I was all set for mini split, but…

[PAndaemonium89]

I was ready to buy and install because I was excited about the efficiency of it plus A/C. Then read how it’s better if it’s on all the time, poor rebound heat, etc. I have a 3 car garage where the main double door does go up and down frequently losing heat and I don’t plan keep heating all the time. I have a 7500W heater I installed and underwhelmed. There really isn’t a good forced air option due to size/placement + venting. Radiant tube??? Vs mini split in red box

Mainly looking to stay comfy playing golf.

Walls r18
Ceiling r38
Doors r6
10ft ceilings.

Edit: twin cities MN, 700sqft garage

 

[ericm]

Mini splits are usually sized with the expectation that they will be on all the time. Gas heaters can be larger (more heat output). But if they're too large they short cycle which is not good for them. If you have a 24k btu mini split and a 24k btu gas heater, they will heat the space up at the same rate. The mini split can at least run at a much lower than maximum output instead of cycling on and off. That makes the heat more consistent and the space more comfortable.

Pulling a cold car into the garage probably cools it off more than the cold air that's let in.

 

[PAndaemonium89]

Mini splits are usually sized with the expectation that they will be on all the time. Gas heaters can be larger (more heat output). But if they're too large they short cycle which is not good for them. If you have a 24k btu mini split and a 24k btu gas heater, they will heat the space up at the same rate. The mini split can at least run at a much lower than maximum output instead of cycling on and off. That makes the heat more consistent and the space more comfortable.

Pulling a cold car into the garage probably cools it off more than the cold air that's let in.

I figured as much, at least placement of the mini split as pictured would blow the warm air at me if I want to bump it higher than likely 46* I’d keep it at.

 

[PoorUB]

I figured as much, at least placement of the mini split as pictured would blow the warm air at me if I want to bump it higher than likely 46* I’d keep it at.

You probably will not be buying a mini split and keeping it at 45 degrees. Some will do it, but no many. Most of them bottom out around 60-65 degrees.

How big, square feet is the garage? Three car is vague. I have a 900 sqft two car garage. It is larger than my buddy's three car!

 

[dcg9381]

Then read how it’s better if it’s on all the time, poor rebound heat, etc. I have a 3 car garage where the main double door does go up and down frequently losing heat and I don’t plan keep heating all the time. I have a 7500W heater I installed and underwhelmed. There really isn’t a good

It's just capacity. Nice thing about mini splits is they aren't as sensitive to over-sizing as traditional HVAC.
My shop is heated and cooled one day out of 15, if that. Sized properly for "rebounding" it'll do fine. You can use it with or without your existing heater.

 

[JohnX14]

I'd go with a gas unit heater. I know the mini-splits are super popular here. I'd have no use for AC - my doors are open if I'm working in the heat. I'd rather a fan. The gas unit heater will raise the shop heat in much faster order. I keep my shop at 40 and turn it up when I'm in there. 60 is too warm for a shop (for me) in the winter.

 

[loganb]

Location? Electric costs?

I have a mini split in my 3 car and it stays upper 60's all year round. Wife parks her daily in it so the double door goes up and down with it coming and going. If it's super hot or cold outside I do try and minimize how many times I cycle the door, but I watched my electric bill closely after install for the first several months and no significant change so it just goes now. 18k Mr Cool DIY unit

 

[u3b3rg33k]

You probably will not be buying a mini split and keeping it at 45 degrees. Some will do it, but no many. Most of them bottom out around 60-65 degrees.

How big, square feet is the garage? Three car is vague. I have a 900 sqft two car garage. It is larger than my buddy's three car!

many minisplits have a freeze protection mode. Mr Cool units have a button that flips the display to say "FP" and it holds 45-46F without fail.
in "heat" mode the bottom is 62F.

it only takes 5-8kWh/day to keep my insulated garage at 45F in single digit weather. much cheaper than my 6kW industrial heater set at 45F (closer to 30kWh/day).
I can keep it 65F in there for 30kWh/day in near zero weather. pulls about 700W to run when it's not single digits, creeps up closer to 1kW as the temp falls off.

if I want it warm fast, I can hit turbo and it'll ramp up to 3kW+ for a while. assuming it's got a COP of 3ish, you're talking about an equivalent 10-12kW heater.

