I have a fully insulated 24’x32’ (768 sq ft) garage with (2) 9’ doors and a walkthrough. Ceilings are ~9.5’. I’m trying to decide what to do about heat and possibly air conditioning. I live in Tn so outside temps range from the teens to upper 90s during the summer. I have a propane tank sitting behind the garage, so a wall mount propane heater is the easiest option for heat. I’m also considering some type of mini split so I can have air, but they are pretty expensive. The thing is I’m on the fence about air conditioning because I typically just use fans and can get by. What would you guys do in my situation? Garage is used for woodworking and general vehicle maintenance stuff.
What would you do?
- Thread starter JA5544
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BillK
Well-known member
A lot of the decision will be if you want to keep it at a steady temp all year or not. I would say a minisplit would be the way to go if that is the case but if youare going to be turning off the heat and then wanting to heat it up quickly the propane furnace will do a much better job of that.
You sould like you have about the same weather that we do and I know one friend that has a mini split and it works great. But he keeps it on 24/7 - 365 That makes a big difference.
You sould like you have about the same weather that we do and I know one friend that has a mini split and it works great. But he keeps it on 24/7 - 365 That makes a big difference.
ghnl
Well-known member
I installed two mini splits (one for the garage, the other for the bonus room above). I find them very efficient. They are marginal for heat when temps are very low (below 20F-25F) but here in North Carolina such temps are rare & I don't need to heat the garage every day. I don't run the units every day but our electric bill did not increase a noticeable amount.
I did enquire about having an HVAC company install them. Their estimates were ridiculously high considering how easy it was to DIY (and I'd never done one before). I did pay them to evacuate the system and ensure the refrigerant level was correct (they come pre-filled but it is a good idea to evacuate the lines).
Edited to add: our mini split does not have a really low setting temp on its thermostat. I think 60F is the lowest the heat setting will go.
I did enquire about having an HVAC company install them. Their estimates were ridiculously high considering how easy it was to DIY (and I'd never done one before). I did pay them to evacuate the system and ensure the refrigerant level was correct (they come pre-filled but it is a good idea to evacuate the lines).
Edited to add: our mini split does not have a really low setting temp on its thermostat. I think 60F is the lowest the heat setting will go.
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If it were me, I would find a used furnace on craigslist and install it. Usually can get an 80% for around $70-100 here.
Since you're already fully insulated it shouldn't be bad. Not sure of propane costs, but I would guess occasional winter use for natural gas 80% 770sqft would run around 20-50 a month depending on temp.
You can also get a low temp programmable for the garage, or a standard mechanical low temp garage thermostat that will go down to 35.
If you had a window that would fit a small AC unit for summer, it should easily cool a garage as long as you arent working out there all the time.
Mini split would be a cleaner install, plus floor space not taken up by a furnace. Not to mention exhaust ducting.
If you went with a ventless heater, you have to be mindful of fumes/sawdust explosions and is immensely helpful to have a ceiling fan with a ventless heater.
Since you're already fully insulated it shouldn't be bad. Not sure of propane costs, but I would guess occasional winter use for natural gas 80% 770sqft would run around 20-50 a month depending on temp.
You can also get a low temp programmable for the garage, or a standard mechanical low temp garage thermostat that will go down to 35.
If you had a window that would fit a small AC unit for summer, it should easily cool a garage as long as you arent working out there all the time.
Mini split would be a cleaner install, plus floor space not taken up by a furnace. Not to mention exhaust ducting.
If you went with a ventless heater, you have to be mindful of fumes/sawdust explosions and is immensely helpful to have a ceiling fan with a ventless heater.
Raisedonadeere
Well-known member
The hyper heat models are a whole different animal from any heat pumps I have had over the past 45 years. Be sure you do the discovery concerning heating abilities of minisplits. They cost 2 or 3 hundred more per unit but they don’t fade like the non hyper heat models. To start with they put out hot air not slightly warm air. It has only been down to 20deg several times here in KY but no signs of a struggle at those temps. It is a shame how confusing all the marketing makes it for any one to get a handle on what is what with these minisplits. I almost jumped on the diy minisplits but they were all lower seer units so in trying to understand what was up with that I homed in on there being a huge difference in heating performance between them and the hyper heat units especially at colder temps.
I just assumed for some time that hyperheat just meat the unit had some sort of backup resistance heaters included with the unit but learned instead that hyperheat literally means the compressor refrigerant cycle operates on a different principle. Heat output doesn’t fade until below zero, on my units it says rated output to -5. Other brands such as Mitsubishi say to -11 etc. People in Maine are using these things with good success.
I just assumed for some time that hyperheat just meat the unit had some sort of backup resistance heaters included with the unit but learned instead that hyperheat literally means the compressor refrigerant cycle operates on a different principle. Heat output doesn’t fade until below zero, on my units it says rated output to -5. Other brands such as Mitsubishi say to -11 etc. People in Maine are using these things with good success.
matt_i
Well-known member
I lived in TN, I had the cheap TVA power (Duck River EMC) and actually heated my house with pure electric for awhile.
