Mini Split for Heating Primarily?

[TylerRNEMT]

Hello,

I am very close to pulling the trigger on a 24k Mr Cool DIY mini split for my 800sq ft. insulated/drywalled stud built detached.... I live in Indiana and my garage is basically useless in the winter and it is starting to drive me nuts. I have an Electric 240v Heater that I can run in the Winter an hour before I need to work and tolerate working out there in overalls at 55-60 degress but that's only when the work is necessary. I don't have much free time in the summer to get anything done out there either so for me Winter would be the primary time to get a lot of stuff done but I hate being cold.

Almost all of the reviews I've read for the Mini Splits focus on the A/C part of these units and most even mention they don't use the heating portion. I would be looking primarily at this unit for it's heating function. I would love to run a Gas Unit but my house is all electric and uses a traditional heat pump. I would have to have 4x the cost of a Mini split in getting gas there to begin with so that's not really a feasible option.

My goals would be to keep the garage at a constant 55 degrees or so and turn it up to 65-68 when I want to actually go out and work. The wifi function of the Mr Cool and along with the ease of installation are what makes me lean this direction.

Any Input on the Heating function of these units would be greatly appriciated!!

-Tyler

 

[Walter_TA]

You need to look at the specs of the unit. How much heat will it make as it gets colder. I have a LG red unit that will heat down to 10 degs and works like a champ. Look at AC wholesalers.$$$ for price on the LG. MR cool is bottom of the line, but they do work. You do need a vacuum pump and other stuff to install. If you look up my past posts you can find my write up for install.

 

[dcg9381]

I'm in Texas, so the conditions are different. My shop is also 2400 sqft with 16 foot ceiling and has 2 x 24K units (Daikin). These are primary heat in the winter and do pretty well until things get really cold (under 35 degrees in Texas). My insulation is probably inferior to an insulated garage as I have some large uninsulated roll up doors. Once we go below freezing, our building starts to get under 70 degrees inside.

Many units have a "performance graph" for heating functions, but almost all of them drop in heating BTU performance below freezing. If you're 800 sqft, a "normal" ceiling, and insulated, I'd be shocked if 24k doesn't get it done for heat and I think you are wise to over size a bit if it isn't heated all the time.

You may be able to find the BTU/temp graph if you dig in their documentation.

There are units, such as the Mitsu "hyper-heat" that are designed to function better in really cold weather...

Also note, at least on my Daikin, that these units have a "defrost mode" which has to run every once in a while. On mine, it means that a unit can drop out for 4-9 minutes while it defrosts itself...

 

[ericm]

Do a Manual J calculation to know how much heat you'll need under the 99% coldest temps. https://www.loadcalc.net/index.php

mini splits are best when left on 24/7. There's not a lot of extra capacity to heat a space quickly like with a gas heater, which is commonly 60k or 75k btus or more.

Many mini splits like Mr Cool have a minimum heat temp of 62 degrees.

If you want to go gas you could get a propane tank for the shop.

 

[65ranchero]

I am using a Mitsu. mini split ( total of3 wall units) and (one condenser) only the large on is used to heat my whole house 1st and second floor with the main unit. Temp set at 72F real house temp is 68/69F
We are doing it as a experiment to actually see if it's worth using it as the main source of energy. It is to see if the extra electricity will off set the heating oil ( HWBB) we use.
So far it works good but the draw back is as it sits right now is that the electric has rose to about average of $150more/month
Yes we are using less fuel oil but will not realize the impact until the heating season is over.
So I will go and say it will be a plus for you to use the mini split it is better to maintain than it is to bring it up to temp Insulate and seal it is your friend
And as a side note they will loose efficiency around < 10F
You may want to look at Propane ceiling mounted hot air heaters the only thing is a higher humidity level if its not vented outside.

 

[TylerRNEMT]

Thank you for all the input! Sounds like it might make more sense to keep the garage at a constant 65 with a mini split..... I know there are far superior mini splits on the market than Mr. Cool... however I can easily install both the electrical and unit itself on my own without doubling the overall cost if I go the Mr Cool DIY route. I'm not looking to put more than about $2k total in the project and this seems very feasible with the Mr. Cool DIY 24k unit. Having a unit installed and lines charged by a shop seems like a huge waste of money when I can do it myself without issue and without the markup of buying through them on top of the install fees. I can't imagine being in under $4k for a similar sized unit if I were to go that direction.

