How to Run Air Conditioning On Solar Power

Today I wanted to share information about running air conditioning on solar power.

When I was first planning to move into my tiny house, considering the possibility of running a solar powered air conditioner and cooling system weighed heavily on my mind. After all, living in a humid state, I’ll tell you, I’m one who can’t tolerate the heat. This is especially true, coming from New Hampshire—I’m a cold weather guy and here in North Carolina, it gets hot! An AC unit is critical, even if you’re running on solar power.

How to Run Air Conditioning On Solar Power

Well, Charlotte’s heat really came full force this week.  I know for many their climate doesn’t get as humid as it does here, so there are other options besides running a house air conditioner. Unfortunately, here, it’s necessary.  Without AC I can’t really sleep, even using a fan to passively cool the house.

Right now, the humidity is still tolerable, but it’s HOT and the humidity is coming soon.  It has been in the high 80’s and low 90’s outside, which made my house in the mid 90’s inside.

So, what are the tiny house air conditioner solutions? How do you cool off your tiny house (even off the grid) and beat the heat?

Deciding to Buy a Solar Powered Air Conditioner

I thought I’d do a post today because I’ve been able to run a few real-world experiments with my tiny house and solar powered AC.  I haven’t seen any experienced reporting on the topic of running air conditioning on solar power, so I figured it would be helpful for you all to hear what I did.

When it comes to cooling a tiny house, there are three areas to look at: isolation, such as shade, seals and insulation; ventilation, such as fans and setting open windows for cross-winds; and artificial cooling. Many tiny homes, by their portable nature, don’t have basements, where you can retreat if you need to cool off. Since heat rises and your entire home is above the ground, you need alternative methods to cool down.

Desert-dwellers may be able to rely on swamp coolers and evaporation-based cooling systems Here in the humid part of the world, these setups never work because our air is already humid. It’s impossible to cool humidity with MORE humidity.

Isolation, using shade and insulation to your advantage, is important if you live in off the grid. You can keep your house fairly cool by simply, closing off your space, especially in the heat of the day. This is why I decided to park my tiny house under the trees for shade and run my solar panels in the wide-open field.  While these methods help and should be employed, of course, chances are you’ll still need to rely on a solar powered air conditioner system to get through the hottest days.

After doing my research on what unit would work best with my solar panel set up and power levels. I ordered my unit before I found an installer. I have yet to hook up my mini split air conditioning system (see the update below where I talk about life on solar with my mini split) because it has taken me a long time to find a HVAC installer who would install my mini split AC. As I discovered after buying my mini split unit, most installers insist they need to sell you the air conditioning equipment if they are going to install it. Obviously, this was an unknown factor to me when I ordered my house air conditioning unit…but these are the bumps in the road you experience when you live The Tiny Life.

Fujitsu air conditioning system.

Fujitsu Air Conditioning System

How Much Power Does an Air Conditioner Use?

For heating and cooling, I opted for the Fujitsu 9RLS2 which is a 9,000 BTU Ductless Mini Split Air Conditioner Heat Pump System with a SEER (Seasonal Energy Efficiency Ratio) rating of 27.  To give you an idea, older, less efficient mini split air conditioning systems have a SEER rating of around 8 to 10. Modern air conditioning systems, labeled highly efficient may have a rating of 15 or so, but most today are around 12-13.

The SEER rating was very important because my tiny house solar panel system simply couldn’t handle the less efficient cooling systems.  The SEER rating is determined by BTUs (British Thermal Units) to Watts.  The higher the number, the better.

The other big reason I choose this particular mini split air conditioning unit versus a standard window air conditioner was aesthetics.  My air handler is wall mounted, out of the way and above eye level.  This has a few advantages. First, it keeps my limited square footage clear of clutter. Secondly, it keeps my windows looking nice because there’s no window unit blighting a good design. Lastly, keeping it above eye level also helps you forget about it because as humans we don’t often look up.

Tiny House Friendly Air Conditioning

While I’m working on getting an HVAC installer lined up to put in my Fujitsu Air Conditioning System, I’m using a portable air conditioner, which has worked pretty well.  The downside to using a portable AC unit is it takes up a lot of space and it’s not as efficient. The portable AC unit I’m using has a SEER rating of 12, which means my new mini split system will be 225% more efficient once it’s installed.