 

[u3b3rg33k]

I was ready to buy and install because I was excited about the efficiency of it plus A/C. Then read how it’s better if it’s on all the time, poor rebound heat, etc. I have a 3 car garage where the main double door does go up and down frequently losing heat and I don’t plan keep heating all the time. I have a 7500W heater I installed and underwhelmed. There really isn’t a good forced air option due to size/placement + venting. Radiant tube??? Vs mini split in red box

Mainly looking to stay comfy playing golf.

Walls r18
Ceiling r38
Doors r6
10ft ceilings.

I'm happy with my 24k mini. I have an industrial electric heater that puts out 6kW, with a fan that throws to the floor (the big difference vs the cheapo that it replaced).

with the minisplit, there's NO issues in the low teens with me opening the door, pushing out my project car, and pulling in a daily for maintenance. all the stuff (floor, cars, tools) hold plenty of heat and reheating the air doesn't take long.
R13 walls, R20 ceiling, vaulted ceiling, insulated overhead door, idk what R value.

about 500sqft.

 

[PAndaemonium89]

Location? Electric costs?

I have a mini split in my 3 car and it stays upper 60's all year round. Wife parks her daily in it so the double door goes up and down with it coming and going. If it's super hot or cold outside I do try and minimize how many times I cycle the door, but I watched my electric bill closely after install for the first several months and no significant change so it just goes now. 18k Mr Cool DIY unit

700sqft in MN and pay $0.14/kw

 

[PoorUB]

700sqft in MN and pay $0.14/kw

Natural gas available?

 

[loganb]

700sqft in MN and pay $0.14/kw

Omaha here, slightly larger garage but pretty well insulated and our rate fully loaded with fees etc was 11.5 c/kwh on the last bill so comparable. The mini split just makes a dramatic improvement in comfort, lowers humidity, improved temperature etc. Even when I have to open the doors and shuffle vehicles, kids running in and out etc all the stuff in it is up to temp and the change in temp from the door isn't noticed for long

 

[WildBill]

I don't know anyone with a mini-split that doesn't love it, but I know many people that don't have one that think they are no good.

 

[PAndaemonium89]

Natural gas available?

Yes but don’t have a place to put the unit in “typical” corners that allows for proper venting. Only corner is where my golf sim is in third bay. first world problems

 

[PAndaemonium89]

Omaha here, slightly larger garage but pretty well insulated and our rate fully loaded with fees etc was 11.5 c/kwh on the last bill so comparable. The mini split just makes a dramatic improvement in comfort, lowers humidity, improved temperature etc. Even when I have to open the doors and shuffle vehicles, kids running in and out etc all the stuff in it is up to temp and the change in temp from the door isn't noticed for long

Yea I’m getting the vibe that mini split may be the way to go. I could get a pioneer 24k unit and do 95% of the install myself. Just hire a random hvac guy to vacuum out the lines.

 

[loganb]

Yea I’m getting the vibe that mini split may be the way to go. I could get a pioneer 24k unit and do 95% of the install myself. Just hire a random hvac guy to vacuum out the lines.

I'm not well equipped to say whether the 24k is the right size for your space or not. My garage is well insulated and bordered on 2.5 sides by the attached house and I personally think the 18k is oversized for my space. Not saying the 24k isn't right for you in your climate, but for me the 18k seems overkill. If you've got easy access to the vac pump the Pioneer is viable, I almost bought a gauge set and vac pump to do it myself but ended up going with the Mr. Cool DIY so no vac'ing out is required at all.

Biggest issue I've got with mine and it's not an issue with the mini split as much as just general HVAC is I need more air movement as I get stratification. I'll run my woodworking focused air cleaner to act as a fan and stir things up at times, but I really need a just general air movement fan in there

 

[pbon]

24k mini split might be 12-18k heat.

