Home improvement

 by: Larry B Lang

Designing an effective radiant heating system takes careful planning and preparation.

With radiant heat, one must calculate the heat loss of the structure, tube spacing, tube sizing, loop length, pump sizing, zoning, boiler capability, and homeowner requirements.

All these things must be engineered to work together and careful consideration must go into calculating the radiant heat output to meet the heat loss demands of the home.

Joseph and Nora Steckly had counted on the even distribution of their in-floor radiant heating system to lower their heating bills during their retirement years.

>From the beginning, they were sold on the benefits of in-floor radiant heat. They had heard how a radiant heat system was comfortable, quiet and cost effective to operate.

Relative to other types of central heating systems, generally with radiant floor heating, thermostats can be set several degrees lower. This is primarily because the entire surface of the floor radiates about the same amount of heat that the human body does, making the occupant feel warm even though the air temperature might be only 65ºF (18ºC).

With an in-floor system, heat radiates for a longer period of time. When compared to a forced-air system, radiant heat results in a lot less outside air penetration. In fact, radiant floor heating boasts a fuel savings of 15% to 20% over forced-air systems.

A floor sensor controls the flow of water that heats the room. It’s this sensor or thermostat that controls the temperature instead of a wall thermostat. The system is often designed to keep the circulation pump(s) running while the thermostat controls the boiler's burner.

Given all these facts, Joseph and Nora were extremely surprised to receive an incredibly outrageous propane bill after their radiant heat installation.

Upon further investigation, I discovered that the size of radiant heat tubing placed in the Steckly home was far too small for their radiant heating needs. Their boiler was working overtime to heat the water and transfer it throughout the house.

This was a significant mistake for a radiant heating system installation that would have easily been avoided with a competent radiant heat system design.

Since the popularity of in-floor radiant heat has increased, so have the number of installers and so-called designers. Keep in mind that not all general contractors are radiant heat specialists. As a homeowner, you need to ask the tough questions and find out exactly how much experience they have in the design and installation of an in-floor radiant heat system.

There are many factors to consider when designing your system, especially the floor covering. Wood flooring and thick carpets act as an insulation blanket, restricting upward heat flow and reducing the efficiency of the system.

It’s important to realize that a change in floor covering can affect your radiant heating system. The water temperature of your radiant heating system would need to be adjusted if changing from a bare or painted finished floor slab to ceramic tile, wood flooring or carpet with underlay.

Joseph and Nora had no idea that the size of radiant heat tubes that were installed was so inefficient. It was a costly radiant heat design error that resulted in a complete gut and reinstallation of their in-floor radiant heating system. Don’t let this type of mistake happen to you.

To make sure you maximize the effectiveness of your in-floor radiant heating system, everyone involved with its installation should be given a copy of the radiant heat design. You, as a homeowner, should be aware of the location of the tubing so that at a later date if you want to do more renovations, you can protect the system from damage.