Radiant floor heat & overhead propane heater?

[bobs409]

Is anyone using both? I'm installing radiant floor heat and will be using a propane water heater for that. I am thinking of keeping that set low all winter to keep it above freezing (maybe 40 or so???) and have an ceiling mounted Big Maxx or similar to heat the garage up quickly when I need to use it.

Good idea or bad? Any thoughts welcome.


Specs:

Garage is 2.5 car, 28X26 with a gable roof that goes about 15' in the highest peak. (only 1 bay will go that high, other side has a loft that will be closed in so only about 7' high in that bay. Fully insulated with R13 in the 2X4 stud walls and R-19 in the 2X8 roof rafters and drywalled.


Thanks,

Bob

 

[G M]

It all depends how often you are going to be out there. Either way I would beef up your attic insulation if possible.

 

[Junkman]

With todays energy costs going up and no sight of them going down, I would consider adding 1" of foil backed Styrofoam to the inside walls and ceilings. Overall, you will loose a little inside space, but the energy cost savings will be dramatic. I would also consider using the building wrap on the outside of the building to minimize the air infiltration. Consider using the ceiling heater that draws outside air for combustion as opposed to those that use the inside air for combustion. All of these suggestions will cost you more in the initial investment, but will save you a lot of money over the years of operation. I have a friend that built a super insulated home about 8 years ago, and everyone laughed at him for spending so much on that one phase of the building project. Today, he laughs at them, since his savings has already more than paid back the investment, and he will continue to save for years to come. Only wish that some of those energy saving concepts were available when I built my home 25+ years ago.

 

[bobs409]

GM: Not sure how often I'll be out there as I never had the luxury of heat in the winter. I like the idea of just heating it up when I need it and keeping the floor and inside temps above 40.

Junkman: I did use the house wrap so that's covered. (no pun intended) I'll give the extra insulation some thought. Drywall is way off so I have time.

Still haven't heard from anyone that runs 2 systems though. I wanted the radiant floor heat because of all the good things I heard but don't want to keep the building heated to 60 degrees all the time. I think with both systems, I can get the best of both worlds.


Thanks for the suggestions.


Bob

 

[G M]

Well you got to look at what it will cost you to install the second heater, and what it will cost to run when you want it on. Compare that cost with what it would take to heat the slab up to 65 or so. You might also consider installing a setup back controller with outdoor reset on your radiant boiler. This will allow you to setback the temperature during the time you don't expect to be in the garage, the control learns the heat curve of your building and calculates at which time to start the boiler so it will be up to temp when you want it. Tekmar makes these controls, if you were to buy them from anywhere other then Ebay you would be spending $1000+, ebay has them from time to time for around $200 brand new. I am no expert but my guess is that once the slab is up to 40 it won't take that much more engery to bring it up to 65.

 

[Vicious_Cycle]

I am doing almost exactly what you describe, Bob (except for the propane part).

I have hydronic radiant in the floor fired by a natural gas burning tankless water heater. That works great, and I usually keep it set around 45, since that's as low as my thermostat goes. I mounted my thermostat right above my manifolds, which is the warmest part of the garage, so I'm cheating a little on that 45 number... it's probably more like 40 away from that area, which is how I want it.

A friend of mine came up with a FREE overhead heater for me, (gas, forced air). I have not installed it yet, but my intention is to fire-up the overhead heater when I'm only spending a couple hours or less out there and I just want to knock the chill out of the air.

Since the overhead isn't installed yet I can't tell you anything from experience, but I believe it's an excellent combination. You have the low operating cost of the radiant and the quick response time of the forced air heater overhead.

 

[bg71361]

I run two, again a different twist. I have the floor heated by tankless propane, I keep it low (cause it was going to break the bank) and when I up there I take the chill off with a Kerosene forced air heater. I think it works great, just my opinion.
Bill

 

[bobs409]

Thank guys. It sounds good in theory anyway.

First will be the radiant floor heat so I'll experiment with that for a while to see how it performs/costs to operate.


Bob

 

[PhantomEB]

The radiant heat floor will be quite efficient itself from what I seen of a buds garage. One thing to acknowledge is if you have side retaining walls out of concrete? Bud pointed out something for me to do when I do mine is to insulate the outside of the retaining walls as uninsulated they will **** the heat out of the floor and I could say good bye to the efficiency of the radiant heated floor.

 

[bobs409]

I have 2 inches of foam board 14 inches wide going around the perimeter of the inside of garage now. Slab will float in between that. 24 inches would have been nice but way too hard to dig by hand so I settled for 14.

That would be great if the radiant floor worked out on it's own but at least I have a back up plan if needed.

If I'm lucky, I'll be testing it out this winter!