How to heat a home garage

The garage at the place I'm renting has a full natural gas furnace mounted up in the ceiling with ducts, etc. and a thermostat on the wall.  It's awesome.  Keeps it from getting too cold in the winter, heats it up fairly quickly when I want to work in there and doesn't add any extra moisture to the air, as the combustion products are all vented outside.  

SVreX said:

Odd...

Canoe without a destination??

i think not a canoe.  yes, first post, but check his profile.   i've never seen a canoe with that level of detail, or that command of the English language.

In reply to NOHOME :

That 12' minimum height requirement is going to make it tough to use in the average attached garage...

This is actually kind of timely for me.  The workshop I share with my brother is 2 10x30 storage units with (most of) the wall removed.  We're in talks with our landlord about moving to a new building that he's putting up right now so we have some opportunities.  Getting natural gas is probably not a reality, but since we're making requests while the place is being built, getting 240V run to the unit will likely be much more cost-effective.  We wouldn't need to keep the place warm all the time, and we've looked at solutions to be able to remotely power on a 240V outlet to, say, start the heater an hour before planning to go out there.  Assuming that we're going to put up some basic Styrofoam insulation panels around the walls and the roof already has some insulation, is one of those 240V heaters going to do anything to take the chill out of the place?  I don't know that we need to get it all the way to 72 degrees, but if we could get it from, say, 30 degrees outside to 55 or 60 degrees inside, I think that would be a workable solution.

In reply to Cooter :

I believe that they have "low intensity" models. The one I have in my shop is like 24' long and sure not that high above the real-estate. You can see it in this picture.

I kow that they make smaller units and most often I see them tucked up against the ceiling along a wall.

I have a garage that faces southeast so the sun beats on it every morning. This helps, but when it wasn't insulated at all (I saw the framing), the Delaware winter (10°F or so) still kept it in the mid-30's. I ended up putting Owens Corning garage door insulation on the doors and regular insulation on the walls, finishing with OSB. It says in the low-mid 40's after that, which is still pretty cold. To make it workable, I have a torpedo heater that I run for 20 minutes and that brings the temp to high 50's. I open up the attic vent and crack open a door by 4" and have never had a problem. I keep a CO alarm in the garage for this very reason.

In reply to wae :

If the place is at least reasonably insulated, it should be plenty possible to heat it with a decent 240v heater.  If the thing is, say, 20 amps at 240 volts, that's 4800 watts or a little over 16,000 BTU / hr.  

Well living on the Gulf Coast of Alabama heating is the least of my problem with A/C being the top priority. However the same principles apply. I found the garage door was like a giant heat sink sometime so hot you could hardly hold your hand on it in summer and cold in the winter. I purchased styrofoam panels with one side coated with a thin shiny plastic from Lowe’s cut them to size and installed. They were thick enough they stay in place without adhesive. That was an immediate improvement for both A/C and heat. The shiny side cleans easily and also provides a more finished look then plain styrofoam.

i also had a local company come in and blow in 18 inches of insulation in the garage ceiling. My garage is attached but had zero insulation even though the garage ceiling is open to the ceiling over the rest house. Another immediate improvement and contributes to lower heating/ac bills for the house.

Finally I installed a 12,000 btu combination heat/ac ( 220 volt)window air conditioner. I cut a hole in a outside wall installed a sleeve and the heat/ac unit is mounted permanently. I rarely use it for heat but it does heat the garage so that it is comfortable to work when temps drop at least for Alabama winters. In the summer it works great for A/C however could not keep up until insulating the garage door and ceiling. I run the unit full time and set temp for low 80’s but turn it down a few hours before I know I will be out there working. 

The thing i don't like with non-vented gas is the moisture that comes with it.  Not a good thing if your around good tools and don't always keep the temp up above the dew point.  Vented is better IMHO.

In reply to NOHOME :

Just so you know, I wasn't trying to be a jerk. I actually would love to use something like this in my garage. I had a counterflow house furnace in my last garage, and loved it, but it would be nice to not take up the floor space that it did. 

An old (or new bought on discount) horizontal furnace in the attic would seem to be the key. One small duct for supply, one small duct for return, gas, PVC sidewall vent, and power and you're set. You can get brand spankin' new 96% efficient ones for less than $800. They're vented so moisture and CO buildup aren't a problem. I have plans to put one in my shop to replace the floor standing 80% efficient updraft furnace I have now, but I'm starting to think about splitting it into two furnaces - one for the garage and one for the workshop / apartment area. I'm not sure on that yet. Doubles the equipment but I could control the areas separately and it would cut down on the ducting involved.

