Metal-framed windows in Alaska; problems with heat pumps; woodworking with birch

Alaska HomeWise: Ask a Builder

By Cold Climate Housing Research Center Staff

The “Ask a Builder” series is dedicated to answering some of the many questions Fairbanks residents have about building, energy and the many other parts of home life.

I heard that metal-framed windows are a bad choice for Alaska. Why and what should I do about it?

Most metal-framed windows are made from aluminum which is a highly conductive material. The laws of physics dictate that heat will always move in the direction of cold. When the temperatures drop outside, the aluminum acts as a pipeline, moving heat from inside to outside. Also, a colder window is more sensitive to moisture and will gather condensation.

Replacing metal frames is the preferable thing to do, however, not always practical. Fortunately, there are some other easy solutions. Covering the inside face of a window with a shrink wrap will create dead air space that will help keep the window warmer. Curtains and shutters will help as well.

I am thinking of putting in a heat pump system for my home. What types of problems are associated with heat pumps?

While they are a proven technology in the lower 48 states, heat pumps are still a relatively new technology in the state of Alaska. Heat pump performance can vary significantly with different soil conditions and site exposures. As a result, installations need to be evaluated on an individual basis.

When installing a heat pump system, caution must be taken around foundations. Installing a system too close to a foundation can increase the risk of potential permafrost problems, such as frost jacking. There is some question as to how a heat pump will work over time if it removes more heat from an area than can be replaced by surrounding soils and seasonal conditions, especially in Alaska where ground temperatures are cooler to begin with. On the positive side, there are methods to curb excessive cooling, such as adding a solar thermal collector to recharge the ground during the warmer seasons. This is also a proven technique, though, again, it has yet to be proven in Alaska.

Installation cost is another consideration, as the systems themselves can cost between $10,000 and $20,000. For the time being, heat pumps are showing good potential but we still need more trials in Alaska’s cold climate to give a definitive answer.

Do you have any advice for woodworking with local birch?

Birch is not used for framing and structural applications the way spruce is, but it does lend itself well to finish work. Birch has a lot of color. The heartwood can be very dark while the sapwood can be very light. In addition, the grain is rarely straight which gives the wood a ‘figure.’ After varnishing, the combination of colors and grain can be quite eye-catching. Each tree is unique and especially with birch, there can be big variations in wood appearance from one tree to the next. As examples, birch can add wonderful highlights to kitchen cabinets, and floors.

Birch is denser than cottonwood or spruce, making it better suited for stairways and tabletops. When working with birch, make sure there is plenty extra so any undesirable defects or twisting can be milled out or replaced. When it comes to panels and drawer fronts it is a good rule to varnish both sides and the edges, to keep the wood stable. As humidity changes over the seasons, moisture will penetrate an unvarnished side to a greater degree, which can cause warping.

Alaska HomeWise articles promote home awareness for the Cold Climate Housing Research Center (CCHRC). If you have a question, e-mail us at You can also call the CCHRC at (907) 457-3454.