New Garage, advice on radiant?

[jlckmj]

HI all,
I have read through most of the radiant heat threads on here, and also contacted several heating contractors about installing radiant heat in my new shop.

THE SHOP:
The shop will be 24X36 (864 sq ft) 10 foot 2x6 walls, scissors trusses with a 12 foot ceiling in the middle. Full insulation in the walls, R40 or so in the ceiling, 2 inch foam under the concrete. I have gotten mixed results and information. I am not sure what way to go.

I have been told by two HVAC guys that a water heater will do the job, One contractor said that the tankless water heater will work best, so far all of the contractors have said that in a small shop the boiler is overkill.

My GOAL:
To heat all winter in SE Wisconsin with radiant heat, I do not want the shop at 70 degrees, I would just like the frost out of the floor, with the room temperature at lets say 50 degrees, possibly using a small electric or gas ceiling mount to bring the temp up after opening a door or to raise it quickly if needed.

OPTION:
I have access to a large water heater that is actually a small boiler mounted to a large 70 gallon tank, it was used in a restaurant for a short time before it closed. Evidently a restaurant needs plenty of hot water to keep up with the dish washing needs. One contractor (a plumber) said that this would be too much for the radiant needs in a shop. Any ideas on this set up for radiant heat?

COST:
This is the most critical, I do not want to spend money needlessly, but I also do not want to install something that will not work properly.

Any help on my set up would be greatly appreciated, again I want to do it right, but not spend more than actually needed.

Thanks, Jim

 

[walrus]

You need to do a heat load calc. How many doors , how many windows, etc. That will tell how big a boiler, heater you need. The 2" foam will keep the frost out with no heat, assuming it has an insulated building over it. If all you ever want is 50 degrees I doubt you need much for a heater but I'd be skeptical of a plain old hot water heater after some of the stuff I've read on here. I used solar to keep mine heated last year, kept it around 50, lowest was 46, used a wood stove to get it up to working temps.

 

[overdriv]

Well you will get as many opinions as you get post here. As said if you want concrete direction then have a knowledgeable, in radiant, HVAC man do a heat load analysis, or what ever they call it and then go by what he says.

With that said, I heat a 30X36X14 addition on to my existing 24X30 garage. That's 60' long and 24' wide then opens to 36' wide at 30'. Only the new part is heated with radiant and it keeps the whole garage at whatever the thermostat is set at, which I have found 60* to be the most comfortable to me. I never have to supplment the heat with anything. I use a 40 gallon NG water heater, on 5 loops, one zone. I am not nearly as well insulated as you.

Good luck and don't over complicate your system.

 

[dave67fd]

Radiant heat is the most efficient but they have a high initial costs. It sounds like the large water heater might and could be overkill and costly.

Northern Tool is a good source for heaters and info as is Greenhouse megastore.

http://www.northerntool.com/shop/tools/category_heaters-stoves-fireplaces
http://www.greenhousemegastore.com/category/heating?gclid=CMeX4PLllqsCFYHc4Aodh05DtA

 

[BadgerBoilerMN]

Your plumber is right. You are describing a commercial water heater, which would probably heat your garage your home and do the same for a couple of neighbors as well.

As suggested, a proper heat load, condensing water heater or boiler if properly sized and installed. Set it and forget it. You will not need fast response time if the garage is properly insulated for the climate and you think to set it up 10 degrees the night before you want to work in the shop.

The cost to operate a condensing appliance on a radiant floor can be as low as half of an atmospheric appliance, which needs outdoor air for combustion.

http://www.badgerboilerservice.com/boilerchoice.html