Heating 690sqft in Nebraska recommendations

[blizz81]

I'm in Omaha NE and am looking at a new construction build with a ~690sqft insulated (batt in walls, eventually do the ceiling) 3car garage. Considering heating for stuff like homebrew brew days, basic car maintenance in winter, and hopefully eventually a golf sim. Have been looking at threads about natural gas vs. mini-split, trying to determine what might be best as the time is approaching where I'd have the builder either do a gas line or a 220v.

I'm not sure that I'd run heat all the time at something like 40*F and bump up when I want to be out there vs. just turn on when I want to be out there. For something appropriately sized to the garage, does it make sense to do one vs. the other? (aka how long does it take to heat up)

If I did gas I would have it vented, attic space is above garage. Builder is mentioning with the garage insulated it can get quite warm in there - I don't mind the summer heat in my 2-car garage so not sure if it'd be drastically different? Current 2-car is a split level with bedrooms above garage, some insulation in between.

Any ballpark guess as to what I could expect for an install of gas + vent (if gas line is already stubbed in) vs. say a mitsu hyper heat mini-split (if 220V is already present)? I imagine the latter is more expensive but don't have an idea how much. mini-split maybe more maintenance/potential for things to break?

Thanks in advance, this forum has already been helpful.

 

[PWilks]

I’m not sure about costs in your area, but installed, the second option will more than likely end up costing more.

A few things to consider are, with a mini split, you get AC.

Something else to consider is the rise time for mini splits typically can’t compete with natural gas furnaces or electric resistance heaters.

If you find yourself wanting to “set it to 40” and go out and work an hour after you increase the temperature, you might find yourself needing to supplement the system with say an electric forced air resistance heater to adequately heat the room in a reasonable amount of time.

This, of course, is where a gas furnace is a huge plus.

 

[bored350]

Regardless of which you choose, have the builder run both a gas and 220 line to the garage now. The small upfront cost now won't compare with the convenience of having it already done down the road.

Personally, I'd invest in a sub panel with at least a 60 amp feed to the garage. You never know if some 220 tools or an electric car might find their way in some day, regardless if it's for you or the next owner.

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[Kaizen]

Go minisplit. Much more versatile. Probably more then a gas wall heater.

I’d recommend a few 220 outlets anyway. Future proof electric car, electric brew kettle, etc.


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[WisJim]

Insulation in the ceiling or roof is more important than in the walls

 

[Jackfre]

I’d go with a 15kbtu mini-split first. Second would be, for heat only, Rinnai EX-22. The advantage of the mshp is that it will do the cooling, it will dehumidify which in Omaha, as I recall is needed. It will eliminate the need for a gas service in the building. Rebates are likely available from the power company with the mini-split. The upgraded electric for car charging, welding, etc is a good idea. I self installed solar on my shop last year and zeroed out the electric usage at the house/shop. Lay out a potential PV system and look at flashing in the mounting system. I used Ironridge and it is slick.

 

[blizz81]

Regardless of which you choose, have the builder run both a gas and 220 line to the garage now. The small upfront cost now won't compare with the convenience of having it already done down the road.

That's probably the smart option. I have a 220/50A to the garage in the plans now (brew kettle, future-proofing on EV) but a subpanel might be optimal. Gas is just on the other side of the wall for the stove already but probably good to get a rough-in during the build.

If I ponder going gas for heater and heating on-demand maybe once a week but otherwise leaving it cold, would there be moisture concerns operating that way if the heater is vented?

 

[Showkey]

If you don’t want or need AC, I would never ever consider a mini split in Nebraska.
Initial cost, slow to heat, higher maintenance, lower life expectancy.......

NAT Gas vented heater......... lower installed cost, quick heat, very low operating cost, almost no maintenance cost for 10 years.

If the building is fully insulated NAT gas will so economical you will likely heat the building all winter. Obviously any heat system would need a full insulation package including the garage door.

If you want AC the mini split starts to make sense. You’ll be committed to heating full time. Cold winter day the mini split might take a day or two to completely warm the building from ice cold state.

 

[Jackfre]

My mini-split in heat mode blows 130* air. My gas Rinnai DV blows 130* air. The only way the gas will heat faster is if it is grossly oversized. Buy the correct sized unit for the space, either gas or mini, and as you live with that appliance and you come to terms with how it works. If the building isn’t up to temp early enough for you, you set it to come on earlier. You live with it and come to terms with it. Show key, I am not sure where you come up with the short life on mini-splits. I was in a contractors shop a couple weeks ago and he has a manky mini-split on his wall. He said his HVAC supplier gave it to him in the late 80’s to try as they were just getting into them. He installed it and said he had never touched it and it was cooling the space. Mine are 13 yrs old and moving along just fine.

 

[Showkey]

The OP is in Nebraska on zero degree day he’s not going to see 130* outlet temperature.

