abandoning my wonderful heated floor

If its a small room such as a bathroom ,you can get those electric heated mats to go under the finished floor. Easy to regulate with a wall thermostat and very low power draw.

My project is a large floor area. The room is about 1100 sf and about 800 of it is wood, the balance is tile. I'm not sure I will do this I'm having second thoughts. I'd hate to mess up that floor. I also wonder how warm the house would feel with floors 85° or less. I have to imagine it would take a long time to warm a room up like that.

In floor heating isn't really intended to warm a room up - rather maintain the warmth 24/7 all winter.

Is your flooring in place - or in the planning stages? What do you have for an existing system now?

I took John Siegenthalers course on modern hydronic heating. He had a lot of good reasons why underfloor heating is not a great idea. If you are ripping out sheet rock, he was a far bigger advocate of properly designed radiant walls and ceiling.

The supply temps have to be higher as the thickness of the intervening materials increase, with wood flooring, there is usually a subfloor and possibly a pad and then the wood flooring this has an effective R value and meanwhile heat is trying to radiate to elsewhere to the space under the floor. The net result is you need to run hotter water under the floor then into radiant emitters or a properly designed radiant wall or celiling.

Yes my floors are already in. I won't be taking any walls apart, that's already been done a couple years ago. Plus I have to think that wall heating would be done on interior walls and there aren't very many of those in this space, its an open concept house. I'm definitely having second thoughts on the through the floor idea. I might be just as well off tying into my forced air system.

Try your existing setup with 85-90 degree water if thats possible ,and see how it works. No way you can ruin anything at those temps.

Seasoned Oak said:

Try your existing setup with 85-90 degree water if thats possible ,and see how it works. No way you can ruin anything at those temps.

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If the floor heating setup isn't installed yet though, it's a pretty big step to do that if not sure on the outcome.

Any possibility of rads? Panels or even old style cast iron?

I have looked at radiators, mainly baseboard. Not big on the aesthetics of it. I'm guessing my wife wouldn't be either.

Panel rads aren't quite the same as 'baseboards' (what I have) - can use lower temps & I think look better. Cost more though.

There are some nice European radiant panels that look like wide trim boards.

http://www.houseneeds.com/heating/h...n-rcv-steel-panel-baseboard-heaters-rcv21-600

http://www.supplyhouse.com/Runtal-Baseboard-Radiators-852000

The hassle with a lot of open space concept homes are that they optimized for the view with high ceilings and lots of glass rather than energy efficiency, they look great but can be a bear to heat.

I saw one a few years ago, daylight basement built into a hillside with floor to ceiling glass, then main floor with cathedral ceilings with glass from floor level up to the roof easily 2- 1/2 stories of glass. Only problem was the view was facing north
The folks who bought it got a great bargain until the first winters heating bill.

i've done the electrical end of many after thought radiant floor jobs and you need to know if there is a floor over another floor you would have to install more tubing or get rid of the extra floor. my floor in front of my stove is starting to lift at the edges. it can't take the heat which there is very little. heat rises. the floor in front of the stove might be 80 or 85. my floor is not a cheapy brand it is a pergo brand (which i will never do again). if you have a pad between the tubes and the finish floor you will not be warm enough. if you have (and i've seen many) floor over the old floor sometimes 3 floors you won't be warm enough. i've been on jobs where the floor was put in as after thought in a old house with two tubes per bay, reflective metal under the tubes, insulated rim joist and insulated from the basement joists running 120 degree water and it was still not enough heat. the guy runs his floor heat as main and if it cools below a certain amount the baseboard kicks in. the water is at 120 because of loses through the 3 floors he has. people usually don't know this but if you have a regular old or new case iron boiler and it is run to low for the radiant they wind up replacing the boiler in a few years because it rots out. if you change to a all radiant heat and run the boiler at 120 it is going to have to be replaced with a condensing boiler meant to run at that low temp. another customer his install was new works perfect except for his bathroom. he decided to put down tile and took up the linoleum and now his bath is cold. it's nice heat when it works.

Your boiler doesn't have to run at the same temps as your supply temps.

maple1 said:

Your boiler doesn't have to run at the same temps as your supply temps.

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Correct , you do need a mixer in this case to allow a small amount hot to mix with cold returning water to maintain the 90 deg feed temps. I think some are trying to run the boiler at low temp to forgo the need for a mixing system ,which may greatly shorten the lifespan of the boiler.

peakbagger said:

I saw one a few years ago, daylight basement built into a hillside with floor to ceiling glass, then main floor with cathedral ceilings with glass from floor level up to the roof easily 2- 1/2 stories of glass. Only problem was the view was facing north
The folks who bought it got a great bargain until the first winters heating bill.

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First rule of thumb in building into a hillside ,if its heat your looking for choose a south facing hillside.