 

[mobetta]

I paid $150 to have a tech put mine into service after i installed it

they are precharged

I went with NON DIY mr cool olympus hyperheat 24k as it heats at a lower ambient temps(-20F advertised)

so far only one night at -6F we'll see how this week goes

mr cool has freeze protection mode at 46F which i use 90%
It does warm my space up within an hour or so

pulling in an 8000lb icecube(service van) does put a chill in the air- I do have a 7500w electric unit heater as well (cheeep enough to buy- not to run tho)

electric seems to only be about $20/ so far(11/20 install)
Mild winter though

24x28x9-12'(scissor truss) well sealed and insulated (r15 mineral wool/ r38+ blow in fiberglass)

 

[rok_hunter]

I've got a 36k Mr Cool DIY in a 30x40x12 enclosed pole barn with 2" of closed cell foam in the Florida panhandle. We saw several days of temps in the teens and my Mr Cool never skipped a beat at keeping the building heated to 72-75 continuously.

Sent from my Pixel 5 using Tapatalk

 

[TylerRNEMT]

I paid $150 to have a tech put mine into service after i installed it

they are precharged

I went with NON DIY mr cool olympus hyperheat 24k as it heats at a lower ambient temps(-20F advertised)

so far only one night at -6F we'll see how this week goes

mr cool has freeze protection mode at 46F which i use 90%
It does warm my space up within an hour or so

pulling in an 8000lb icecube(service van) does put a chill in the air- I do have a 7500w electric unit heater as well (cheeep enough to buy- not to run tho)

electric seems to only be about $20/ so far(11/20 install)
Mild winter though

24x28x9-12'(scissor truss) well sealed and insulated (r15 mineral wool/ r38+ blow in fiberglass)

Awesome Feedback thank you!
So when you say they are pre-charged I'm a little confused... I thought only the DIY units come precharged.... This making them "DIY".

The other units have to have a vacuum pulled and then be charged by a tech using their refrigerant correct? Or is the unit itself precharged and then only the lines will then need to have a vacuum pulled by a tech?

I do see an advantage going with a non precharged line set as you can easily cut to appropriate length for your install without having to coil excess like the DIY kits..... Did you have to flair your own lines with that kit?

 

[TylerRNEMT]

I've got a 36k Mr Cool DIY in a 30x40x12 enclosed pole barn with 2" of closed cell foam in the Florida panhandle. We saw several days of temps in the teens and my Mr Cool never skipped a beat at keeping the building heated to 72-75 continuously.

Sent from my Pixel 5 using Tapatalk

Thanks for your input!
Didn't realize it was in the teens frequently in the panhandle! That makes me feel more confident in my choice as my building is a fair amount smaller than yours.

-Tyler

 

[mobetta]

THe refriferant is in the compressor from the factory. if you add extralong lineset you may need to adjust charge. so yes- the lineset needs to be evacuated (some pro guys will also nitrogen charge to check for leaks first)

I did cut and flare my lines HOWEVER after talking to my HVAC guy i should have left it to them do it- they dont like to use the cheapo flare nuts that are included- apparently they have issues cracking. and getting a good flare is easy enough to NOT do right.

I do have an existing relationship with an HVAC company.
I have read of peeps having trouble getting someone out to work on new equipment they didnt sell or install( As a Contractor I get it)- others have just put in a service call for no AC to get a tech out.
If you go that route I suggest a cash tip for the tech...

 

[SALIV8]

I’d suggest a gree sapphire model. The cold weather performance is impressive and what I would go with.

 

[TylerRNEMT]

THe refriferant is in the compressor from the factory. if you add extralong lineset you may need to adjust charge. so yes- the lineset needs to be evacuated (some pro guys will also nitrogen charge to check for leaks first)

I did cut and flare my lines HOWEVER after talking to my HVAC guy i should have left it to them do it- they dont like to use the cheapo flare nuts that are included- apparently they have issues cracking. and getting a good flare is easy enough to NOT do right.

I do have an existing relationship with an HVAC company.
I have read of peeps having trouble getting someone out to work on new equipment they didnt sell or install( As a Contractor I get it)- others have just put in a service call for no AC to get a tech out.
If you go that route I suggest a cash tip for the tech...

Thanks for the reply that part makes sense now...... This is exactly why I'm leaning towards the DIY kit...... Getting a company to come out and work on a unit they didn't sell or install will be a complete nightmare in my area ...... if not impossible..... hence my original post discussing a similar sized unit being easily 2x the cost of the DIY system..... Dang I wish Mr. Cool would sell the HyperHeat in a DIY version!!

 

[TylerRNEMT]

I’d suggest a gree sapphire model. The cold weather performance is impressive and what I would go with.

I looked through your Mini Split thread and am thoroughly impressed! Great work!

However the DIY factor of not having to have a tech come out and refuse to service(pull a vacuum and charge) a unit they didn't sell or install is a big hurdle for me to overcome. I'm surprise more companies haven't come out with DIY mini split systems.... All it appears to be is a couple of sealed fittings and precharging the lines.... I can't imagine that would be hard to do for a lot of these large companies. I'm sure there are some liability issues that tend to hold them back but man the idea of a full DIY system is very appealing to a buyer like myself.

