Home Energy Q&A
By
KEN SHEINKOPF - McClatchy-Tribune News Service --
Q: I'm trying to learn as much as I can about saving energy so that
we can start saving some money. One term I keep running into is
"building envelope." I think I can figure out what this is, but can
you please clarify the term for me?
A: Sure. This simply refers to the basic elements of your home that
protect it from the outdoors - the walls, roof, windows and the
foundation.
The reason you're seeing this so often in articles about energy
efficiency is not only that that the building envelope (sometimes
called the thermal envelope) is really the key to a home's energy
use, but any needed improvements to make it even better are usually
easy to do and in many cases are fairly inexpensive.
Here's what I mean. Over the years, I've written dozens of columns
on the need to caulk and weatherstrip the basic elements of the
building envelope. By filling in any gaps or holes where air can
flow into and out of your home, you can keep the interior more
comfortable, quieter, and insect-free while minimizing energy waste.
Air infiltration (the unwanted flow of air into and out of a
building) can be a major source of energy waste, driving up your
power bills unnecessarily. Even someone with minimal do-it-yourself
skills can calk holes and apply weatherstripping to doors and
windows.
IIf you've got some basic home fix-it ability, you can add insulation
in your attic to bring it up to recommended levels for your climate,
though contractors can be hired to do this job. Insulation is a
critical component of your home's envelope. Many homes in the
The most expensive parts of the envelope to keep at their optimum
effectiveness are the windows, once considered the weak link in the
building envelope. Today's window technologies, however, make them
an integral part of your home's envelope while successfully
protecting the home from the elements. The investment a homeowner
makes in good windows will pay back that cost over time in greatly
increased indoor comfort and lowered utility bills.
The laws of physics tell us that heat flows from warm objects to
cooler ones, meaning that any gaps in your home's thermal envelope
will allow your heated air in winter to flow outside, while the hot
outdoor air in summer will flow indoors. Having a good building
envelope protects your home while minimizing energy waste and
keeping your utility bills low.
By the way, I often get into discussions on a home's building
envelope when people talk to me about drafts in their home, a fairly
common problem caused by gaps in walls (especially around areas
where wires or pipes come into the home) or around windows or doors
(a problem that occurs often because these objects are opened and
closed often).
(Ken Sheinkopf is a communications specialist with the American
Solar Energy Society (www.ases.org). Send your energy questions to
askken(AT)ases.org.)