UPDATE:  It’s been several years now since I first wrote this post and I’ve been living full time totally off the grid and it’s wonderful.  I was able to find an installer to pull the vacuum in my system and this thing cools like a dream.

During the summer the AC pulls between 450 watts and 700 watts, on “powerful” mode it draws about 1,000 watts.  As a side note for heat, it pulls about 700 watts to 1,000 watts, 1,100 on “powerful”.

If I had to do things all over again I’d go with a Mitsubishi brand mini split over the Fujitsu, because they seem to be a bit more well-designed. The Mitsubishi has also the critical feature of auto dry, which dries the coil of moisture before shutting down.  I’ve had to clean my coils several times in the 5 years and a drying feature would almost eliminate this.

Stress Testing My Portable AC Unit and Solar Panel Power System

I decided to “stress test” my solar panel system by turning the portable AC unit on high and setting the thermostat to 60 degrees. I wanted to see how long it would take for my solar panel system batteries to bottom out (50% discharge).  The charge controller on my solar panel system automatically turns off the power to my house if the batteries power discharges down to 50%. This automatic shut off on the solar panel system prevents damage to the batteries by discharging too deep.

Solar panel batteries and a chart of number of cycles and depth of discharge to determine battery life.

As you see by the chart above, keeping battery discharge at 50% or above gives me a little shy of 2,000 cycles or 5.4 years for the life of my batteries.  I plan to add another set of four batteries to the solar panel system pretty soon, which will give me improved capacity and keep my discharge rate much higher than 50% (though I don’t often get that low).  In about 5 more years we should start seeing really interesting battery technologies hit the market. This should coincide with the life of my current batteries, so I plan to hop on these new technologies as soon as my batteries begin to fade.

UPDATE:  It’s been several years now since I posted this. Last year I bit the bullet and added 6 more solar panels and 4 more batteries.  This was mainly to avoid needing a generator in the winter months because they’re a royal pain.  Cooling my house in the summer is still pretty simple since my house is so small.  I usually turn my air conditioner on when I get home and shut it off when I leave.  This allows the batteries to fully recharge and doesn’t really impact cooling.

My solar panel battery stress test was an interesting experiment. I ran the less efficient, portable air conditioner for three days solid, starting with a very warm house.  At the end of the three days, I was very close to hitting 50% on my battery reserve, but it didn’t ever dip below that threshold.  I decided, after three days, the test had gone on long enough to get an accurate reading and I stopped the test.  I typically turn off the AC whenever I’m gone.

Following the test, the past few days were a bit trickier because since my solar panel battery system was so low, I needed it to build back up. Unfortunately, we had a series of cloudy days, making it tough to get more energy.  While I’ve had plenty of power to run the AC overnight, the battery reserve is lower than I’d like.  To give you an idea: on a normal sunny day my solar panel power system makes about 8,000 Watts, but on a cloudy day (when the clouds are very thick with no gaps) I get between 2,000 and 4,000 Watts.

The Advantage of Solar Powered Air Conditioning

When it’s hottest and the sun is shining the brightest, I can make lots of power!  This allows me to run the AC full blast to keep my house nice and cool. Even with the air conditioner on high my solar panel system still makes enough power to add 2,000 Watts into the batteries. Compare this to heating, where you often need the heat the most at night when the sun isn’t out. This results in a major drain on your batteries.  Compounding the issue of running heating off solar panel energy, heaters are more energy intensive than cooling and air conditioning units.

The other night I decided to conduct another experiment.  I got my house very cold by running the AC unit. Then, I turned off the cool air at midnight (when I usually go to bed).  Outside it was about 65 degrees and about 45% humidity–so not bad.  I left all the windows closed to see how much my body heat would warm up the house. In the summer, opening the windows doesn’t often doesn’t help anyway, even if it is cooler outside because the humidity increases the “feels like” temperature.

As it turns out in just three hours my body heat warmed up the loft of my tiny house to the point I woke up from being so uncomfortable from the heat!  Around 3:30 am I woke up and it was very hot in my loft.  I checked the time and was surprised how little time it took.  I should note when I fall asleep, I usually stay asleep all night, even if I get warm. The fact I woke up from the heat, shows how uncomfortable it was in my loft because it takes a lot!

