Heating My Garage

[Mountainman42]

Hey there,

I hope you all can help me out a bit on a question I have. Here is the scenario:

- My home is in Bozeman MT so it gets quite cold here in the winters.
- I have a 2 car garage that roughly measures 23x23 with one big garage door and high ceilings.
- The garage is well insulated and finished out.
- My home is headed by a gas / water / boiler / baseboard set up.

My desire is to heat the garage.

- I will not be heating it as a work space, so I only need the temperature to be high enough to keep the cars comfortable and melt off the snow they accumulate from driving around. Let's just say 40 degrees.
- The only thing in the garage is two cars. I am a minimalist

My idea, which I cannot find much about online, is to have my plumber extend the hot water baseboard system into the garage and install a baseboard heater in there. The idea would be that when the heat is running inside (water circulating through baseboards) that some heat will be delivered to the garage as well.

This seams like a good idea as it doesn't require me do deal with gas lines and it seems economical when compared to installing one off garage heaters whether they be forced air or whatever.

My questions are:
- What I am concerned about is whether or not on a going forward basis if this approach is more economical than other one off options. I realize that doing this would be a strain on my boiler, but heating the garage is going to require energy no matter what.

- If I do this, should i try and figure out what it would take to add a separate thermostat for the garage or keep it simple like I stated above and just let the garage benefit from when the house is heating based on it's own thermostat.

- Is this just a horrible idea and is the reason that I can't find anything online in regards to this topic because this approach is simply not as good as one off garage heater units.

Thanks for any thoughts or help any of you may be able to provide!

 

[ambenz]

Attached or detached garage?
I am assuming it is a attached garage as the only feasible heat in a detached gaarge is a dedicated gas line and a separate heater like I have..ventless Procom.
Cost me less than $200 for the heater and about $75 to run the gas line, 40 feet.

If we are talking attached garage, how far a run is it from the nearest hot water supply to the garage?
You could run a line with a auto valved actuator ran off a thermostat and tee into the closest supply/return...maybe needing a booster pump.

Figure a Baseboard heater $100, copper pipe depending on the run $12 for 10 feet, connectors, valve, actuator, stat, flux, soldier, etc...could add up to equal the cost of running a gas line and dedicated ventless furnace for the attached garage too!
Considering the hot water heater could fail, open the garage door to the house, add a box fan, and you have emergency heat to the home too.
Leaving one furnace to depend on isn't the best scenario when living on the cold plains of Montana!
Just my 2 cents....

 

[jvitez]

Your idea is good, and bad!

You definitely need to zone the garage differently than the rest of the house. How much heat the garage will need is completely independent of the needs of the house, eg.: nice sunny winter day, sun streaming through the windows of the house, so no call for heat. Garage: you just opened the door, drove a snow covered cold car in there, and now closed the door. The house thermostat is not calling for heat, and you've got freezing temps in the garage but no heat being delivered because the house isn't calling for heat. What's the point of having a heating system then?

Your choices include adding some type of separate garage heater, or adding a zone to your home's boiler system. Both will work. Which is best depends on several aspects:

1. What is the heat load of your garage? (level of insulation, garage door insulated or not, desired garage temp, coldest winter temps you see, level of air sealing, etc)

2. Heat input size of your home's boiler.

3. Size of your home's electric service panel.

4. Cost of electricity vs NG.

5. Size your home's NG meter.

I live in probably a similar climate to you. We see -30°C regularly in winter. I heated a 22x24' attached garage (R12 walls, R40 ceiling, insulated garage door with very good weather stripping) with a 4800 watt electric heater with good results. That calculates to 9.1 watts/sq ft or 31 btu/sq ft. For arguments sake, let's use this number for your situation.

A separate NG unit heater has a combustion efficiency of about 80%. Let's say your boiler is the same. You'd need 39 btu/sq ft input to heat your garage. Can you boiler handle the added load of 20,600 btu? The only way to know is to do a heat loss calculation for your home and a proper heat loss calculation for your garage, then add the two. If your boiler was properly sized you probably do not have the added capacity to add the load of a Montana garage, but only actual numbers will tell.

