AUTHOR: Brandon De Young
In my last post, I described some of the cutting-edge equipment used to heat and cool our De Young homes. With high-efficient HVAC technology, our homes use much less energy than a new home merely built to the standard California energy code. This makes a big difference for our homeowners when it comes to comfort and their energy bills. Especially here in the Central Valley given the drastic temperatures during the summer and winter months.
Another aspect of the home that we really focus on is the thermal envelope. This is what keeps heat in your home when it’s cold outside, and out when it’s hot. The two crucial characteristics of a high-performing thermal envelope are its insulation value and its air-tightness. The higher the insulation value and air-tightness of the envelope, the more you’ll be able to control whether heat stays inside, or outside depending upon the season, and ultimately, save money!
Generally, your home’s walls, ceiling and floor are all part of this envelope. Therefore, every material that goes into these areas of the home are specifically chosen to create the most effective envelope possible. For example, in addition to the insulation we install between the wood 2×4’s in our walls, we install a continuous wrap of 1” thick insulation board around the exterior of the home before installing stucco. It’s a really cost-effective way to add insulation, as well as help with the air-tightness of the home, too.
Another example of a component that we focus on in the thermal envelope is the window. Windows are GREAT for letting natural light in and making a room feel more spacious, but they’re generally terrible at insulating. Even some of the highest performing out there only achieve an R value of around 4. To put that in perspective, a section of our walls without a window can achieve up to R-19! That said, it’s important to use high-efficient windows when trying to reduce heat loss (in winter) and heat gain (in summer). Our Monte Verde windows (made locally by Anlin) are some of the best out there with great thermal performance.
The next important step is to ensure a tight fit when putting the pieces together. A common way of doing this is by air-sealing the insides of our walls and attic floor wherever there are penetrations before insulating. Here is a great image that may help you visualize the thermal envelope and where air leaks most commonly occur. Once air-sealed, insulated and drywalled, our homes are third-party tested using what’s known as the “Blower Door”, to ensure a very air-tight fit. This saves our homeowners lots of energy throughout the year.
Obviously, there is a lot of research and science involved when it comes to building an energy-efficient home these days. We feel that it is worth spending the time on, and given the great feedback we’ve received from our homeowners, it appears they do, too.