Fortunately, I had prepared for this and all I did was crank open my skylight (the highest point in my house) and the loft end window. I switched on a fan to draw in cool air.  Within 5 minutes the whole place dropped about 5 degrees and I was back asleep.

So that has been my real-world experiences with the tiny house, AC units and solar panel power systems.  I know I had always been frustrated by not enough stories and real-life examples of AC and cooling issues, so hopefully my story will help others.

Key resources for those wanting more technical stuff:

My Setup For Solar Power

  • Details of my tiny house solar panel system
  • Calculating solar power system requirements
  • Building racks to hold solar panels
  • Adding a solar panel gear cabinet
  • Understanding solar panel electric systems
  • Choosing a backup generator
  1. Good stuff. Thanks!

    Where are you located? I’d be happy to help with installation of new system, but may be too far away…

    • Charlotte NC

      • Why did’t you use 18 225 ah

        Why did’t you make the panels so they receive the Sun 2 times a day

        What is the draw on your on your Mini split AC .

        Whdid youy did’t you use 18 100 watt Panels in Series Parallel format

  2. Thanks for doing this.
    So few with tiny houses go for independent energy. The AC is the first thing you give up because of the enormous cost. My 500 watt design would never make it. I’m hoping to supplement that with a generator when it’s so bad I can’t stand it. (Only about two weeks a year it’s that hot/humid in Ohio.)

    A quick search puts the Fujitsu at ~$1500 on the smallest model.
    9000 btu is still overkill for me, but the efficiency is hard to beat.

    • You must be a glutton for punishment! I live in southeastern ohio and I LOATHE heat and humidity! I certainly suffer from humidity issues tons more days than 14 or so….

      • No, I just do a LOT of things to keep the house cool without running the AC.

        Opening the windows at night goes a long way to help.
        The ceiling fans help too. 🙂

  3. Hey Ryan,
    Have you tried advertising for an installer on a goods and services website, in Australia we use Gumtree. That’s how I found a local guy who worked for a bigger company but did mine on a weekend. If the local companies have declined to fit it for a reasonable price you need not feel guilty. Just be sure he has the vacuum pump and gauges and that he is willing to come back if you have any issues.

  4. Hi Ryan,
    I too have learned this the hard way regarding if you don’t buy it from them they don’t want the jobs. But I have just told several of them to stuff it! I am not paying 2x for a unit for them to make extra money! Don’t want the job? Fine! As a previous posted stated, have you checked into local job walls or ads or craigslist?
    Thats how I found mine. and I got a rheem tankless hot water unit for the new house for $998 on sale at Home Depot that would have easily cost me more than 2x that much from a local plumbing contractor. I know I know, its how they make their living, but I like most of us have a super tight budget..
    New small house is moving right along, slower than I would like but we should be painting by the beginning of next week and hopefully moving in 2 weeks.
    Thanks for all your great info! Without you I would never have jumped into this the way I have!!

  5. Would give anything for a bit of heat and humidity. Over here in the UK (up north) it’s still like winter!

  6. Great information, especially about the SEER numbers– thanks! Have you checked YouTube for installation videos for a mini-split? We found some really good ones, and the mini-split wasn’t hard to install at all– even for relative beginners with only basic carpentry skills.

  7. Installation yourself isn’t that difficult. Assuming it came pre-charged, you don’t even need to pull a vacuum (the air in the lines and indoor unit will be <5% by mass). The only tools you'll need (other than for mounting the units) is a pipe cutter and a 45-degree flare tool (both together <$50).

  8. Thanks, Ryan, for the great information. I’ve become totally intolerant of temps above 80ª, and hope that I don’t need this, but I’m glad I know where to reference if I do. It’s been heating up here in the PNW in recent years, too.

  9. Have you tried shades, curtains, leaving windows open at night and not sleeping in the loft?

  10. Ryan,
    I’ll chime in here on the topic, because I have used mini split air conditioners (some with heat pump capabilities for the winter) for the 9 years that I lived in Mexico in the state of Sonora. I’ve lived in the desert, both along the sea of cortez and the high sierra madres (which are hotter than you would think they should be in the summer before the monsoons arrive).

