Garage Heat: Electric vs Mini Split

ckruzer

ckruzer

Infidel
Joined
Jul 2, 2015
Location
asheville nc
My garage is just shy of 800 sqft. Three block walls, one window, standard rez ceiling height. I want to have heat this winter. Ive been using 40lb propane and a forced air heater. Im fine to continue this, but the main reason I want to upgrade is the ability to turn the heat on (say from my phone on the way home from work) (wood/pellet options wont work for me). I can put the mini split on a smart tstat, or i can i have the electric heat pass through a 220v smart relay.

Anywho. Figured you sExperts would have some good input on what the best option would be.
Efficiency of how quick it will heat up
$$$ Monthly costs
Ease of install

Thanks gents
 
Whats the air conditioning situation? Major advantage of mini split is you'd get A/C too.
Overall efficiency and mosthly cost will better with the mini split.
BUT - how cold does it get in you area ad how hot do oyu wnat it to get? B/c the mini split, bein ga heat pump, won't ever get really hot on the really hold days and will take a long time to warm up the space.

The electric heat (I'm assuming you just mean resistance coils) is definite easier and cheaper to install. And it will get HOT and heat the space faster.

what these two boil down to is probably if you're just goin gto do it on weekends and it will be unheated for 80% of the time, then electric is probably the way to go. But if this will be daily and you want AC then mini split may be better in the long run.
 
RatLabGuy said:
Whats the air conditioning situation? Major advantage of mini split is you'd get A/C too.
Overall efficiency and mosthly cost will better with the mini split.
BUT - how cold does it get in you area ad how hot do oyu wnat it to get? B/c the mini split, bein ga heat pump, won't ever get really hot on the really hold days and will take a long time to warm up the space.

The electric heat (I'm assuming you just mean resistance coils) is definite easier and cheaper to install. And it will get HOT and heat the space faster.

what these two boil down to is probably if you're just goin gto do it on weekends and it will be unheated for 80% of the time, then electric is probably the way to go. But if this will be daily and you want AC then mini split may be better in the long run.
Click to expand...

Two walls are underground and one is shaded and one is garage doors. In the summer it truly never gets uncomfortable warm in there and up here in wnc, a simple fan is always fine for the hottest days i keep the doors open.

That is an excellent point with the heat pump. When its 20f outside, and 45f or colder in the garage, thats when i really want it to get to a reasonable 60-65f.

Yeah it would be for weekends and certainly not every weekend

Logically i think youre right, electric would probably be best
 
ckruzer said:
Two walls are underground and one is shaded and one is garage doors. In the summer it truly never gets uncomfortable warm in there and up here in wnc, a simple fan is always fine for the hottest days i keep the doors open.

That is an excellent point with the heat pump. When its 20f outside, and 45f or colder in the garage, thats when i really want it to get to a reasonable 60-65f.

Yeah it would be for weekends and certainly not every weekend

Logically i think youre right, electric would probably be best
Click to expand...
Sounds like 220v electric is the way to go. I think this thread is done before @jeepinmatt even had a chance for a smartass comment
 
You said block walls, so I’ll assume no insulation. I have a 600sqft garage with 2x4 stud walls and fiberglass insulation and a little $150 radiator looking heater from Lowe’s will keep it warm all winter long on even the coldest of days, and only have a minimal effect on the power bill. I’m sure insulation is a big factor in that and it also helps that there’s a finished living space above. But given the cost and ease of installation, might be worth a shot. And easy to return if it doesn’t work out. Combine it with a fan and they actually heat really well.
 
jeepinmatt said:
You said block walls, so I’ll assume no insulation. I have a 600sqft garage with 2x4 stud walls and fiberglass insulation and a little $150 radiator looking heater from Lowe’s will keep it warm all winter long on even the coldest of days, and only have a minimal effect on the power bill. I’m sure insulation is a big factor in that and it also helps that there’s a finished living space above. But given the cost and ease of installation, might be worth a shot. And easy to return if it doesn’t work out. Combine it with a fan and they actually heat really well.
Click to expand...

two side block walls one underground the other shaded by cantilever 2nd story deck, unfinished block no insulation.
back wall is a finished stud wall separating a finished downstairs den
two door bay wall is shaded all but the first few hours of the am
ceiling sheetrock
finished living space above the garage

ive thought of pulling everything out, insulating the walls with alt least some blue board and 2x2 and epoxy coat the floor. would love to do that, but have too many projects floating

based on how many btu's ive needed in the past with the propane forced air heater, I dont think such a radiator would be able to keep up
 
Last edited:
ckruzer said:
two side block walls one underground the other shaded by cantilever 2nd story deck, unfinished block no insulation.
back wall is a finished stud wall separating a finished downstairs den
two door bay wall is shaded all but the first few hours of the am
finished living space above the garage

ive thought of pulling everything out, insulating the walls with alt least some blue board and 2x2 and epoxy coat the floor. would love to do that, but have too many projects floating

based on how many btu's ive needed in the past with the propane forced air heater, I dont think such a radiator would be able to keep up
Click to expand...
During the summer that subterrain wall is giving you some free cool air, but in winter its sucking your heat out too. I agree that some insulation could help a lot.
However unless this heater is fixed in place on the wall or something retrofitting the insulation will be an equal PITA now and later, so the quick fix is just add heat and see how it goes.
Is there at least good insulation in the ceiling?

it sounds like this is a drive-in basement garage. My house in Lewisville was a ranch on a hill and similar scenario. No ceiling insulation and when I cranked up the heat to be warm in there the room upstairs would get hot. Added a bunch of faced batting and it helped a ton.
 