Mini splits have gotten cheaper in the last few years with drop in quality and longevity........often stated on this forum and other forums......with a post my 3 year mini split crapped out and no service guy wants to touch it.

Not all together that much different than pushing tankless water heater when the tank heater runs at $8.00/month with no moving parts, no maintenance for 10 years or more.

My theory is if NAT gas is available........use it nothing is cheaper to buy* or operate.
*Yes, base board electric is cheap to buy but not practical or economical in every way.

OP can buy a 30k btu ceiling mounted heater for $300. Install variable by location. New build $500 extra ?

Menards 50k Mr. Heater® Big Maxx 50,000 BTU Dual-Fuel Forced Air Garage Heater is $355 (30k are out of stock).


There no question Mini split will heat and cool.......there just other choices like chocolate and vanilla ice cream.

 

[wanderer]

The Modine hotdog heater is what I have installed in my garage in Northeast Kansas and you’ll be more than happy with it. I use it exactly like you do, keep it set on about 45° all the time and when I go out there I kick up the temperature.

A few things worth noting:

1) if you’re trying to heat the whole space it cycles a lot. I have the 60,000 BTU model and I wish I had gone with a smaller one so it would cycle less. I find it loud and irritating to hear it cycle all the time. Sometimes by the time it has finished running the fan it’s kicking on again with heat. The issue is if the concrete and everything in the room is still 40°, so even though the air is to temperature cools off very rapidly.

2) don’t set it on 70. Will be too hot in the winter while you’re working. 60° is about perfect.

3) don’t use the thermostat to adjust the temperature like I did. Install the whole thing on a switched electrical outlet. Just turn it on when you go in the room. Most thermostat bottom out at about 50° and some of the mechanical ones don’t have an on off switch.

4) get a thermostat that allows a high degree of temperature variability. 5° temperature swing would be ideal. Most thermostats are like 1°.




I’m recommending the hanging heater instead of a heat pump because you will not get the recovery you’re looking for, especially in the winter. If you don’t want to heat it all the time and you don’t need air-conditioning, don’t even consider a heat pump.

 

[Yankeefarmer]

I’m recommending the hanging heater instead of a heat pump because you will not get the recovery you’re looking for, especially in the winter. If you don’t want to heat it all the time and you don’t need air-conditioning, don’t even consider a heat pump.

Please explain how a 60k BTU hanging heater produces more heat than a 60k BTU heat pump, other than at low outdoor temperatures where the heat pump output is reduced. Also explain why a heat pump cannot be used to only heat a workspace 8 hours per day.

 

[PWilks]

Please explain how a 60k BTU hanging heater produces more heat than a 60k BTU heat pump, other than at low outdoor temperatures where the heat pump output is reduced. Also explain why a heat pump cannot be used to only heat a workspace 8 hours per day.

I think this is a little misleading. People tend to size heat pumps in the ballpark of the load required by the building. Installing a 60k btu heat pump for a building this size doesn’t make much sense.

What makes more sense is installing a 60k btu natural gas furnace, as wanderer claims to have. You get more heat on demand and makes more sense if you only plan to heat a few hours of the day when in the shop. The downside, as he pointed out, was how much it cycles. A smaller unit should have been chosen.

It wouldn’t make sense nor is it cost effective to put an extremely oversized heat pump into a building for the sole purpose of having the desired heat on demand that is easily obtained at a cheaper price point with a gas furnace.

An interesting option would be using a heat pump that is properly sized and using a cheap ceiling mount electric heater for quicker temperature rise times. Won’t have to run a NG line.

 

[Yankeefarmer]

Perhaps I misunderstood Wanderer. I never intended to imply that 60k was the right size heat source for the OP. I still question why people say heat pumps can’t be used for part time heating. A BTU is a BTU, regardless of how it is delivered to the building.

 

[PWilks]

It’s for the reason I mentioned. You definitely are correct and they definitely COULD be used.

It just seems like the majority of people come on this forum saying “I’m going to set it at 40 and turn it up to work in the shop”, and with a properly sized heat pump, this isn’t really feasible.

Much easier to achieve this with a gas or electric resistance heater that’s oversized for the space (much like a furnace in your house)

 

[Yankeefarmer]

.....
It just seems like the majority of people come on this forum saying “I’m going to set it at 40 and turn it up to work in the shop”, and with a properly sized heat pump, this isn’t really feasible.

Much easier to achieve this with a gas or electric resistance heater that’s oversized for the space (much like a furnace in your house)

How is a “properly sized heat pump” different than a properly sized furnace? Or are you just saying that it’s more acceptable to oversize a furnace than a heat pump? I could understand the latter, as the cost of a larger furnace seems to rise more slowly than the cost of a larger heat pump.

