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radiant floor heat in addition

My ranch house is heated with an oil burner/boiler through a monoflo system to room radiators. A 320 sq. ft. addition was added to the back a number of years ago and heated via baseboard heating elements on the same loop. Is it possible to eliminate the baseboard heat in the addition and use radiant floor heat off a separate zone on the same boiler? Doesn't radiant heat require a lesser temperature?

Re: radiant floor heat in addition

Yes, it is quite possible & is done all the time.

Radiant heat does require a somewhat lower temperature for the hot water of approx 100-120 degrees F, where the ordinary heating temp for radiators & baseboard is more like 170-180 degrees F, but this can be easily accomplished with what's known as a 3-way or 4-way mixing valve using the same boiler for the radiant zone---the major modification would be in the area of materials & cost & labor which involves installing the underfloor loops of tubing, usually hi-temp plastic PEX tubing under the flooring, either in installed floor panels, or (from the cellar) in the floor joist cavities, stapled to the sub-flooring.

But I wonder why you feel you need to make any modifications at all to your present system---baseboard usually does an excellent job of heating a room, but sometimes the heat may be inadequate for some reason, or the baseboards may make a certain amount of noise when they are heating up or some people may not like the appearance they make in a room---all of these problems can be addressed & rectified in most cases.

I can't see spending what could be thousands of dollars on a radiant floor system for a particular room if you can get the existing baseboard system working to your satisfaction---please let us know why you want to make this change.

But if you still want to get quotes from local hydronic contractors, I suggest consulting the Yellow Pages under 'Heating Equipment--Parts & Supplies" to get the names of several dedicated hydronic parts jobbers in your area & ask for the COUNTERMAN in these shops----tell him you want to have a radiant zone installed on your HW system & can he/she recommend someone with lots of experience in doing these installs with an existing boiler.

I've listed some sites below that will give you more background info on how radiant floor zones are installed using an existing boiler, for informational purposes only----please don't infer any endorsement of any products or services offered on these sites---if the segment on radiant heat doesn't come up immediately on the 1st site below, click onto the beginning of the red line to reset the video to the beginning of the presentation---on the last site below, scroll down & click onto "images for hydronic radiant heat for wood-framed-floors" to get a wide range of different radiant floor heat applications.


Re: radiant floor heat in addition

Pelton, thank you for your response. I thought it was possible but wanted to be sure before contacting a plumber/hydronic contractor (like a good lawyer knows the answer to every question he asks).

To answer your question, I want to change from baseboard to radiant heat for a room remodel. The baseboard heat is currently adequate, but I want the room to become a kitchen. The cabinets will take up most of the wall space and a french door will take up most of what little is left.

The ask-this-old-house video you linked to almost exactly what I hope to do. I'm hoping to find a contractor I can work with and save some $ doing the pex looping myself and having the plumber tie in the new zone.

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