I’m taking my air conditioning off the grid this summer — here’s how

Anker SOLIX PS400 Solar Panel
(Image credit: Future)

As it does for many people, summer for me means more time spent outdoors at barbecues and at the beach. But it also means higher electricity costs as I run my air conditioning to keep my house cool. While I’ve helped mitigate this somewhat by using smart air conditioners that use less energy, I still see my utility prices increase as the weather gets hotter. 

This summer, though, I’m going to try something different and take my air conditioning off the grid, so I’m not paying for electricity. Here’s how.

My home setup

My house was built in the 1930s; while central air conditioning had been invented by then, it would be another couple of decades until it became common in residential homes. Some of my neighbors have retrofitted their homes with mini-duct and split systems, but I have to look enviously on as I heave units into my windows every June and put them in storage in September.

But this also provides me with a unique opportunity to see if I can power my window units using nothing but renewable energy this summer.

At the moment, I have a Midea U air conditioner, an LG dual inverter, a TCL, and Hisense air conditioners in various rooms of my house; all use inverter technology, which is more efficient than compressors, and have a more gentle start-up cycle, which I hope will keep from straining the system too much.

How I’m taking my air conditioning off the grid

To provide energy to the air conditioners, I set up an Anker Solix F3800 Portable Power Station in my basement along with a BP3800 expansion battery, and connected it to two Anker SOLIX PS400 Portable Solar Panels. All told, we’re talking about $8,000 worth of equipment, so I don’t expect it to pay for itself in just one summer. Still, that’s less than half the price it would cost to get solar panels installed on the roof, and it will provide me a nice backup should the power go out this summer.

Anker Solix F3800 Power Station: $3,999 @ Amazon

Anker Solix F3800 Power Station: $3,999 @ Amazon
The F3800 has a capacity of 3840Wh and a 6000W output, works with both 120 and 240V, and has a NEMA 14-50 port for RVs, and a NEMA L14-30R port for EVs. It can be recharged by plugging it into your house, or by connecting solar panels. You can also connect additional battery packs for a max of 53.8kWh. 

For the month of May, my house used a total of 392kWh, which ranks among the most efficient in my area. Historically, that increases to 500-600kWh during the summer months, when we’re running our air conditioners more often.

In terms of storage, the F3800 has a capacity of 3,840Wh, as does the expansion battery, so I have a total of 7,680Wh of electricity to play with. It remains to be seen how quickly it will drain once I’ve got everything connected.

Anker SOLIX PS400 Solar Panel: $999 @ Amazon

Anker SOLIX PS400 Solar Panel: $999 @ Amazon
The PS400 can generate up to 400W of electricity, has stands on the back to adjust its angle to 40°, 50°, or 60°, IP67 Waterproof Protection, and comes with two 9.84-foot MC4 solar charging extension cables, and an MC4 to XT-60 solar charging cable converter. The panel weighs 25.6 pounds and measures 35.9 x 26.9 x 2 inches when fully extended, but can be folded for storage and transportation.

The F3800 is a pretty beefy unit, weighing 132 pounds: even though it’s on wheels and has a retractable handle, it still took me and my wife to lug it down the basement stairs. The unit itself has six 110-volt outlets, one 220V, a NEMA 14-50 port for RVs, and three USB-C and two USB-A ports on the front. 

Each solar panel can generate up to 400 W of electricity and, according to Anker, fully recharge the F3800 in about two hours. They’re not small: Each measures about 100 inches long by 36 inches tall, and weighs 35 pounds. Fortunately, they fold up, and have big handles to carry them around. The panels also have flaps on the back so you can stand them up at various angles, but I found they were on the flimsy side, so I built a triangular stand out of some old aluminum tubing I had lying around. 

To connect the F3800 to my air conditioners, I have to run some pretty beefy extension cords — it’s generally recommended not to connect an air conditioner to an extension cord, but for this purpose, I bought some heavy duty cords rated for 15 amps and 1875 watts, so while I’ll lose a little energy along the way, it’s plenty capable of handling the current.

Because we have air conditioners scattered throughout the house, we generally don’t run them all at the same time. During the day, for instance, we might only use the A/C in our attic, where we have our work-from-home setup; in the evening, we may only use the one on the first floor of the house, and at night, we’ll only use the ones in our bedrooms. So, I don’t expect the individual load on the power bank to be all that great.

