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Passive solar homes a reality at Rainbow

Design uses sunlight, insulation to cut energy costs
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At the top of the Rainbow subdivision, just below the future Baxter Creek development, sit three partially built single-family homes on three small lots. In a neighbourhood that is very much still under construction they don't stick out, but from top to bottom they were designed to be different.

Constructed by RDC Fine Homes, these units will use significantly less power than other homes in the subdivision by employing passive solar construction techniques as well as high-end building materials and inventive design.

Not only will these houses require less energy to heat and cool, the design will also improve indoor air quality. The kicker? Thanks to some design innovations, they actually cost less to build than units across the road with similar square footage.

RDC president Bob Deeks explains how this is possible.

"The big thing (about passive solar) is about getting the majority of your glazing to the sun," he said, indicating the second floor sliding doors and windows that overlook Green Lake. "These windows were aligned so they get optimal sunlight during the winter months when the sun is at a low angle in the sky."

Using computer modeling, Deeks said the design also takes into account the sun's position during the summer. The sliding doors are recessed slightly to increase shade, and there is a four-foot overhang from the roof that keeps the sun off the windows when the sun is directly overhead.

In fact, the majority of windows in the unit are south facing, aside from one window in the kitchen to provide light and fresh air and another window off the laundry room to accommodate a clothesline to the backyard. Upstairs there are large dormer windows to provide light and large bedroom windows on the south facing side.

The energy savings will be significant, says Deeks. For example, he says a home that uses passive solar can immediately reduce their power demands by up to 30 per cent. By comparison, a home that aligns its windows to face north can see a 30 per cent increase.

Drying your clothes outside can also reduce power costs by up to 25 per cent if you do a lot of laundry.

Deeks says he has heard the rumour that clotheslines are against Whistler's bylaws, but says he has yet to come across that law in all his years of building and renovating homes. If there is such a thing, he says he would welcome the debate.

"That's not something I would imagine would ever get enforced in Whistler, even if it did exist. If it is on the books then we should be getting rid of it and encouraging more dry racks and lines," said Deeks.

All three of the passive houses are plumbed for solar hot water heaters, although only one of the residents will be installing a system. The trick to making that technology work in Whistler, says Deeks, is to change habits and use hot water for dishes and laundry during the day when the sun is brightest.

"The industry will tell you that you can service up to 50 per cent of your domestic hot water needs over 12 months, but it hasn't really been tested up here," he said. "I think the biggest benefit will require adjusting your lifestyle and using hot water when it's hot and sunny out."

All of the glass in the units is triple glazed, which provides a higher insulation rating than double-glazed windows. As Deeks explains, windows are usually the weakest point in a home's insulation, unless you install the most efficient windows and frames.

The walls also contain the highest quality insulation, which is covered by prefabricated structurally insulated panels (SIP). The panels themselves are delivered cut to size. In order to reduce costs Deeks's team designed the home with specific dimensions to accommodate the four-foot wide panels and ensure a minimum of cutting. As well, the gaps between panels have been filled with silicon and insulation, creating a seal.

"The best insulated home is the one that is completely sealed," explained Deeks.

The roof was also designed using single sheets of SIP with no cuts required, easily allowing Deeks's crew to install the roofs over all three units in a single day.

"Typically the roof is the most expensive part of building a house, and for us it was the easiest," said Deeks.

Each home also includes an airtight wood-burning stove, which can heat the entire house. Deeks says he wrestled with the idea of installing the wood stoves but after doing some research he determined that an airtight unit was extremely efficient and only requires a small amount of wood to heat a place. As well, burning wood produced the same amount of carbon dioxide as a dead tree left in a forest.

The homes are also designed with a heat recovery ventilation (HRV) system installed that will improve indoor air quality.

Under the provincial building code a home is required to vent a certain amount of inside air each day, which is usually accomplished by bathroom fans that are programmed to run on their own. However, that usually means that heated air is blown outside and cold air is drawn in through gaps in the windows and from under doors to maintain air pressure. By comparison, an HRV system draws in cool air where it's warmed by the waste air before venting it back into the house. The systems can recover around 80 per cent of waste heat, says Deeks.

"The result is a house that's very comfortable in every room, warm in the winter and cool in the summer," said Deeks.

Two of the three homes are already spoken for, one for a couple that works at RDC and another by a contractor that works with the company. Both qualified through the Whistler Housing Authority.

The third home is still available, and will also be offered through the WHA.