Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

1850s house - adding an addition

Last year we purchased a home originally built in the 1850s in the Chicago area. It has a 4 year old boiler and old radiators throughout, which we actually love.

We are planning to expand the house soon and would love to do radiant heating in the addition. I've done a bunch of research but could really use some advice.

The planned addition basically opens up the back of the house and goes back about 40 ft. Full unfinished basement and a two story addition. (kitchen, family room and master suite)

For numerous reasons, we are trying to minimize what we do to the existing house. So, we are not planning to change out our existing boiler / radiators or spacepak.

For the addition, we were thinking to do radiant heat in the floor with hardwood. But I'm a little stuck between warmboard and thermofin. They both seem like good products. I hear that thermofin is cheaper but from what I've seen it looks like it would take more labor to install and you still have to install a sub-floor. With the warmboard, it looks like it cost more but is easier to install and you don't pay for the plywood sub-floor.

Am I thinking about this right? Is this the type of install you would recommend and if the performance is the same, for new construction which product ends up being less cost total to install?

Or, do you have something totally different you would recommend. (one contractor told us not to do radiant with wood floors and we should do baseboard heat instead)

Really happy to find this site. Thanks in advance!


  • Steamhead
    Steamhead Member Posts: 15,350
    First question- is your existing system steam or hot-water?
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • Rich_49
    Rich_49 Member Posts: 2,692
    Radiant heat is not the culprit for most botched hardwood jobs . RH% is the biggest offender , Tin guys love when there is radiant installed that they can point at as opposed to their admitting they did not do their job right and the RH is allover the place .
    You didn't get what you didn't pay for and it will never be what you thought it would .
    Langans Plumbing & Heating LLC
    Serving most of New Jersey, Eastern Pa .
    Consultation, Design & Installation anywhere
    Rich McGrath 732-581-3833