Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.

If you've found help here, check back in to let us know how everything worked out.
It's a great way to thank those who helped you.
Need to contact us? Visit

Radiant Help.

Tom HopkinsTom Hopkins Posts: 539Member
Why is it that people will spend an inordinate amount of effort on the wall and roof insulation and then put big thin, low R value windows in, and wonder why the heat losses are so big? The other issue that must be considered is that the windows will act like large radiant cooling panels in the winter if they aren't high performance units.

What climate zone are you in? You can't alter the laws of physics, if you've input the envelope data correctly and the program sez you need supplemental heat, then, you probably do. I guess it's too late to go back and get better windows?


  • Dan SedensDan Sedens Posts: 48Member
    Is it possible

    that I neede supplemental heat in a new addition that is 17' X 11'. I am using slant fins heat loss program and it states that I need 1800 BTU of supplemental heat in a radiant application. We are talking maximum insulation with four large windows and three cold walls. Flooring to be 3/4" plywood, wirsbo panels, and pergo flooring. Am I way off base here. Shoudln't there be enough floor space to carry the load? Please help me out. Customer would really like radiant however if supplumental heat is in order than they will probably choose fintube.
    Thank You
  • if that is what...

    the numbers say...that wahat they are. What is the design temp?(bith outdoor temp and water temp? Remember that most of these numbers are @ design temp would be ok most of the time. are you using plates? kpc
This discussion has been closed.


It looks like you're new here. If you want to get involved, click one of these buttons!