[RE-wrenches] mini splits

Thu Mar 13 15:26:21 PDT 2025

I've installed two DIY mini splits and both work very well, one was MRCOOL
and the other was Pioneer. Many of our clients and my parents have
professionally installed mini splits - I'm not sure whether there are major
advantages of getting the professionally installed variants other than a
preference of DIY versus having a contractor do it.

I have found that in our coastal California climate the cooling is
particularly low cost with these heat pumps. Cooling tends to match the
solar curve nicely too. Heating during winter tends to run for many hours a
day and use a pretty good amount of juice, although it of course is several
times less than a comparable resistive heater. Most folks I've talked with
who own mini splits have mentioned the same thing, that heating during
winter costs more than they were expecting. Of course our electricity rates
are $0.30 to $0.60/kWh, so that doesn't help.

Kris, if you Google "energy star heat pump calculator" you'll find a
energstar.gov spreadsheet to help calculate heat pump usage. I've found
that the default numbers are conservative but if you can find the energy
specs from the product finder for a specific model, it will help a lot:
https://www.energystar.gov/productfinder/product/certified-heat-pumps/
actual usage varies a lot depending on the building characteristics
(insulation, heat gain, square footage, etc) and owner habits so sometimes
it feels like a shot in the dark.

Good topic as electrification becomes more and more common.

August

On Thu, Mar 13, 2025 at 3:04 PM Kristopher Schmid via RE-wrenches <
re-wrenches at lists.re-wrenches.org> 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
> 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> 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> 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 <pieter at offgridenterprises.org>
>>> *Sent:* Thursday, March 13, 2025 4:09 PM
>>> *To:* RE-wrenches <re-wrenches at lists.re-wrenches.org>
>>> *Cc:* Wayne Irwin <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> on
>>> behalf of Wayne Irwin via RE-wrenches <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>
>>> *Cc:* Wayne Irwin <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> on
>>> behalf of Michael Morningstar via RE-wrenches <
>>> 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>
>>> *Cc:* Michael Morningstar <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> 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
>>>
>>> _______________________________________________
>> List sponsored by Redwood Alliance
>>
>> Pay optional member dues here: http://re-wrenches.org
>>
>> List Address: RE-wrenches at lists.re-wrenches.org
>>
>> Change listserver email address & settings:
>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>>
>> There are two list archives for searching. When one doesn't work, try the
>> other:
>> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/
>> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>>
>> List rules & etiquette:
>> http://www.re-wrenches.org/etiquette.htm
>>
>> Check out or update participant bios:
>> http://www.members.re-wrenches.org
>>
>> _______________________________________________
> List sponsored by Redwood Alliance
>
> Pay optional member dues here: http://re-wrenches.org
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Change listserver email address & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> There are two list archives for searching. When one doesn't work, try the
> other:
> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/
> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
> List rules & etiquette:
> http://www.re-wrenches.org/etiquette.htm
>
> Check out or update participant bios:
> http://www.members.re-wrenches.org
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20250313/63346fc7/attachment.htm>