 

[SALIV8]

Thanks and I get the appeal of the diy for sure. But.

The mr cool diy does not have the cold weather performance you will need, imo. Also, I was able to qualify for electric rebates of $400 per system with using the tech. This offset his charge and I also got the warranty.

I’d check to see about your available rebates.

I had to call many approved companies to find one willing but I bet you’ll find someone if you keep looking or do it all yourself.

 

[SLAYER6669]

I wanted to do the Mr. Cool DIY myself just to be able to do it completely myself without having to buy the tools needed to vacuum the lines but as mentioned above I realized the Mr. Cool DIY wasn't rated to work too well at really cold temps (The Hyperheat model is better but not DIY). I plan to use mine mainly for heat as well.

I ended up with a Senville Aura 24k unit rated down to -22*. I wish I could say how well it performs but I am having that exact same issue finding someone to come out and vacuum the lines. One guy wanted $400, I got him to $325 and he was a no show. Another wanted $400 and he was having health issues and disappeared. I really wanted a tech to do that part to maintain the warranty but at this point I am just going to have to buy tools myself and do it. At those prices above, I may as well spend the money on the tools anyway. A little much for maybe an hour of work.

 

[SALIV8]

If you call ecomfort they will give you some local tech info that will do it. I didn’t use their recommendation but did call the company to confirm they would do it and they would.

Try calling ecomfort.com

 

[Notgrownup]

I have a 18000 btu 18 seer in my 24x24 and keep it at 61 degrees and it’s so comfortable in there. I love it and it cools the shop nicely in the summer, i would do it again if I had to.

 

[Phuckin' Jim]

I installed a Senville Aura unit, and it seems to work well. It is a hyperheat model, but not full diy..
I think it sells for about $800 usd.

For those who can't find an HVAC guy to come out to do the final steps, auto or diesel
mechanics posess the tools and skills necessary to complete the installation.

And most families have at least 1 mechanic in them.

It's at least another option if you don't know any HVAC guys....

 

[Phuckin' Jim]

My mistake, it's 900 usd.


https://senville.com/9000-btu-mini-split-air-conditioner-sena-09hf/

You might need a bigger one for your application.

 

[HoosierBuddy]

To the OP...I'll assume you can't get NG. If you can....you need to rethink this.

Lots of people in Indiana use heat pumps to heat their homes. Your garage is insulated and it's certainly possible to heat it with a mini split.

The downside as others have pointed out is your original strategy of low temp heating or part time heating won't work with a heat pump. They use power in a very miserly fashion, but they don't have the "catch up" capacity that a fuel fired heater has to bring the temperature up if you've used a set back to save $ when you aren't out there.

So, now you are looking at having to change how you use the heater to match up with it's capabilities...leading you to a 24 X 7 solution at a higher temp than you originally speced.

Point is....you have significantly increased what it may cost you to heat the garage from where you started.

The cheapest way (by far) to heat a garage is to only heat it when your are going to be out there....and that is going to require something other than a heat pump/mini split.

That being said, many of us start out thinking we are going to only heat our garage part time, and end up leaving the heat on most of the winter because it is so convenient to be able to run out there on a moment's notice and it's already comfortable.

So...my suggestion, if part time heat or low temperature is what you want DON't get the mini split.

If full time, higher temperature space is what you decide you want...get the mini-split.

I use NG to heat mine...but I do envy the mini-split guys for having A/C. There are some days in the summer where my garage gets pretty hot...and a good A/C solution would be nice.

Good luck!

Phil

 

[Raisedonadeere]

If DIY is your only option the Mr Cool will probably do a decent job but there is a really nice heat boost going with the Hyper heat models once it gets sub 30 deg F. Senville hyperheat is their Sena models, hyper might be a trade mark thing, so you have to verify it is hyperheat type unit by digging through their jargon if they dont say hyperheat. Or just call your brand of choice.

If it is heat you want hyperheat units will put a smile on your face when it gets into single digits and below. It makes little sense to me that Hyper Heat is not sold with the DIY setup. Perhaps they will soon.

 

[theoldwizard1]

You need to look at the specs of the unit. How much heat will it make as it gets colder.

And that is the problem !

The way mini-splits are spec'd, it is not always clear how well they heat during cold weather, especially below 0F.

Definitely "buyer beware" territory.

 

[theoldwizard1]

The downside as others have pointed out is your original strategy of low temp heating or part time heating won't work with a heat pump. They use power in a very miserly fashion, but they don't have the "catch up" capacity that a fuel fired heater has to bring the temperature up if you've used a set back to save $ when you aren't out there.

BTUs are BTUs. It doe not matter what creates them, a natural gas flame or a heat pump.

Proper sizing is the key.

