Too many BTUs? other options?

[Willysgarage]

I picked up a used heater for my detatched garage. 30x50 with 10' ceilings on half and catherdral on the rest. Insulated.
Its a propane fired Reznor rated at 300,000 BTUs. I found a calculator here somewhere that makes that 300K rating seem extremely excessive.The Reznor isn't hooked up yet (propane guy is a bit busy I guess) so I'm wondering if I should go another route. Someone suggested a hot water unit with one of those instant water heaters (electric).
I have a large portable propane heater that works nicely but I'm not crazy about the fumes and such. Garage will be used a few days a week.
Thanks!

 

[Winmon]

Wow, that is BIG!!!! I have a 40' x 40' and am using a 75,000 propane heater and that is even a little over kill. I would say sell it and a get a 60,000 or
75,ooo btu unit....

 

[JohnZ]

My finished/insulated garage is 2500 SF with a 12' ceiling, and a 125,000-BTU Reznor is way too much; could probably get away with 75,000 in mine (misjudged the effectiveness of the total insulation package).

 

[HoosierBuddy]

Heater is way too big. 300,000 BTU's is over 3 gallons per hour on propane. The propane company would definitely put you on their Christmas card list, if you hooked that beast up!

I'd suggest a more "right sized" gas fired unit heater. Maybe something in the 70,000 BTU range. It will be vented. Get something with electronic ignition so you don't have a pilot to mess with and burn up fuel. High efficiency would be better...but may not be worth it if you are only using it occasionally.

Hydronic heat does not work well for occasional heating. It takes a long time to heat up and if you leave it off too long you could freeze up the piping.

Phil

 

[Willysgarage]

Thanks!
I found one of these used for sale locally for a decent price.

Would this be a better choice?

http://brooksco.com/index.php?ACTION=view_item.php&i_id=41639

 

[franksinatra]

Not sure if I should start my own thread or not, I just have a question dealing with the same type of issue. Is there a formula a person should use to decide on the correct size of heater? I purchased a HotDawg 75,000 btu heater on natural gas. I thought the more the marrier so I went with the biggest one my local heating store carried. My garage is 24X24 with 8' ceilings. I was told that it isnt good to have a heater that turns on and off a lot which mine does. Its better to have one that runs a bit longer to keep the garage at the specified temps. Also are smaller units quieter. Any help would be great. Sorry to threadjack. Grant

 

[HoosierBuddy]

Thanks!
I found one of these used for sale locally for a decent price.

Would this be a better choice?

http://brooksco.com/index.php?ACTION=view_item.php&i_id=41639

That Dayton heater looks pretty nice.

As far as the sizing question, do a google search for heat loss calculator. When I was designing mine, I used a couple of different calculators and went with the larger number.

Phil

 

[Winmon]

Would this be a better choice?

Boy, that baby is pricey! Northern Tool has the Big Maxx 75k btu unit on sale for $449 right now.

Here is a guide @ Northern Tool that helps determine what size you need. Go down to "Size Your Heater"... .
http://www.northerntool.com/catalog/buyersguides/heaters/

 

[Willysgarage]

well, I'm looking at half the price of that Big Maxx for this used Dayton