    Our first home in Mexico was just a tad over 400sq ft.. It was a size / design common throughout Mexico, often refered to as Infonovit houses (Infonovit is a gov’t burrowing program to help home buyers…obviously most poor families purchase the tiny 2 bedroom casitas.. hence the name). They are made of narrow concrete blocks with concrete floors, concrete ceilings and single pane windows. Yes, without mini splits.. they bake in the summer. It’s brutal.. That first home required two mini splits… One for the two bedrooms.. One for the common areas (kitchen/dining/living).

    We found we could place them in Dehumidify mode and it conserved energy and the house became comfortable… We also found with the air dry in the home, that 80degF felt very comfortable indoors.

    I have used several brands, York (way too loud), Japando (good when new, but it’s performance seemed to deteriote after about a year.. even with good servicing) and Mirage. Mirage was so good, that we purchased several different units over the years.. In Mexico, that brand enjoys good distribution, so repair/replacement is quite easy and affordable. The prices of mini-splits in Mexico is about half the cost of those in the USA.

    Couple of other lessons learned… Don’t install the compressor unit in a direct wind stream… If you have a prevailing wind, try to orient the unit so that it does not take that wind directly (obviously on the sea of cortez, the offshore winds were strong… even miles from the sea where we lived). Another help is to build a small roof shade over the compressor unit. Don’t let the compressor take direct sunlight. Just a roof is sufficient, you don’t need to enclose it (in fact you shouldn’t).

    Awnings to keep hot sunlight off of your windows and front door during the hottest part of the days helps immensely… Windows and doors are poorly insulated in relation to the walls.

    Granted, my conditions were a bit more extreme with regards to heat.. maybe a little less with regards to humidity.. (I’d have to check, but I’m pretty sure Charlotte, NC gets more humidity than Guaymas, Sonora).

    When someone installs your minisplit… They have to evacuate the system thoroughly…. achieving a negative pressure (just like you would with automotive AC systems).. before charging with the refrigerant.

    One thing to get used to with a mini-split… a factor that contributes to it’s higher seer value… is that there is no air-makeup…you are always recycling the same interior air… When weather permits, you’ll want to shut it down and open a few windows with a fan running to change your air out.

    Sometimes the condensate drain can slow down as it accumulates mud… this will result in the interior portion of the unit spitting a little moisture… Don’t put anything directly in front of it that can’t handle an occasional spritz… It’s an item that you have to keep up on if things get a little dusty in your area.

    We now live in Arizona (still in the Sonora Desert), just north of the border. We and are blessed that our pueblo styled town home (about 1200 sq ft) stays cool enough without AC so far.. Good enclosed pations, front and back.. as well as a few mesquite trees on the south facing side probably helps as well. Previous owners installed a heat pump on this home, so that will be a new experience for us when we fire that up in a few weeks.

  11. Hey Ryan,

    This article is very usefull, if you do not mind can you take a wattage reading on your portable ac while it is running? I have looked online and it seems like the numbers vary wildly on how much energy HVAC systems use. We know what the manufacturers SAY it should be but it helps to have a physical example. Another question that I have is do you do your laundry in-house? Washing does not use much energy but drying can be very energy intensive. If you would I was hoping you could get me a wattage reading on your dryer too.


  12. I can run my 8000 BTU A/C unit on the few days it is really needed and cool down the 136sq ft rather quickly by use of bamboo shades which are rolled down to cover all southern exposure windows. The need for greater battery capacity is greatly lowered.

  13. Ryan,
    Sorry to hear you’re having a hard time getting your A/C setup. I too have trouble sleeping in the month or two that it just stays a little too warm at night, but mold is the bigger issue I’m after with an A/C unit as cooling the air also allows one to remove moisture from the air when it condenses (like on a glass of ice water in the summer) on the cold coils of the air conditioner.

    I’ll be setting up my little home,, off the grid. I plan to use this unit for air conditioning,, mainly for dehumidifying as I live in the temperate rainforest mountains of WNC and mold becomes a serious problem in the late summer.

