attached garage heating ideas

   / attached garage heating ideas #1  

Jeff H

Gold Member
Joined
May 24, 2009
Messages
264
Location
South Jersey
Tractor
Kubota BX25D
HVAC trained tractor guys please weigh in on my idea.

My attached garage is fully insulated, but not heated. If I leave the door to the house open on the weekends it will get comfortable in the garage. But dust, dirt, fumes of course make this not an ideal solution. Not to mention the rabbit that got into the house from the garage with the door open! :laughing:

So to me this proves there is enough heat in the house to share with the garage, just have to share the heat without commingling the air.

On a day like today it's 20 something outside, and 40 something in the garage with no heater.

First idea
So I thought I could run maybe 6" or 8" well sealed metal duct in a loop from the garage. Run it in a large loop through the basement rafters and return it to the garage. If I ran the length of the house and back it would be over 100', and put a fan one end to move the air through. All that surface area of duct could grab some heat from the basement, while keeping the air separate. And in the summer it could give the added benefit of some cool air.

Second idea
A radiator/heat exchanger/coil or whatever you call it in the garage, looped to another one in the basement, fan , and a pump, again to share the heat without commingling the air.

Yes I have examined many of the other options, electric, natural gas,solar, etc. But right now I want to focus on this idea.

So has anyone tried anything like this? I am looking forward to constructive criticism.
 
   / attached garage heating ideas #2  
HVAC trained tractor guys please weigh in on my idea.

My attached garage is fully insulated, but not heated. If I leave the door to the house open on the weekends it will get comfortable in the garage. But dust, dirt, fumes of course make this not an ideal solution. Not to mention the rabbit that got into the house from the garage with the door open! :laughing:

So to me this proves there is enough heat in the house to share with the garage, just have to share the heat without commingling the air.

On a day like today it's 20 something outside, and 40 something in the garage with no heater.

First idea
So I thought I could run maybe 6" or 8" well sealed metal duct in a loop from the garage. Run it in a large loop through the basement rafters and return it to the garage. If I ran the length of the house and back it would be over 100', and put a fan one end to move the air through. All that surface area of duct could grab some heat from the basement, while keeping the air separate. And in the summer it could give the added benefit of some cool air.

Second idea
A radiator/heat exchanger/coil or whatever you call it in the garage, looped to another one in the basement, fan , and a pump, again to share the heat without commingling the air.

Yes I have examined many of the other options, electric, natural gas,solar, etc. But right now I want to focus on this idea.

So has anyone tried anything like this? I am looking forward to constructive criticism.

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Rabbits prefer cooler temps. so 40 something is just fine. In summer turn him outdoors where he can cool with ducting under the slab floor. At 98 F he only needs rump contact but at 104 F full body contact is desirable.:laughing: I had to have a rabbit show me how ignorant I was.

OH, you said constructive. I'm sorry.
 

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   / attached garage heating ideas #3  
I am certain you can make either of your ideas work eventually -- for the first one, air-to-air heat exchangers are well understood industrial technology. You will either have to understand this technology on your own, or hire someone who does (not a residential HVAC guy who does not usually deal with this technology).

For the second one, liquid-air heat exchangers are even more well understood than air-to-air ones, but again you will need to either develop your own understanding or get an industrial engineer. HVAC people will usually have little understanding of the process.

I suspect the DIY air-to-air solutions you propose do not have enough surface area to really heat the garage to a comfortable temperature, and there will be a learning curve with more and more surface area added over time to get this to work adequately. (Think $$.) The two air-to-liquid heat exchangers in idea 2 are probably more workable but you have the issue of very low temperature gradients working against you, and really need an engineering analysis to get a system right the first time. You can do it by trial and error, but it will not be an inexpensive process.

I am not certain you have gone through all the downsides of the plan. Every BTU of energy you transfer into the garage is going to come out of the house and your HVAC system in the house is going to have to make up that energy. You don't say how the house is heated, but you are going to use more of whatever fuel you burn due to the added heat load of the garage.

Plus, you are going to be constantly heating the garage. If this is your intent, that is good. If all you really want is heat in the garage a few evenings and weekends for project use, it will use far less energy to put a dedicated, separate heating system in the garage which you can control independent from the house system.

This alternative has two outstanding advantages.

