How to build a home that if it were a car, would get 100 mpg - Part I

Energy efficiency is, and has always been, one of the key reasons for building a radiant floor heated home. Given the rapidly escalating cost of energy, the efficiency of radiant has never been more important.

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What makes radiant heat so energy efficient?

- Parasitic losses.
- Lower ceiling temperatures.
- Zoning reduces energy usage.
- Lower air temperatures for the same comfort.
- Blowing hot air paradoxically can cool us.
- KSU study. A study of all of these effects was done at Kansas State University in conjunction with the American Society of Heating Refrigeration and Air-conditioning Engineers (ASHRAE) that established that a more or less typical radiant heated home in the US can expect 25% savings over a conventional forced air home.

Warmboard drives these energy savings numbers higher for several reasons:

- Warmboard is the most conductive radiant panel assembly.
The basic equation for heat flow is: heat flow (F) equals delta T (ΔT) times Coefficient of Conductivity (K) times cross sectional area (A) divided by the length (L) over which heat must flow.

It is a principle of thermodynamics, established by this formula that as conductivity goes up, water temperature can go down. It is always less expensive to heat water to a low temperature han a high one. It is well accepted in the boiler industry that for every three degrees that you lower the water temperature, you save 1% of the cost to heat that water. This means that compared to the least conductive radiant floor systems (staple up) our water temperatures are as much as 60 degrees lower for the same heat output. Compared to the commonly used thin slab systems, Warmboard uses as much as 30 degree lower water temperatures. This means an additional 10-20% savings over these more antiquated radiant panel assemblies.

- Warmboard maximizes the efficiency of condensing boilers. See Part II of this blog for specifics.
- Warmboard’s low mass allows the efficiency of temporary temperature set back.
- Warmboard’s low mass prevents overshoot.
- Warmboard’s low water temperature requirements are ideal for alternative heat sources.

Save thousands on fuel costs each year.
Modern homes are well insulated, have excellent glazing, low energy usage lighting and many energy efficient solutions that make them seem more like the 40 mpg gallon economy cars we see on the road today than the gas guzzlers of the past. But if you add a radiant heat system to that otherwise efficient home and combine it with a fast response, low mass, highly conductive Warmboard radiant subfloor, in effect, you can start approaching the ownership of a home that behaves, by comparison, more like a car that gets 100MPG. We say this not only because of the theoretical savings detailed above, but because we have many homeowners living with the comfort of Warmboard heat in their homes who report heating bills as much as 60% lower than similar sized homes in the same community. If you might normally expect to pay $5,000 to heat your home through the cold months, bills in the $2,000 range are what many Warmboard homeowners are experiencing. But remember, your mileage may vary.