Hot Dawg size help needed

[Teikas Dad]

I searched all the posts I could find here regarding what size heater to get, but couldn't find what I was looking for.

My new shop is 20 X 20. There are two exterior walls with 2X6 framing, R19 insulation and two interior facing walls that are 2X4 framing that are insulated to R13. The ceiling is 10' high with 5/8 drywall and R30 insulation. Floor is a concrete slab with R5 foam insulation on the outside all the way to the bottom of the wood siding.

I found the link to the Heat Loss Calculator and according to that my shop has a heat loss of 5960 BTUHS. I figured a Design Temperature Difference of 50 degrees. That would take me up to 70 degrees if it's 20 degrees outside. I'm in western Connecticut and we do get some cold weather here. Past couple of mornings were 5 and 6 degrees, but the majority of the time it's in the upper teens to low 30's for most of the winter around here.

Hot Dawg's website has a lot of info, but they list 1 to 1 1/2 car garage, 2 to 2 1/2 car, etc. My shop is not a garage so I'm trying to figure how my size fits into their recommendations. I don't want to go too big on the heater as I have read here that using too large of a unit is just as bad as too small of a unit.

Bottom line, I'm trying to figure out if I need the 30kBTU or 45kBTU unit....or, do I need a 60kBTU unit?

 

[mikeyr]

I dont see where the problem is if you go with the 45k unit, I am in S. Cal. where we don't get your temps and I went with the 60k unit for my 20x24 insulated garage, it worked great for 4 years with no obvious issues from way too big.

I got it big because I planned on moving to my current garage which is much bigger, the 60k unit is sized just right for this garage. I am not sure there are any issues with going to big (within reason) but there sure are some if you go too small.

I vote 45k because where you are its stupid cold, it was freezing here last week in high 40s for me.

 

[foss]

I put in the a 60000 unit with the same l and w, but a 15' ceiling and it works fantastic, as in heating the place the place up fast when I turn the thermostat up( 5 to 10 min to room temp.). I have about the same insulation ( a couple bags of R40).
I'm probably should purchased 45000 unit, but it works great.

 

[rwhite692]

I don't think you can go wrong with 60KBTU....It gets pretty cold where you are!

I would get as long of a tube format to cover as much of the length of your shop as possible. Have you looked at Sunstar? This is 20' long, 50KBTU in my shop (test run prior to insulation and drywall)

 

[ripsnortMN]

I have almost the same size garage. Its a 20x22' with r13 in the walls and r49 in the ceiling. I went with the 45k hotdawg. It heats it nicely. And im in MN where it get stupid cold.

 

[regguy1]

I searched all the posts I could find here regarding what size heater to get, but couldn't find what I was looking for.

My new shop is 20 X 20. There are two exterior walls with 2X6 framing, R19 insulation and two interior facing walls that are 2X4 framing that are insulated to R13. The ceiling is 10' high with 5/8 drywall and R30 insulation. Floor is a concrete slab with R5 foam insulation on the outside all the way to the bottom of the wood siding.

I found the link to the Heat Loss Calculator and according to that my shop has a heat loss of 5960 BTUHS. I figured a Design Temperature Difference of 50 degrees. That would take me up to 70 degrees if it's 20 degrees outside. I'm in western Connecticut and we do get some cold weather here. Past couple of mornings were 5 and 6 degrees, but the majority of the time it's in the upper teens to low 30's for most of the winter around here.

Hot Dawg's website has a lot of info, but they list 1 to 1 1/2 car garage, 2 to 2 1/2 car, etc. My shop is not a garage so I'm trying to figure how my size fits into their recommendations. I don't want to go too big on the heater as I have read here that using too large of a unit is just as bad as too small of a unit.

Bottom line, I'm trying to figure out if I need the 30kBTU or 45kBTU unit....or, do I need a 60kBTU unit?

See my post here:

http://www.garagejournal.com/forum/showthread.php?t=54767

It has a link with info on how to select proper heater size

You have the nice looking dog? I saw it on other post....

Here is our girl:

 

[little jimmy]

I have a 20x28 with simiular insulation and a hotdawg 45k it works very well and I keep the garage set at 45 unless im working in it then it takes only a short time to heat it to 70 l live in South Dakota and yes it is cold here.

 

[Teikas Dad]

If you mean this one? Yep, she's mine....the other woman in my life.

 

[Teikas Dad]

I ran a bunch of the different calculator sites that I found. Mr. Heater's PDF shows 30k BTU, others show 45k BTU....that's where the confusion comes in. I don't mind paying the extra cost for the 45k unit, but I've read bad things on the forum here about oversizing because it makes the unit cycle on/off too much. I've only got one dealer in the area for Hot Dawg and he's recommending a 60k BTU unit which I know is way too big...but he gets to charge me more. Obviously I'm not buying it from him.

 

[regguy1]

I ran a bunch of the different calculator sites that I found. Mr. Heater's PDF shows 30k BTU, others show 45k BTU....that's where the confusion comes in. I don't mind paying the extra cost for the 45k unit, but I've read bad things on the forum here about oversizing because it makes the unit cycle on/off too much. I've only got one dealer in the area for Hot Dawg and he's recommending a 60k BTU unit which I know is way too big...but he gets to charge me more. Obviously I'm not buying it from him.

I bought my Mr. Heater 45K Here:
They also have hot dawgs (link)

http://www.djsonline.com/modineunitheaters.htm

They shipped it quickly. It was 510.00 with shipping and Honeywell 5000
Focus Pro Tstat. I could've got it for slightly less if I'd waited for Northern Tool Sale price... I'd probably go with to 45K your space falls betweem 30-45K

Dog is a beauty....

 

[Iroc-Z]

Dj's is great place. They are local to me. Picked up a new furnace and ac unit for my house at a great price.

 

[FlameOut]

I have a 45000 btu Mr Heater in my 28 x 34 and I have NO PROBLEM getting it up to 70 deg with an outside temp of 10 to 20 deg. I really never need 70 deg though. It's very comfortable working in 60 deg. I drop thew the temp to about 46-48 when not being used. R-13 in the walls and R-19 ceiling (10' high)

 

[Teikas Dad]

Thanks for the input guys. Looks like I'll go with the 45k unit. Regguy1, thanks for the link to DJ's and thanks for the compliments on my girl!

 

[cartunes]

Good info. My space is 12,1840sf so looking at the chart I think a 60k would do. I assume thats output BTUs, correct? Which would be a 75K unit? They list both input & output in the spec sheet.

 

[regguy1]

Good info. My space is 12,1840sf so looking at the chart I think a 60k would do. I assume thats output BTUs, correct? Which would be a 75K unit? They list both input & output in the spec sheet.

Do you mean 12,184 Cubic feet ? if so 75K input should be the one for you.

If your shop 12000+ square feet you'll need a lot larger unit.

My 26 x 30 x 9 is about 7020 Cubic feet and the 45K input unit works just fine.

 

[cartunes]

DOH - meant 12000 cubic feet.
Thanks