    AC=Alternating Current Electricity
    A/C= Air Conditioner

    Pretty much all refrigerant compressors (for A/C, fridges, freezers, etc) use DC (direct current) electricity pumps. If you have an AC (alternating current, which is the standard in most houses and appliances) air conditioner unit, you will be converting the AC electricity into DC to turn the compressor pump, which is the component in an A/C system that uses the most power. Converting power from AC to DC or DC to AC always loses power, at best you’ll lose 10%. If you’re off the grid producing DC solar power, you’ll have lost 10% or more through your inverter to get AC power out, then lose another 10% or more changing that AC back to DC for the air conditioner compressor.

    I think the unit I linked above is in a similar price range ($1800) to high efficiency AC A/C units out there. It has a cooling EER rating of 18.61. EER (energy efficiency rating) is slightly different than a SEER rating (seasonal energy efficieny rating) in that a SEER rating takes into account the use of the unit for heating and cooling purposes. Modern A/C units can heat buy running the compressor pump in reverse.

    Unfortunately the Hot Spot Energy A/C unit runs off of 48VDC rather than the common 12VDC of most battery banks and DC solar appliances. To remedy this I’ll be using a DC to DC voltage converter to step up my 12VDC to 48VDC. There is much less loss of efficiency when staying with DC or AC and only changing the voltage.

    Check out the How Stuff Works write-up for air conditioners.

    • What a great find Keenan ! I’m a strong advocate of DC appliances wherever possible just for that reason. I built a 12v PC and lowered my AC need, so I can use a much smaller inverter. Just a refrigerator is planned for it’s use.

      The A/C will have to be run on generator or on the grid.

  14. Hi everyone.
    Just thought I’d describe my experience with my two person tiny house with AC on tiny solar.
    Location: The Kimberley, far NW of Australia. Subtropical. Hot and humid summers (25-40 C) Warm winters (15-30 C)
    AC supplied to only the studio/office space measuring 18m2
    Bedroom and open plan living area have large fine mesh wall panels to allow for sea breeze. Low power consumption Aerotron ceiling fans to these. Amazing fans.

    Tiny Solar Power system:
    12v 1000W PV array, roof mounted.
    Twin 45A Morningstar PWM regulators.
    12v 1000W Latronics DC-AC Pure sine wave inverter (can surge to 3000w for 5 sec)
    12v 560ah sonnenschien gel battery bank

    Major power loads:
    Chest freezer 190kwh/year
    Small refrigerator. 240kwh/year

    Mitsubishi heavy industries 2kw split AC unit. Average power consumption 350w. Max power draw 750w only for v short time.
    This is the smallest and most efficient available in Australia at the moment. We only use it during daylight hours so the energy is never really taxing the batteries.
    Prior to installing AC we installed an extra 400w of panels to compensate.
    $900 unit model number SRK20ZMXA
    A lifesaver in this extra hot El Niño year!
    DIY install.

    • Hi Gerrad,
      I just read your post. It really gives an idea about setting up PV powered AC system. As I am also setting up solar powered AC system,I would like to know if the same configuration which you used can be applicable for my system. My only load will be AC (residential 2.5KW capacity split AC)
      I am doing this for my project and wanted to see the performance of the whole system with batteries and without batteries (grid tie)
      Your advise will be highly appreciated.
      Thanks in advanced

  15. nice – Very nice idea… Solar with AC… i like it

  16. Any update. Did you ever get minisplit installed? Btw you can do the job yourself. Just rent the tools.

  17. I have a 74 m2 (796 aq ft) flat in Spain which I’ve refurbished to a pretty high energy efficiency standard. All the walls are well insulated, the windows are of very high quality, awnings and blinds (operated automatically by a home automation system) keep the sun and heat out as much as possible, and a heat recovery ventilation system (for summer, it should more accurately be called a heat removal ventilation system, since it cools in incoming air) avoids the need to open windows (and let in heat) to ventilate the house. At night I open the windows to allow the house to cool.

    All this is enough to prevent the house ever going over 30 degrees even on very hot days, but not enough to keep the temperature stable at 25-27 degrees, which for me would be sufficient. In hot weather (max temp 34-39C) it can gain 0.5-1 degree of heat per day, until it stabilises at 28-30 degrees, depending on the weather.

