Radiant floor heat with carpeting

realolman

A space has a heat loss that is determined by the construction of the insulation envelope around it. In order to heat that space you must supply an adequate number of BTU's per hour to match the heat loss.

I'm really not sure, but I believe I have heard that you can only count on about 20 BTU/ square foot from radiant heat under a carpeted floor, which would likely not be enough to heat the space.

Now, maybe someone knowlegeable will correct me, and you'll have your answer.

Craig_19

Radiant floor heat with carpeting

I have an older house (1910) currently heated with forced air. I am looking to install radiat floor heat for the first floor only. The first floor area is around 1275 sf, with about 1/3 being carpeted with padding. Heat loss calculations from a supply house come in at 40,000. I was told that I should not do radiant floor because of the carpeted floors.
The reason that I am changing is the draft blower on the furnace crapped out and there is some concern that there may be bigger problems with the furnace. Natural gas is used for heating fuel.
Any comments, suggestions, etc. would be appreciated.

Mark Custis

A blower motor would be cheaper

than converting to hydronic/radiant. I like moving heat with water.

The more tubing the better as you can lower the water temperature supplying the floor circut. Heat goes to cold so you will need to insulate the loops so the heat goes into the living space and not into the basement. The R value of carpeting can be over come.

Unknown

I did a room on seprate

I did a room that was converted from screen porch into a rompus room on seprated zone.
Concrete overpour on concrete with insulated sheetings, a lot of windows and patio door. Knowily they will use heavy padding and carpet, I ran two coils and each end of loop installed under exposed title entryway. The supplement cast iron baseboard heat comes on when temps outside get about 10-15 degrees. I stressed the builder to build extra lower exteroir wall for more insulations. And that made a HUGE differnence.

Bob Bona_4

it's not

the carpet so much as the infiltration in a 1910 house, especially one perforated for existing warm air ductwork. That would be the most important consideration in my mind-the infiltration gremlin.

Keep in mind the the existing furnasty is now going to be at least twice the size needed, if not more, for the rest of the house (heads up for short cycling/heat exchanger failure), and the ductwork will be horribly mismatched from killing the first floor section- unless you plan on A/C with dampers to shut off heat to the radiant portion (or use warm air as a second stage supplement).

This one calls for a very close and meticulous design analysis. Supplemental heat may be needed. The padding/carpet may have to be altered.

What are your long term goals? Equipment choices can range from a boiler to drive the radiant and future hydroair for the second floor to a wall hung tankless for the radiant and getting an appropriately sized 90+ furnasty for the second floor/other..

What is going to happen to the second floor heat if you go radiant? Is there even a second floor?:)