Why hydronic? Cheaper? Tank cost?

[thammel]

Hi,

I'm real close to starting my 32 x 28 garage addition. Walls will be 2 x 6 and ceiling height will be 12'. I'm using attic trusses so I'll have a 12' x 32' room in the attic. I'm planning on two 10' x 8' fully insulated doors as well as fully insulating the walls and ceiling (but will insulate around the attic room). I'm planning on 2" foam board under the slab.

I'm thinking of installing pex to be ready for a heated floor. But the tank cost looks really high from Radiantec - $3000 or more. So now I'm comparing all the options. I'm in MD and am also running water to the garage for a toilet and sink so don't want it to freeze. I do have the option of propane already as we use it for the house heat, etc.

The other options are gas furnace (can add AC also) or heat pump. The heat pump is probably the cheapest to install but also the worst for quick heatups from 50-55 which is where I might keep it most of the time to avoid freezing (can you get thermostats that go lower than this?) If I go the pex route, then AC becomes a more expensive option (needed to add ducts,etc.) and heating the attic room also probably is a problem, I guess. How effective is a heated floor in heating the entire area? Why go this way - just because it feels cozy on the feet? If we have an insulated floor and also a heated room via a gas furnace forced air system, then won't the floor attain the air temp roughly?

Any experience along these lines? I've never had an air conditioned garage, but I know how much I sweat in the summer in MD and it might be a really neat thing to have, so I'm starting to think that a gas furnace/AC sounds really good. The other advantage is that it would be really easy to heat the attic room. The total cost might be about the same as a heated floor and adding AC would be easy.

Comments?

By the way, my plan is to go for a 2 post assymetric lift. This is in additon to my 20 x 20 tiny "2 car" house garage/ That will be for one car and the other half will be the "shed" for the tractor and other stuff.

Thanks!
Tom

 

[oldbones]

There's no reason you can't add a zone to your radiant system to heat the upstairs room. I am building a shop much like what you are looking at, I already have the tubing in the slab, but I'm seriously thinking of running another loop between the trusses under the attic room (14x40). Added cost should be minimal. I would have to go back and insulate under the tubing to force that heat up through the floor, but that's no problem.

 

[rlme36]

Seems like everyone is headed in this direction lately. I am working on get approval for a 28x36 as we speak and have done some research on the pex tubing/radiant floor heat option as well. To just put the tubing in the floor isn't a lot of money and if I decide to heat another way, no real loss in my eyes. In CT we only get some really hot days for a month or so then its pretty tolerable so my focus is more on working in the cooler days. The micro boilers appear to be a better option instead of a water tank, but I may have mis-read that point.

 

[thammel]

Yep, that's the way I'm thinking - that it makes sense to put in the pex even if we decide to go with another kind of system. What have you turned up with your research? Where would you buy the pex and what kind and also what about a manifold? The reliantec stuff looks good but is not cheap.

Thanks,
Tom

 

[tdkkart]

Yes, the Polaris water heaters are obscenely expensive.
Come on people, you can only get so much efficiency out of a tank of water with a flame under it. Once all the heat is gone it's gone, you cannot create more heat with efficiency.
Spend the money for a forced draft gas fired heater and you'll probably be very close for less than 1/3 the money. Anything that requires a fan to generate a draft for the exhaust is going to be very close to all you can do efficiency wise.

 

[rlme36]

thammel,

My research keeps pointing me back to seisco or some such micro bolier that takes electricity to work. Unfortunately I don't have NG in my town. I can get LP, but that would be an additional expense for that tank as well and that isn't exactly getting any cheaper on a per pound basis. My other alt is to use an oil burner, but that isn't very appealing as my garage is detached and a good 150 ft from the house. So I would have to add a tank for oil and then some type of furnance. Elec is the cheapest, but when you weigh your options it might just be. Plus I am too cheap with the heat anyways that I'll have it set for 50 at the slab from Oct to Feb/Mar only.

 

[Harv]

3 grand for a water heater?
I know your not talking about a regular water heater, but aren't there any other options? Tankless?
I'm starting to think I'll go with an electric source for my heated floor in my garage.

John

 

[thammel]

I found out a great site for pex supplies - houseneeds.com. Check it out. Now, I have another question. As I state in my original post, I'm planning an attic room. So I should get a 4 loop manifold so I can use 3 for the garage floor and another one for the attic room. But now I'm wondering how to run the pex from the manifold and how to bridge from truss to truss. It'll be easy to run it up to the attic, but how to go from truss to truss without drilling holes in the truss bottom chords, which I really don't want to do. I guess I could always loop it over the top of the trusses at the ends, but would need to be sure that that's not in the cold zone (or at least well insulated). Any suggestions?

Thanks!
Tom

 

[swandog]

I'm looking at this unit for my basement....
thermolec