 

[pembol]

24k mini split might be 12-18k heat.

Not if you choose the right minisplit for the job. A cold climate or 'hyper heat' should produce close to it's rated output down to 0F or lower. For example my Gree 24k is above 24k down to 5f and above 20k down to -15f.

 

[PoorUB]

Not if you choose the right minisplit for the job. A cold climate or 'hyper heat' should produce close to it's rated output down to 0F or lower. For example my Gree 24k is above 24k down to 5f and above 20k down to -15f.

What does it do at -30F? This is Minnesota after all!

 

[pembol]

What does it do at -30F? This is Minnesota after all!

Luckily the minimum design temp for the Twin Cities is -8F - so no worries there.

 

[American Locomotive]

Being in Minnesota, you'll definitely want quite a beefy unit, probably 30,000+ BTU-ish, if your 7500w heater is underwhelming. 7500 watts is ~26k BTU.

Keep in mind that "rebound heat" isn't really about air temperature, it's about the temperature of the stuff in the space. Air has very little thermal mass. A space will always feel cold, and will not recover fast if everything inside of it is cold. If the "stuff" in the garage stays warmer, opening and closing the garage door won't have as big of an impact on temperature as you'd think.

That's also the crux of the issue with giant oversized gas heaters. They heat the air up fast, but everything inside the space is cold. So as soon as the heater turns off, the space immediately starts feeling cold again.

 

[Skellyii]

Yea I’m getting the vibe that mini split may be the way to go. I could get a pioneer 24k unit and do 95% of the install myself. Just hire a random hvac guy to vacuum out the lines.

I have a Pioneer 24K unit, 980 Sqft 3 car garage well insulated including the doors. Not quite as cold here as in MN. I did the install myself since I already had the vacuum pump.

While not as easy as a Mr Cool, Pioneer does support user installs, they have posted how-to videos and have a kit to purge the lines so that you don't need a vacuum pump.

Because of where I live and my insulation I have one of the standard units, but they offer hyper heat units as well. I think you can get an add-on to program the thermostat so you can schedule it to warm up your area to a specific temp at specific times.

Gree makes good units as well. I have an HVAC friend that installs those all the time.

 

[u3b3rg33k]

Being in Minnesota, you'll definitely want quite a beefy unit, probably 30,000+ BTU-ish, if your 7500w heater is underwhelming. 7500 watts is ~26k BTU.

Keep in mind that "rebound heat" isn't really about air temperature, it's about the temperature of the stuff in the space. Air has very little thermal mass. A space will always feel cold, and will not recover fast if everything inside of it is cold. If the "stuff" in the garage stays warmer, opening and closing the garage door won't have as big of an impact on temperature as you'd think.

That's also the crux of the issue with giant oversized gas heaters. They heat the air up fast, but everything inside the space is cold. So as soon as the heater turns off, the space immediately starts feeling cold again.

the heater in the picture, if it's like the 5kW version i used to have, has a fan barely adequate to function, nevermind throw heat to the floor.

it's been a while so maybe they're better now, but I doubt it. it looks nearly identical to what I used to have.

 

[daws87]

I'm in Twin Cities area as well, I renovated our attached garage w/ insulated door, new sheetrock w/ R15 in the walls and ~R55 blow in in the attic. Did it all myself as the house already had insulated door.

I installed a Big Maxx 50k and keep temp set at 45 degrees all winter. If we plan on being out there for some time I just crank it up to 65-70 and usually within 20-30 minutes its up to temp. We also have a south facing garage door so the sun hitting the door all day certainly helps.

 

[jkeyser14]

You probably will not be buying a mini split and keeping it at 45 degrees. Some will do it, but no many. Most of them bottom out around 60-65 degrees.

How big, square feet is the garage? Three car is vague. I have a 900 sqft two car garage. It is larger than my buddy's three car!

Daikin and Mitsubishi typically bottom out around 55F.