RatLabGuy said:
During the summer that subterrain wall is giving you some free cool air, but in winter its sucking your heat out too. I agree that some insulation could help a lot.
However unless this heater is fixed in place on the wall or something retrofitting the insulation will be an equal PITA now and later, so the quick fix is just add heat and see how it goes.
Is there at least good insulation in the ceiling?

it sounds like this is a drive-in basement garage. My house in Lewisville was a ranch on a hill and similar scenario. No ceiling insulation and when I cranked up the heat to be warm in there the room upstairs would get hot. Added a bunch of faced batting and it helped a ton.
Click to expand...

Thats a solid recall. Yeah the sub floor between them is zero insulation. In winter I wouldnt worry about that heat rise I think because I try and do wood stove heat only and cycle the hvac fan to move heat around

I think the electric heater I would get would suspend from the ceiling
 
ckruzer said:
Thats a solid recall. Yeah the sub floor between them is zero insulation. In winter I wouldnt worry about that heat rise I think because I try and do wood stove heat only and cycle the hvac fan to move heat around

I think the electric heater I would get would suspend from the ceiling
Click to expand...
My point is there is a ton of heat loss into the house. Maybe thats helpful to the house but it hurts your cold shop problem.
Adding batting in the joist spaces is super easy and pretty darn cheap. I'd at least do that. its a Saturday job for a couple of guys and beer.
Inserting obligatory note that as a shop ceiling, a paper facing is a potential fire hazard. Do what you wish with said information.
 
RatLabGuy said:
Adding batting in the joist spaces is super easy and pretty darn cheap. I'd at least do that. its a Saturday job for a couple of guys and beer.
Inserting obligatory note that as a shop ceiling, a paper facing is a potential fire hazard. Do what you wish with said information.
Click to expand...

dude. hows my ass supposed to fit through this to add batting?
Edit: i presume there is miscommunication. Trusses separate bottom floor with upper floor. Garage ceiling has sheetrock.

1725458002143.png
 
Last edited:
Did you ever end up doing anything to add heat?

My 20x24 detached garage is freaking COLD. I just had a 100amp sub panel added to the garage before Christmas so I finally have power in there to do some real work.

This unit keeps popping up on my google searches:
I don't know that I want to hardwire it though.. I mean I could... I'm just lazy
 
orange150 said:
Did you ever end up doing anything to add heat?

My 20x24 detached garage is freaking COLD. I just had a 100amp sub panel added to the garage before Christmas so I finally have power in there to do some real work.

This unit keeps popping up on my google searches:
I don't know that I want to hardwire it though.. I mean I could... I'm just lazy
Click to expand...
IMG_4811.jpeg

I have this 7500 watt from Northern tools. It is definitely enough heat for your space, but my power bill goes up by a hundred or more doll hairs when I use. I have a propane gas pack now and a wood stove that I use mostly.
 
Scott86MJ said:
but my power bill goes up by a hundred or more doll hairs when I use
Click to expand...
Ew.

Scott86MJ said:
I have a propane gas pack now and a wood stove that I use mostly
Click to expand...
My other option was running a propane heater... I haven't really explored which one would work for my space yet. I may have a line on a coal burning stove but I honestly don't know where I would squeeze it in.
 
Scott86MJ said:
It is definitely enough heat for your space, but my power bill goes up by a hundred or more doll hairs when I use.
Click to expand...
orange150 said:
Ew.


My other option was running a propane heater... I haven't really explored which one would work for my space yet. I may have a line on a coal burning stove but I honestly don't know where I would squeeze it in.
Click to expand...
To cross over from the other thread... note if you use a min-split the power usage is about 20% of what that resistance heater is. The efficiency difference is just massive. However its of course more susceptible to outdoor temps and a bigger up front cost... but not dramatically higher cost for a chinese DIY unit, and if you're using it that much it may pay off quickly.

@orange150 I'm guessing your electric and propane costs are in the realm of mine, and I found there wasn't a massive difference in cost for propane over resistance heat. Biggest thing is you can get a shitpile of BTUs at once. Don't forget about the moisture though. What about kerosene heater?
 
orange150 said:
You talking with propane?


What you talkin' 'bout


Haven't thought of kerosene
Click to expand...
- Yes- a lot of propane heaters are 30k BTUs, you can get them as high at 100k. Very difficult to get that kind of heat at once with resistance electric
- When propane burns it creates water. Chemistry! You actually create over a gallon of water for every gallon of LPG burned. If thats your primary heat in a small space for a long period and no ventilation you'll get moisture buildup.
- Keroene has 50% more BTUs per gallon than propane. Not at all sure what the cost per lb is comparably. There is the smell and ventilation question, which depends on your situation.

