Radiant floor heating question
Fiddler110
| Posted in Energy, Heating & Insulation on
I am about to lay 3/4″ solid maple flooring in a dining room and a bedroom. We are thinking of adding a radiant underfloor heating mat. The sub-floor is plywood on joists that are insulated with fiberglass. The easiest approach is the electric mat. That’s probably the most expensive to run also. We don’t want to add another water heater for a hydronic system. What do I need to know?
Replies
Is this for supplementary heat or primary? Where are you located (hint--fill out your profile)? Are the joists accessible from below? New construction or renovation? How do you heat the rest of the house?
This is supplementary heat. We are in the foothills of California, near Yosemite. The joists are accessible but it's tight down there. (Crawl space) This is a renovation of a Victorian house. We have a wood stove in the living room and electric baseboard heaters in the bedrooms on programmable thermostats.
you may want to look at your fuse box i would think you need a 400 amp service
The only heat mats I've installed have been directly under a tile floor. I can't think of a good way to install them with a wood floor. I suppose you could install them under the subfloor, but like Calvin said, you would be heating a thick floor. The response time would be very slow, and I would think the energy cost would add up quickly.
Alternatively, you could install the mat between the subfloor and the finish floor but that poses another set of challenges.
Here's a question: what is it you are trying to achieve with a radiant heated floor? Is your goal warmer floors?
Edited 10/4/2009 9:30 pm ET by Mike_Maines
I was planning on putting the mat down on top of the subfloor, then the maple. I believe you can see where the wires run and choose to nail elsewhere. Never done it before, but I see the ads in FH all the time.
Guess I've missed those ads. Sounds like a recipe for squeaks to me.
How are you planning on laying the maple floor?
A Great Place for Information, Comraderie, and a Sucker Punch.
Remodeling Contractor just outside the Glass City.
http://www.quittintime.com/
It's pre-finished. 2 1/4" wide x 3/4" thick. I will lay down tar paper over the plywood and then nail 'er down with a pneumatic floor nailer. I have already done two bedrooms this way. It's been two years and they still look great. I got the flooring from Springtree Flooring in Los Angeles. Around $3 per square foot. They don't have radiant heating, though.
So you are planning on installing the mat under the subfloor.
What is the verdict on electric mat under that thick of floor?
And what about the penetration of your staples or cleats through that subfloor and working around that with the mat?A Great Place for Information, Comraderie, and a Sucker Punch.
Remodeling Contractor just outside the Glass City.
http://www.quittintime.com/
Some have said that they have expirenced smell with elec/hydronic heat under tarpaper. Certain types of tar paper have been known to out gassing.
Take a sample of the tarpaper you plan on using and cook it in the oven @ approx the temps you will be using.
Or use rosin paper.
I have tarpaper under my oak floor and no smell with the heated floors, but it was a concern!!