What’s a Watt Meter and Why Do I Need One?
A watt meter is a device that allows you to measure the number of watts a given device pulls down from your home’s electrical system.
While some things have power loads that are easy to calculate, very few things use the exact wattage written on the box or label—a point we emphasized strongly in our guide to measuring your energy use.
A traditional 60W bulb in a non-dimming fixture will use 60W of energy, but most appliances, devices, and even lights, will use different amounts of power depending on what they are doing.
Computers are an excellent example of this. The power supply unit on a computer might be rated for up to 800W of power, but the computer only uses as much power as its components demand.
And that’s exactly why you need a watt meter. Without one, you really have no idea how much power a particular device is using at any given moment or over time. With a watt meter, you can plug your device or appliance and get detailed real-time power stats.
Armed with that information, you can then make informed choices. For example, I scored a deal on a beefy rackmount server that I repurposed as a home server. When I slapped a watt meter on the server after noticing my power bill had crept up, measuring the power use revealed that the server was tacking $370 a year onto my power bill.
At that point, I had to ask myself, was I getting nearly four hundred dollars worth of utility out of the server, or would it be better to replace it with something more energy efficient?
After playing with a watt meter around your home, you’ll likely find yourself asking similar questions. And while you might not have a home server to give you a shockingly high readout, you’ll certainly be surprised by many things—including how high the phantom load of various devices and appliances is.
And if you’re a curious sort of person like we are, you can answer pressing questions like whether or not the energy saver mode on your TV is worth putting up with the dimmer picture.
Here Are The Watt Meters We Recommend
When it comes to watt meters, there are two common designs for measuring electrical use around the home: a dedicated meter or a smart plug with power monitoring.
There’s a lot to be said for the simplicity of a dedicated watt meter. You don’t need access to the local network, you don’t need to set it up or pair it, and there’s no need for a smartphone with a companion app—you just plug it in, and it works.
We’ve used the P4460 Kill a Watt meter from P3 International for years. In fact, we have zero complaints about the device except that we would absolutely love it if they released a model with a back-lit display.
If you’d like to measure multiple things concurrently or you’d like additional functionality from your watt meter, however, there’s a lot to be said for picking up one or more smart plugs with a power monitoring function.
Then, you’re not just getting data about the power consumption of the devices plugged into them but you’re also able to control the device. And in the end, if you decide you’re not that interested in closely monitoring power anymore, you can still use the smart plugs for holiday displays and smart home automation.
We use and recommend the Kasa KP115 smart plug with power monitoring. If you just want one to play around with, a single KP115 isn’t expensive, but buying a 4-pack will halve your cost-per-plug.
Whatever kind of meter you use, you’ll get a clear picture of exactly how much power your computer, old fridge, dehumidifier, TV, cable box, or any other number of things actually uses.
