2 car garage heater

[Short Track]

standard size 2 car garage. Cold snowy NY. I'm looking at a 43,000 BTU Dayton hydronic unit heater. Is it big enough ?

I will only use it when I want to warm up my garage to work on my cars. Otherwise it'll be off 90% of the time.

So I want fast heat, not a gradual wait time heater.

I can do 2 of them if necessary. I'm bringing 1" pipe up from my boiler. I'm a weekend car guy... so I figure I need 1 or 2 unit heaters for my weekend auto repairs...

 

[mik386]

Will the ambient temperature in the garage get below freezing when the system is off? If so you will have to antifreeze the entire system. Also your piping arrangement will need to be designed so that you do not shock the boiler with the cold return water coming back to the boiler from the unit heaters.

 

[Short Track]

That doesn't answer the BTU question.

Boilers with bypass loops short cycle, and have condensation problems from short cycling. I'd rather see a large temperature swing in a boiler.

 

[CNGsaves]

Way too little information . . .
. . . . . . any insulation what-so-ever ??
. . . . . . size ?? (length / width / height)
. . . . . . size of heat loss items like windows and doors ??

 

[fury9]

^ This, we see the same questions over and over again, SEARCH! It's all there for ya already, probably a hundred threads on this.

 

[ForceFed70]

If your garage is decently insulated - that will be enough BTU.

Never heard of a hydronic unit heater tho. Wouldn't it normally be called a boiler? Or is this something different?

 

[thickhead]

If you have an outdoor wood fired boiler, this sounds like a neat solution.

I agree that if the garage is insulated and about 24x24x10 the one unit should do just fine.

 

[nafterclifen]

43,000 BTU for a 2 car garage? Sounds like overkill if you ask me, especially if the garage is insulated. I have a 7,500W (25,600 BTU) heater in my 2 car garage (20x22) and at the lowest setting, it keeps the garage about 45 in the dead cold of winter (0 degress). I've never timed how long it takes to bring the temperature to 70 but I would guess no more than 30 minutes.

 

[James-W]

If you are talking about hydronic heat as in a boiler and baseboard radiators, then you are NOT going to like it because it will take a long time to heat up the garage. Hydronic heat is wonderful, IF you keep a constant temperature. If you turn it down it takes quite awhile to raise the temperature, especially if you have a garage that is not insulated, or poorly insulated. Also, on really cold days it will take extra long to warm it up to a comfortable level.

If you want quick heat, go with a natural gas, or propane, modine type heater. They provide quick heat and since the price of natural gas is quite low, (not sure about propane costs) and will likely stay that way in the foreseeable future, it will provide you with economical heat for years to come.

 

[theoldwizard1]

What fuel is your boiler using ? Oil ?

If you only are using it a limited amount of time, a good direct vent, propane, wall furnace (Rinnai) will heat fast and not break the bank. Easy to install.

 

[tomroblee]

I'm no HVAC expert, but I am a geezer who has lived with a lot if different heating systems for 68 years.

I can't find much information on Dayton hydronic unit heaters, but assume that the specs would be similar to one made by Modine.

https://m.johnstonesupply.com/storefront/product-view.ep?pID=L96-233

43,000 BTU should heat up the air in an insulated two car garage fairly quickly (by my standards of quick.) If you bring a car packed with slush into an unheated garage, it's not going to be very comfortable laying on your back under the car for a considerably longer period even though the air in the garage is shirt sleeve comfortable.

The BTU output of a hydronic unit heater depends on the temperature and flow rate of the supply. To get 43,000 BTU output you will need about 4.7 GPM of 200 degree water. (you can get 60,00+ BTU output if you are using steam). Lesser flow and/or water temperature will give you lesser BTU output. The unit heater will have 1 1/4" inlet an outlet fittings. (You say that you will be using 1" pipe.) I have no idea of whether the boiler and circulating pumps in your basement can supply 4.7 GPM of 200 degree water to your garage (double that amount if you use two heaters in parallel.)

A gas fired or electric resistance heater will supply some pretty hot air. The specs on the Modine heater say that the unit will put out 97 degree air--if the intake air is 60 degrees and your boiler is supplying an adequate amount of 200 degree water. This will feel more like a heat pump rather than gas fired or electric resistance forced air system. I know that a BTU is a BTU, but I split my time between two homes with heat pumps. Sometimes you feel like you need to open the refrigerator door to get warm.

 

[Kevin54]

^ This, we see the same questions over and over again, SEARCH! It's all there for ya already, probably a hundred threads on this.

Really not a way to treat someone new on here

 

[bzinsky]

How fast you heat it up will likely more depend on your radiator surface area.

Also if you're mostly just heating on demand, are big temperature swings and short cycling really that important? I can see them being important on a heating system that is left at a constant 65-70 degrees all winter long like in a house.

Personally if I was using hydronic for a garage, I'd want high btu and high radiator surface area. Just set the thermostat to have a large temperature swing before it kicks on, its not like your going to notice 3-5 degree swing while your working.