P3 P4400 Kill A Watt Electricity Usage Monitor

Accurate, Simple, and Addictively Useful The P3 Kill A Watt Electricity Usage Monitor is one of those inexpensive gadgets that quietly changes how you think about energy use. I first bought it to see how much power my old refrigerator was pulling—and ended up testing every appliance in the house. Setup is instant: plug it into the wall, connect any device, and the bright LCD display immediately shows volts, amps, and watts in real time. Leave it running for hours or days, and it totals up the kilowatt-hours (kWh), letting you see exactly what that appliance costs you per day or month. What makes it so helpful is how accurate and intuitive it is. You don’t need to be an engineer—just read the wattage and multiply by your utility rate. I found a few “phantom” power hogs drawing 10–20 watts even when off (like a cable box and an older UPS). It’s also great for testing PC builds, aquarium setups, or any electronics to ensure your power supply is sufficient. The build quality is solid, and the display remains easy to read even after years of use. The only caution: it’s designed for 115V North American outlets only—not for international use. Bottom line: A must-have tool for anyone curious about energy use or looking to cut electric bills. Simple, accurate, and surprisingly enlightening—it pays for itself quickly.

The P3 P4400 Kill A Watt Electricity Usage Monitor is an absolute essential tool that has easily proven its worth over years of diverse technical projects. While it was originally purchased to meticulously track power draws and ensure stability for a cryptomining system, its utility expanded far beyond that initial setup. Over the years, it has transformed into an indispensable diagnostic device for testing household appliances, auditing general electronics, and evaluating solar consumption and battery backup limits. The brilliance of the P4400 lies in its straightforward, no-nonsense design. By simply plugging an appliance directly into the unit, the clear LCD screen immediately reveals critical real-time electrical metrics including voltage, current, true wattage, frequency, and power factor. This level of precise monitoring takes the guesswork out of energy management, allowing you to see exactly how much cumulative kilowatt-hour (kWh) consumption a device is drawing over a specific duration. Beyond crypto rigs, its long-term versatility shines when mapping out off-grid energy storage or checking real-world solar generation loads. Before connecting sensitive electronics to a portable power station or calculating inverter thresholds, plugging devices into the Kill A Watt ensures you never exceed maximum capacity limits. It provides exact, empirical data rather than relying on manufacturer estimates, safeguarding backup setups against unexpected surges or overloads. Ultimately, the Kill A Watt P4400 is a rugged, reliable, and timeless diagnostic instrument that belongs in every tech enthusiast's toolkit. Its ability to adapt from high-intensity mining audits to everyday DIY power management underscores its enduring value. For anyone serious about understanding their electrical ecosystem, measuring device efficiency, or stress-testing backup battery thresholds, this meter remains a five-star recommendation.

Ever wonder how many watts an appliance is using? I have. That's why I bought this; I was wondering if my "tea machine" Tiger PDN-A50U Electric Water Dispenser, 5.0-Liter was an energy hog or a conservation appliance. Thanks to this, I now know it's an energy SAVER. This could not be easier to use. Simply plug the meter into any wall socket. Leave it there as long as you like and use this meter like an electrical outlet. When you want to measure an appliance's electricity use, you simply press the "Watt" button & the LCD display will show you the real-time wattage usage. For example, with my "tea machine," when it boils water, it uses about 900 watts. Once it stops boiling, it uses just .3 watts, on average, to keep warm. When dispensing, it uses 62 watts (to power an electric pump), then immediately reverts back to its .3 watt "keep warm" usage. This can also be used as a voltmeter (measuring the electricity flow INTO the outlet). For American household power, this is roughly around 120 volts (except in "brown out" conditions). Useful to check during brownout conditions, simply because using some appliances during low voltage conditions can potentially damage them (this, fortunately, rarely happens in the US, but some Californians have occasionally experienced this). There's also a purple KwH button. This will let you measure the KwH usage of an appliance over a period of time. If you have an appliance (say, like a stereo subwoofer) that you suspect might be a Vampire Power Energy Hog (one that uses a lot of power, even when turned off), you can easily confirm this suspicion by plugging it into this meter, pressing the KwH button, & then check in 24 hours and see how many KwH your appliance has consumed. If your subwoofer's an energy hog, just unplug it when you're not using it & you'll lower your electrical bills. I LOVE this device, because it's helped me logically evaluate actual energy usage, instead of just going by my "gut" feeling. Knowledge is Power! This is easy to use & well worth every penny of its cost. In just a month, it more than pays for itself, if you've not been paying sufficient attention to your energy use. Now, instead of guessing how much power you're actually using to operate an appliance, now you can know. Great for everything from rice cookers, tea machines, toaster ovens, computers, printers, stereo equipment, battery chargers & more. A+!

