How many BTU's for my garage

[riggsjr]

Hello,
New here to the site.I am in the process of insulating my 24'x32' garage. It has 9' walls.I have R-19 on the walls and R-30 on the ceiling.Was wondering how many BTU's I should get.I am going to do a vented propane ceiling mounted heater.I am thinking about a 45,00 BTU Hot Dawg but are up for other suggestions also.

 

[mygarageone]

Before it's over your going to get more advice and several different opinions .

But I think you are right on the money. But then again were do you live , that does make a difference

 

[Texas]

This Mr. Heater chart has always been helpful to me (Link below). According to the chart 45K BTU would be more than sufficient to raise the temperature of our space by 45 degress.

https://www.mrheater.com/upload/10-27-08%20MH%202008%20NT%20Heat%20Guide.pdf

 

[mygarageone]

This Mr. Heater chart has always been helpful to me (Link below). According to the chart 45K BTU would be more than sufficient to raise the temperature of our space by 45 degress.

https://www.mrheater.com/upload/10-27-08%20MH%202008%20NT%20Heat%20Guide.pdf

How can you make this statement as a fact ? You don't even know where he lives.
But it may very well do the job , not sure.

 

[rlitman]

How can you make this statement as a fact ? You don't even know where he lives.
But it may very well do the job , not sure.

45 degrees is the same no matter where he lives.

The question you have, is whether or not 45 degrees rise is sufficient, and that depends on where he lives (and his cold tolerance, since in a garage, we're not all expecting the same living temperature as we would in our homes).

 

[riggsjr]

BTW.It would be going in the Northeast of PA.

 

[mygarageone]

45 degrees is the same no matter where he lives.

The question you have, is whether or not 45 degrees rise is sufficient, and that depends on where he lives (and his cold tolerance, since in a garage, we're not all expecting the same living temperature as we would in our homes).

Well I'm not going to get into a peeing match with you but your statement about it being ok no matter were he lives is a non educated statement .
There a Hugh difference from a state like NC and for instance minn .
One place it may be fine at 45,000 btu's and the other may require 55,000 btu's
And we really have no idea what his goals are .
That's the biggest problem with the DIY sites , too much ignorant information being spewed out.

 

[jethrodawg]

BTW.It would be going in the Northeast of PA.

You need follow that link posted above showing how to figure it out. Pretty easy to follow their table.

From the volume of the garage, you need to decide what temp you want your garage to be at. Then look on the table from that link and you'll know what size works for your needs/wants.

The only real variables are what you want for working temp of the space and what you expect the outside temps to be.

 

[mygarageone]

You need follow that link posted above showing how to figure it out. Pretty easy to follow their table.

From the volume of the garage, you need to decide what temp you want your garage to be at. Then look on the table from that link and you'll know what size works for your needs/wants.

The only real variables are what you want for working temp of the space and what you expect the outside temps to be.

You do not do a heat load calculation by building volume ,
That's like shooting a target in the dark , you may hitit and most likely not.

 

[jethrodawg]

You do not do a heat load calculation by building volume ,
That's like shooting a target in the dark , you may hitit and most likely not.

No it's not wrong but instead of trying to compare dicks and tell people they are wrong, why not just offer a solution for OP. You've now posted several times and not offered one bit of help.

 

[Majordisorder]

Do a heat load calculation. Did you insulate under the slab? Sounds high since you are pretty well insulated. Another factor will be if you plan to maintain heat or only bring it up to comfort level occasionally.

 

[Texas]

From what I have read, most peoples garages will remain at or above freezing on it own with no heat as long as there is decent insulation and any doors are somewhat sealed up with weatherstripping. So assuming on a cold day your garage is 32 degrees and a 45,000 BTU heater will raise that temperature by 45 degrees - you are now at 77 degrees. That is wearing a t-shirt kind of warm! Even If your garage was 15 degrees raising it by 45 is still pretty warm, a heck of a lot warmer than 15!
I have a 50,000 BTU natural gas heater in my garage. My garage is a little smaller than yours, my insulation is not as good as yours and my garage door leaks air. I have run the heater when it is in the mid 20's outside (inside garage temperature was mid to low 30's), once I warm the garage up with the heater on high I turn it to LOW and it will keep my garage in the 70's (which was warmer than inside my house that day haha).

 

[riggsjr]

All sounds good just not sure if I want to use propane or electric.Really undecided...

 

[Falcon67]

All sounds good just not sure if I want to use propane or electric.Really undecided...

Figure the cost per therm. Here, if propane goes over $2.50, my electric heater is saving me $.

http://www.erpud.com/comparison.htm

 

[rlitman]

Figure the cost per therm. Here, if propane goes over $2.50, my electric heater is saving me $.

http://www.erpud.com/comparison.htm

Good source.

If you're using unvented propane (I understand you're not), I'd thing strongly about electric. You don't want that moisture or exhaust gases.

With vented propane, you need to consider the heater's efficiency when comparing. Electric will be 100% efficient heat. Vented propane is going to be a little over 80%. So 100 therms of propane only buys you 80 therms of heat (with the rest going out the vent).

 

[riggsjr]

Falcon67...Great source......rlitman I would vent it after researching on this site and others.I am though leaning toward electric more and more.Also and easier installation and no holes in the side of my new garage.

 

[riggsjr]

If I went electric which one would you buy.Again it is a 24x32 garage with a 50amp sub panel?