Northern Lights: Gordon & Janice
Wrap-around porch. Corner sun room. Walk up attic. 3 BR. 1 story, 2328 sf
The Northern Lights plan is one of Sun Plans' earliest custom house designs and still represents the value of passive solar that Sun Plans incorporates today.
The first Northern Lights design was in NC in the early 1990's. It was one of the early passive solar homes designed by Debra Rucker Coleman based on the same principles integrated into her designs today. The Northern Lights plan was featured in a passive solar article in 1993 Fine Homebuilding Magazine. In an excerpt, the house is described: "Attention to details like insulation and air infiltration, plus selecting a builder sympathetic to their objectives also helped. The results have been gratifying. The passive-solar design, along with off-peak power rates, keeps the house comfortable year-round for an average of less than $30 a month." The all-electric home’s total energy bills averaged $68 per month and have increased very little since then. Gordon has meticulously recorded the energy consumption.
Rex Terrell, retired, of Burlington, N.C. was a builder who paid attention to details. Incorporating passive solar ideas was just one example of paying attention to what the clients wanted in their home. Walls were framed with 2x4’s, but the excellent fiberglass installation job compensates for the lesser depth available for insulation. ½” of rigid insulation on the exterior seals thermal breaks at each stud. The roof is framed with manufactured roof trusses, some of which are sloped on the bottom chord for a slightly vaulted effect. They are insulated with blown cellulose in the flat sections and carefully fitted fiberglass batts in the sloped areas. The entire roof is vented.
The south glass in the wood framed, aluminum clad windows is clear and the other sides have low-e glass. In moderate climates, it can be difficult to obtain low-e glass that lets in as much sun as is desired in a passive solar house. Homeowners often opt for clear glass to assure that the warmth of the winter sun makes it inside. Gordon wonders if low-e on the south would have made much difference in the energy bills. Their bills probably would have been higher in the winter and lower in the summer. Because the glass area of the south windows equals 10% of the floor area, the house needed additional thermal mass to maintain interior comfort. The thermal mass is in brick pavers in the southern rooms. Brick walls close to the south windows also help store heat.
There is a separate electrical meter for the air to air heat pump system installed by Harry Boody, who served as the third party energy consultant. Harry oversaw the insulation, caulking, and design of the HVAC system to be sure it was not over-sized which would reduce the efficiency and home comfort. He was so confident of the homes ability to conserve energy that he guaranteed their energy bills for the first three years.
Janice and Gordon only open their windows when humidity is low for several weeks in both spring and summer. The rest of the year they are either heating or cooling to some degree to maintain temperatures 68 degrees F in winter and 76 degrees F in summer. They use ceiling fans in the sun room and living room. Gordon, Janice, and their visitors like the open design, year-round comfort, and energy savings.
After the summer of 2010, Gordon gave us an update on their energy savings!
"Summer has been brutal here with record breaking number of days over 90 degrees - this is reflected in our total electric bill which was $110 for the month of July. Its usually in the $60-$70 range for all electric. Of course our friends tell us, 'Be thankful!'" - Gordon