Love this little guy, combined with something else I will get to in a minute will quickly pay itself off in a matter of months. If I had any complaints it would be 2 things: 1. when plugged in it blocks the other outlet on the plug so if you have limited outlets in a room it could be an issue 2. the display can be hard to read, I often have to shine a light directly onto it, this is my main reason for giving it 4 stars it is also very dated looking, like it belongs in the early 90's from an aesthetic point of view. after a month or 2 of using this I have been able to test virtually every appliance I use (outside of the dryer and water heater, since they operate off of 230/240 volt), my toaster oven that is large enough to fit a Tombstone brand (or any other brand for that matter) frozen pizza uses around 1100 watts in the normal baking mode (with the convection fan running) and about 1400 with in toast mode (with the upper heating elements on) my 1000 watt microwave (Hamilton Beach brand from walmart) uses 1700 WATTS on high and this is where I learned something interesting, as you approach the upper threshold of what this meter is rated for (1800 watts) it begins to beep warning you to watch your power usage so you don't fry it, my wireless router and cable modem use about 12 watts and my 50" LED 4k TV uses around 110 watts, but if I enable the energy saving options that really just dim the back light I can get it down below 70 watts and my new HE LG washing machine uses less then 2 cents of electricity per load (0.1 something Kw) which frankly surprised me, your dryer is the power user there everybody (fyi, they several Kw per load to run a dryer). This has also allowed me to test the actual consumption of my LED light bulbs, the GE 10.5 and 11 watt (60 watt equivalent) bulbs actually use around 13 watts and the Utilitech (Lowes brand) 9 watt (60 watt equivalent) use exactly 9 watt and the 5.5 watt (40 watt equivalent) actually use 5.1-5.2 watts, also ALL incandescent bulbs I tested used MORE then listed wattage, 65 watt flood bulbs used 67 watts, 100 watt shop light used 106 watts and so on. I currently live alone and as such I am able to really track the whole house usage, my power company has a daily usage bar graph that I track in an excel spreadsheet to monitor usage. Currently I have turned off the central air and am using a propane powered wall mounted space heater for heat so I have a very steady power consumption of 8-9 Kw a day (with no dishwasher or dryer running days and a caveat I will get to in a minute) as monitored on the power company website of which I have established the older side by side fridge in the basement apartment (where I am staying) is using 2.6 Kw per day, the way I reached this average is to leave the killawatt connected for several days and divide total usage by number of hours plugged in, since fridges cycle on and off the longer you leave it hooked up the more accurate it gets, I find 1-2 days is enough to get a good number and the fridge in the vacant upstairs unit uses 1.3 Kw per day, so between the 2 fridges I have accounted for nearly half my power usage in a typical day. using my math skills I have estimated my daily person usage (tv, internet, laptop, cooking and lighting) to be around 2.5Kw so this leaves 1.5-2.5Kw un-accounted for that would have to be attributed to the hot water heater and the LED displays on kitchen appliances and the garage door opener backlight. Now for the big power hog, this house had a concrete sidewalk installed upstairs that VIOLATES building codes and causes a fairly major issue, the top of the sidewalk is about 2 inches below the top of the foundation wall (code minimum is 8" above grade for top of wall) and worse yet it was poured after construction and as a result doesn't have proper support underneath and so it has begun sagging and slopping toward the house which results in extremely high humidity in the basement room on the other side of that wall that requires running a dehumidifier most days of the week, now this is the big deal and a REAL EYE OPENER, that this little kill-a-watt showed me, when in operation the dehumidifier (despite being energy star rated) uses 400+ WATTS, if left running all day it can use upwards of 10Kw a day BY ITSELF, this is more then EVERYTHING else in the house combined (thanks to my energy saving methods) so seeing this I went out and bought a 10 dollar digital thermometer/humidistat so I can monitor the actual humidity level in the room and power the dehumidifier off and on as needed as the humidity setting on the unit is virtually useless, once it reaches the set humidity it just goes into a fan only mode that still uses like 200 Watts, so it's better to just shut it off, with this meter I can monitor how much power the dehumidifier uses a day and the humidistat shows me when I need to run it, so instead of DOUBLING my power bill by doing like my parents did when they where living here (they moved to Florida and I moved in to watch over the house while it's on the market) and leave it running 24/7 I was able to shave over a 100Kw off my monthly usage and thats not even accounting for the 6 days I didn't monitor usage and at about .11 cents per Kw (with all fees factored in) I've already saved the cost of the Humidistat/thermometer and in the next month or 2 will save the cost of this guy. I will soon be addressing the sidewalk issue by removing it and laying a paver walkway that still leaves room for proper drainage. As is even with 5 days of not using the dehumidifier at all and 6 days of not monitoring it the dehumidifer accounted for 20% of the overall power usage (likely much higher due to the missing days). If your power bills are high even when you don't have the A/C or heat going then get you one of these and find out what is costing you money. For me the biggest offender is the Dehumidifier followed by the side by side fridge (which is way to much for 1 person), my total power usage for November was 531 Kw, 112 Kw of that was the MONITORED usage of the dehumidifier and like 80 Kw was the fridge, so for black friday I bought myself a new smaller fridge that I will use and disconnect the bigger one, the new one should use 1/3 the power of the old one saving me about 6 bucks a month.