 

[Jackfre]

Look at a Rinnai EX22 for gas heat. You can locate it on any exterior wall and use the supplied vent Which goes thru the wall behind the heater and requires only a 3” hole. A feature of the built in programmable stat is you can manually set it to adjust for a maintained temp as low as 38*f on up in 2* increments. It will take you two hours to do the install yourself. Quiet and a good companion in the space. If you go mini-split make sure you understand the particular models tech specs.

 

[My Old Tools]

You probably will not be buying a mini split and keeping it at 45 degrees. Some will do it, but no many. Most of them bottom out around 60-65 degrees.

How big, square feet is the garage? Three car is vague. I have a 900 sqft two car garage. It is larger than my buddy's three car!

FP mode on MrCool is 47.

 

[PoorUB]

FP mode on MrCool is 47.

Like I said, some will do it.

 

[tncatadjuster]

 

[WildBill]

Mr.Cool setups let you set it down to 40F using their "comfy temp" setting. I have mine turn on at 40F and off at 45F if I am not going to be in the shop for weeks, but normally just let it stay set at 62 as it makes almost no difference in cost.

 

[u3b3rg33k]

Mr.Cool setups let you set it down to 40F using their "comfy temp" setting. I have mine turn on at 40F and off at 45F if I am not going to be in the shop for weeks, but normally just let it stay set at 62 as it makes almost no difference in cost.

that's a good use for it.
i'm having issues with the app refusing to update the settings, so i just gave up on it and switched back to the remote.
also i seem unable to delete a comfy setting i no longer want.

but i find it useful to set an "auto" like "heat 65, cool 75" vs what the remote auto will do at auto 73. aka heat 72, cool 74.

 

[Steve W.]

Yea I’m getting the vibe that mini split may be the way to go. I could get a pioneer 24k unit and do 95% of the install myself. Just hire a random hvac guy to vacuum out the lines.

If you are already considering a Pioneer unit, be aware that not all of them have to mount to a wall. I installed a 24k flex mount unit in my 720 sq.ft. shop. My son and I mounted the unit, had a pro vacuum it out and charge it. We have been in single digits for the last few days, temp is still doing well. Remote is set for 72°, an external thermometer is consistently showing 70 or 71. It's more of a work area, not a parking area, but the door does go up to get the snowblower out (and back in). Pioneer's documentation says something like "Maintains output to -13°F", but does not say how much output there is. So far, it seems to be adequate.

I have a Pioneer 24K unit, 980 Sqft 3 car garage well insulated including the doors. Not quite as cold here as in MN. I did the install myself since I already had the vacuum pump.

Because of where I live and my insulation I have one of the standard units, but they offer hyper heat units as well. I think you can get an add-on to program the thermostat so you can schedule it to warm up your area to a specific temp at specific times.

My 24k Pioneer (linked above) is in a 720 sq.ft. shop. Decently-insulated. One overhead door, but it's more of a working shop than it is a parking area. However, the door does need to go up to get the snow blower out (and back in).

The lowest setting on the remote is 62°. I have let it stay there for a few days, then bumped it up to 72° to see how long it takes to get there. In 10-15° outside temps, it takes about an hour, which is not bad. Depending on what I am going to do and how long I might be out there, I might not even bump it up. Will have to go through the manual a bit closer to see if there is a Freeze Protect mode.

I got one of the last of the units from last summer, uses 410a refrigerant. The newer units are using 454b. The newer units also brag about "out-of-the-box WiFi compatability", so you should be able to control it remotely, if not actually apply a schedule.

.

 

[Skellyii]

If you are already considering a Pioneer unit, be aware that not all of them have to mount to a wall. I installed a 24k flex mount unit in my 720 sq.ft. shop. My son and I mounted the unit, had a pro vacuum it out and charge it. We have been in single digits for the last few days, temp is still doing well. Remote is set for 72°, an external thermometer is consistently showing 70 or 71. It's more of a work area, not a parking area, but the door does go up to get the snowblower out (and back in). Pioneer's documentation says something like "Maintains output to -13°F", but does not say how much output there is. So far, it seems to be adequate.


