Radiant heating

Specific Inspection Topics Inspecting HVAC Systems
1

I inspected a home today with in floor electric radiant heat. The heating coils did not draw defined signatures on my infared pictures.

The temperature of the floor before the heating system was turned on was approximately 21 C / 69 F

After the heating system was on for about 2 hours the temperature was approximately 23 C / 74 F

My concern is the radiant in floor heating may not provide enough heat during the cold season. The floor structure is concrete slab.

The top level had radiant heating in the ceiling. Flexwatt. The temperature in the ceiling was approximately 50 C / 122 F
after about 15 minutes.

What are the optimal temperatures these products typically run at?

What is your recommendation?

Thank you.

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2

It does take a very long time, like half a day, to heat up a floor on a slab. It might be fine, you just need to heat the earth first. :cool:
By contrast, a second story tile on plywood floor heated from 23 C to 30 C in about an hour for me yesterday. I had the thermostat cranked! :stuck_out_tongue:

3

Mark,

My concerns would be Flexwatt as this particular brand of radiant heating has been known to cause fires…

*En décembre 1994, après une série d’incendies, la Régie du bâtiment du Québec (RBQ) élargissait, pour des motifs de sécurité du public, l’ordre de débranchement des marques de pellicules de chauffage radiant *Flexwatt et Thermaflex, aussi commercialisées sous les marques Flexel Safe-T-Flex, Safe-T-Heat, Aztec Flexel, Aztec Flexel Scotland et Thermo-flex Scotland. Installées derrière le revêtement des plafonds, ces pellicules étaient susceptibles du surchauffer et de causer des incendies.

4

Mark,

jkogel is right it will take a long time for the electric radiant heat pads to warm up a concrete slab. I usually see the the liquid/water systems in slabs.