How it's going so far

Anker Solix app

(Image credit: Future)

I’m most interested in finding out how much the air conditioners will drain the battery, and how fast the solar panels will be able to keep it topped off. At the moment, I have one air conditioner — the Midea U — connected to the power bank. It initially drew between 500 to 700W as it worked to cool my office to 78 degrees — the recommended temperature you should set your thermostat, according to the Department of Energy — but then settled down to around 300-400W. 

The Anker Solix has an app that lets you monitor the input and outputs to the system, as well as manage what devices are getting power. 

However, the solar panels are pulling in around 350W, so I'm definitely running a deficit. I believe I may have connected the solar panels incorrectly the the power station — I should be getting closer to 800W — so I'm going to play around with that. I'm also curious to see what happens as I add another air conditioner to the mix.

We're just entering a heat wave in the eastern U.S. where I live, so we're finally using our air conditioners. Stay tuned for my updates on how this project goes.

More from Tom's Guide

Mike Prospero
U.S. Editor-in-Chief, Tom's Guide

Michael A. Prospero is the U.S. Editor-in-Chief for Tom’s Guide. He oversees all evergreen content and oversees the Homes, Smart Home, and Fitness/Wearables categories for the site. In his spare time, he also tests out the latest drones, electric scooters, and smart home gadgets, such as video doorbells. Before his tenure at Tom's Guide, he was the Reviews Editor for Laptop Magazine, a reporter at Fast Company, the Times of Trenton, and, many eons back, an intern at George magazine. He received his undergraduate degree from Boston College, where he worked on the campus newspaper The Heights, and then attended the Columbia University school of Journalism. When he’s not testing out the latest running watch, electric scooter, or skiing or training for a marathon, he’s probably using the latest sous vide machine, smoker, or pizza oven, to the delight — or chagrin — of his family.

  • TomXP411
    Hi, Mike

    You'll want more panels than that. My primary station (which I use for my Work From Home setup) has 8KWh of battery and 1.2KW of panels. With that setup, my batteries will get about 4-5KWh of charge on a good day..

    Your excess usage in the summer is about 200KWh, or 6.67KWh/day. So I think you sized the battery right, but the panels you have won't generate nearly enough power. You need to at least double that.

    The biggest mistake everyone makes is under-paneling their system, assuming that the panels will put out the rated amount all day. In reality, the output is more like a sine wave, and you get about 4-5 watt-hours per watt of panel over the course of a day.

    So those panels will give you around 3-4KWh on a good day and much less in cloudy weather.

    So with 8KWh of battery, you need more like 2KW of panels to fully charge that battery in one day.

    Finally - those foldable panels tend to not do even their rated output. You should really get some proper stationary panels, probably something like 250 watt bifacial panels with a vertical mount setup.

    You can definitely cut back on the electric bill, but to do 100% will need about twice the generation of what you're going to get with those 400 watt portable panels.
  • bhunter736 at YouTube
    Tom has offered a lot of great information. I think something key to your issue is simply that the panels will only produce at their peak when the sky is clear and the panels are fully perpendicular to to the sun. The energy fall off as the angle shifts is more than you might expect. Great to see an article like yours on Toms Guide. Every step someone takes in this direction is an overall benefit.
  • TomXP411
    bhunter736 at YouTube said:
    Every step someone takes in this direction is an overall benefit.
    Thank you!

    And I agree. I'd love to see every house out there with solar on the roof and batteries in the garage. The more power we can gather and store from the sun, the better it is for everyone! =)
  • solarac
    Unfortunately Anker as well as other portable solar generator manufacturers use low cost, short lived, high frequency, transformerless inverter technology in their designs that offer poorer surge capacities and lack galvanic isolation which can not only shorten this inverter tech's life expectancy, but can also damage or can even set your AC unit on fire. If you want to safely power an AC unit long term, then you need to use a low frequency, transformer based inverter instead.
  • MangoCat
    I have a smaller Anker battery+inverter, it's a nice piece of kit to power devices in parts of our (large) yard that don't have electric service.

    However, pay attention to the battery cycle lifetime spec: ours says 3000 cycles. At that rate, even charging the battery "for free" from solar, the cost of replacing the battery every 3000 or so cycles will be higher per kWh than buying electricity from the grid at $0.12/kWh.

    So, hopefully most of your air-conditioning power is coming directly from the solar panels, not being stored in and drawn from your battery system. The battery+inverter is a nice way to avoid "grid dependence" but it's not usually a money saver in the long run, unless grid prices for power inflate much faster than they have historically.