Radiant Question

Alan(CaliforniaRadiant)Forbes

R-value for the heat to go through on your carpeted floors. I had the same problem in my house, i.e. I wanted to do staple-up with plates and the wife wanted wool carpets, R-value came out to be 4.51. I think you'd end up cooking the floors.

You might consider staple-up under the Pergo and radiators in the carpeted areas.

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Nick_16

Radiant Question

Hi all. I want to install radiant heat in my home. I have read several books about it and learned a lot. I used Slant Fin's Hydronic Explorer to figure heatloss calculations. In half of the house, I have carpet. The other half I have Pergo flooring. On the carpet, total R value of 4.22 with carpet, pad, subfloor, etc. I would want to run the temp as high as possible which as far as I know is 140 F. On the Pergo, total R value of 2.16 with Pergo, subfloor, etc. Anyway, my problem is that 2 zones have a mix of carpet and Pergo. Could I run double tubes under the carpet area and single under the Pergo. I will be working with 1/2" Pex and aluminum heat transfer plates. The system will be over a heated living area basement. Also, what sort of heat up time can I expect with a system like this. I have heard that the higher water temp. helps. Thanks in advance!

Weezbo

it isnt quite so simple as that.

there are other factors that might preclude the line of endeavour you suggest. try a room by room heat loss,first. having someone who does this type of work stop by the house before spending money and cranking up the water temps to discover you didnt get what you had your heart set on..i am not really enamoured with staple up systems,after doing a heat loss i discovered that what i wanted to do would be about 12,500 btus under...as it was in the neighbourhood i thought well, if i have to i can go add some more heat..well when it was cold thats what i did.you may not have someone close by to help or who will stop by to make sure your system is keeping up with the cold...it was a bit overly optomistic of me to have done the work knowing that it wouldnt quite meet the mark in the first place.i dont know where you live however you be very careful doing designe i know better and that doesnt hoe a row of beans with mother nature and the laws of physics......Man ! i type slow.this reply had one cup of coffee and a telephone call in it...God Bless *~/:)

Bert_2

agree with Alan

Wirsbo design program would show that staple up with aluminum plates and an R-4.5 floor covering would require 8" spacing, 170 degree water, and only provide 13 btu's per square foot to the space. Depends on your actual requirement for btu's per square foot as calculated by an accurate heat loss for the carpeted areas.
Where I am in Wisconsin, the only areas in a typical home that need only 13 btu's per square foot are completely interior rooms, or well insulated below grade basements.

Nick_16

It is 14" from middle of one joist cavity to the other. I could do 7" spacing by running double tubing and double heat transfer plates. I thought 140 was maximum for staple up installation?

STEVE N

Consider this as well

Nick,
Another thing to consider with this is flow. In areas where the R values are higher you slow the flow down so those btu's can transfer. In areas of lesser R values you can increase the flow. I have never ran a radiant system at 170. You can run the risk of over heat... remember you do not want the floor temp higher than your skin temp ( approx 84 degrees.)Some areas may require a second stage of heat.. its not that uncommon nor is it hard. A 2 stage stat and a floorvector works well. If you lay it out right you can use flow to your advantage and eliminate some over and under heat problems.

Steve