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programmable thermostat for radiant floor heat

Is it best to, and necessary for maximum energy savings, to use a programmable thermostat for radiant floor heat? I just installed a radiant floor system in my cabin, installing in the crawl space, and have a standard thermostat for adjusting the heat. Should I be turning down the thermostat setting in the evenings and turning up each morning to conserve energy (the energy source comes from propane)? If so, the problem is that the radiant floors take so long to heat up that the cabin is not up to temperature for 2-4 hours, after resetting, therefore wouldn't a programmable thermostat would work much better? My hvac guy, who did the install, told me that it was best to just keep the temperature constant and not move it up and down each day/night, but I have been going through much more propane than I had hoped to use in just the first 3 weeks of operation with that method.
If anyone can help, please let me know.



Re: programmable thermostat for radiant floor heat

I know little about Radiant but when working on them I was told that you should keep it constant, I imagine it would have to do with Heating the floor itself before it is able to Heat the space, every time you shut it off or turn it down and back on or up it has to heat the floor all over again before it Heats the space. I hope that Nashua Tech takes a look at this, very knowledgeable and may be able to explain it better. Good Luck!!! :)

Re: programmable thermostat for radiant floor heat

You mentioned it was a cabin and I guess it would depend on how it was used.

Mine have been in the mountains of CO and are not used year round. I have shut them down in the winter after I know the pipes will freeze and then the water is drained and the place winterized until spring.

I do not know about you but in the colder months I want fast heat if I go for a weekend. I have depended on wood and/or pellet stoves to get that done.

Radiant heat might work well for you but it would never work for me unless I lived there year round.

Re: programmable thermostat for radiant floor heat


It sounds like you're clearly dissatisfied with the radiant heating system---you're burning a lot of propane and the cabin is still not warm and comfortable, as it should be.

From your post, it points to the HVAC installer, who may not have properly designed the system so that adequate heat is supplied.

If he continues to be unresponsive, get additional help and opinions from other radiant techs in the area.

It is the installer who is responsible for providing you with the heating system you paid good money for---if some design or installation errors become obvious, now's the time to find out & do something about it---I have my doubts that a programmable t-stat will solve the problem.

There are a number of radiant floor heat forums that have expertise on radiant issues---Google "radiant floor heat" forums.

A few radiant forums follow:

On the last one listed, click onto "the glitch and the fix" for Siegenthaler's series on things that can go wrong with radiant installs.

The houseneeds site lists general design considerations when installing radiant heat floor systems.

The heating help site is frequented by many radiant installation techs, and you should post there as well.

Many homeowners feel more comfortable with a combo of 25' to 50' or so of hi-temp baseboard and lo-temp sub-floor radiant---the baseboard is used to "take the chill off" when needed, then turned down---since they are both hydronic, baseboard and radiant can be run off the same boiler using a 3-way mixing valve---you might talk your installer into installing this option if no other remedy can be found, since he probably screwed up the system design.


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