1509 State Hwy 102 | Bar Harbor, ME 04609 | Phone (207) 288-3163 | Fax (207) 288-8061
1509 State Hwy 102 | Bar Harbor, ME 04609 | Phone (207) 288-3163 | Fax (207) 288-8061
Radiant Floor
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Radiant Floor heating is not new. The ancient Romans built fires under masonry floors. Over the ages it has appeared and reappeared. Thankfully now, do to modern Materials you don't have to be a roman emperor to have warm feet. Of course, the best feature of radiant heat is the level of comfort, but I personally am very excited about the energy savings. By using radiant heating systems homes can be heated with very low water temperatures.
I have witnessed, over the years, different technologies become popular, some fade away and some stick. In the mid nineteen-seventies wood boilers & furnaces became the rage. It seemed like everyone was building & selling them. I was fortunate because at my school was the "Energy Testing Laboratory of Maine" (This was the national listing agency, the U.L. of solid fuel ). I saw what happens when a type of product becomes in vogue, and the market becomes flooded by manufacturers out to cash in. "A Lot of Garbage hits the Streets".
In the late Seventies and early Eighties, Solar Hot Water Heating was the ticket. Once again it happened hundreds of solar manufacturers were out there peddling their stuff and once again, "A Lot of Garbage hits the Streets".
Now we are in the age of "Radiant Floor Heating" and it seems that everyone and his brother is making it & selling it. And, you guessed it, "A Lot of Garbage hits the Streets". Whether it be their method of installation, their tubing, the fittings, their insulation, or any other of the multitude of accessories, consumers should be cautious.
Two major tubing failures have already occurred resulting in multimillion dollar lawsuits, & settlements. Those are Polybutylene, & Heatway Entran (rubber tubing). It seems certain now we have shaken out the bad tubing. Maybe.
PEX is the right stuff. But now the challenge is, everyone & his brother that can extrude polyethylene is making PEX. (By the way PE stands for polyethylene & X stands for cross linking of the PE at a molecular level, giving the tubing great strength, to withstand pressure & temperature). As with all products there is good, and not so good.
I visited a plant on a hillside in the middle of nowhere in Ireland. Among my group was an American boiler company representative, he was checking out the products to consider importing their tubing & re-labeling it with their name. While it was truly fascinating watching the production, I felt I was visitng an illegal moonshine operation. It was an eye opening experience. Seeing, what type of operation is probably, producing a lot of the obscure PEX products flooding the market.
The internet has become a source for a lot of shaky science & products. Beware! Internet is wonderful in many ways, but people to often use it to find bargains. Being a frugal yankee , I love a good deal but I try to recognize "if it sounds to good to be true, it probably is". I strongly suggest sticking with the big name products - "Wirsbo", "Stadler", and "Rehau", just to name a few.
Buy tubing that is manufactured by the company whose name is on it. A product may say "ACME TUBING" on it but that does not mean "ACME" produced it. There are many companies that change their supplier based on a penny-or-two price difference per foot, and you may end up buying a different product than what your neighbor bought last month.
Another important consideration is the "Oxygen Barrier". I was surprised and very skeptical when I first heard that oxygen will pass through the walls of plastic pipe (and concrete). There was a great deal of debate when plastic tubing was first being used for radiant heat. Why should it Matter..? Well, first of all fresh water is very corrosive (it will eat through steel (even low grade Stainless, or cast Iron). In our "closed" heating systems the water becomes "dead". The systems do not continually add water as some people believe, but it is in fact the same water reheated and re-circulated. The air (with oxygen) is expelled from the system and the water loses it corrosive characteristics.
It is hard to believe that this water we drink can ruin a boiler vessel, but it does.
Polybutylene tubing was used extensively for radiant heat, it had no barrier. We replace 2-3 failed boilers per year, because of non Barrier tubing. When we perform the replacement we install a heat exchanger to protect the new boiler from the old tubing.
In the rush to radiant floor heat systems, people are working like hell to find a way to do it cheaper.
Because the water Temperatures are relatively low many people have decided a simple water heater can do the job. There are some hybrid water heaters, (but they cost as much as a boiler) available for this type of application and they do work, but the regular household models are not intended for this usage. Because they can stand fresh water, some internet companies propose there use and then sell non barrier tubing, to go with them.
There are several reasons not to try this. First of all it is against Maine State Plumbing Code. While you can do it yourself and it can be made to work, you might get away with it for a while, but someday for some reason you may have to call a professional to work on it and you will probably find it hard to get a licensed pro to touch it. Also, it can affect the sale of your property. There is also potential health risk if you are circulating domestic water through your floor, and then shower in it later. Legoinare's Disease is one of the problems that can occur as well as other bacterial growth that can happen in stagnant water.
I hope I have not scared anyone away from Radiant Heat, this was not my intention. I strongly believe it is the best heat system going.
Methods of installation have been developed to install the heat tubes in ceilings & walls, as well the floor.
There are several
methods for installing the tubing in floors. In "concrete
slab" is hands down the best method the mass is a great
sink, and you can run very low temperatures.
Many homes are conventional wood frame construction, so methods
have been developed to incorporate tubing, into the structure.
The most common & effective is a light weight "concrete
overpour".
Methods of
attaching the tubing to the underside of the floor are very
common in retrofit applications. the most effective of this type
employ aluminum plates to transfer the heat by way of conduction
directly to the sub-floor.
The least
effective is called "joist bay" heating.The idea being
that the tubing heats the air in a space in the joist bay.
This is the fastest, easiest, and cheapest installation method,
but it is also the leading method of systems that do not work
effectively. Operating costs are also higher than any other
system.
Getting the
tubing closer to the surface is most effective. It allows the use
of lower water temperatures, and delivers much quicker
response times. Some very well developed products are available
which make these systems easy to install. "Wirsbo Quick
Trak" and and "RauPanels".
(I think this happy couple is looking at some photos of our work.)
There are many factors that must be considered in the installation of Radiant floor systems, but are too numerous to fit into in this short article.
What ever you do,
make sure it is a decision you are willing to live with for years
to come. Initial cost is only part of the selection process. Over
time the cheaper system will cost more.