Radiant Heat, Installation Options

[pricejj]

What a great resource!

We are building a home this spring (Ranch, 2300sq/ft + full finished walkout basement), and are planning on Radiant heat for the entire house. The basement is an easy decision as we will pour the basement concrete floor and have the tubes run in the floor.

But the how to heat the first floor, what is the most effective install method? There seems to be lots of options and our contractor has proposed to hang the tubes on the bottom of the I-Joists. This is a less expensive install approach.

However, is it worth the money to run the tubes above the floor and apply a lite-crete (gypcrete based product) pour? There is quite a cost difference, but this is our last home and we plan on being here for the next 20+ years. Is the BTU/hr/ft heating advantage of this slab type install more cost effective over time?

Will I be happy with the radiant installation underneath or between the floor joists?

[johnsp]

You should look into how thick the sub floor and flooring thickness and type. You should also be using transfer plates on the tubing in the joists.

[Midwest]

First, I recommend a heat loss/gain calculation be done and you can perform your own with the red "HVAC Calc" tab at the top right of the pages on this site. This is essential to knowing where to start with equipment choices. A poorly designed radiant system can haunt you worse than a poorly designed scorched air system. There is a lot to be gained (supreme comfort) from radiant heat and if the system is not engineered or installed properly, these systems get bad-mouthed terribly.

The next thing I recommend is to tiptoe over to a site called heatinghelp.com The 'wet heads' there talk hydronic radiant heat mainly and you will probably get a lot of excellent advice.


The third thing I suggest is to make certain your contractor is experienced, talks the talk and walks the walk of modern radiant principles. Talk to past customers and get their views on systems they've had installed by your contractor. If his systems work well, you will hear great reviews, if not just the opposite will happen. Listen carefully to your contractor's claims and listen to his customers comments on their systems. Nothing rewards like radiant heating.

I would seriously consider looking at heat transfer plates and installing them immediately beneath the subfloor as mentioned already or a surface mounted system such as what Stadler-Viega, Rehau or many others make. If I undertand what your contractor is proposing, running tubing at the lower edge of the I-joists does make for a cheap & easy install. However, this installation usually provides limited performance. Very high water temps are needed among other energy robbing and performance problems. Whenever you can run your supply water at lower temps, you benefit from reduced energy costs. Also, if you choose a condensing boiler, these babies really shine when the water temps are low benefitting you even more. The plates can even be mounted in walls and ceilings for special cases such as a warm shower wall area or if heavy carpet is planned for flooring. Remember: heat does NOT rise, hot air does.

The surface mounted panel systems may work out to be a little less labor intensive than below floor transfer plates and neither requires extra floor engineering as gypsum or lightweight concrete subfloor systems do. These come with a caveat of increased installation cost over bottom of joist application, but with lower water temps and better heating transfer, you will realize benefits from these options.

[gmcd]

The most energy efficient and lowest long term energy use, with the higher level of comfort, radiant floor system is to have the tubes in the topping layer of concrete/gypcrete. This insures the best conductive contact from tube to floor material and reduces thermal striping. The hydronic system also runs at a lower temperature range compared to the staple-up system. An alternative to the concrete embedded tubing is to look at products like Warmboard, Raupanel, etc. that are a high density subfloor type of system which still keeps the tubing in good contact with the upper zone of the floor assembly.

Personally I think staple up systems ought to be banished due to their inherent energy inefficiency and poor installation practices. There is lots of radiant information at the following websites:

http://www.healthyheating.com

http://www.radiantpanelassociation.com

http://www.heatinghelp.com

Another thing to consider in the house design is to start at STEP #1: Reduce the heat losses to as low as possible in the first place as the primary, best bang for the buck energy efficiency "system" for the house. Eliminate thermal bridging, infiltration, use high performance glass/windows with a thermal resistance of at least R-3.5 or better (yes, $$, but a $ spent on the envelope is a $ saved on the heating plant, and $$ saved for the life of the house). Don't forget the ventilation system, a radiant system must have a ventilation system, especially in a tightly constructed house. Small heat recovery ventilators (HRV's) like Lifebreath, Venmar, VanEE, etc. sized for the required ventilation rate plus supplemental heating and/or cooling must also be integrated.

If you are looking at lots of carpet or other floor insulatinf coverings, consider the ceiling as an alternate radiant emitter- just like an upside down floor system.

[propmanage]

Has given you good advice. First pick some one with experience and updated training. It all has to do with planning and design. They don’t have to be a rocket scientist but they have to take the time to do the home work before starting the project. Sounds like you would be looking at Quick track or joist plates.

Good luck and give an update on how you make out.

[mechanicalmaster]

Are you considering Central air if so you might want to look at doing a Hydro Air system for the first floor it incorporates an air handler with both a Hot water coil for Heat and also a Coil for A/C. I like these systems a lot ESP in a ranch style home.

[casturbo]

Originally posted by mechanicalmaster
Are you considering Central air if so you might want to look at doing a Hydro Air system for the first floor it incorporates an air handler with both a Hot water coil for Heat and also a Coil for A/C. I like these systems a lot ESP in a ranch style home.

Yup, latest 'craze' in new building HVAC is hydro-air with floor warming radiant for bathrooms and tiled surfaces. Makes for comfortable heat (radiant), yet fast recovery (hydro) since radiant is soooo slow to do that by itself. Use of programable thermostats are viable too with this type of hybrid-heat.

[beenthere]

Originally posted by mechanicalmaster
Are you considering Central air if so you might want to look at doing a Hydro Air system for the first floor it incorporates an air handler with both a Hot water coil for Heat and also a Coil for A/C. I like these systems a lot ESP in a ranch style home.

It will never be as comfortable as infloor radiant.

[markwolf]

Originally posted by beenthere

Originally posted by mechanicalmaster
Are you considering Central air if so you might want to look at doing a Hydro Air system for the first floor it incorporates an air handler with both a Hot water coil for Heat and also a Coil for A/C. I like these systems a lot ESP in a ranch style home.

It will never be as comfortable as infloor radiant.

I agree.Also I would suggest touring a home with a gypcrete pour.The difference is worth every penny IMO