I’m not sure how I first discovered Therm, which is a software program developed by the Department of Energy. I think Therm started in Berkeley. Let’s just say it is a singularly elegant and useful software application for energy investigations.
Therm provides the answer to the question: What is the thermal performance of this particular assembly? Let’s say you have studs at 16 inches on center, with batt insulation in between. Therm can provide the overall U value. Let’s say you have a particular window jamb detail. Therm can tell you the overall U value.
Therm let’s you know what your wall and opening assemblies are really giving you. I think that’s why Passive House Institute U.S is enamored with Therm. We happen to be quite adept at using it.
PassiveHaus, or Passive House in the United States, is interested in a minimal amount of energy expenditure for human comfort in an interior environment. What is this minimum amount? Well, it seems to be the amount of energy necessary to modulate ventilation air. In other words, the energy consumption of a house or other building should be no greater than the amount of energy necessary to either heat or cool fresh air required for ventilation purposes. That’s not a lot of energy.
How can you reach this? Well, one needs to know their exterior envelope design is optimized for a minimum of energy transfer. Therm is the perfect software tool to do this analysis.