Ok here's my dilemma I have a 3 story 30 x 45 garage and the second floor has PEX in the floor radiant heat tube installed but no heat source for the tubing as of yet. I have no natural gas in my area so my options are propane and electric. Below are the specs of the garage: Outside walls are 10" thick cement block with a 6" air gap and then R21 fiberglass insulation. The walls themselves are 1/2" plywood all the way around the building. The inner walls are all R15 fiberglass insulation. The ceiling is 1/2" hard board insulation with R30 blown in insulation above that. The PEX tubing is stapled directly to the floor with a reflective barrier below it with R21 fiberglass insulation below that in the ceiling of the first floor. The ceiling height is only 6' 6" high not the standard 8'. The second floor is set up into 4 separate zones. Zone one is roughly 400 square feet and would need to be heated to normal room temperature. Zone two is roughly 300 square feet and would need to be heated to 77-79 degrees. Zone three is roughly 200 square feet and would need to be heated to 72-75 degrees. Zone 4 is roughly 75 square feet with a 5' 5" ceiling height (yes it's really low) and needs to be heated to 86-89 degrees. I'm located NE PA so winter here can be pretty brutal. The current overnight is about 10 degrees. I also need potable hot water for a bathroom sink, and a wash basin for cleaning things. The potable water will not be used too much. What I need help with is figuring out what type of unit to heat the hot water. I've been told an electric hot water heater in a closed loop system would be best by one local plumber and an electric boiler in the same set up by another. Yet another plumber suggested a propane boiler with an electric on demand hot water system for the potable hot water. I'm so confused and have no clue what to do. Any help would be great. If you need more info please let me know. Thanks Tom

Near what major city in NE PA so we can figure out an outside design temp. Your description seems to jump around a bit and I am not quite understanding your layout. 30X45 is 1350 SQ/FT minus stairwells. Can you describe it from bottom to top? IE: Main floor is garage, wall height, wall insulation, ceiling insulation. First floor, wall height, insulation, zone descrip and temps, ceiling insulation. Second Floor wall height, wall insulation, zone description and temps, ceiling insulation...

price is often the guide for fuel choice as well.
Price per KW in your area?
Price per gallon of propane?
Both appliances have there advantages,
Propane, yes combi boiler gets the domestic H20
Electric boiler, easy no stack, no gas lines, tank, 100% efficiency,
But if your electric rate is sky high, propane starts looking good,
Dan

no natural gas in my area so my options are propane and electric.

Or a heat pump (like Chiltrix) for much lower operating cost. For small amounts of washing, I'd use a small electric tank heater.

I wouldn’t recommend getting advice from plumbers with regard to anything HVAC related. You ultimately need to accomplish a room-by-room heat loss analysis in order to properly design a HR heating system and then properly select/size the heat source. You might find this free software useful for your project:

Borst Heat Loss Analysis Software

Borst Hydronic Radiant Floor Heating Design Software

Borst Integrated Heating System Performance Software

@ ronmar...... I'm right in between Stroudsburg and Easton PA. Those are the 2 closest "cities" to me. The first floor is mostly storage and has a ceiling height of 8' 3". There is a 15' high garage door in the front of the building that is opened twice a week for a very brief time to get deliveries. All the exterior walls have a 6" air gap and then R21 fiberglass insulation. The ceiling has R21 fiberglass insulation with a radiant barrier above that. The first floor does not need to have an external heat source as there are appliances that generate enough heat to keep the first floor at roughly 60 degrees. Second floor has a ceiling height of 6' 6" expect the small room which is only 5' 5". All the exterior walls have a 6" air gap and then R21 fiberglass insulation. The floor has 5/8" pex tubing stapled to the underside. The ceiling has 1/2 hard board insulation with an additional layer of R30 blown in insulation above that. All interior walls have R15 fiberglass insulation in them. All doors are exterior solid core doors. Zone 1 office space 68 degrees approx 400 square feet laid out around the other rooms in a U shape. there is a window in both the right and left hand sides. Below this area is the entrance to the building and the hallway to the right hand side stairwell. Zone 2 hot room 77-79 degrees approx 300 square feet on the left hand side of the second floor. Below is open space for storage. zone 3 warm room 72-75 degrees approx 200 square feet on the right hand side of the second floor. Below is a hallway and open space for storage. zone 4 small room 86-89 degrees approx 75 square feet. This room is in behind the other 2 rooms with an entrance in the far right corner. Below is open storage space. Third floor is unfinished attic type space with an approx ceiling height of just under 7'. There is no insulation in the ceiling and R13 along the outer walls. Will be finished at a later time and will not use the zoned heat from the second floor. The second floor is the only floor that needs heat right now and will have it's own system separate from any other floor. For right now all i'm concerned with is the heating system for the second floor. Hope that helps.

Posted By Blueridgecompany.com on 08 Jan 2017 12:44 AM
price is often the guide for fuel choice as well.
Price per KW in your area?
Price per gallon of propane?
Both appliances have there advantages,
Propane, yes combi boiler gets the domestic H20
Electric boiler, easy no stack, no gas lines, tank, 100% efficiency,
But if your electric rate is sky high, propane starts looking good,
Dan

Checking into better rates for both in the AM as i'm not getting the "business" rate I should be getting.

Posted By jonr on 08 Jan 2017 10:13 AM

no natural gas in my area so my options are propane and electric.

Or a heat pump (like Chiltrix) for much lower operating cost. For small amounts of washing, I'd use a small electric tank heater.

Going to look into a heat pump not really too familiar with them. Thanks

Posted By sailawayrb on 08 Jan 2017 11:41 AM
I wouldn’t recommend getting advice from plumbers with regard to anything HVAC related. You ultimately need to accomplish a room-by-room heat loss analysis in order to properly design a HR heating system and then properly select/size the heat source. You might find this free software useful for your project:

Borst Heat Loss Analysis Software

Borst Hydronic Radiant Floor Heating Design Software

Borst Integrated Heating System Performance Software

Wish I had this info before all the work was done. The guy who did the work up to this point didn't do any of these calculations at all. I have a lot of reading and figuring to do. Thanks for the info.

The local 99% outside design temp in your area is about +10F (like Allentown's design temp), so you need not design for much cooler than that, even though the Polar Vortex event lows can be well into negative digits. See:

http://articles.extension.org/sites/default/files/7.%20Outdoor_Design_Conditions_508.pdf

At your local costs of electricity & propane, heating/cooling with air source heat pumps (ductless or ducted) will come in cheaper than propane, and would be quite a bit cheaper than electric boilers, but you'd be giving up the cushy barefoot comfort of radiant floors (which may not matter much in a commercial building.) The up-front cost of engineering an adequate solution using hydronic reversible chillers, and the dearth of local support make that a riskier solution.

But it all starts with the load calculations, without which it's all just shooting in the dark.