Building Science Theory
It comes down to a catch-phrase known to all building scientists: the House as a System. The Department of Energy’s Building America program has been busy teaching this to homebuilders in recent years. In short, the house components interact with one another, with the external environment, and with you, the occupants. If one part changes, all the other parts adjust.
What is a Good “House System”?
As stated above, the house parts interact. We look to see if the key elements are working together. The house needs an effective thermal envelope (continuous insulation) that is also a good pressure envelope (continuously airtight) in order for the mechanical systems (furnace, A/C, water heater, ventilation) to do their jobs (maintaining comfort).
We look for appropriate amounts of insulation in the attic, exterior walls, and foundation. If the home has adequate insulation but there are many open penetrations (air leaks), then the thermal envelope is not effective. The same is true if penetrations are sealed but insulation is lacking. We also examine windows and window shading – which can help or hurt winter warmth and/or summer coolth.
We check the mechanical systems for size, efficiency, and delivery effectiveness. Restating what was said above, the heating and cooling systems should be capable of efficiently maintaining comfort – NOT establishing comfort! Establishing comfort is the job of the house envelope.
What About Occupants?
You, the occupants, are the most important (and variable) elements of the home. We’re alert to two issues; first, that the envelope and mechanical systems act in ways that guard your health; and second, how your lifestyle interacts with the house systems.
Looking first at safety, consider this: with a tight thermal envelope, less energy is used, but the home’s natural air exchange is decreased. Thus, less fresh air enters the home to dilute pollutants within the home – ranging from carbon monoxide, to basic household cleaners, to VOC’s outgassing from cabinets, carpets, etc. To reduce the threat from these pollutants, we check whether the home is exchanging enough air with the outside. If not, air exchange fans can be added to the home. The addition of a carbon monoxide detector on every level where occupants sleep is HIGHLY encouraged as well.
Finally, your lifestyle choices have a huge impact on energy use. We understand and respect that these are YOUR choices – and we will let you know how small changes can be made in daily habits to make a large difference in energy consumption. Getting a year’s worth of your utility bills to us a few days before your audit is very helpful. This allows us to begin to see patterns that are clues for a more effective audit.
Our Goal on Your Behalf
Lightly Treading, home energy efficiency experts, want to help you optimize and improve your home so that it is the most effective system possible, within limits you define. It should waste little while providing you comfort – physical, mental & spiritual comfort… and financial comfort.