Garage won’t go past 50 degrees

[busybeemadeit]

It’s about 20 degrees outside. I have the pellet stove running on 5 in my insulated garage. The garage is a 2.5 car garage. I need to be about 70 degrees, however it won’t heat up past 50 degrees. What is going on?

 

[Highbeam]

I heat an insulated shop building with wood. Intermittently heated spaces, especially those with huge thermal mass slabs of concrete, take a long time to heat up. Once there it’s pretty easy to keep it warm if it’s insulated well.

That initial warm up can take forever.

 

[busybeemadeit]

I heat an insulated shop building with wood. Intermittently heated spaces, especially those with huge thermal mass slabs of concrete, take a long time to heat up. Once there it’s pretty easy to keep it warm if it’s insulated well.

That initial warm up can take forever.

the floor is concrete! A long time as in a few days of running constantly? It’s been running for 1.5 days now.

 

[tlc1976]

Did it work before under the same conditions? If so, then the stove and venting likely need a good cleaning. Other than that, yes even in a house it can take a long time if starting from stone cold. Easier to maintain heat.

 

[busybeemadeit]

Did it work before under the same conditions? If so, then the stove and venting likely need a good cleaning. Other than that, yes even in a house it can take a long time if starting from stone cold. Easier to maintain heat.

we just installed it so I can work with epoxy in the cold weather. But it won’t get up to the 70 that I need.
we cleaned it when we installed it. It’s been running for 1.5 days now and the garage is still only 50 degrees.

 

[jackman]

Tell us about your stove, e.g., make, model, and year. Maybe it's not big enough.

 

[busybeemadeit]

Tell us about your stove, e.g., make, model, and year. Maybe it's not big enough.

It’s a countryside multifuel burner, we weren’t given a ton of information on the burner, it was sitting in my father in laws shed and he didn’t know much about it either.

 

[SidecarFlip]

I heat my shop and t5ractor shop with in floor PEX and I start the heat in the fall so the slab is at temp. I keep it at 60 all winter.

 

[johneh]

When I redid my 3 bay shop we poured an 8 in 3200psi concrete floor
For the next 2 years fought with the pellet stove to get that space over 55
Because we had 12 ft. ceilings we laid 4x4 pressure-treated lumber on a gasket
but 4 in of blue styrofoam and covered it with 3/4 G1S ply. Now the shop is
warm and the stove is on low. No longer trying to heat that huge thermal mass

 

[Highbeam]

the floor is concrete! A long time as in a few days of running constantly? It’s been running for 1.5 days now.

What was the start temp? Is it “really” insulated like 2” foam under the slab, r19 walls, r50 ceiling? Overhead doors insulated and reasonably well sealed on edge? How many SF? Looks full of other thermal mass too.

It takes me all day to go from 50-70 burning about 150# of wood. When it’s 40 outside. Then takes 3-6 days to cool back down. Mine insulated as above, 1800sf, 15’ ceiling.

How many pellets have you burned in 1.5 days?

I just clear coated my slab last fall! Pex lines in the floor haven’t been used yet.

 

[gfreek]

I'd get a torpedo heater in there and get the temp up. Then you "may" be able to maintain the temp

 

[Highbeam]

This might be a summer time project. You don’t want to screw up that very expensive epoxy because the slab got below 70. The slab, especially if not insulated, will be colder than the room.

I’m not sure if the fumes are flammable so if you have to shut off the stove it’s going to get cold faster than you want.

 

[zrock]

Really hope you pulled that all apart and cleaned every thing you could reach in that.. who knows what nested in it... How good are your garage door seals? how good do the doors seal to the floor? Do you have a fan moving air around? heat rises so no heat is getting to the concrete so the concrete is also pulling cold from outside. Does not take a big fan mounted up high pointing downward to move the air and help circulate the heat. I had to do that in my shop as the ceiling was cooking hot and down low was still cold.. I put the fan on a adjustable thermostat and it would kick in after the stove warmed up and started pumping heat. Not sure where i got the control but it was just plug it in and plug fan into that

 

[Lordtimothy200]

It might take a while and that depends greatly on your insulation and how drafty the garage is. If it is a small project, consider walling off part of the garage so you are not heating the whole area.

 

[railfanron]

The other posters are on the right track. My workshop is 40 x 40 with 16 ft walled off so the heated area is 24 x 40 with 10ft walls and a vaulted ceiling. My furnace is 120,000 btus and will heat the shop rather quickly if I turn on my big commercial fan that's blowing upwards towards the ceiling. I can get my shop to 65 from 32 in a few hours but it's well insulated with thermopane windows and an insulated single wide garage door. Also it's pretty air tight. I would think a 50,000btu pellet stove wouldn't handle it. So if you're marginally insulated and no insulated doors or window I would say no chance.

 

[MalcolmH]

That stove look like its been rode hard and put away wet, give the heat exchanger a good scraping & wire brushing while cleaning it out, and you will want a OAK to retain the heat made and not draw in epoxy and acetone fumes to the combustion chamber, and you will want to keep an eye on humidity if your working with clear epoxy so you might aswell heat the shop all winter.

 

[Highbeam]

These infrared point and shoot thermometers are great. Cheap too. Even if you got the air to 70, the slab will not be 70. The coating temperature will match the slab temperature, not the air temperature, so if it needs 70 to cure then you need a very warm shop.

 

[SidecarFlip]

That stove look like its been rode hard and put away wet,

+10 on that. Rode real hard from the looks of it and probably filthy inside and out.

With as concrete slab floor (with no in slab heat), you'll never get the ambient temp up to anything comfortable because the concrete slab is constantly sucking BTU's from the air and transferring them to the ground under the slab, a constant loosing proposition.

My slab (12" thick) has 6" of pink polystyrene insulation between it and the ground, with a plastic vapor barrier on top of it, then metal matting with PEX standoff's attached to it and PEX lines spaces 12-14", and concrete poured on top.

I start my in floor heat in the fall before the ambient (outside temp) drops to take advantage of the warmer ground temps and allow the slab to come to temperature. That mitigates the heat loss / load during the winter when the ground temperature is cold. I tend o run my PEX system year around anyway (no heat in the summer) to take advantage of ground temperature to keep the hop cool in the summer. Poor man's air conditioning.