    The combination of A/C and solar panels flashed into my mind the other day and I started researching it, but it seems that for my needs all the A/C units are overpowered. If I could take just 1-2 degreess of heat out of the house during the day with the A/C, it would give me the temperature I need. Would it therefore not be better to have a very low-powered A/C unit that uses solar power exclusively, running throughout the hours of daylight, rather than a high-powered unit running for a few hours and requiring supplementary power from the grid? Most A/C units are designed to cool down a space relatively quickly, because owners switch them on when they’re too hot, and then switch them off when they’re cool enough. I would like a low-power setup that runs automatically throughout the day and delivers the temperature I want when I get home, so it wouldn’t matter if it pulled heat out of the house very slowly.

    I’m not 100% of my calculations, but an efficient A/C unit running for 12 hours at between 200-500w would probably be enough for this small temperature adjustment. Since the flat is in a block of 10, the roof space available for my panels would be limited (perhaps 4 m2 on the south side). At peak output that would give me perhaps 800-1000w, given 2x250w panels.

    My ideal setup would therefore be:
    – An A/C unit capable of running at very low (and variable?) power, using only the output from solar panels
    – The option to use grid power and higher output for exceptional circumstances (e.g. having lots of people over in the house)
    – Control via home automation

    I suspect such a beast doesn’t exist. Am I right?

  18. Panasonic have some a/c units that appear to run on less than 200 watts, after start up, when on a low setting. I am considering one of them for some background heating at home in the UK during the autumn & spring when the solar panels should be producing enough to power it and multiply the wattage by just over 4 times.

  19. We are located in Nashville, Tn. We haven’t tried any installation any solar power installation but seems quite interesting. We will do it as a test and will let you know, thanks for sharing.

  20. Store solar heated water in an insulated, underground tank and pump through a fan blown radiator at night during winter. Should help save your batteries.

    • I hadn’t thought of burying water tanks, because my house is on wheels, and I don’t want to commit, but if I ever settle ‘forever,’ it’s something I’d look into. I’ve been playing with different “hot” water capture and recycling for interior heating. One of these ideas is once I get a greenhouse built, have black plastic barrels filled with water that can circulate from the black roof hoses I’d use for heating bath water. I notice my home temperature goes up several degrees when I take a bath in my 100 gallon trough/tub. I love my propane on-demand heater, but wouldn’t it be nice to have that as back-up rather than primary? If I could add on house heating, that would be even better.
      There are also the tin can solar heaters, which I’m trying first, but will only work in fall and spring here, I’m pretty sure, because of all our rain and clouds, and of course, the coil in the compost pile, which will take me a few years to try out. I see a D/C pump being helpful in any of these situations, with a strategically placed fan. Then again, a mini-split sounds expensive, but foolproof, but no sense of accomplishment after experimentation. Trade-off.

  21. This article is still missing the information all other ones discussing AC in a tiny home situation. How many watts is your solar array, what panels are you using, how many watts per panel, how many panels, how many batteries….

    • It is missing because there are extreme differences in our needs/uses.
      Climate, solar days, wind, temperatures, shading, energy use, mobile or stationary… are just a few of the differences that would make it impossible to package a system for one person. Each has to be custom designed for those variables and the lifestyle one has.

      • While that is understandable, not putting any information about your solar setup doesn’t help anyone coming to your site because of an article titled “Air Conditioning On Solar Power

        • HIS solar set up is on another page. Mine is also.

  22. Kudos on the fujitsu. Top of the line inverter variable speed with the best warranty going. Although without a regestered fujitsu installer your warranty will be cut from 10 years to 5.when talking AC your fujitsu is only going to draw 2 or 3 amps 80% of the me it runs. You do need to be a bit cautious of the voltage being supplied to the unit as the electronics are quite voltage sensitive. A good voltage regulator that will cut power and switch to grid before your battery bank drops to low would be a good idea.

  23. I find it amusing that with solar you are charging a battery bank with DC using an inverter to change to AC then through the bridge rectifier to convert back to DC to run the compressor and fan motor. Kind of a shame you can’t bypass the power supply board and run stright DC.

  24. Hi,

    Its always a bad idea to dedicate solar to devices that generates heat as a byproduct. ACs are power hungry devices and the best method to reduce their consumption is enforcing careful usage rather than spend thousands on solar system to try and minimize your bills. I know the post is about the technical side of it but never the less I think readers should be aware that its not the most efficient way of doing it. I work for a home automation company and we did robust test with such setups and the conclusion is always to monitor and control usage than install solar systems. Some smart devices can save you upto 80% just by controlling your AC usage patterns.