Apologies if I sound argumentative, because that’s not my intent. If we are going to discuss heat sources and heating practices, we should be careful to clarify all our assumptions. One of those assumptions might be how quickly the occupant expects the temperature to rIse when they turn the thermostat up. If they expect the space to heat up in 10 or 15 minutes, the heat source needs to be appreciably oversized. But if their daily habits enable them to turn it up an hour or three ahead of time, it’s a different story.

 

[wanderer]

How is a “properly sized heat pump” different than a properly sized furnace? Or are you just saying that it’s more acceptable to oversize a furnace than a heat pump? I could understand the latter, as the cost of a larger furnace seems to rise more slowly than the cost of a larger heat pump.

Apologies if I sound argumentative, because that’s not my intent. If we are going to discuss heat sources and heating practices, we should be careful to clarify all our assumptions. One of those assumptions might be how quickly the occupant expects the temperature to rIse when they turn the thermostat up. If they expect the space to heat up in 10 or 15 minutes, the heat source needs to be appreciably oversized. But if their daily habits enable them to turn it up an hour or three ahead of time, it’s a different story.

60,000 btu is 5 tons of heating or cooling. He’s not going to install a 5 ton unit for that space. My guess is a 2 ton, which he will probably get 24,000 btu of cooling and 20,000 btu of heating from. It’s fine if you want to heat and cool the space all the time, but we both know that turning the air conditioner on when it’s hot means it will take a day to get the house down to temperature. That’s what a properly sized heating and cooling unit would look like.

I’m not suggesting he install a properly sized heating and cooling unit. All of the modine units are the same physical size and the cost is very similar, so most people put in one that is too big. That’s why mine is a 60,000 BTU unit.

That’s why most people just hang a big unit in the corner of the shop. It’s easy to just go out there and turn on thermostat when you start working and five or 10 minutes later and temp the temperature.

 

[blizz81]

3) don’t use the thermostat to adjust the temperature like I did. Install the whole thing on a switched electrical outlet. Just turn it on when you go in the room. Most thermostat bottom out at about 50° and some of the mechanical ones don’t have an on off switch.

4) get a thermostat that allows a high degree of temperature variability. 5° temperature swing would be ideal. Most thermostats are like 1°.

I imagine something like an Inkbird ITC-308 would work? Can be controlled via wifi, set value goes below zero, differential can be set between 1-30*F

 

[wanderer]

I imagine something like an Inkbird ITC-308 would work? Can be controlled via wifi, set value goes below zero, differential can be set between 1-30*F

Never heard of it. One problem I have is that I only ran a two wire thermostat when I wired the garage. No common wire.

 

[PWilks]

How is a “properly sized heat pump” different than a properly sized furnace? Or are you just saying that it’s more acceptable to oversize a furnace than a heat pump? I could understand the latter, as the cost of a larger furnace seems to rise more slowly than the cost of a larger heat pump.

Apologies if I sound argumentative, because that’s not my intent. If we are going to discuss heat sources and heating practices, we should be careful to clarify all our assumptions. One of those assumptions might be how quickly the occupant expects the temperature to rIse when they turn the thermostat up. If they expect the space to heat up in 10 or 15 minutes, the heat source needs to be appreciably oversized. But if their daily habits enable them to turn it up an hour or three ahead of time, it’s a different story.

This is where I was trying to go and for whatever reason couldn’t express it in words.

the initial investment for a larger system in the realm of NG furnaces (especially unit heaters) grows much slower per many thousands of BTUs more than the smaller unit.

As you stated, if temperature rise time is desirable, than a NG option that’s oversized substantially would be the way to go.

The cost (and overall design) of heat pumps aren’t really a cost effective way to reach this desire of rapid heating.

it’s why I personally have a heat pump for sustaining temperatures and flip my electric resistance heater on for quicker more on demand heat. The heat pump is sized such that it can maintain my desired shop temp given my climate, but would take a substantial amount of time to rise from something like 40 to 60 F.

 

[Glemon]

Greetings from Nebraska. I have a three stall which I built 2 years ago, insulated, wired with a 60 amp sub-panel, which is great,although I seldom trip breakers, I did at the under amped old house all the time. No fun running to the basement all the time to trip a breaker.

Anyway, the insulation should help with heat and cold, but as you know we get extreme heat and cold at times in Nebraska, and in those extremes it still gets pretty extreme in the garage too. Most of the winter it is at 40 or so, but when we had the old snap and 20 below last winter it got into the teens or even single digits inside.

I have an oversized resistance heater to heat up my shop (separate from the car parking about 320 sq. ft). I turn it on when I want to work out there and it warms up pretty quickly.

You just have to decide if you want A/C. I grew up working in hot garages in the summer and I get dirty when I work on cars anyway. A little sweat cuts the grease, plus I can always benefit from losing a few pounds. If you don't like the heat, or do more precise work you don't want to drip on A/C mini split probably is the better option. I don't have experience with those.