The Macon Telegraph
Energy Efficiency in Log Homes
When it comes to energy efficiency, a log home is very hard to beat. In addition to using materials and building techniques that most conventional builders are not aware of, the owner of a log home has another advantage sometimes not available to a home built in a predetermined subdivision layout, location! If a home can be designed from the start with the building site as a part of the plan, characteristics of the site can have a significant impact on the heating and cooling costs for many decades to come.
Most log homes are built on larger acreage tracts with both wooded and open sites available. Deliberately choosing a location that will allow the home to face South, with the predominance of porches on that side, and a stand of trees on the West will give the perfect conditions to incorporate passive solar into the home. How expensive is passive solar? In reality, it does not have a cost upgrade attached to it because it is simply the result of good design and common sense. Porches, combined with Low E (or low emissivity) glass will provide some pretty impressive benefits.
It works like this: In the summer, when the sun is high on the horizon, a South-facing porch will block most of the heat from the windows and the front wall of the home. What infrared heat energy that does get to the glass is reflected back off while still allowing visible light to enter the home. An added benefit is the filtering of approximately 84% of the harmful ultraviolet rays that damage and fade furniture, wall coverings, carpet, and window treatments. In the winter, it works a little differently. The sun is about 30 degrees lower on the horizon and can get under the porch to the south wall and windows where the bias coating on the Low E glass allows the radiant heat into the home. It still blocks most of the damaging ultraviolet rays.
The extra boost you receive is when the sun goes down and the outside temperature drops. Heat migrates from hot toward cold and this means toward windows. The Low E glass actually works to reflect the stored energy back into the home instead of allowing it to escape through the glass. While your walls may be well insulated, a single pane window will have an R=value of less than R=.5, yes thats ½ of an R=value and offers no radiant or UV protection. A quality insulated glass window with Low E coating will offer an average R=value of about R=3 and has the ability to block radiant heat while filtering out harmful UV.
As an example, a 2,500 s/f home in Macon can save approximately $400 per year in heating and cooling costs over a comparable home using only single pane clear glass. