Mr Heater Big Maxx Sizing Sale

[m123]

Mr Heater Big Maxx garage heaters on sale and also an 11% off rebate going on at Menards right now.

So Im going to buy myself a heater at these prices. Heres the dilemma:
I have a 35 wide by 40 deep shop, 10 ft ceiling (1400 sq ft), spray foam walls and cellulose blown ceiling. Pretty good insulation, pretty cold Iowa winters.

The options are 50k BTU rated up to 1250 sq ft
80k BTU up to 2000 sq ft

Im in between (1400 sq ft)

I know bigger is not always better, due to short cycling, etc, but what do you all recommend based on these 2 heaters? Id rather not it run constantly due to noise, etc, but don’t want to undersize it either. Help?

 

[zak77]

I'd go with 80K. I have a 576 sq ft garage with no insulation and the 50k is adequate but with a shop more than twice this size, go bigger.

 

[38Chevy454]

I am kind of in the same boat, but I am between the 80K and 125K heaters. My detached garage is 50x70, so 3500 sq ft. The 80K is for 2500 sq ft insulated, and 125K is for 5000 sq ft insulated. Given that my garage is well insulated also, R-19 walls and R-38 ceiling, plus insulated garage doors, I am going to go with the smaller 80K unit. I figure if it runs longer I may get a little better distribution of the heat, and by cycling less it seems that is inherently better for the longer term reliability. I also do not keep it heated all the time. Yes it may take longer to heat up, but my experience is that I just need to get it to around 60F for working comfortably. Use of some cardboard or old carpet/rug to insulate me from the concrete helps tremendously when on the floor. My garage is for working, so the extra noise is acceptable for me. Efficiency is the same for all BTU sizes (80%).

The 80K also saves me approx $300 in cost vs the 125K unit. The horizontal stainless venting is the expensive part, but that is needed for either size. Since the 80K unit is also more popular size, i figure if I ever need repair parts that it will be potentially less trouble.

I also plan to take advantage of the Menards sale this week!

 

[m123]

I read that wrong, the 50k says up to 1500 insulated, 1250 uninsulated. Based on the recommendations from previous post, maybe I will be too big with a 80k....


Sent from my iPhone using The Garage Journal mobile app

 

[renloy]

I think all those calculations assume regular ceiling height. Shops have way more volume.

 

[biggziff]

You can de-rate a larger unit, you cannot up-rate a smaller unit.

 

[D45]

I have an 80k with my 1,000 square foot area

I originally had a 45k and it ran too long and took too long to heat up the garage

 

[Showkey]

1000 sqft 10’ ceiling well insulated........45k does the job with no issues, cold climate.