I think you are in the climate where you can do a lot of good with a minisplit. Of course they cool and that's a great benefit in the summer. It might not get you thru the coldest day of the year comfortably but I think it will do alot of good the rest of the winter.
I think you are in the climate where you can do a lot of good with a minisplit. Of course they cool and that's a great benefit in the summer. It might not get you thru the coldest day of the year comfortably but I think it will do alot of good the rest of the winter.
NickTheGreat
Well-known member
I'm a bit further north than you, but I think i'd install a gas furnace. And if I needed to cool, just get a PTAC unit. Or a big "window" unit.
I have a friend with a 24x32 similar to yours and he uses a ventless LP heater mounted on the wall. It serves him well here in Ohio.
As far as A/C goes, got any windows and a low crime rate ? A simple window unit might be the simplest solution until you figure which way you want to go.
As far as A/C goes, got any windows and a low crime rate ? A simple window unit might be the simplest solution until you figure which way you want to go.
I do not have any windows.
Well, that narrows it to a bit. You could always get a window A/C unit, sit it on a HF mover's Dolley and place it under the overhead door. You'll have to fill in the remaining space under the door with wood or something similar.
The dolley will allow you to easily move the A/C unit into place and close the garage up tight when not in use.
6768rogues
Banned
My building is a little over twice as big, and I use two window air conditioners. I am in NY, but it gets in the 90s with high humidity. One is 18K BTU and the other is 12K BTU. The small unit will maintain the building at 70 degrees if I do not open an overhead door. If I open an overhead door, I might need the second unit. If I drive a hot car with a hot engine in, I need the second unit. They are cheap to buy, if one dies the other can keep me alive, and replacements are cheap. They are about 10 years old and no problems, only clean their filters and blow them out with an air hose once in a while.
6768rogues
Banned
Mini split is a great idea. For me, they are too expensive and when something that expensive breaks, I have to spend the money to fix it because I have too much money in it to jettison it and buy another.
SALIV8
Well-known member
I vote mini split with heating.
My comparably inexpensive Gree system (3 indoor units) has been heating the whole apt (1200sq ft) and we've seen steady low temps in the mid teens so far. Snow, ice, wind, no prob yet.
Can't believe I'm not using the h.w. boiler and radiators. Saving money also so far.
My comparably inexpensive Gree system (3 indoor units) has been heating the whole apt (1200sq ft) and we've seen steady low temps in the mid teens so far. Snow, ice, wind, no prob yet.
Can't believe I'm not using the h.w. boiler and radiators. Saving money also so far.
I have an insulated 675 SF garage in NH. I bought an 18k Friedrich AC with internal 12k heater for about $650. It’s about 17”x26” and I mounted it through the wall. I have the heat on the lowest setting, 60F, and it’s working fine in temps that have been as low as 6F. I do have a gas shop heater that I am installing and it will be overkill but will cycle less and recover faster when the doors are opened.
firebirdparts
Well-known member
I live in TN and I put in a heat pump. I don't heat and cool the shop at all unless I'm in it. i use air conditioning a lot more than heat, so in that case the heating is basically without any up front cost, and it's cheap to operate. I think I paid $1500 for a package unit brand new, but I could have scrounged one a lot cheaper if I wanted to.
rburke65
Well-known member
What is “cheap” TVA electricalpower? Cheap does not define anything. Thanks.
Skiff Builder
Well-known member
JA,
I'm running a 30k btu non vented gas heater(for now) in a 32x34x9, R13 walls R30 ceiling , 224sq' of overhead doors. Use only when working in the shop.No problem reaching 70 dead of winter.
I make a lot of dust, but unit easy to clean out with air hose. I'll turn it off if I'm working with any flammable thinners etc.
Units priced at $150.00. Easy setup, runs trouble free/simple.
If needed in a Winter outage, I can disconnect the unit and bring into house and tap into an existing gas stub and have emergency heat in about 15 minutes.
Pic below-unit next to OH door. Get Working and Get Warm and have fun in the shop
SkiffBuilder
I'm running a 30k btu non vented gas heater(for now) in a 32x34x9, R13 walls R30 ceiling , 224sq' of overhead doors. Use only when working in the shop.No problem reaching 70 dead of winter.
I make a lot of dust, but unit easy to clean out with air hose. I'll turn it off if I'm working with any flammable thinners etc.
Units priced at $150.00. Easy setup, runs trouble free/simple.
If needed in a Winter outage, I can disconnect the unit and bring into house and tap into an existing gas stub and have emergency heat in about 15 minutes.
Pic below-unit next to OH door. Get Working and Get Warm and have fun in the shop
SkiffBuilder
