How Thermal Mass Works In Your Home



Getting a little free heating can go a long way on your utility bill, particularly over the life of a structure. Passive solar heating is the methodology used to achieve this goal. It is a process wherein a home is built or upgraded in such a way as to catch and contain as much of the sunlight in the form of heat as possible. To effectively use solar for heating, thermal mass is a subject you need to understand.

Thermal mass simply refers to any material that absorbs and stores heat. In this case, we are obviously talking about material that stores the heat inherent in sunlight and disperses it at a later time once the sunlight is no longer hitting it. You may not realize it, but your home already has thermal mass producing heat. Any material exposed to the sun, furniture, floors and such, acts as thermal mass. Unfortunately, it is usually on a pretty small scale.

Often called intentional thermal mass, a passive solar home will have strategically placed materials that are very efficient at absorbing and radiating heat. While this may sound complex, it really is not. The materials include items such as bricks, tile and masonry. Adobe and clay materials also function well in certain situations.

In a passive solar home, you need the thermal mass in the interior of the home. Strategically placing tile and brick in areas below windows that receive significant sun during the day will often do the trick. Depending on your heating needs, the amount of thermal mass you use will vary. In colder climates, it should be used in bulk while homes in Arizona need only nominal amounts.

One common misunderstanding regarding thermal materials refers to their color. Logically, it would seem to make sense that the materials need to be dark since dark colors absorb more heat. This is not particularly true in passive solar. It is the material, not the color, that makes the difference. Bricks can be just about any light color, but not white. This may sound insignificant, but it can be a major benefit if you want to avoid a dark, gloomy interior in your home.

If you are trying to harness the power of the sun for heating purposes, you need to get a good grasp of the thermal products you will use. This should give you a head start.