  25. Thanks for the article, good info.

  26. Is that Fujitsu 9RLS2 reasonable to use on a 480 watt system with a standard battery bank? I’m from Minnesota and have a 10×16 160 square foot cabin with a 13 foot peak. I’ll be moving into the cabin soon. It can get into the 90’s in the summer time and high humidity.

  27. I’m a Fujitsu Contractor. First, Legitimate installers don’t like to install other’s equipment because they can’t truly know, or guarantee the condition of the unit. If you live in a cold or especially a damp climate I recommend the Fujitsu “X.L.T.H.” models. These units work extremely well in COLD & DAMP conditions, and the newer model 9,000 is 33 seer. NO other split system comes close to Fujitsu’s cold temp performance regardless of “others” claims. However, please be aware that you should have purchased the “H” model of the 9000 Fujitsu in my opinion, and this is but one reason why this equipment should be purchased from a “Authorized” Contractor. You also get a much better guarantee from an authorized contractor. That said, you will find that any Fujitsu properly installed will live up to whatever it is rated for AND MORE. I love em. Best wishes.

  28. I’ve had a off grid cabin for 17 years . Size is 160 sf for main cabin,also 10 x 10 washroom and kitchen cabin and a 800 square foot shop. I have 2400 watts of solar and a windmill. I would never put a battery bank in to run a heat pump under 400 amp hours. Mine is 600 amp hours and I am going to increase it to 750. Each 100 amp hour will draw down to 50% of battery discharge from full will give you 1 kw of usable power. I have a Danby 11000 btu heat pump, I had it for 7 years for heating and cooling plus a window shaker in the garage. Go over board on battery’s and use 24 volts . Why, You gain 50% in just going from 12 to 24 volts. It lowers the amp draw from the batteries. I use an electric blanket and fans before I turn the heat pump. I use an outback inverter and have 3 generators as well. I do not use the cabin from Xmas to early April due to snow and cold weather.

  29. Hey
    Thank you for posting your experience. I am in the Charlotte area (Indian Trail) so pretty close to you and I am thinking about doing a Small House (if not a Tiny House) close by. I would love to pick your brain about so details and gain from your experience. Shoot me a message if you’re interested. Thanks

  30. I also want to achieve the same by using Solar Powered for my 12,000 BTU Inverter A/C and came accross your site.

    Would you please tell me which parts I need.
    Right now I’m thinking of these following:

    Solar Panels (mono 310W x 10)
    Charge Controller
    Battery Bank (4 x 12V batteries)
    DC Disconnect (additional)
    Inverter (2kw or 3kw)

    Is that enough?

    I am thinking further in night/cloudy/rainy days I want to switch to our electricity GRID. Is that possible, how to achieve?

    best regards

    • No ! It’s never enough. What is the draw of the AC ? How long will it need to run ? What SIZE of batteries ? What is the start up SURGE for the AC unit ?

      This takes a lot of careful planning. AC is a MAJOR user of electricity.

  31. I was born and grew up in Puerto Rico’s west coast. You cannot live there nowadays without air conditioning. After hurricane Maria, the entire 1930’electrical grid of the island was destroyed. Now there are still thousands living without electricity and the government there is so dumb that they have not made a move to solar. Talk about idiots and retards, you can find so many in the government of Puerto Rico.

  32. How many panel you use to run the mini split

    • ONE, if it’s big enough. 😉

      It really all depends on how many watts you are using and how long it needs to run. The FIRST step is to determine how many things you want to run and how may watts you need to run them.

  33. Thanks so much for being open and detailed with your experience!

  34. I looked for a while to get some info on solar powered AC and the current requirements – your article was spot on with additional points I hadn’t considered – thanks for taking thr time to write and post!!

    the mini-split seems like a good solution for a tiny-house, but I’m hoping to locate an “all-in-one” unit for a sprinter van conversion– any thoughts/recommendations?