.

First time I've seen the Flex Mount. Too bad that they don't have a 36K unit yet, I might have a use for one of those.

 

[Steve W.]

Installed it in late August, so only had a few weeks warm enough to test cooling. So far, heating has been fine. What has really surprised me, though, was that I found if I leave the sliding door to the stairway open, enough heat goes up the stairs to make the upper room somewhat comfortable. Not sure about cooling the upstairs in the same manner. I might be looking to add something upstairs this coming summer, as I might be spending more time up there with a train layout that has been neglected for far too long. Since it is a long, narrow room formed by attic trusses, and has a window at the end walls, there is not enough room for a 'traditional' mini-split, but a flex unit mounted under the window will work just fine.

.

 

[theoldwizard1]

You probably will not be buying a mini split and keeping it at 45 degrees. Some will do it, but no many. Most of them bottom out around 60-65 degrees.

I challenge that statement !

Yes, we are in "buyer beware" territory, but more and more (most?) mini-splits will produce heat, without a resistance strip, at ambient temps below 0F ! Whether it keeps you area at your desired temperature depends on the amount of insulation you have and if the unit is correctly sized for the area !

 

[PoorUB]

I challenge that statement !

Yes, we are in "buyer beware" territory, but more and more (most?) mini-splits will produce heat, without a resistance strip, at ambient temps below 0F ! Whether it keeps you area at your desired temperature depends on the amount of insulation you have and if the unit is correctly sized for the area !

He wants to run the heat at 45F. Not all mini splits will do that, and really, most will not. There is a fair number that will, the buyer just has to do some research.

I hadn't even mentioned heating in extreme cold yet!

 

[u3b3rg33k]

I challenge that statement !

Yes, we are in "buyer beware" territory, but more and more (most?) mini-splits will produce heat, without a resistance strip, at ambient temps below 0F ! Whether it keeps you area at your desired temperature depends on the amount of insulation you have and if the unit is correctly sized for the area !

he means indoor setpoint not outside temp

 

[PAndaemonium89]

He wants to run the heat at 45F. Not all mini splits will do that, and really, most will not. There is a fair number that will, the buyer just has to do some research.

I hadn't even mentioned heating in extreme cold yet!

I feel most I’ve read about have a freeze protection setting at 46deg.

 

[PAndaemonium89]

If you are already considering a Pioneer unit, be aware that not all of them have to mount to a wall. I installed a 24k flex mount unit in my 720 sq.ft. shop. My son and I mounted the unit, had a pro vacuum it out and charge it. We have been in single digits for the last few days, temp is still doing well. Remote is set for 72°, an external thermometer is consistently showing 70 or 71. It's more of a work area, not a parking area, but the door does go up to get the snowblower out (and back in). Pioneer's documentation says something like "Maintains output to -13°F", but does not say how much output there is. So far, it seems to be adequate.


My 24k Pioneer (linked above) is in a 720 sq.ft. shop. Decently-insulated. One overhead door, but it's more of a working shop than it is a parking area. However, the door does need to go up to get the snow blower out (and back in).

The lowest setting on the remote is 62°. I have let it stay there for a few days, then bumped it up to 72° to see how long it takes to get there. In 10-15° outside temps, it takes about an hour, which is not bad. Depending on what I am going to do and how long I might be out there, I might not even bump it up. Will have to go through the manual a bit closer to see if there is a Freeze Protect mode.

I got one of the last of the units from last summer, uses 410a refrigerant. The newer units are using 454b. The newer units also brag about "out-of-the-box WiFi compatability", so you should be able to control it remotely, if not actually apply a schedule.

.

Did you mount yours on the ceiling? How does it look like with line sets exiting? Best option is high on wall like most. Trying to keep lower wall space clear

 

[PoorUB]

I feel most I’ve read about have a freeze protection setting at 46deg.

My point was to just make certain the one you buy does, as not all do, many don't. Some people assume, then they are annoyed when the unit didn't have a feature they wanted.