Foundation Heating Loss

Heat loss is influenced by many different factors. One of them is the thermal resistance of materials. Thermal resistance has to do with a material's resistance to heat flow. The higher the resistance, the more a material resist heat flow. Thus, the greater the resistance, given equal temperatures on the giving and receiving material, the slower the transfer of heat. 

It is important to note that if the difference of temperature increases, so does the heat of transfer. In addition, the larger the surface area, the greater the heat of transfer.

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For hydronic heating in San Francisco, please contact Arch Plumbing. 

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Now, regarding the foundation, heat flow from it depends on several factors, including the surrounding soil, insulation materials, and the air temperature. In a building with a heated floor but uninsulated floor, the heat flow travels downward from the slab to the soil. 

This can be improved by using 2 inches of insulation that is installed under the floor slab, cutting down the heat loss by 50%. Insulation definitely pays off in this scenario.

Now, when analyzing foundation heat loss, there is also the factor of the walls. When the soil outside the walls is higher, the more thermal resistance and thus the lower the heat loss. 

Another factor is slab on grade (instead of basement or crawl types) in which heat flows downward. It is interesting that in this foundation type, heat will flow faster on the edges as they are exposed to the colder air outside vs the soil beneath the center of the foundation. Thus, different insulating materials can be used near the edges on this type of foundation.