Hello all,

I am looking at building a new home in about 2 years .

I plan on going with an oil fired boiler to circulate hot water through pipes in the basement slab and garage slab as well as to radiators in the bedroom.

I would like to add an unattached workshop around 20-25' away from the garage.

What are my options to heat the workshop? I can and likely will put a small woodstove in there but I would like to keep the heat from dipping too low when I am away or when the fire goes out.

-Can I run a buried line all the way from the house to heat the workshop slab?
-Should I get a small separate boiler to heat the workshop slab only?
-Do I install a propane or oil fired hot air blower (no ng option)


Wondering what the pros think.

Thank you so much

Al

 

You could. Check out the manufacturer websites of outdoor wood boilers. They use INSULATED PEX lines to run from the boiler to the home, you could use the same. If you went this route it absolutely MUST be insulated!

You should probably run propylene glycol anti-freeze in the system even with the insulated lines.

That's another option... but you might have trouble finding a small enough heating boiler for the size of the shop. For something like a 20x20 building I doubt you would need much more than 15K BTUH to heat it. How many square feet are you planning for the shop?

A lot of the answer to this depends on the availability of each in your area and the price. Propane boilers require less maintenance, but (at least around here) it costs more. You get roughly 1.5 times the BTU from a gallon of oil than you get from propane, so consider this when comparing prices.

I'm not sure why you are asking about a 'hot air blower' (aka 'unit heater')? Or are you talking about as an option versus the radiant in slab heat?

If you run radiant tubing in the slab, you absolutely MUST insulate under the slab before it is poured, and MORE importantly, insulate the entire PERIMETER of the slab. If you don't a tremendous amount of heat will be lost from the slab to heat the ground under and around the building. This goes for the basement slab as well. 2" EPS is usually recommended.

Also realize that if you run 'mixed' heat emitters, tubing in slab and radiators/baseboard, that you need TWO TEMPERATURES of water. The radiant slab is usually run at around 120F water and radiators/baseboard at 180F. System needs to be piped appropriately for this.

 

Great info all around thanks so much!

I agree that I would need a well-insulated line and running glycol would be a good move too. How deep do you bury that in the north?

I would be looking at a unit heater instead of heating the slab. I am looking at a size around 20x20'.
That might be the cheapest option in the long run as I dont have to worry about insulating the slab as tightly or problems with buried piping and fuel should last me a while since it would only come on here and there.

 

Here in NJ I would probably want to be down around 3' or so, north of the 49th you might be safer with 4' ... I might even add additional insulation... maybe some strips of EPS before backfilling. maybe...

Even if not going radiant, you might still want to insulate the foundaton perimeter before backfilling. Concrete gets mighty cold on the feet in a short time.

I would probably consider a propane fired unit heater in the shop if it were me/mine.

The Modine HDS is a 'sealed combustion' type that can direct vent and also draws combustion air from outside. I'm sure that the smallest one would do the job for you.

Modine HVAC - Hot Dawg

I have a friend that has one of these in his garage and it does a great job.

 

Heating the slab would be okay if you want to keep it a steady temp but I would think you'd normally keep it quite cool except when you are working out there, in which case you might want to over-radiate it, maybe use an AHU so you can get it up to temp quickly. Good luck.

 

Thanks for the great info guys.

I think that you are right going with a propane unit heater is probably the best option taking into account cost and convenience. Good thing is I could build this after the main house and thus not have to worry about tying into the boiler at time of construction.

NJTrooper, can you recommend a representative model of boiler that has two temps for in-floor and radiator heating?


Thanks again
BZ

 

It's not the boiler itself that does this, but the way that the boiler is installed and the piping configured.

In order to serve the low temperature loads a 'mixing valve' would be used that would control the temperature of the water being sent to the floor tubing.

Are you planning on self-install? or will you be subbing the work out?

 

Im planning on doing as many projects myself as I can to cut down on costs but when it comes to installing a boiler I would certainly leave that to the pros. I'll probably help pull the lines or some other labour type tasks.

 

Heating with propane costs a lot in short order.
We are mid 80 cents per liter right now.

People with 2500 sqft homes (well built) are spending 800 to 1000 per month on propane.

I really think this needs to be considered before just jumping in and going with propane.

I heat my workshop to 55 F all year round using radiant, but I am up there every week end. 55F is a good temp, it's quite comfortable to work in and it is low enough not to cost a fortune to heat.

 

Propane is pretty close in price to oil here in NJ per gallon, but as mentioned previous, oil is about 1.5 times more BTU per gallon, so the price per BTU is cheaper.

Still, for an occasional use, it might be worth considering.

I think he said there would also be a wood stove.......... the unit heater could keep the shop at some nominal temp, say 45-50 and the woody to stoke up the heat when working in the shop.

I would definitely super-insulate... even under and around slab... and might even consider laying in tubing for radiant ----- Justin Case.

 

Yah thats exactly it unit heater just to keep the temp from getting too low as I store my lumber in there and keep my liquids from freezing.

I guess nothing beats doing things right the first time when you have the chance to when it comes in insulating.

TOHeating, what kind of boiler set-up do you have for your shop? Is it tied into the house or a stand alone unit?

You guys have any experience with EK System-2000? Not sure if that is available in Canada?

BZ

 

I use 100% geothermal heat pump energy, feed with a lake loop.

My garage has tubing 6" o/c, and the main building is heated with oversized steel panel rads.

I do have a back up propane, and a back up electric boiler. They don't get used.

I do supplement when I am there with a air tight wood stove.

If I had only propane to use to heat the place I would not heat it at all.
I would just have to wait till the wood stove heated it up.

 

Noice! how many feets you got in the water?

Sorry... not to hijack the thread, but it's interesting!