[RE-wrenches] mini splits

Fri Mar 14 14:05:33 PDT 2025

HI Dave

Interesting that you bring that up, as far as I can tell, Energy Star rated DIY units are only up to about 24kBTU, I don’t know why.  

Another piece of data I can’t find is actual efficiency curves.  Which would be based on outside and inside temps.  

I wonder if anyone has info as to those two things

Thanks for all the input, very helpful

jay

> On Mar 14, 2025, at 2:07 PM, Dave Angelini Offgrid Solar via RE-wrenches <re-wrenches at lists.re-wrenches.org> wrote:
> 
> It would depend on the size of the split 😉 It would also depend on the SEER rating and the climate you are in. I try to only use the best model in the brand for Offgrid. It cost more for a reason and can run longer into the evening before using the battery. The smaller 33 SEER units work well as you can keep a medium house cool before it ever warms up. Also can easily run on a 400AH battery all night with a reserve. They sip the power and as long as the maintenance is done, can last a long time.
>  
> For instance, the Fujitsu 9000 btu. 
>  
> <e7291169.jpeg>
>  
> Dave Angelini Offgrid Solar
> "we go where powerlines don't"
>    <http://members.sti.net/offgridsolar/>https://offgridsolar1.com/  <http://members.sti.net/offgridsolar/>
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> 
> On 2025-03-13 3:03 pm, Kristopher Schmid via RE-wrenches wrote:
> 
>> Hi All,
>>  
>> Since we are on the topic, does anyone have a good method for predicting the kwh consumption of a mini-split?
>>  
>> Thanks,
>> Kris
>>  
>>  
>> Shine On!
>> 
>> Kris Schmid
>> Legacy Solar, LLC
>> 137 West 1st Avenue
>> Luck, WI 54853
>> www.legacysolar.com <http://www.legacysolar.com/>
>> 715-653-4295
>> NABCEP Certified PV Installation Professional
>> Licensed Wisconsin Master Electrician
>> BSEE
>>  
>> 
>> On Thu, Mar 13, 2025 at 3:58 PM Jason Szumlanski via RE-wrenches <re-wrenches at lists.re-wrenches.org <mailto:re-wrenches at lists.re-wrenches.org>> wrote:
>> Most off-grid homes here in Southwest Florida, one of the most challenging air conditioning places in the country due to heat and humidity, have moved to mini-splits. I have a client's system with quad Sol-Ark 15K that is running eight separate mini-splits and a 4-ton central air unit at a sprawling residential complex. There are no issues to report. These were all installed by a reputable local HVAC contractor, so they are not likely DIY brands. I am not certain about the tonnage, but I believe each mini-split is 1.5 tons. These are in a highly corrosive/salt environment. I can't imagine they will last more than a few years each. But from what I hear, clients on the islands are treating them as disposable in a way. It's still much cheaper than replacing central air units every few years.
>>  
>> I have another client's system with a single Sol-Ark 15K and it has two 2-ton mini-splits that are DIY by the homeowner. They barely dent the batteries each day. I see them using as little as 400W to maintain temp in high ambient heat. Most other clients have single mini-splits. I concur with one of the earlier comments to stay away from multi-zone if possible. I don't think there are considerable cost savings anyway, and I have not been able to detect any energy savings going that route.
>>  
>> There is a guy I did some work for who is running a few old school window shakers on a Sol-Ark 12K and he has constant problems with surges and performance of the units. He is in line for a mini-split soon, and plans to DIY.
>>  
>> Personally, I have a 2-ton DIY cooling my uninsulated garage at home (on grid) when I need to use it for short periods in the summer. It works like a champ, and it was dead easy to install. The hardest part was getting the line set out through the block wall. I think I paid $1,200 for it, including the trim kit to hide the line set and a wall bracket for the compressor unit.
>>  
>> I think the bottom line for me is super low startup surge and then fairly consistent power draw once desired temperature is reached. I feel this is much easier to plan for off-grid rather than repeated start/stop cycles.
>> 
>> Jason Szumlanski
>> Principal Solar Designer | Florida Solar Design Group
>> NABCEP Certified Solar Professional (PVIP)
>> Florida State Certified Solar Contractor CVC56956
>> Florida Certified Electrical Contractor EC13013208
>> 
>> On Thu, Mar 13, 2025 at 4:41 PM Wayne Irwin via RE-wrenches <re-wrenches at lists.re-wrenches.org <mailto:re-wrenches at lists.re-wrenches.org>> wrote:
>> Hi Pieter,
>>  
>> I should have said that I "No Longer" vacuum them as the extra step that I previously applied made no difference in my experience. We are also in FL. with extremely high humidity which might be the difference. Most of the AC contractors here confirm the same experience.
>>  
>> That said, they do work well with solar applications.
>>  
>>  
>> Wayne Irwin
>> President
>> License #CVC56695
>> State Licensed Solar Contractor
>> Pure Energy Solar International Inc.
>> Wayne at PureEnergySolar.com
>> PureEnergySolar.com <http://pureenergysolar.com/>
>> SolarChargingStation.com <http://solarchargingstation.com/>
>> 352 377-6527 Office
>> 352 336-3299 Fax
>> 
>> 
>> The Sun Is Always Shining!
>> 
>> The content of this message is Pure Energy Solar Confidential. If you are not the intended recipient and have received this message in error, any use or distribution is prohibited. Please notify me immediately by reply e-mail and delete this message from your computer system. Thank you.
