Real questions, straight answers.
What homeowners, builders and engineers ask before choosing radiant heat, answered from years of ThermaRay installs.
Asked by customers.
Three real questions, with the whole answer.
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Costs and Efficiency
How efficient is radiant heat, really?
Efficiency percentages are mostly marketing. Real operating costs are a better test: ThermaRay systems typically cost 30% to 60% less to run than forced air, baseboard, hydronic or infrared heat, with no maintenance or replacement. -
Costs and Efficiency
Why doesn’t thermal mass floor heat need insulation underneath?
Heat only moves toward something colder. The panels warm the slab and ground until it reaches the earth’s temperature, about 2 to 2½ feet down, and then stop. That deep mass stores heat, and the bigger it is, the lower the operating cost. -
Choosing and Installing
Won’t a radiant ceiling lose heat through the roof?
Not if the ceiling is insulated properly. Drywall has a very low R-value, and the radiant energy passes right through it, while the insulation above sends the heat down into the room. On a cold day, a thermal camera in the attic shows no heat coming through.
Radiant Basics.
Why put heat in the ceiling if hot air rises?
Hot air rises, but radiant heat doesn’t. Like sunlight, it travels in straight lines until it reaches the floor, furniture and people, and warms them directly. Those warmed surfaces then help heat the room.
How does a radiant ceiling compare with baseboard heat?
Baseboards are cheap to buy but cost about three times as much to run in a cold climate. They heat a room from one wall and need 10 to 12 watts per square foot. A radiant ceiling spreads the heat across the whole room, usually at 6 to 8.
What is the ideal heating curve?
People are most comfortable with 65–68°F at head height and warmer air at the floor. Forced air does the opposite, piling heat at the ceiling. Radiant floors come closest to the ideal, and radiant ceilings come close too.
Is radiant heat the same as infrared?
Infrared is one kind of radiant heat. Radiant heat is any heat carried by electromagnetic waves, like sunlight. Infrared is the part of that spectrum just past visible red light, and it’s especially good at warming surfaces and people. Both warm objects directly instead of heating the air first.
Is radiant heat healthier than forced air?
Radiant heat warms people and objects instead of blowing air around, so it doesn’t dry out eyes, noses and throats or move dust and other airborne contaminants through the house. The space is warmed evenly, from the ceiling or the floor.
Costs and Efficiency.
How efficient is radiant heat, really?Asked by a prospective client
Efficiency percentages are mostly marketing. Real operating costs are a better test: ThermaRay systems typically cost 30% to 60% less to run than forced air, baseboard, hydronic or infrared heat, with no maintenance or replacement.
Why doesn’t thermal mass floor heat need insulation underneath?Asked by an engineer
Heat only moves toward something colder. The panels warm the slab and ground until it reaches the earth’s temperature, about 2 to 2½ feet down, and then stop. That deep mass stores heat, and the bigger it is, the lower the operating cost.
Does thermal mass floor heat work in large buildings?
It works better. A 1,200 sq ft building may need 10 to 12 watts per square foot, while a 100,000 sq ft building typically needs 5 to 8. High walls, lots of glass and dock doors are hard for forced air, but radiant heat only has to warm the bottom 6 feet, where people are.
In a cold climate, should I spend more on heating or cooling?
Heating. In colder climates homes heat about ten times more than they cool. A radiant ceiling typically costs half as much to run as gas forced air and a third less than electric forced air, so pair it with simple, well-placed AC.
Can you estimate what it will cost to heat my building?
Estimates vary with construction, climate and how the space is used, so Premier Energy USA prefers to share actual operating costs from similar homes and buildings in similar or colder climates. There are hundreds to draw from.
Why is my builder pushing back on radiant heat?
Builders run on schedules, and something new looks like a delay. Once they install a ThermaRay system, most are surprised how simple it is. Premier Energy USA works with builders, remodelers and homeowners from ordering through installation.
Choosing and Installing.
Won’t a radiant ceiling lose heat through the roof?Asked by Eric, adding a small shop in Durango, Colorado
Not if the ceiling is insulated properly. Drywall has a very low R-value, and the radiant energy passes right through it, while the insulation above sends the heat down into the room. On a cold day, a thermal camera in the attic shows no heat coming through.
What’s the best way to heat a garage or shop?
There are three ThermaRay options. Thermal mass panels go under a new slab. Radiant ceiling panels hide above the ceiling, new or existing. Architectural Series metal heaters mount on or hang from the ceiling where you can see them.
Can I add radiant ceiling heat to an existing home?
Yes. With attic access, the panels go above the existing ceiling. Without it, furring strips go on the existing ceiling, the panels go between them, and new drywall covers everything.
Can I heat a floor from below without tearing it up?
Yes. Floor joist heating hangs radiant panels 1½ to 2 inches below the subfloor, in the joist spaces. It doesn’t raise the floor, isn’t in the wear surface, and the flooring can be changed later without touching it.
Will floor warming raise my floor?
Barely. ThermaRay floor warming cable is very thin, and it’s covered with a thin layer of self-leveler or thin-set, so tile stays nearly level with the next room. Because it’s a cable, not a mat, it fits curves and angles too.
How is thermal mass floor heat installed?
The panels are laid evenly across the sand before the slab, wired in parallel in circuits of 6 to 9, and run back to the mechanical room. Then 6 to 10 inches of fill and the concrete go on top. A typical home takes 3 to 5 hours with two people.
Why shouldn’t snow melt go directly in the concrete?
Concrete expands, contracts, heaves, cracks and settles, and its chemicals attack materials over time. That eventually destroys a system cast inside it. ThermaRay’s limited-mass panels go below the wear surface, under concrete, asphalt or pavers, where they’re protected.
Have a question of your own?
Call or describe your project, and you'll get a straight answer, with real operating costs from similar buildings.