Confusion about radiant floor heating

R Bess

I have been looking at radiant floor heating (hydronic) for several years after seeing it many times on tv. We are building a new log house this summer, and we do not have anyone around where we live to consult about radiant floor heating. The only sources we have are the ones on the internet. The guy who is going to appraise our future house is saying that he does not believe this "new" heating system is all that good and we would be better off, and it would be cheaper to operate a "geothermal" heat pump. What we are looking for is an unbiased opinion if it is actually out there. What should be look for in radiant floor heating and what should we watch out for (I know we should use a closed system)? Should we install ourselves or try to find someone to install for us? What size tubing should we use? Do we do 16" on center or less? I think my questions could go on, but I will stop there for now.

Thanks in advance,
Rob

imatellerslie

You can have your cake and eat it too

Do geothermal with radiant. They work very well together.

S Ebels

Ah yes ....questions questions

Answers Answers.

Tube spacing depends on many variables. These would be the heating load of the structure or room, above floor or below floor, insulation under the tube, water temp, wet system or dry (gypcrete or panel type), floor warming or full blown 100% heating, type of floor covering and on and on.

Tubing size is also determined by a lot of factors although 1/2" is by far the most commonly used size for a number of reasons.

A lot of systems can be installed by yourselves with a little guidance. I do this on a lot of jobs to help folks save some $$$$. I lay it out after doing a heatloss calculation and the home owner, friends and a couple cases of your favorite beverage later..... it's usually done. Basing the tubing layout on a good heatloss is imperative if you want it to work correctly. None of this "How many sq. ft. do you have? Oh, you'll need this much tube and this type of layout."

Mark Eatherton1

What's...

the use patterns oif the cabin going to be. Permenant status, or weekend wannabe. If its the latter, radiant doesn't react well to deep set backs and set ups. If its a permenant residence, then go radiant. Maybe radiant floors in the bathrooms and kitchen and living rooms, and radiant ceilings or walls in the other spaces.

Radaint floors are THE best system in the world, but they're also the slowest to react, and have certain btu/sq ft limitations, and are overkill in most cases and expensive..

Radiant heating is comfortable regardless of the source. Warm Floors are the best.

This slow reaction can be overcome with the use of telephone or internet based controls and you acting as an "anticipator".

As Steve said, got lots of questions...

IMHO, with GEO, the temp of availablity is real low, and warrants the use of WarmBoard. Yes, its not cheap, it's the best. It's ideally matched to low temperature oparation. If you must do warm floors, do WarmBoard.

ME

ME

hr

Run the calcs, first

log homes are, by far, the biggest challange for heat loads calculations. Very hard to pin down an infiltration number. Make sure you select a log style, and gasketing that has a history of good performance.

You should find a knowledgable, experienced, RADIANT designer to do the calcs for you. Some hang out here and at the RPA site.

I find bedrooms are often better served with baseboard style heat, or panel radiators. Quicker response, not hampered by furniture and carpet choices.

Sometimes a hybrid of radiant floor, wall, and maybe radiators or hydro air supplemental work best.

Got AC loads??

hot rod

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Tom Meyer

Start with the basics

You have to decide how agile you need your system to be. Large mass systems (radiant in a concrete slab, for example) do not respond well to temperature changes (like Mark said, setbacks). If you want an agile (fast response) system, you need to have a system designed around that concept.

Next, like Hot Rod said, you need a solid heat load calculation.

Then you get the system designed. You can go from bare bones to the Cadillac. Just depends on what you want. Generally, when we do a design, we ask lots of questions about wants and needs, and lifestyle, and design the system accordingly.

Without a doubt, picking the right type of system and having it designed correctly with all the calculations is going to make the difference on how satisfied you are.

Tom Meyer
Senior Designer/Trainer
Precision Hydronics Corp
www.precisionhydronics.com

scrook_2

first...

geothermal heat pump is a heat *source* (an alternate to a fossel fuel fired hot water boiler for example) which may or may not make sense, depending on geothermal source conditions and electric rates -- look into it anyway.

Radiant floor heating is a (very nice) heat delivery system using (usually) warm/hot water as the transfer media. It is a relatively new heating method (first used by the Romans over a millenium ago) compared to older methods such as open fires used by cave dwellers tens or hundreds of thousands of years ago, but old relative to cast iron (and other materials) radiators and convectors, finned baseboards, panel radiators, fancoil units, or even forced hot air (ugh!), etc. It's modern use probably dates to post WW 2, 50+ years ago, so it's hardly new. As it is generally a low temperature system it should work well w/ a geothermal heat pump system or a high efficiency, condensing type boiler.

At the least have the system designed by a radiant specialist (use "find a professional" here) you may be able to do th eactual installation of the tubing though. Tubing size, spacing etc. will depend on the details of th estructure, climate, heat source, etc. -- there are no simple or one size fits all answers!

R Bess

Thanks

Thanks to all of you for your input. We are still mulling over the use of radiant, its upfront cost (although I realized the longterm benefits)and finding a reputable company.

Steve Eayrs

Keep in mind that geothermal ........

does not always work well. If your ground temps. are too cold, it will cost you more to operate than what you might think. In our area you would need a boiler for backup, and it would most likely end up being the main heat sourse.

The load on the electric pumps needed for the geothermal, use's of course....electricity, which quite often is produced by consuming fuel of some sort, (NG, coal, etc.)

Have had customers who insist on using an electric boiler, because they want to do their part in conservation, when most electricity in our area is produced by a NG plant up the road. At about .11/kw they do suffer for the cause, but they usually feel like they are better people, than the rest of us, for it.

Steve

prm_8

Where are you building?

Geography has a pretty big impact on heating system design. Radiant floors rule, but radiant panels and radiant (not convector) baseboards aren't bad. Keep asking questions here or privatly. I've done a lot of research in designing my own system and approached the system as openly as I could. The end result has been fantastic. My research also debunked (to my satisfaction anyway) a great many myths. With many back woods contractors (those that aren't enlightened enough to be on the Wall), there are more myths about heating than there are facts.