Unit Heater Sizing Help

[buckshot1822]

I've read through a lot of prior threads on this subject and they tend to lean towards the smaller end of the btu range vs the calculations that I have seen online.

The general calculations are an estimate for sure, but they come out to me needing around 100k btu. Which is fine if that's actually what I need.

I have a detached 30x50 pole buing with 12' ceilings. It is wrapped in 1/2" foam fanfold and will have r19 fiberglass in the walls and ceiling.

Most likely I will keep the building 45 degrees or so unless I am out there, which case I'd probably try and get it to 60 or 65.

I am in the north central part of PA which zone 6 dips down in to.

Anyone with a similar sized building that can speak to the difference with a say 80k btu unit and a 100k or 125k btu unit. I definitely don't want to oversize and cause it to short cycle etc.

Thanks

 

[The Cobbler]

r-19 is very lite for the ceiling . 100 K seems in the ballpark , I nicely do 400 sqft with a 27K with a lot more insulation in the ceiling

 

[buckshot1822]

r-19 is very lite for the ceiling . 100 K seems in the ballpark , I nicely do 400 sqft with a 27K with a lot more insulation in the ceiling

It would be light for sure and I may end up going with r30 or r38 on the ceiling. Walls and ceiling will also be covered in 7/16 osb

 

[Bert_]

100,000 could heat that with no insulation. Too big.

 

[PoorUB]

With reasonable insulation you could heat it with a 50,000 BTU heater. I would not go over 75,000 BTU Reznor or Modine.

 

[gmcgeo]

I've read through a lot of prior threads on this subject and they tend to lean towards the smaller end of the btu range vs the calculations that I have seen online.

The general calculations are an estimate for sure, but they come out to me needing around 100k btu. Which is fine if that's actually what I need.

I have a detached 30x50 pole buing with 12' ceilings. It is wrapped in 1/2" foam fanfold and will have r19 fiberglass in the walls and ceiling.

Most likely I will keep the building 45 degrees or so unless I am out there, which case I'd probably try and get it to 60 or 65.

I am in the north central part of PA which zone 6 dips down in to.

Anyone with a similar sized building that can speak to the difference with a say 80k btu unit and a 100k or 125k btu unit. I definitely don't want to oversize and cause it to short cycle etc.

Thanks

You need an output of 49,248 BTU. anything over that would be oversized.

 

[yeldogt]

Insulation is the cheapest thing you can do .... pays for a lifetime.

With NG and the correct size heater ... proper air sealing you will find keeping the space warmer will be easy and not expensive