Sidenote - I wish everything were sold by mass instead of volume.that would make things a lot more clear. I rarely care how much space a thing takes up, I want to know how much is there :D

It all comes down to BTUs. How many do you need to warm up the space, how fast do you want them and what are you willing to pay for it.
 
For what it’s worth, the mini split I put in my shop is barely keeping it 50 degrees the past week. Not sure if it’s just way undersized or something is wrong or the minisplit just sucks for heating. Shop is 34x40with a 16ft average ceiling height, so similar to a 2800sqft ranch with 8ft ceilings. 6” fiberglass in the ceiling and 1.5-2” closed cell spray foam in the walls. Minisplit is supposed to be 36k BTU heating and 10.0 HSPF.
 
jeepinmatt said:
For what it’s worth, the mini split I put in my shop is barely keeping it 50 degrees the past week. Not sure if it’s just way undersized or something is wrong or the minisplit just sucks for heating. Shop is 34x40with a 16ft average ceiling height, so similar to a 2800sqft ranch with 8ft ceilings. 6” fiberglass in the ceiling and 1.5-2” closed cell spray foam in the walls. Minisplit is supposed to be 36k BTU heating and 10.0 HSPF.
Click to expand...
This makes me feel a little better about my $100+ propane per month (Nov-Feb) for my 30x30 shop. I keep it 67. I was thinking about switching to mini splits to save $
 
Scott86MJ said:
This makes me feel a little better about my $100+ propane per month (Nov-Feb) for my 30x30 shop. I keep it 67. I was thinking about switching to mini splits to save $
Click to expand...
It seemed to work better a few weeks ago when it first got cold, so I’m wondering if it has lost refrigerant or something. But it’s been too cold and I’ve not had the motivation to check.
 
jeepinmatt said:
It seemed to work better a few weeks ago when it first got cold, so I’m wondering if it has lost refrigerant or something. But it’s been too cold and I’ve not had the motivation to check.
Click to expand...
Does it have emergency heat? Our mini split for the bonus room has emergency heat for when it gets really cold.
 
jeepinmatt said:
For what it’s worth, the mini split I put in my shop is barely keeping it 50 degrees the past week. Not sure if it’s just way undersized or something is wrong or the minisplit just sucks for heating. Shop is 34x40with a 16ft average ceiling height, so similar to a 2800sqft ranch with 8ft ceilings. 6” fiberglass in the ceiling and 1.5-2” closed cell spray foam in the walls. Minisplit is supposed to be 36k BTU heating and 10.0 HSPF.
Click to expand...
Do you leave it on or just turn on when you go out to the shop?
A heat pump only works on a differential, raising the intaken air by 30 degrees or whatever (depnding on its efficiency, how well that compressor is working etc). So if the indoor air is really cold already its going to struggle, while forced air's output is hot with little regards to what the intaken air is.

Mini splits really are a better solution for cases where you're just mainitaining it. Lots of bad performance at the startup.
 
Scott86MJ said:
Does it have emergency heat? Our mini split for the bonus room has emergency heat for when it gets really cold.
Click to expand...
I don’t know. I thought it did. It has an 8C/46F setting with a dollar sign that comes on when you set it to that mode, but it also doesn’t allow you to change the temperature, it’s just set to 46F.

RatLabGuy said:
Do you leave it on or just turn on when you go out to the shop?
A heat pump only works on a differential, raising the intaken air by 30 degrees or whatever (depnding on its efficiency, how well that compressor is working etc). So if the indoor air is really cold already its going to struggle, while forced air's output is hot with little regards to what the intaken air is.

Mini splits really are a better solution for cases where you're just mainitaining it. Lots of bad performance at the startup.
Click to expand...
On all the time.
 
jeepinmatt said:
For what it’s worth, the mini split I put in my shop is barely keeping it 50 degrees the past week. Not sure if it’s just way undersized or something is wrong or the minisplit just sucks for heating. Shop is 34x40with a 16ft average ceiling height, so similar to a 2800sqft ranch with 8ft ceilings. 6” fiberglass in the ceiling and 1.5-2” closed cell spray foam in the walls. Minisplit is supposed to be 36k BTU heating and 10.0 HSPF.
Click to expand...

Same size shop and my Daiken 3T SS has no problem keeping it 70+ when the OAT is in the twenties. An important component on any heat pump is a low ambient outdoor kit which a lot of people overlook. Most mini SS do not have electric emergency heat. Sizing depends on the climate zone, insulation factor, building envelop, and cu/ft (not sq/ft). Having a tight building envelop and good insulation will drastically reduce the heat/cooling loads.

Instead of turning it off while unoccupied keeping a night setback temperature will (60F) will greatly reduce the load and increase recovery time. I have mine on a weekly schedule to control occupied/unoccupied times each day of the week via a wifi-thermostat. If it's operating properly you should see a delta T of ~25F across the coil (inlet temp vs outlet temp). On cold days I have a 100K propane I run for a few minutes to supplement initial warm up.
 
Back
Top