Is a 30,000 BTU heater big enough for a two car gar-shop with 10 foot
ceilings? This would be a ventless natural gas heater.
Does anyone have a link for a conversion table for BTU needed per square
I heat a 630 cubic foot, three car garage with 11 foot ceilings with a
24,000 btu kerosene heater and a ceramic heat cube. The garage is pretty
well insulated including foam backed door panels. It also shares a wall
with the house.
On moderated days (around 40 degrees) I can usually let the kero heater run
for an hour or so, turn it off and the cube can keep up.
On really cold Kansas days (0 to teens, both units can keep the temp around
50- 60 depending on wind.
Depends on a few variables! How well insulated, quality of the doors and
windows, outdoor temps for a start. But, a well insulated garage should heat
fine with 30,000 BTU. I have a 24'x38' garage with 10 foot ceilings that I
heat with 50,000 BTU, insulation is good, but could be better, but the
furnace is plenty large. North Dakota climate.
I would avoid a ventless heater though. Our area they are not even allowed
which means temps down to zero (occasionally, more like teens), ceiling of
the garage is drywall with 12" of insulation blown in, but the walls are
bare brick. Door is relatively well insulated. Garage dimensions are: 18'
X 21' with 9' ceilings (not 10" as in original post). I wouldn't do
ventless with kerosene or propane (do they even make them?) but how about
with natural gas?
IMO, not going to make it. I have that sized heater for my shop (propane) ,
about the size of yours. I get a 30 degree temperature rise, so when it is
zero outside, plan on 30 inside. From the end of December until the end of
February, I do very little in the shop. Add some insulation on the walls
and you will get better performance. If I was buying a heater now, I'd go
for a variable model from 30 to 80,000 Btu. If I was going to spend every
day out there, I'd install a small furnace.
Geez Ed, here I go agreeing with you again! (ABPW!)
To the OP
Those bare brick walls are going to be a killer for heat. Some 2x2 furring
strips, some 1-1/2 styrofoam, plastic, and a few pieces of sheetrock would
When you were talking ventless I was assuming a ventless wall mount heater.
You can buy wall mount vented heaters too, propane or natural gas. I still
caution against a ventless heater.
I think you will need at least 60,000 BTU, maybe more unless you add some
insulation to the walls. Although a 30,000 may buy you some comfort on most
days. A Reznor or Hot Dawg heater is really the way to go.
Hi Greg. What part of N.D. are you in? I see that Menards has the
ventless type heaters in Fargo. I'm surprised they can sell them if
they are not code rated. I think that Harbor Freight has them as well.
Not allowed in the city of Fargo. Out in the sticks you can kill yourself
anyway you want, so they can sell them. Here in the big city we have codes
to prevent you from doing that! Just mention non-wented heaters to the
mechanical imspector and watch him get excited!
Hmmm. I'll have to check the codes here in D.L. I was thinking of
getting one for my shop. One thing I don't like (as mentioned
elsewhere in the thread) is the high condensation you get going from 20
degrees up to 65 or so with the gas heaters. I have a couple of
electric heaters now, but usually blast a small gas heater to preheat
the shop quickly. I run around wiping everything down as it heats up
to fend off the rust. On another aside, I just got an email from the
wife & it looks like we're getting a Menards in D.L. Woohoo! Not a
Rockler or Woodcraft, but pretty big doin's for us.
Condensation is from non-vented heaters, vented heaters do not create
condesation in the shop as it is vented outside. As for Menards, I rarely go
there! The one in Fargo is so damned busy all the time it takes over an hour
to get some sticks if you get them out of the yard. I hit the local yards,
Simonsons, Crane Johnson. Most of the big box stores' prices are not any
better than I can get else where, and get help that actually knows their
product too. I may hit Home depot, Lowes or Menards on a sunday when the
locals are closed.
If D.L. gets a Menards, you will lose the local lumber yards, perhaps a
hardware store too!
This is true, and I generally support the "small guy" over the big box
retail, but there is an attitude at some of the places in town where if
"you don't like it you can go to Fargo". I am also willing to pay more
for service, but do not like being gouged. If the service is not
there, then you may as well go for price. I agree totally with you
however and the places I do frequent that give me service may be hurt.
That to me would not be worth the convenience and slightly lower
prices. I guess I just want to have my cake & eat it too.
Also thanks for the tip on the vented /nonvented condensation problem.
I guess I will look into punching a hole in the wall. Not really a big
deal I suppose
If you are looking for shop heat, consider a Modine Hot Dawg or a Reznor
UDAP heater. I think you can buy the Hot Dawg heater at Mills Fleet Farm for
about $400. Also the venting will add to the cost too. In the end instead of
just a convection wall heater you get a heater hanging from the ceiling, out
of the way, with a fan to help circulate the air.
It depends on how big of shop you are heating as to the size of heater, of
I'm only going to be heating a largeish single car size garage. I'm
not sure right off hand what the measurements are. It is well
insulated, but being a garage, there are areas around the door etc.,
that show some light. I will check into the Hot Dawg and see what size
they recommend. Sounds like I will need a good heater. The wife said
snowing, blowing and 50mph gusts. Not nice...
1-1/2 car garage should heat very well with a 30,000 BTU Hot Dawg. That is
the smallest they make. Weather strip the door well to cut down on the
I assume the overhead door in insulated?
I have a 50,000 BTU residential furnace in my garage. It is a model that can
be laid sideways so I hung it near the ceiling, added a air filter and a bit
of duct to it. My garage is 24 x 38 feet, and it heats it well, t-shirt
weather all year 'round. Plus I also have AC connected to it all to, so in
those hot humid, misquito filled evenings I can close the door to stay bite
and sweat free!
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