A couple weeks ago a contractor installed hydronic radiant heating at my place. The building is two floors (studio above a garage) and the heating was installed under the floorboards. When he finished installing the piping and pumps he told me I'd need to install reflective insulation.
After a few google searches I'm seeing mixed information on whether reflective barriers/insulation works or not. Some sites claim more heat is lost to the lower floor than the upper floor where the heat is intended to go (not that that's entirely a bad thing, the garage isn't heated and it's my workout/laundry room). They suggest using regular foam insulation.
My questions are:
- Do I need the reflective barrier/insulation?
- If I need reflective barrier/insulation, do I also need foam insulation installed?
Brand suggestions are also appreciated.
Best Answer
theory is that the pipes are hot enough that radiation is signficant. Putting a low IR emmisivity surface reduces the amount of radiant energy the bottom of the cavity absorbs.
If you just have a low e foil, then you cut the radiation in half. However by conduction the entire air space gets warm. So you will have the foil as a barrier for conduction too. It's not very good at that.
Me, I would put friction fit paper backed bats in. leave a 2" thick air space at the top of the cavity, so that you have fewer hot/cold spots on the floor above.