So I am in final planning stages of improvements on our detached garage. Part of that project is heating, ok, maybe not just part, but a major , #1/#2 on list part.

We are going to have a new 100A service run from the house to the garage to replace the old 30A. I already have a small electric furnace unit and thermostat which was demo'd from a mobile home. Unfortunately there is no ducting or base for it. It has a filter in the housing and looks to be setup to just pull air from around itself and not use any sort of return plenum. This is a 36x24 ft totally open space, no sub rooms or other walls.

That is where I need help, do any of you have a good source for a basic HVAC duct/plenum base for the outgoing air? I see two options for installation.

• Mount the entire unit up in the "attic" and have it either dump straight down, or a basic plenum with a couple ducts to spread air out.
  
  • Problem with this is that the attic area is extremely dirty and unhealthy and I do not think it is safe to pull air from that area.
  • Obviously higher cost to this as it will need plenum and ducting for the heated air.
• Somehow mount it below the ceiling in a totally exposed setup.
  
  • Problem with this is it will eat up limited floor space in a low ceiling structure. Maybe if I could re-orient the tip over safety i could mount it on it's side?
  • Lower cost as probably only need a divertor to direct the air thru the space.

Anyone able to help or point me to someone/place that can without having to hire a full blown HVAC Co? The ones I contacted had zero interest in installing anything they are not or did not sell. I will get some info off the data plate for the furnace tonight if that helps.

I have a gas furnace in my crawlspace that I haven't gotten around to throwing out. It worked when I disconnected it years ago

It's yours if you want it. Gas would be more efficient than electric

I think I recycled all the duct work connected to it but there might be some that you can use.

Thanks for the offer. I am going to stay Elect. this will only be on when I am going out there, and our Electric rates are insanely low.

How is it currently setup? Return or supply at the bottom?

What I would do is build a platform on the wall and mount it as high as possible, maybe even partially into the attic if you can squeak it in between the gable truss and the first standard truss. Then run the top duct (doesn't matter if it's the supply or return) as far down the shop as possible.

In reality though, the time and $$ to build a custom duct system on an older unit that can fry out.. You might be better off self-installing a cheap ductless system.

Currently it is setup with supply out the bottom and it has no actual single return opening, is just pulls from air around it. My original plan was to put it up in the attic with just the bottom supply blowing down into the garage. But based on what I have found up in the attic the last thing I want to do is bring that air down into the main working space.

That is what has me thinking about just mounting it up in a corner and getting some sort of base plenum/diverter and spread out the hot air.

I will see what ductless systems run as well.

It might be worth noting that this is a system that will not be running all the time. My plan is to even install a Thermostat wire to the house to be able to turn the system on from the house only when I plan to go out there. This would just be a simple on/off to interrupt the signal from thermostat telling the furnace to turn on.

Anyone here have experience with the ductless systems? They are a good bit more than I was looking to spend, but the AC might be nice in the summer.

My big concern is that heat pumps do not do well in cold weather, I have one for main house heat and if not for the aux heating elements our house would be very cold when temps are low outside. Having AC would be nice, but primary need is heat. It would be a bit counter productive if it could not heat the garage when I need it the most on cold winter days.

I had a ductless system installed 2 years ago...best move I ever made! I used wood exclusively before that. My largest monthly electric bill increase in the dead of winter was only $40 over any previous bill. My highest bill has never been over $160 a month. And that's running a 220 volt air compressor and other gizmo's.

And yes...the A/C is great!

Larry, most good heat pumps will still work great into the teens outside.

I have a Goldman system and when it hit in the teens a few years ago, it was still able to keep my house 68.

Granted, it’s not a ductless. But the Daykin brand is made by Goldman and just as efficient. Our new offices we are installing a daykin VAV system (which is basically a huuuuuge heat pump).

Been a while, figured I would do a brief update. Been keeping eye out every week or so for options on CL/offerup. Saw a posting lastnight that caught my eye and got me curious if it would work.
Looked into it lastngiht and some this morning then found a deal on a ceiling mounted electric furnace. It is a hair small for the sqft of the garage, but I am not heating full time and only need it to take the edge off. Best part is that it is rated to run on the service I currently have to the garage so I do not have to get the service upgraded yet to get heat out there.
For the $ I could not say no and it gets me moving forward and able to use the garage in winter and start chipping away at the project. Vendor has already sent me tracking number too.

https://www.farmandfleet.com/products/1 ... -mEALw_wcB

It may not be the long term solution, but will get me thru the winter, and upgrading later is always an option.

Late to the party, I see this is an old post but noticed a few references to being worried about drawing air from the attic. Just FYI, that is what air filters are for and there should be a place to install an air filter on the unit you described.

Probably should have updated this.

I sold the mobile home furnace and bought a 5KW ceiling mounted shop electric heater. I ti s definitely taking the edge off and once I have the ceiling sealed up it should be plenty for what I need.