>> From: pieter offgridenterprises.org <http://offgridenterprises.org/> <pieter at offgridenterprises.org <mailto:pieter at offgridenterprises.org>>
>> Sent: Thursday, March 13, 2025 4:09 PM
>> To: RE-wrenches <re-wrenches at lists.re-wrenches.org <mailto:re-wrenches at lists.re-wrenches.org>>
>> Cc: Wayne Irwin <pureenergysolar at hotmail.com <mailto:pureenergysolar at hotmail.com>>
>> Subject: Re: [RE-wrenches] mini splits
>>  
>> Wayne, I saw your post regarding the use of ductless mini splits. I too use them extensively, and have an unblemished track record using them. I must say that your failures may be in part due to the fact that you do not evacuate the system during the installation process. For what it is worth the proper procedure is to precharge the system with nitrogen to about 200PSI. Then check for leaks and verify the system will hold pressure. Then pull a vacuum on the system for maybe 15 or 20 minutes before releasing the refrigerant. If you skip these steps you are vulnerbale to diminished performance caused by any air left in the circuit, any  moisture will react with the refrigerant and turn acidic eventually leading to corrosion. I see you keep the lines closed as much as possible but non the less I think will find your system longevity will increase, and potentially the performance will be better.
>>       You are getting about ten years so not to bad but I have some healthy systems that are 20 years old still going strong.
>> Pieter
>> From: RE-wrenches <re-wrenches-bounces at lists.re-wrenches.org <mailto:re-wrenches-bounces at lists.re-wrenches.org>> on behalf of Wayne Irwin via RE-wrenches <re-wrenches at lists.re-wrenches.org <mailto:re-wrenches at lists.re-wrenches.org>>
>> Sent: Thursday, March 13, 2025 12:02 PM
>> To: RE-wrenches <re-wrenches at lists.re-wrenches.org <mailto:re-wrenches at lists.re-wrenches.org>>
>> Cc: Wayne Irwin <pureenergysolar at hotmail.com <mailto:pureenergysolar at hotmail.com>>
>> Subject: Re: [RE-wrenches] mini splits
>>  
>> Hey Jay,
>>  
>> I live off grid (25yrs) in North Fla. (temp range is teens - 100+ F) with mini-splits throughout the house (2,700sq'). 
>> I have used just about every brand. We primarily use them for cooling but also use heat to supplement the wood stove. 
>> I can't imagine living without them. Although it's a love/hate relationship.
>> My experience is that you get about 10 years max from whatever brand you buy. Typically, the inside unit corrodes from condensation and leaks out, or the outside unit reversing valve locks up in cold or heat position. IMO They are not worth repairing. We currently have 4 - 1 Ton units and 1 - 2 ton. I only buy 1 to1 systems vs 1 -4 as it offers redundancy. I initially tried "reputable" brands which typically cost more but have since migrated to whatever is the cheapest. 
>> That said I like Gree and/or the knock off brand that they make (good for the price and holding up well). When I am in need of more than one, I always buy an extra to swap out whichever unit dies first. 
>> Fortunately for me, years ago, I had a buddy show me how to install them. Pretty simple. They come pre-charged and can typically handle up to 30' of line with no issues. If possible, find someone to show you once.  YouTube will offer many WRONG ways to do it videos.
>> I don't use the vacuum on the lines. I just keep the lines plugged and dry until I hook them up.
>>  
>> My 15kW array with 2 - VFX3648R's has had no issue powering any of them.
>>  
>> I hope this info helps.
>>  
>> Wayne Irwin
>> President
>> License #CVC56695
>> State Licensed Solar Contractor
>> Pure Energy Solar International Inc.
>> Wayne at PureEnergySolar.com
>> PureEnergySolar.com <http://pureenergysolar.com/>
>> SolarChargingStation.com <http://solarchargingstation.com/>
>> 352 377-6527 Office
>> 352 336-3299 Fax
>> 352 316-1637 Cell
>> 
>> The Sun Is Always Shining!
>> 
>> The content of this message is Pure Energy Solar Confidential. If you are not the intended recipient and have received this message in error, any use or distribution is prohibited. Please notify me immediately by reply e-mail and delete this message from your computer system. Thank you.
>> From: RE-wrenches <re-wrenches-bounces at lists.re-wrenches.org <mailto:re-wrenches-bounces at lists.re-wrenches.org>> on behalf of Michael Morningstar via RE-wrenches <re-wrenches at lists.re-wrenches.org <mailto:re-wrenches at lists.re-wrenches.org>>
>> Sent: Thursday, March 13, 2025 11:05 AM
>> To: RE-wrenches <re-wrenches at lists.re-wrenches.org <mailto:re-wrenches at lists.re-wrenches.org>>
>> Cc: Michael Morningstar <mjmorningstar at gmail.com <mailto:mjmorningstar at gmail.com>>
>> Subject: Re: [RE-wrenches] mini splits
>>  
>> I'm interested in this too
>> 
>> On Thu, Mar 13, 2025 at 7:39 AM jay via RE-wrenches <re-wrenches at lists.re-wrenches.org <mailto:re-wrenches at lists.re-wrenches.org>> wrote:
>> HI All,
>> 
>> I have been getting a lot of questions about people wanting to install mini splits in their off grid homes, and in normal homes. 
>> 
>> The line of questions usually involves DIY vs contractor.  Of course the price difference is staggering, roughly 5X more for contractor.  And I'm being asked all sorts of questions about the DIY versions. 
>> 
>> Is there a good place for information so I can educate myself as to the different brands etc
>> Or maybe someone can contact me off list if they have some info to share.  
>> 
>> Thanks'
>> 
>> jay
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