This works great, easy to use.

Installation: literally plug-n-play. Very straightforward with no surprises . Versatility: Works well across different setups and applications, giving you flexibility in how you use it. Value for money: Priced fairly for the performance and build quality you get. Safety: Feels secure in use with no concerning heat, wiring, or stability issues. Power: Delivers consistent power without drops or fluctuations during operation. Size: Compact enough to fit in tight spaces while still being easy to handle.

Does what its supposed to do. Just basic numbers, does not go into detail.

Love this little device. I should have bought this YEARS AGO!!! I got it via Amazon Prime in less than 36 hours. Okay, I must be getting seriously frugal in my old age! ;>) I am trying to convert my gas heated house to be as electrically energy efficient as possible to run off a small 2000 watt generator when we have another extended power outages from an ICE storm. I am amazed some of the 'little' things that consume 2 to 5 watts of power just being plugged in and not even being used; with limited wattage available via a generator every watt counts. EG: Have an old TV and DVD player in a guest bedroom that has not been used in years consumes 8 watts of power. (Translates into $6.73 per year ((8*24*365*)/1000)*$0.096perKwh) They are NOW unplugged. Converting my family room 60 watt light bulbs to VOLT brand LED FOREVER bulbs (7 watt-60watt equivalent lumens) at a cost of $9 a bulb will save me $21 per year per bulb if bulb is used 6 hours a day. WOW! LED bulbs can save a TON of money over incandescent without the risk of mercury in fluorescents bulbs and LED will last forever unlike fluorescent that claim long life and die just as fast as normal bulbs! I have a bathroom that has six lights which consumed 60 watts each; changing these bulbs out at a cost of $54 for all six bulbs will save me $2 per month (usage of 2 hours a day). Pay off in savings for bulb costs in less than 27 months and the bulbs should last three times as long as a incandescent without the extreme heat! All-in-all I like this meter. Though I wish I had purchased the model with a built-in battery back up. Next one I purchase will. You HAVE to use this with an 6 ft appliance extension cord if you plan on using this. Display is next to impossible to read otherwise when plugged into an outlet 15 inches off the floor. You unplug it losses ALL it data.

To start , I lent someone my 12000 watt generator . They said it was too hard on gas so they turned the idle down .. a lot . When I got it back , I turned it up to were I thought it was before .. but not so . with in 3 days of out power outage .. it fried my microwave , because it was not putting out 60hz . I bought this P3 .. ran my generator and plugged it in a wall plug in my house . the meter said 42hz . So I was was able to adjust it to run at 60hz .. in my house . Great meter , it does a whole lot more that what I wanted it for . BUY ONE !!!

If you live in the UK, do NOT buy this product. It is not designed for the UK and you will have to return it. The company, so far, has refused to pay the return postage, even though this is entirely their mistake. I have no idea why it is not clearly labelled.

Fantástica compra, cumplió todas mis expectativas y al tener un soporte de hasta 1.8kw me permite medir dispositivos de alto consumo. Quien iba a decir que mi PC (solo el gabinete) consume 4 veces mas que mi refri de 7 pies. Gracias a esta maravilla, ahora lo sé. Recomendadísimo, entrega en excelentes condiciones y vino empaquetado con su bolsa antigolpes.

1. Operating voltage is incompatible with Japan's 100VAC. 2. Seller support is poor and maker (P3) doesn't respond to emailed questions. A waste of money.

Bought this on Amazon UK and it does not state that it is not suitable for UK use - plugs are US(?). Will now have to pay a lot to return it to a US address. Not impressed.