A look at High Thermal Mass (HTM) homes in warm and cold climates.

The topic of High Thermal Mass homes is generating a lot of buzz lately, and that has many people wondering if it is just hype or something real?

What is thermal mass?

Thermal mass is simply a solid or liquid that is capable of storing heat. Most objects in your home can be thought of as thermal mass, like furniture, books, and plaster. However, these items are not intentionally designed to store heat for home heating. When it comes to home construction, thermal mass usually refers to building materials such as stone, concrete, and gypsum. Generally speaking, denser materials can store more heat than less dense materials.

High Thermal Mass Homes

Traditional hot climate homes usually have thick stone or adobe walls. When daytime temperates climb above 80 degrees F or so and nighttime temperatures are below 65 degrees F, this type of wall construction works well. At dawn, the interior walls are cool and heat gradually penetrates the material through the afternoon. By the time the sun has set and temperatures are dropping, heat has completely penetrated the thick walls. Then the walls release some of their home heating into the interior, keeping the occupants warm even though outside temperatures are cool. The cycle is then repeated the next day.

When weather does not follow this pattern, thing do not work as well. In winter, if the outside temperatures are cold for 24 hours, the walls do not get warm. Conversely, during the summer, they are not able to cool off.

When it comes to heating options and htm buildings, there is an important point to remember. When this type of home was commonly built, whether it is Arizona or Iraq, the builders had limited options when it came to construction materials. Their choices were basically mud or stone. They had no access to insulation, air conditioners, or heating systems. If so, they probably would have used them.

Heating Options and Savings

Research has found that htm buildings only produce energy savings in a few select parts of the country. Areas in the Southwest like Arizona and New Mexico see the most benefit. Almost no benefit is seen in northern climates where outdoor temperatures in winter are far below indoor temperatures. So, for example, htm buildings would work best in Phoenix and perform poorly in Minneapolis.