A smart plug is a cheap way to control "dumb" appliances with a smartphone or tablet.

Smart plugs are about the size of a plug-in nightlight. They connect to a wall outlet and they have a three-prong plug that can power a single appliance. These plugs are "smart" because of the WiFi radio inside: This allows the plugged-in appliance to be controlled by an app. Some plugs are also compatible with smart home systems like Alexa, HomeKit or Google Home. 

Many smart plugs have useful features like timers (e.g. shut off the coffee machine at 9:00 a.m.), schedulers (e.g. turn on the air conditioning 30 minutes before I get home) and vacation modes (e.g. make it look like someone is around by turning lights on and off). More advanced plugs can measure power consumption and highlight ways to save money by reducing electricity usage.

How Much Does a Good Smart Plug Cost?

A basic smart plug (with verified, above-average reviews) costs approximately $15, according to a 12-month analysis of price trends. Those same Wi-Fi plugs cost around $9 while on sale: an average discount of 40%.

One Day, Smart Plugs Will Be Given Out for Free

Smart plugs and smart power strips are frequently mentioned in the Environmental Protection Agency's discussion of smart home energy management systems. Why?

U.S. energy usage is climbing to new highs, according to the U.S. Energy Information Administration. At the same time, the shift toward renewable energy sources is making it harder to meet demand.

A study published by the Institute of Electrical and Electronics Engineers suggests using smart plugs as a way to reduce the strain on utility companies without having to upgrade the power grid or personal appliances. "We may never see smart controls on [low cost appliances]," predicts Steve Montgomery, Chairman of the NEMA Internet of Things Council. 

When Energy Star-certified smart plugs arrive, utility companies will almost certainly subsidize them. Visit the Energy Star Rebate Finder to see a list of discounted energy-efficient products.

The best smart plugs are "UL" or "ETL" listed (unfortunately, many smart plugs aren’t). These marks mean a plug has been certified by a Nationally Recognized Testing Laboratory to meet certain safety standards.

Here are the best affordable smart plugs (indoor and outdoor) and smart power strips for the money:

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1. Kasa Smart Plug 2-Pack, UL Certified (HS103P2)

Good Value: $20 | Great Deal: $15

Check Current Price on: Amazon

Wireless Protocol: 2.4 GHz WiFi

Works With: Alexa, Google Assistant, IFTTT

UL/ETL Certified: Yes

Kasa's inexpensive smart plugs are easy to set up and integrate easily with Alexa and Google Assistant, according to several online customers who praise the simplicity of the Kasa Smart app. Some reviewers wish that Kasa's app was faster and more secure; others complain that scheduling functions are limited.

2. Meross ETL-Certified Smart Plug 3-Pack

Good Value: $25 | Great Deal: $18

Check Current Price on: Amazon

Wireless Protocol: 2.4 GHz WiFi

Works With: Alexa, Google Assistant, IFTTT

UL/ETL Certified: Yes

Meross' smart plugs are well-designed, easy to install and they pair well with voice assistants like Alexa and Google Home, according to several online customers. Some reviewers dislike the Meross app (and the necessity of creating yet another account); others say that the plugs produce an audible sound.

3. Kasa Smart Plug by TP-Link (HS-100)

Good Value: $15 | Great Deal: $10

Check Current Price on: Amazon | Walmart

Wireless Protocol: 2.4 GHz WiFi

Works With: Alexa, Google Assistant, Cortana

UL/ETL Certified: Yes

TP-Link's Kasa smart plug is easy to install and works well with Google Home and Alexa, according to several online customers. Some reviewers warn that this plug is so large, that it obstructs the second outlet.

4. Globe Electric Collection Wi-Fi Smart Plug (50114)

Good Value: $20 | Great Deal: $13

Check Current Price on: Amazon | Home Depot | Walmart

Wireless Protocol: 2.4 GHz WiFi

Works With: Alexa, Google Assistant

UL/ETL Certified: Yes

Globe Electric's smart plug is a reliable way to schedule and time appliance usage, according to several online customers. Reviewers say that the WiFi setup took longer than expected, yet the plug is easy to use.

5. Kasa Outdoor Smart Plug KP400 by TP-Link

Good Value: $25 | Great Deal: $20

Check Current Price on: Amazon | Best Buy

Wireless Protocol: 2.4 GHz WiFi

Works With: Alexa, Google Assistant

UL/ETL Certified: Yes

This inexpensive outdoor smart plug is ideal for Christmas lights and holiday decorations, according to several online customers. Reviewers have three common criticisms: This plug isn't fully waterproof; the plug is not flat (making it difficult to use with weather protected outlets); and it doesn't work well with pool pumps.

6. Peace AE1002 Wi-Fi Smart Plugs (2-Pack)

Good Value: $19 | Great Deal: $15

Check Current Price on: Best Buy

Wireless Protocol: 2.4 GHz WiFi

Works With: Alexa, Google Assistant

UL/ETL Certified: Yes

These no-frills smart plugs work well with Alexa and Google Assistant and are a great value overall, according to several customers. Some reviewers say these plugs have a limited range; others dislike the LED indicators.

7. Sengled E1C-NB6 Smart Plug With Timer (Hub Required)

Good Value: $19 | Great Deal: $15

Check Current Price on: Amazon | Best Buy

Wireless Protocol: Zigbee

Works With: Alexa, Google Assistant, IFTTT, SmartThings

UL/ETL Certified: Yes

Sengled's smart plug is reliable and it pairs well with SmartThings, according to several online customers. Some reviewers say the setup process was confusing; others say the plug occasionally loses connectivity.

8. eufy Alexa-Compatible Smart Plug (AK-T1201121)

Good Value: $20 | Great Deal: $14

Check Current Price on: Amazon

Wireless Protocol: 2.4 GHz WiFi

Works With: Alexa, Google Assistant

UL/ETL Certified: No

This budget smart plug works well with Alexa and Google Home, according to several online customers. Many reviewers dislike the EufyHome app; others say the setup process is quirky and frustrating.