Lower Thermostat Setting?

Mark Faultersack

Some research done with the Canada Mortgage and Housing Corporation says that homeowners with radiant in-floor heating systems do not set their thermostats significantly lower than homeowners with other types of heating systems. This supposedly refutes energy saving claims by in-floor sales people that you can "save 20 to 40 percent over traditional heating systems. " (Quote from Wirsbo's web site)
Any one aware of other studies, evidence, professional opinions?

keith

strictlty personal opinion

on my part. Altho this is not scientific data, I installed a underfloor radiant system in my last house and loved it. I was able to lower my tstat considerably (4 dergrees)and the family was very comfortable. The benefits to the radiant system come in many colors. Comfort, energy, visually it is very clean, constant and steady temps. thru out the house are just a few things that come to mind. Have you ever lived in a house with radiant?

kf_2

t-stat settings are...

just one minor item that contributes to the savings of a radiant infloor system.

Lets look at the lower heat loss through the roof. Because radiant mainly heats the lower level of the room and heat goes to cold there are lower temps at the ceiling than conventional so the heat loss is slowed. ASHRAE says that when figuring a heat load for a radiant building, the room volume can be reduced by 15% and the R-Value of the roof can be increased by 1.5%. This can considerably reduce the heat load for the same building when heated by radiant as opposed to conventional.

Lets also look at lower system water temps. In most cases radiant runs between 85 and 120 degrees as opposed to baseboard running between 160 and 200 degrees. Lower water temps mean less off cycle losses and longer off cycle periods. This of course means less fuel burned. If the system utilizes condensing boiler technology these lower water temps become extremely lucrative.

And about the t-stat settings... Most radiant systems are controled with outdoor reset and constant circ so the t-stats act more like high limit room sensors than actual t-stats. So even though the thermostats are set at, lets say 72, the room temp may never actually get there based on the selected heating curve. Also just because people can set there thermostats lower doesn't mean they will. It has been my experience that some people have it in there head that they are not comfortable unless the thermostat says they are.

Just some things to ponder.

kf

Mark Faultersack

Yes, I currently live in a house where I've retrofitted a whole lower level , walk out basement to radiant floor. And I love it. And yes I do set back at night. And I use lower temps during the day than the rest of the house. "But am I typical ?"... is the real question...
And are there any studies....

Mark Faultersack

Actually I have pondered those things, and agree they are reasonable. But are there studies?

Aidan (UK)

Are there studies?

I think Mr. Faultersack would like to know if there are any studies.

The question has been asked before on this site. There were many expert opinions, mostly supporting the comfort and energy efficiency benefits of radiant systems, but I don't recall that anyone quoted a study. I will have a rummage in my extensive technical library, i.e., heap. Please let me know if you find one.