1. The initial cost will be known ahead of time, and there will be no trial and error engineering to produce a working system, and

2. The energy cost will almost certainly be lower due to the independent control of the garage system, even if the energy source has a higher cost per BTU than the main house system.

Your initial post implies that natural gas is available as a fuel source, and the right gas heater will both use an economical, high efficiency fuel source and will have a relatively low initial cost, backed by sound factory engineering.

* * * * *

I am a Chemical Engineer by training, not an HVAC guy, but I know how to do energy balances and operating cost analysis. I hope you take this in the constructive manner I intend.
 
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   / attached garage heating ideas #4  
I occasionally heat my garage with a kerosene torpedo heater. We have no gas or propane heat here. The house is geothermal. We have a pellet stove in the house for back up heat. I can run the pellet stove with my portable generator. If I would ever go dedicated heat for my garage it would be a pellet stove.
 
   / attached garage heating ideas
  • Thread Starter
#5  
Hi Dave
The house is natural gas, forced hot air.
Yes I realize that the house would have to make up energy transfered to the garage. I hear you on only heating on the weekends I figured turning off the fan and dampers on each end stopping the air flow would take care of shutting it off.

I was just hoping on a low tech , low maintenance, way to share some heat without having a second heater unit to maintain.


Thank you
Jeff
 
   / attached garage heating ideas #6  
I have 2300 square feet on the main level with a full, partly finished basement. My 600 square foot garage is attached at one end, about 4 steps below the main floor. At temps about freezing, my garage stayed about 38 degrees, too cold to work comfortably, and makes you put on a hat and coat to go find tools. My HVAC system is forced air, geo-thermal. I ran a 6" duct from the upstairs main heat duct through the floor space and terminated it on the garage wall with a plastic adjustable diffuser, left wide open, but easily closeable when heat is not needed. There is no return air from the garage. The thermostat is located on the common wall and now about 52 degrees. I then noticed I had a heat register in the basement ceiling that came from the upstairs zone. I re-directed this to the garage the same way and the temp is now another 2 or three degrees higher. I now find I can work out there in a jacket or my coveralls without getting cold. I'm about to add 220 volt power out there and will add any more necessary heat with a 30 amp, 220 volt construction heater which I've used elswhere and expect that it will raise the temp to toasty in less than 10 minutes. I recently received an electricity bill for the last 2 months for $466.00. The neighbour pays over $500.00 every month for all electric on a smaller house. Works well for me.
 
   / attached garage heating ideas #7  
Pellet stoves are sweet if you have ever used one. Not the cheapest heat but for sure a lot cheaper than kerosene. Venting (chimney) is minimal. Just a vent directly out the wall. Pellet stoves are clean burning (no deposits in the flue) and there is virtually no ash to clean out. The heat is as comforting as wood heat with out the hassle of cutting the wood. With only electric here for our geothermal I don't want set up a propane for a garage heater. It would be wood or pellet stove. I did wood as a young pup. Not going back to wood.
 
   / attached garage heating ideas #8  
I posted this recommendation previously but will mention it again. I have a 24x40 pole building with 1/2 inch insulboard on walls, roof and ceiling. I found a salvaged Coleman electric furnace taken from a damaged mobile home. The furnace is approx 2'x2'x5', takes air in from the top, past two standard furnace filters and discharges from the bottom. The only modifcation required was a steel stand for the furnace to sit on. The furnace is thermostat controlled and does a great job. This set up is very simple, requiring only a 220v line, no duct work or venting required. I have been using this unit for many years with no problem. Hope this helps.
 
   / attached garage heating ideas #9  
If you have gas just run a line to the garage, put a forced air modine type gas heater in and call it good. That is what I had in my shop in Anchorage years ago and it worked superbly.
 
   / attached garage heating ideas #10  
Jeff:

I understand your desire for low-tech and clever; but I think Curly Dave is giving you good advice.

I don't know how high your garage ceiling is; but if it's high enough, have you looked into natural gas fired radiant heaters? You get the advantage of relatively compact design, sealed combustion with minimal venting requirements, you're not heating the air that will escape from any open gap in your garage it can find, namely around the garage doors. You're keeping your garage and house systems separate. Other than venting, you won't have ductwork to run.

In any case, I think for a residential application, you'll be $$$$ ahead by sticking with a tried and true method to heat the garage.
 
 
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