Understanding and Calculating Building Heat Loss to the Ground

Starting with with the 2D THERM model of a basement, we'll look at the U factor that THERM calculates for the foundation assembly, and use that to calculate the design heat loss of the basement, and estimate the annual heat loss as well.

We'll do a quick reality check to vet that calculation, then present the simplified Los Alamos algorithms for calculating heat loss from basements and slab-on-grade foundations. We'll apply use these to analyze our model and compare the result with the THERM calculation. We'll discuss how to apply these algorithms to a walk-out basement condition. Finally, we'll look at how to estimate design heat loss in the case where the insulation is in the frame floor over a basement.

Learning Takeaways

• Learn about relative conductivity and heat capacity of soils vs. air
• Learn about variations in soil temperature with time and depth
• See the results of a 2D THERM model of a basement, including the temperature distribution, direction of heat flow, and heat loss rates
• Learn about using the U factor calculated by THERM to estimate foundation heat loss
• Learn how to do simplified heat loss calculations for basements, slab-on-grade, and walkout basement foundations
• Learn how to estimate design heat loss through an insulated floor to a basement below