Looking for thoughts on heating the garage

[anaxagoras]

My garage is roughly 25x30x10. This is for residential use by your average gearhead. I'll be lucky to use it 1 or 2 nights a week, so i'm looking for something that will heat up fast. I'd probably like quick recovery for when i open the garage door as well. From what I understand 45k btu should suffice, but i'm leaning towards 75k btu for fast heating/recovery since it's going to see intermittent use anyways and the price difference seems negligible for a mr heater.


I have 3 options:

1.) Mr Heater 75k btu

2.) Mr heater 45k btu.

3.) I found a 100k btu modine heater on craigslist for $300. it's from 1992, I'm sure I could talk him down on the price, but it seems like over kill, it's an old unit, and I had a problem finding many details of the specific model on google, it seems discontinued. How reliable are these things? Is it worth checking out?

 

[Shocker]

45k BTU Mr. Heater. Best choice for your setup.

 

[regguy1]

My garage is roughly 25x30x10. This is for residential use by your average gearhead. I'll be lucky to use it 1 or 2 nights a week, so i'm looking for something that will heat up fast. I'd probably like quick recovery for when i open the garage door as well. From what I understand 45k btu should suffice, but i'm leaning towards 75k btu for fast heating/recovery since it's going to see intermittent use anyways and the price difference seems negligible for a mr heater.


I have 3 options:

1.) Mr Heater 75k btu

2.) Mr heater 45k btu.

3.) I found a 100k btu modine heater on craigslist for $300. it's from 1992, I'm sure I could talk him down on the price, but it seems like over kill, it's an old unit, and I had a problem finding many details of the specific model on google, it seems discontinued. How reliable are these things? Is it worth checking out?

I just installed a 45K Mr Heater in my 26 X 30 X 9 and it is plenty big enough.
3 1/2" R13 in cieling....nothing as yet in walls. I'm keeping it at 40 deg. when I come in and turn it to 65 it takes less than 20 min. to get to temp.
It's more efficient to have to unit run longer than to oversize it.

 

[anaxagoras]

I see a lot of people say that you should not oversize a heater, but I've yet to really understand why. Could somebody please explain? or just give me a link to some place that does explain why?

 

[regguy1]

I see a lot of people say that you should not oversize a heater, but I've yet to really understand why. Could somebody please explain? or just give me a link to some place that does explain why?

An oversized heater will heat the space faster and come on and off more often, the heating and cooling of the heat exchanger is less efficient than having the unit run longer after the exchanger is heated up. And probably consumes a larger amount of gas during the prosess. Natural gas contains 1,000,000 BTU per 1000 Cu Ft. a 45k BTU heater operate 22.22 hours on 1000
CF of natural Gas. A 75K Btu will operate 13.33 hours. Insulation / Building Integrity / Thermostat setting and outdoor temp. will determine how many hours per month the heater must run. By either calculation an oversized heater will cost more. If you open the overhead doors alot a larger heater will have faster recovery...but you'll pay for it.