Second, I learned that if you want to take advantage of passive solar energy, you should design the roof overhangs to allow winter sunlight in while keeping most of the summer light out. This would reduce the need for summer cooling and winter heating. I was all for that.

After much searching, I found a beautiful 5-acre piece of land in northern Wake County, NC, that sat 100 feet above a small private lake surrounded by hundreds of acres of (at least currently) undeveloped land. Great! Unfortunately the orientation of the house to the lake would have to be east/west, not north/south. “That’s okay,” I thought. I could still build a passive solar home and make up some of the loss in orientation. Then I found out that most passive solar houses are ranch style, and given the need for bedrooms for our large family, the cost of building a ranch style home large enough (an estimated 4,400 square feet) to accommodate our needs was impractical.

Not a good start. Oh, and one more thing. The site had a stunning view of the lake, so I wanted lots of windows facing the water. I read that while the extra glass would reduce the need for interior lighting, windows are notoriously poor insulators compared to solid walls. But to be near water and not see it, impossible!

As a long-time climate change researcher, I was used to adversity. So with shovel in hand, I began to dig myself out of the energy use hole that I had created for myself.

But You Just Might Find...

My task was to reduce heating and cooling energy use for 4,400 square feet of heated space. After some Internet surfing, I learned that building supply manufactures have developed oriented strand board (OSB) with an aluminum side designed to reflect heat. Most heat exchange actually occurs through the roof, so I decided to cover the roof in the reflective material and use traditional (uncoated) OSB for the side walls. The cost of the reflective OSB was about $3 more per 4- by 8-foot panel compared to the uncoated panels; the total cost for the roof upgrade was about $500.

Next I needed to address the windows, which took up 23 percent of the total wall space of the house. Wherever possible, I used fixed glass panels, which reduce air transfer. Since they are less expensive to build and install than other options, I was able to have them built as double panes with an argon gas-filled interior that can reduce solar radiant heat by 80 percent. By combining these options, I ended up not paying any extra for the windows, and greatly improved home energy efficiency.

The windows were set, so it was time to turn my attention toward the other 77 percent of the exterior space, i.e., the walls and doors. First, I looked at insulating the walls. There are some really remarkable products on the market these days; insulated concrete forms—basically poured concrete forms made out of insulated foam—are very attractive as building materials. Though the norm in Europe, this very energy efficient form of construction is still relatively new here and very expensive.

So I decided to use blown insulation in the walls. An air permeable mesh was placed over the stud walls, and the insulating material blown into the cavity. Made mostly from recycled newspaper, this material seals much better than traditional fiberglass batting (the pink stuff that comes on a roll), and uses material that would otherwise go into a landfill; the good news is that blown insulation for the whole house only cost $400 more than traditional fiberglass batting. Cellulose foam was another attractive option, but the cost for my house would have been three times that of the blown insulation ($14,000 vs. $5,000).

All the major door manufacturers sell insulated exterior doors that cost only a little more than hollow core versions, so that was an easy choice to make. Whenever possible, I used doors and other materials from the local Habitat for Humanity Recycle Center (HHRC), which always has wonderful donated new and used material. Another plus is that proceeds from the sales go towards building new homes for low-income families. I found a beautiful front door that had been special ordered at one of the local hardware stores and never picked up. The store had donated the $3,300 door to HHRC, where I bought it for $1,000.

You Get What You Need

After the house was completed, I was anxious to see if all my attempts at energy savings paid off. I was very pleased to see my July utility bill was $178, which was about half the bill from my previous smaller—but far less energy efficient—home. Raleigh had eight (yes, eight!) record highs in August, but I experienced far less dread about what the mail would bring me!

For more information:

Cathryn Greenberg at 828–667–5261, x118 or kgreenberg@fs.fed.us.