Electric heaters are the easiest to install, cheapest to buy, and work just as well as fuel burning heaters, but almost everywhere are more expensive to run than NG. Check your costs. NG will probably be the cheapest to operate for you.

Now if your boiler does have the added capacity, a good option would be to add a fan coil on it's own thermostat to your garage. Your boiler would send hot water to the fan coil, and it would only run the fan and a pump when the garage calls for heat. But, you would need to add anti-freeze to your boiler water, as it could freeze if the garage temp dropped for a long period.

So all in all, adding a garage zone to your home's boiler is doable, but I doubt it would be cost effective. If I were you, I would install a residential garage spec'd radiant tube heater. It will heat objects, ie your snow covered cars, be on it's own zone, not interfere with your home's heating system, and I'd bet be cheaper to install.

Here's one example:

https://www.reverberray.com/?product=ls3-series

 

[Bondo]

- If I do this, should i try and figure out what it would take to add a separate thermostat for the garage or keep it simple like I stated above and just let the garage benefit from when the house is heating based on it's own thermostat.

Ayuh,... Make it, it's own zone,...

If ya rely on another t-stat in another part of the house, it(the t-stat) might not know the pipes in the garage are freezin', 'n about to burst,...

 

[JCByrd24]

Keeping a well insulated attached garage at 40 even in Bozeman will not be that hard. Most residential boilers are oversized to start with, or at least oversized on most days as they're designed for the coldest day. Unless your boiler struggles to heat your house now, adding a zone to your baseboard system should not be a problem. I would guess it would be cheaper to do this then add a dedicated heater. As has been said, you want to give it it's own zone/t-stat, otherwise you won't be able to control it well and you'd be stuck with it reacting with the house with little chance to adjust. This won't cost much more than extending an existing zone. You can either use another circulator and controller or add zone valves to one of your current loops, your plumber can tell you which is easier based on your current equipment. This will also likely be more efficient than a dedicated garage heater as most are only around 80% efficient and chances are your houses system is better than that.

 

[GMBracing]

I have a zone off the furnace run into the attached garage, I keep the thermostat at 50 works real well and has the ability to heat the 26x42 space to 65 in about 30 min

 

[Bricen18]

A


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[Mountainman42]

What an excellent collection of insights and suggestions. Thank you so much.

It looks like the best course is to create a new zone in the garage with my existing boiler system. That makes sense to me.

I think the load would be a bit much, but I am going to have to get a new boiler this coming summer so I will take that time to extend the system into the garage as well as take this into consideration when selecting the size for my new boiler.

Thank you again!!!!!!

 

[jvitez]

Ah, a new boiler. With that bit of information, adding a new zone with a fan coil in your garage does make the most sense.

Please post back when you have the new system installed, whenever that might be. We love pictures!

 

[danho]

I had one of these in my 24x24 garage and now its in my work shed (we moved). Heated fine and has a built in thermostat and blower.

http://www.amazon.com/dp/B004BG81AK/?tag=atomicindus08-20

 

[NUTTSGT]

If your garage is for parking only, I'd say adding the extra zone when you put the new boiler would be the way to go.

If you work in it or have that possibilty in the future, I'd suggest the ventless NG wall heater. This would allow you maintain the temperature in the garage and I believe allow for a faster increase in heat if you are working out there. Like ambenz also mentioned, it gives you a back up heat source too.

 

[James-W]

If you work in it or have that possibility in the future, I'd suggest the vent-less NG wall heater. This would allow you maintain the temperature in the garage and I believe allow for a faster increase in heat if you are working out there. Like ambenz also mentioned, it gives you a back up heat source too.

I would suggest this rather than trying to run a baseboard heater using the house heating system. I think it would be less expensive in the long run and it would give him the option of cranking up the heat should the need arise. Additionally, if he should decide to sell the house and move, having a really nice heater in the garage would be a good selling point for a potential buyer who works on his own cars/trucks, etc.