up to 15 A (1,875 VA, 125 V max). No Wi-Fi, no app, no account, and you can move it from device to device in seconds.

• Good: about $32.99 (P3, October 2026); precise; no setup; good for testing a fridge or freezer, which Emporia says not to put on its smart plug.
• Watch out: no remote switching or schedules; you read it in person; the manual lists a six-month warranty.
• Best for: one-off checks, renters, and anyone who doesn’t want another app.

Check the Kill A Watt P4400 price on Amazon

Step up: Emporia Vue 3 for the whole house

Smart plugs can’t see anything hard-wired or on a 240 V outlet: the water heater, dryer, range, AC, heat pump or EV charger, which are usually the biggest users. For those, a panel monitor like the Emporia Vue 3 measures the whole home plus up to 16 circuits and tracks solar, for about $199.99 with 16 sensors (Emporia, October 2026). It goes inside the breaker panel, so have a licensed electrician install it, with a permit where required. Full comparison in our best home energy monitors guide.

Check the Emporia Vue 3 price on Amazon

What not to plug into a smart plug

• Space heaters. CPSC says to “always plug electric space heaters directly into a wall outlet” and never into an extension cord or power strip. A 1,500 W heater draws about 12.5 A for hours. Follow the heater’s manual: if it says plug directly into the wall, don’t put a smart plug in between. Use a Kill A Watt only for a short check, and stay within its 15 A rating.
• Anything over the plug’s rating. Check the watts on the appliance label against the plug: 1,800 W for most, 10 A continuous (about 1,200 W at 120 V) for the Emporia plug.
• Fridges, freezers and medical equipment on a plug that can be switched off by an app, a schedule or a glitch. Emporia names these as not recommended. Measure a fridge with a Kill A Watt instead.
• Your router or modem, if the plug needs Wi-Fi to be switched back on. Emporia lists critical network devices as not recommended.
• 240 V appliances. These plugs are for standard 120 V outlets only.

How to choose an energy-monitoring smart plug

• Match your smart home. Matter plugs (KP125M, Eve) work across Apple, Google, Amazon and SmartThings. The EP25 lists HomeKit, Alexa and Google. Eve needs a Thread border router hub.
• Look for history and cost, not just watts. Live watts tell you what’s on now; daily and monthly kWh and a cost estimate tell you what it’s worth fixing. Kasa’s KP125M adds time-of-use rates.
• Check the rating. 15 A / 1,800 W is standard; the Emporia plug is 10 A continuous.
• Check the safety listing. All the smart plugs here list UL or ETL certification.
• Slim shape matters. The two Kasa plugs are compact enough to leave the second outlet free.
• Wi-Fi at 2.4 GHz. The Kasa and Emporia plugs use 2.4 GHz Wi-Fi; check the signal where the plug goes.

How to use one to cut your bill

1. Measure “off”. Turn everything at the TV or desk off as you normally would and read the watts. That’s your standby load for that spot.
2. Do the math. Watts × 8,760 hours ÷ 1,000 = kWh a year; multiply by your rate. Example (our math): a 10 W standby load is about 88 kWh a year, about $15 at the 2025 US average of 17.3 cents per kWh (EIA).
3. Schedule it off. Set the plug to cut power overnight or while you’re at work, for things that don’t need to stay on (and not for things that do, like a DVR that records at night).
4. Move big loads off-peak. If you’re on time-of-use rates, schedule what you can for cheaper hours. See time-of-use rates explained.
5. Rotate. After a week, move the plug to the next suspect: dehumidifier, aquarium, second fridge in the garage (measured with a Kill A Watt), old gaming PC.

Remember the plug uses a little power itself (Emporia lists about 1 W for its plug), so it pays off where it switches off more than that.

Keep exploring

Start with our guide to how to lower your electric bill. For the whole house, compare the best home energy monitors (and Emporia vs Sense). Hunt down standby waste with phantom power, and see what uses the most electricity in a typical home. Learn what watts and kilowatt-hours mean in electrical energy, and browse all our energy-saving tips.

Energy-monitoring smart plug questions

What is the best energy-monitoring smart plug?

For most homes, the Kasa Smart Plug Slim KP125M: live and historical use, a bill estimate that handles time-of-use rates, auto-off above a power limit, and Matter support for Apple Home, Alexa and Google Home. For local control with no account, the Eve Energy. If you own an Emporia Vue, Emporia’s own plug keeps everything in one app.

Do smart plugs save electricity?

They can, when you use them to switch off standby loads or shift use to cheaper hours. The plug itself uses a little power (Emporia lists about 1 W for its plug), so it pays off on devices that waste more than that when idle. The monitoring part matters most: it shows you which devices are worth bothering with.

Can I plug a space heater into a smart plug?

We don’t recommend it. CPSC says to plug space heaters directly into a wall outlet, never an extension cord or power strip, and a 1,500 W heater draws about 12.5 A for hours. Follow your heater’s manual. If you want to know what a heater costs to run, measure it briefly with a Kill A Watt, within its 15 A rating, and do the math.

How accurate are smart plug energy readings?

Good enough to compare devices and spot waste, but most makers don’t publish an accuracy figure; none of the smart plug pages we read did. For a precise number, P3’s manual rates the Kill A Watt P4400 within 0.5% for watts. For anything that cycles, read the kWh over several days rather than watts at one moment.

Can a smart plug measure my whole house?

No. A plug only sees the device plugged into it, and nothing on a 240 V or hard-wired circuit. For the whole home, you need a panel monitor such as the Emporia Vue 3, installed by a licensed electrician. Your utility’s smart meter data (often downloadable with the Green Button) also shows whole-home use by the hour.