Creating an Energy Efficient Envelope

The EarthCraft House Standard rests solidly on the EPA EnergyStar energy efficiency platform. While much can be done to address energy conservation inside the house -- lighting, appliances, etc. -- the most important step is to make sure that the "building envelope" is tight.

Starting with the Foundation
To ensure an energy efficient and waterproof basement and foundation we went with the Arxx ICF (Insulated Concrete Forms) that yield an R-50 equivalent wall. The quick construction, clean look and ease of covering both the exterior and interior, were added benefits. While we could have opted for the entire frame to have been ICF and therefore addressed walls and insulation in one step, we had already decided on traditional woodframe for the above-ground portions of the house.

Invest in Good Windows
Windows are a very expensive component in any construction project. While almost all codes require double-pane windows, not all windows are created equally. In our past homes we've had all-too-much experience with double-hung windows that begin to fail early in their life -- rotted seals, sagging weatherstripping and slipping upper windows that leave cracks for air infiltration. In our last neighborhood of custom homes, most owners were faced with replacing all windows at somewhere between 12 and 18 years.

After deciding that we would indeed "invest" in good windows we arrived at Marvin Windows & Doors -- www.marvin.com. Marvin produces one of the best products in the market and they have additionally taken a leadership role in ensuring that their product components (e.g. wood) come from well-managed sources. We went with the casement windows because they offer a much tighter fit and, in our experience, have a longer life than double-hung windows. The wood frames are all clad with aluminum exterior to withstand the harsh southern environment.

We could have purchased windows at a much lower price, but when looking at "total cost of ownership" (original cost + maintenance + durability) -- not just original purchase price, we think Marvin offered real value.

Insulating the Rest
With the Arxx ICF's making up the basement walls and Marvin windows efficiently letting light into the structure, the next decision was how to insulate the remainder of the envelope. After having had traditional batt or blown- Fiberglas insulation in all of our other houses, we knew that this wasn't the direction we wanted to go. In fact, that decision was driven home when I visited a $750,ooo house under construction. As the sun was setting in the west, there were numerous "lines of light" streaming through the walls where the batts didn't quite meet the studs. Sure, many of these gaps would be addressed by the siding, but clearly there would still be lots of opportunities for air infiltration.

We focused our review on one of the many spray foam insulation products on the market and came down on BioBased System's spray foam -- www.biobased.net -- a product that wasn't then available in the Carolinas. Spray foams offer a host of benefits, among them 1) complete seals with no gaps, 2) none of the dust or airborne particles that persist forever with Fiberglas, 3) a "sound proofing" effect that far exceeds that of Fiberglas, and 4) moisture resistance that essentially eliminates the possibility of mold or mildew and other allergens. Yet, on the environmental side, all spray foams are produced with petroleum. That's where BioBased rises above the rest. While it has all of the same benefits of other foam products, BioBased replaces a significant portion of the petroleum with American-grown and renewable soybean oil.

Addressing the Entire Envelope
One of the other added benefits of spray foam is that insulation is applied directly to the underside of the roof. Thus, instead of having a layer of insulation in the ceiling thus leaving the attic space to overheat in the summer and be cold and damp in the winter, the attic becomes a "semi-conditioned" space. Not only can one go into the attic without having to wear a mask and goggles to avoid Fiberglas particles, but the space now will vary from that within the house by perhaps only a couple of degrees in any season. Thus, our HVAC won't have to be "competing against" the temperature in the attic or the unfinished basement, as both are semi-conditioned. We were especially pleased by the enthusiasm that John Bessettia Enterprises, LLC of Greenville (the Upstate BioBased Dealer) 864-277-4240) brought to our job.

Saving Money from Day One
BioBased Insulating Foam is at least twice as expensive as traditional Fiberglas insulation at the beginning. However, if one factors that cost into a mortgage and then considers the monthly savings in energy bills, the product actually begins paying off in the first month of operation ... and every month thereafter as the added cost of the mortgage will likely be far less than the savings in energy. In fact, a number of lenders have caught on to the fact that the energy and health gains of environmentally-friendly construction allow the average homeowner to qualify for a larger loan. These "green loans" are increasingly popular and available.