Yet another size question...

[HoZr]

Sorry if this is redundant but I've been researching for hours to no avail mainly due to all the conflicting info out there.

I'm trying to source a LNG furnace for my shop.

Three different companies gave me three different calcs for our shop and I can't see how they are so far off. All three of course insist they are correct. One came in at 24k, one at 49k and one at 100k.

I ran the numbers and come up around 50ish.

Zone 4 - prefer shop to be 60-65F

50 x 34 shop. Avg 20 foot ceiling (16 eave - 24 peak). R21 walls, R38 Roof. All steel construction. 3 roll ups all double pane and insulated (100 sqft, 100 sqft, 170 sqft). 1 insulated man door no windows. Slab on grade with r15 edge insulation.

I was thinking 50k furnace as 100k is huge - I think maybe they ran the entire house not just the shop? I think the low estimate ran short walls? Either way the terrible customer service from the "pros" makes me want to install it myself.

Help? Thanks!

 

[1MtnGoat]

Install yourself but usually no warranty on equipment. I've run into the same problem.

 

[Showkey]

Install yourself but usually no warranty on equipment. I've run into the same problem.

A ceiling mounted furnace like the Mr. Heater makes no mention of professional installation for warranty. It does mention date of install and proof of purchase for the dealer. The dealer could be BIG box store like Menards or Northern Tool both do retail or mail order.

Installation instructions with warranty documentation

https://hw.menardc.com/main/items/media/MRHEA001/Install_Instruct/6350031_UsersManual.pdf






As far as sizing for the OP 1700 sgft well insulated an 80k makes perfect sense. The seat of the pantS wall charts pretty much agree.
Oregon a 50k might be ok with a relative mild climate, 100k is too big by almost any measure.

 

[klassenl]

For a normally insulates building in a non-extreme environment 100 000 btu works with the math that I have always used 10 watts per square foot - 8 to 10ft ceiling.