    – \\//\\//olf

  35. Very interesting read….I was curious about an AC system running on solar.

  36. While this is a decent article I feel I should point out just a couple things. HEAT is always the “enemy”, be it for your comfort OR your solar panels. They are actually NOT at the best efficiency when it is HOT outside. Solar power just needs SUNLIGHT, hence they still work fine in the Arctic regions in sub-zero temps (which also has a disadvantage effect on the batteries themselves if they are not insulated). I’ve looked this over and it’s not clear, but I’m guessing, if you are running 120 volts, not 240 volts. The biggest drain of electric is upon “startup” when the unit needs to “BANG” the fan and the compressor. When everything is spinning and pumping (warmed up, yet cooling) the demand goes down significantly,15-40% depending on the unit. There has, and is, been some developing technical capacitors that have been developed to “try” to ease this “demand” of power, yet it is still not perfected at this time. Battery temperature for solar is often overlooked. Ask any auto parts store clerk and they will tell you about the “surge of battery sales” after the first freeze or high temperatures.
    I honestly would be interested in your battery containment area temperatures. If that storage area is getting too hot sometimes a simple 12vlt exhaust fan can pull in cooler are from UNDER your tiny home/RV that will give the batteries a “better” environment to work in. Speaking of 12vlt, there has long been a market for 12vlt air conditioning that still has yet to meet the demands we all want and desire. Mitsubishi has always been one of the innovators for MANY products and I just laugh at how my own country (United States) has lagged behind the rest of the world in many ways, but “mini-splits” being a BIG one. While HVAC isn’t my main channel of income, I am forced to deal with it in my industry. We have put in various mini-splits over the years and people here think it’s some “magical NEW system”, yet they have been around for at least 30+ years. They just keep getting better and should be considered not just for tiny homes but multiple units for regular homes too. They are fast AND efficient to cool (or heat) the area of almost any decent size room that you are using. In fact, there have been some amazing developing electronics that monitor your “whereabouts” and “time” there/use to help automate the hvac system in a “on-demand” for the 9-5 crowd.
    As far as your “installation” issues go it’s a real bummer that CO’s do that. On certain items these days I regularly point customers to the web for a MUCH better price. However, I do make it CRYSTAL CLEAR that we will not warranty any parts of the unit we replace. With hvac it’s often uncertain if the unit is “pre-charged” or not when dealing with the customer (they just don’t know, which is fine). We make it (again!) crystal clear before starting install that “IF” we need more juice in the system it cost “this, this and this”. Most of the time it doesn’t take a whole lot to top them off, or fill them after vac down (sucking air out of system). Heck, LINE UM’ UP! I’ll take $300/$500 SIMPLE installs all day long myself. Easily set up 3-4 a day they are that simple and BEST for customers.

  37. Interesting article. I appreciate it. It made me realize I need to rethink heating for my tiny home to be. It will likely be a tiny wood stove. I had considered radiant heat under the flooring. I live in Texas so cooling will be my main issue, but it can get chilly in the winter. (Many Texans long for winter.) I have a lot to learn about building my tiny home to be solar ready.

  38. Hello!
    Just read your post on setting up an air conditioning system with solar panels. Very interested in doing the same thing. Just a couple of questions. How many square feet is your house – mine is just over 800 square feet. How much did it cost to setup your solar panel system – price of panels and price of batteries? What type of batteries did you use? Some friends suggested using marine batteries – not sure if this is the best choice. Thanks in advance for any information you can provide.

  39. I am desperate to do something like this.
    I saw Youtube video where the guy, “Technology Connections” cools his house on cheap grid power. he has demand pricing, and when the grid get pricy, off it goes. He uses his houses thermal lag, or stored COLD to keep cool during the expensive periods.

    Your experience has been helpful in allowing me to see that his solution may just work with solar as the Cheap Rate and grid as an off line backup.

    Jus need to bite the, dam, bullet!


  40. with your setup sir, you didnt mention how many batteries and their capacities use, how many solar power and their capacities too, hop you can give me idea what is the minimum capacity of a solar power system to run an Air conditioner, thank you

  41. Thanks for your insight & experience. It help understand a lot.

  42. Hello
    I have seen a lot of Tubies on this,
    But my Solar panel is putting out 38 DCV (in sun).
    I popped 1 controller that does 12V/24V.
    Will you help me set it up.


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