In reply to Cooter :

The setup in my current garage is a horizontal house furnace mounted up in the rafters.  Works like home heat, but it's up away from any low hanging fumes and takes up no floor space.  The ceiling is closed off with a raised box built above the rafters in the middle where the furnace sits.  I'll have to grab a picture at some point.  

I put this in my shop last winter. It's a RV furnace I picked up at LKQ for $25. IIRC it's 30K btu and does a decent job of heating the place. 

I love those ideas. 

But that counterflow was soooo sweet at heating up the floor for me.

In reply to Cooter :

Ah, my setup doesn't really heat the floor itself, but it pushes a large enough volume of hot air around when running that even at floor level it's warm.  The setup is return vents at middle and back of garage on the ceiling, heat vents on the ceiling near middle and front of garage and a vent 2 feet above the floor between the 2 garage doors.  

This is what I have - https://www.amazon.com/gp/product/B00HS8FZAC/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

Works pretty well

I also run a dehumidifier 24/7 year round to cut down on moisture especially in the south where it is humid year round. It is amazing how much it helps with rusting of raw metal projects and keeps tools from rusting.

I insulated my 28' by 28' garage walls and ceiling when I bought my place.  The doors were already insulated.  I use one of those 5600 watt 240v electric heaters, it's the red one on the red tool box with the wood top in this photo.  

Untitled by Petrolburner, on Flickr

I also put two of these vertical tower style fans up in the peak of the roof to push the warm air back down a little.  I'm not sure how effective it is.  

Untitled by Petrolburner, on Flickr

If it's really cold in the morning I turn on the electric heater in the morning before breakfast, as well as my 55,000 BTU jet fuel/kerosene/diesel powered heater.  That smelly monster brings the temp up quick and then the electric heater can keep up just fine for the rest of the day.  If I were doing a weekend long project or something I might just leave the electric heater on overnight to keep the stuff in the garage a little warmer.  

Amazingly in the summer when it's in the mid 90s everyday, that big slab of concrete keeps it comfortable all day if the doors stay closed.  I don't really need the 14,000 BTU air conditioner.  

SVreX said:

Odd...

Canoe without a destination??. Probably just did a search for this topic and cut and pastes this into 

It’s some sort service that is planting that post to boost the ranking of that site it linked to. Part of Google’s page ranking algorithm relies on links to a site from other pages, so people you hire to boost your page ranking come in and post these things.

There are a lot more. Someone should delete the post and ban the user.

In reply to Harvey :

When he made the initial post, there was no link. Not wanting to delete a legit user I waited to see what would come of it. Yep, spammer. Deleted now.

Toyman01 said:

I put this in my shop last winter. It's a RV furnace I picked up at LKQ for $25. IIRC it's 30K btu and does a decent job of heating the place. 

I like this for the price.  The small heater size means it probably runs quite a bit which is nice because there's always hot air coming out and the heater burns clean.  The exhaust pipe looks really long, evidently there's no flow issues?  And the long exhaust pipe gives you even more heat exchanger like surface area.  

In reply to Petrolburner :

There were no flow issues last year. It burns clean. The exhaust at the unit is right at 400*. At the wall it's right at 250*. One of my projects for the fall is to add fins to the exhaust to scavenge more heat from it. I'd like to see a exit temperature under 100*. 

EastCoastMojo said:

In reply to Harvey :

When he made the initial post, there was no link. Not wanting to delete a legit user I waited to see what would come of it. Yep, spammer. Deleted now.

That's fairly clever overall. Throw the post in there without any links and then add it after the fact.

Good call deleting my links to the other threads.   

My solution to the cold garage problem: 

1970's dryer heating element, some wiring (with thermal safety in factory location, plus an extra), some ducting, and a shop fan.  So much airflow, way more than a dryer, that he element case doesn't get hot

just DON'T TOUCH THE EXPOSED 240V WIRING!!! 

Yes, it's a total death trap.  No, you shouldn't build one.  And yes, it works VERY well.

It was around -5f outside at the time of that photo.

Roughly 5400 watt heater, shop fan blows so hard it circulates the air around the whole garage.

2 by 8 wood making a frame  to fit   around a sliding glass door with glass frame. Makings a box and the backdrop is a Black Coroplast sheet. Add a fan and a Radiator style intake exhaust.   Solar fan for the win Face South . Free heat .pipe into shop