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February 14, 2008
Anyone done radiant heat?
Hi all:
I'm going to be embarking on a gut rehab of a South Slope brick home, and was thinking of doing radiant heat, as the floor is in bad shape and has to be replaced anyway.
Anyone done similar? Happy with the results? How much per sft?
Comments
Did it, so glad we did. It's fabulous -- even, silent, clean heat. The house just feels warm when you come in -- no hot spots, no hissing. Don't know about price psf, as it was part of a big gut renovation, but I know that to put it under wood floors, we had to upgrade to quarter-sawn (a little more expensive) because it shrinks and expands less than regular-cut wood, which is neccessary right over the heat source.
Go for it. You'll be happy you did.
Posted by: guest at February 14, 2008 7:34 AM
Actually quartersawn expands and contracts up and down -- not sideways. That is why it is better for radiant. The grain pattern also looks great.
Posted by: guest at February 14, 2008 9:07 AM
Yup, did it and love it. Actually installed it myself, which is not too difficult. There are quite a few posts on this already if you do a search.
Posted by: Left Hook at February 14, 2008 9:45 AM
I am planning to do the same in my place and would appreciate some advise from those who have done it....
Did you do water or electric? Which brand did you use?
Why did you do hardwood on top instead of tile (slate)? Doesn't tile work as a better conductor of the heat?
Posted by: guest at February 14, 2008 1:34 PM
Radiant heat is far more effective with stone or brick as a flooring. Stone has far more thermal mass than wood.
Posted by: Smokychimp at February 14, 2008 1:41 PM
Sorry for yet another hijack post, but does anyone know whether it's possible to install radiant heat in some (but not all) rooms? We need to reno our kitchen and bathrooms, and I would love to have radiant heat in those rooms.
Posted by: guest at February 14, 2008 2:13 PM
We used hydronic radiant heat with pex tubing. Electric radiant heat is not particularly efficient. We have places in the house where the floor is tile, wood floors in other places, and a concrete slab in the bathroom with tile on top. The concrete slab has the most thermal mass and retains heat the longest. The tile in the kitchen is concrete board with slate on top and this also warms up but not as much as the bathroom. Places where we have wood, the floor is not warm to the touch, but is certainly not cold, but room seems to stay just as warm. I would say you should choose what floor material you want to use and don't worry to much about which will be more efficient. The only one that is significantly more efficient is the concrete slab. You do have to be careful about what type of wood you choose. Quarter cut is better, narrower the plank the better, some species are more stable than others.
2:13, yes you can have radiant heat mixed with other forms of heat. The problem is that the water running through pex tubing for radiant heat should not be hotter than 140 degrees, even less if it is installed in a concrete slab. The water running through your radiators is at least 180 degrees and often much hotter. So you have to have your plumber install a mixing valve that cools the water going to the radiant pex tubing.
Posted by: Left Hook at February 14, 2008 2:50 PM
OP here, thanks to all. BTW I was planning to use engineered wood flooring, which by all accounts seems better than any kind of wood, at least from what we hear so far.
Posted by: denton at February 14, 2008 3:04 PM
We used a product called warmboard with hydronic heat in gut reno which is effective & perhaps easier than some other installations if you are replacing the subfloor anyway. Very happy with the end result (even heat etc) though subfloor heat does introduce complexities to the overall project - pipe in the floor mustn't be damaged by errant screws etc, & plumbing is perhaps more involved than standard system. FYI I believe the question of thermal mass adding efficiency isn't always relevant - it depends on how dynamic the boiler / heat source is (http://www.eere.energy.gov/consumer/your_home/space_heating_cooling/index.cfm/mytopic=12590).
Posted by: guest at February 14, 2008 3:48 PM
you can prevent the water temperature differential being needed - between the radiant floor and the other parts of the house - by using "oversized" flat panel radiators (myson/runtal) - you can then run the entire system up to 140 and should be fine.
Posted by: guest at February 14, 2008 6:06 PM
We installed radiant heat ourselves in the course of a gut reno with bad floors, and so far its cost (about 10K for three floors plus about $1000 to hire a plumber to set up the manifold system) has been totally worth it.
We went with this product:
www.florheat.com
that's made of recycled plastic, then you put hardee board on top. This creates insulation (for both noise and heat) between floors.
Flattening the floors first was really really important. We did not do the greatest job with this, and have some kind of wavy hex tile in our kitchen.
We laid engineered wood where we didn't use hex tile. There is little difference between the rooms in terms of heat.
We haven't had it for very long and we only have one floor out of three done, but so far our gas bill still looks like we don't have heat at all! This could be because we keep the thermostat really low, it's still a construction site. But still. The baseboard heaters we had last year were outrageously expensive, even set at 60.
Hooked the boiler up to the heat as well as an indirect H20 heater, and this is genius. Even with guests over and people doing dishes and showering at the same time, there is always more than enough hot water, and this is similarly efficient--the difference in the gas bill from the old water heater is profound. Indirect tank was only $800, installing it was part of the other heat hookup stuff.
Posted by: guest at February 15, 2008 7:20 AM
Oh,
I forgot to add: I liked working with the florheat people because all the engineering for your system is included in the cost, and I think they did a good job with this part.
They explain how they arrive at the loops, so that you can redesign the pattern a little if you need to. And you can draw out your new pattern and fax it to them and they will check it if you're nervous. They're helpful.
They also have a good sense of your house as a system and understand how to work with you if you have weird things. Like our boiler is not that efficient, but we were on a strict budget and can't afford a new one yet. So they understood that and engineered the most efficient system for our boiler, which is really too big for radiant heat--we have to add cold water.
They were also really available for questions and worked well with our plumber.
The drawback to the florheat stuff is that it adds 1.5" to your floor. You get thermal mass and a nicely insulated airspace for that, and don't hear footsteps above. For us, we didn't have anything resembling a doorway left so it wasn't a problem. But if you have existing doors, you would have to do some serious trimming, build up the hallways, etc.
Posted by: guest at February 15, 2008 7:29 AM
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