VThe cheapest way (by far) to heat a garage is to only heat it when your are going to be out there....and that is going to require something other than a heat pump/mini split.[/quote]
I disagree. It may mean a LARGER heat pump. I may even mean 2 heat pumps (2 smaller ones does cost more, but are typically more efficient to operate, especially in spring/fall when you can leave on turned off).

That being said, many of us start out thinking we are going to only heat our garage part time, and end up leaving the heat on most of the winter because it is so convenient to be able to run out there on a moment's notice and it's already comfortable.

So...my suggestion, if part time heat or low temperature is what you want DON't get the mini split.

You have no data to support your claim, neither do I.

Here is my thought, any residence heated by a heat pump needs to have a backup because you may be without power form more than a few hours. Generators to heat pumps need to be VERY large (expensive). If I was in the OPs position, I would go with a mini-split and 1 or maybe 2 "tank top" propane heaters. They are cheap, and will get the temp up quickly. Plus you have an extra BBQ tank come summer !

 

[NWOhioChevyGuy]

I would look at getting (Purchase or lease) a 200# LP cylinder. Then use something like this: https://www.menards.com/main/heatin...665-c-6861.htm?tid=9050919157106714612&ipos=7

Should be well under your $2000 project target.

 

[HoosierBuddy]

BTUs are BTUs. It doe not matter what creates them, a natural gas flame or a heat pump.

Proper sizing is the key.

VThe cheapest way (by far) to heat a garage is to only heat it when your are going to be out there....and that is going to require something other than a heat pump/mini split.

I disagree. It may mean a LARGER heat pump. I may even mean 2 heat pumps (2 smaller ones does cost more, but are typically more efficient to operate, especially in spring/fall when you can leave on turned off).


You have no data to support your claim, neither do I.

Here is my thought, any residence heated by a heat pump needs to have a backup because you may be without power form more than a few hours. Generators to heat pumps need to be VERY large (expensive). If I was in the OPs position, I would go with a mini-split and 1 or maybe 2 "tank top" propane heaters. They are cheap, and will get the temp up quickly. Plus you have an extra BBQ tank come summer [/QUOTE]

If you are speaking to the part time heating? I absolutely have data and you do to if you do a simple heat loss calculation. Heat loss is predicated on a temperature differential between the inside and outside of a structure. If you only heat a garage 1 day out of 7, then for about 5 days out of 7 you will have no heat loss and you drastically reduce your overall heat loss and thereby the cost to condition the space.

I've seen this in real world energy bills too. Many times.

Phil

 

[WP9]

[The cheapest way (by far) to heat a garage is to only heat it when your are going to be out there....and that is going to require something other than a heat pump/mini split.

That being said, many of us start out thinking we are going to only heat our garage part time, and end up leaving the heat on most of the winter because it is so convenient to be able to run out there on a moment's notice and it's already comfortable.

So...my suggestion, if part time heat or low temperature is what you want DON't get the mini split.

If full time, higher temperature space is what you decide you want...get the mini-split

Phil

Last fall had a 32K mini-split installed with -15 degree heating capabilities( actual recommended size was a 24k unit, but I wanted more reserve). ( previously had a "Hot Dawg" style Reznor heater in previous workshop.
The natural gas fired heater could bring temp up 10 degrees in 15 minutes. My mini-split is far slower, taking 2 hours to get the temp up as it cycles through heat/defrost cycles and is of smaller BTU capability than the Reznor.
Mini-splits , in my opinion, are best when they are to operate in a relatively narrow range of temps. They are remarkably quiet compared to a forced air gas unit like the Reznor or Hot Dawg. Also, at least where I live (SW Michigan) natural gas is still more economical for heating than my 16.7 SEER mini-split. Now once the heat of summer occurs, the AC with the mini-split will be better than just opening windows with the natural gas fired unit!

 

[theoldwizard1]

If you are speaking to the part time heating? I absolutely have data and you do to if you do a simple heat loss calculation.

BTUs are BTUs regardless of the source.

The big win for mini-splits heating is when the outside temperature is between about 40F and 60F. Much cheaper than NG or propane.

 

[theoldwizard1]

I would look at getting (Purchase or lease) a 200# LP cylinder. Then use something like this: https://www.menards.com/main/heatin...665-c-6861.htm?tid=9050919157106714612&ipos=7

Should be well under your $2000 project target.

Not a "level playing field" ! 50,000 BTU will bring any space up to a comfortable temperature very quick. Much quicker than a comparably priced mini-split.

A Mr Cool Hyper Heat 24,000 BTU 2 Ton Ductless Mini Split Air Conditioner and Heat Pump is under $1,900 and includes A/C.

Is that adequate BTUs for the application ? I don't know. I do know that at the end of 1 year, your electric consumption measured in $$$ will be less than your propane consumption measured in $$$ and you will be cool all summer long.