How Does Insulation Work With Radiant Heating And Cooling?

How does insulation work with radiant heating and cooling? Reflective insulation is better for energy efficiency in any home, but that's especially true for homes with radiant floor heating systems and radiant cooling systems.

R value is always a factor, but it is not the only factor when it comes to insulation, especially with radiant heat. If you have got radiant heat in your house, you want to keep that heat in during the winter. Reflective insulation does a better job of that than fiberglass. Also, in the summer, your house picks up most of its energy from above. It is radiant energy from the sun getting into the attic, then radiating down through the ceiling and into the house, making it hot. If you can keep that out with reflective insulation, you can knock off 30 to 40 percent of your cooling bill. If you can prevent heat from coming in, then you do not have to get it out. That is the theory there. There are other ways to insulate, where you can take advantage of R value and reflectivity. There is also foam board insulation. Sometimes you can get those with a foil-coated side. There is a product we have had some customers use called Icynene. It is a kind of foam that you spray in and it expands. There are also insulated concrete form structures where you have two inches of foam and you have an 8-inch channel between them. The Channel is filled with concrete and you build your walls from that, so they are about a foot thick and filled with concrete. They have an R value of about 40, which is twice as good as most houses, plus it is a solid concrete wall inside. Another factor is the air infiltration that you can get with the standard framed house. In terms of radiant heating and cooling, proper insulation going into the design of the house can help reduce your estimated heat loads and reduce your cost to run the system over time, both in the summer and winter, just by taking advantage of either really well-insulated walls and attics or reflective technology or a combination of both.


In terms of structurally insulating the house, you can insulate between the floors. Sometimes that also helps with noise. But it really improves the zone controllability, keeping the heat where you want it to stay and not heating the floors above. In a poorly insulated house, you can get some heat from the basement going up to the first floor. Slab insulation is something that we recommend a lot of times in projects where there is a lot of groundwater content or moist soil underneath. A high water table can conduct heat away from a radiant slab. So, lot of people will install foam insulation or sometimes a foil double-poly reflective insulation. They use a barrier insulation under the slab and help keep the radiant heat moving up, not down.




Crawl spaces are another place that we recommend a lot of radiant barrier insulation or reflective insulation. My house is mostly built over a crawl space and when we put that tubing in, we then went underneath with a reflective insulation and I really noticed the difference immediately. We had the heating system on as we were putting that insulation in place in January and my crawl space was about 85 degrees, but the temperature in my house was at 60 degrees. Once I started putting that reflective insulation in place, I crawled under a section of it to grab some extra staples and it was like 20 degrees cooler than it had been before, because the reflective insulation was keeping all that heat going up.

It was weird! And the thermostat in the area above warmed the room up to 70 degrees just about the same time I finished putting insulation in place. So, in a crawl space particularly, it is important to use foil insulation and take to advantage of that reflective technology to make your heating system work the way you want it to. Those are insulation issues that we try to address as we are putting a project together for somebody.

One is a heated garage or a shop. You can pull in from grocery store or whatever, close the door and it is 45 to 55 degrees in the garage. Any snow or ice on your vehicle melts right off and you can unload the groceries in a comfortable setting instead of a 20 degree garage. My garage is radiant heated, and I have watched neighbors groceries with the coats on and hats on and thought, "Man! It must be cold in there, but not over here!" I also have this in my driveway and the walk way up to the front door. I never have to worry about ice or shoveling. I have to shovel the sidewalk out front by the street, but that just takes me a couple of minutes and I am back inside sipping on cocoa, while everybody is out there with their snow blowers!

We've also helped people with greenhouses, kennels, hangars and shops - if it's a space that needs heat, there's probably a way to utilize radiant heat.

© High Speed Ventures 2011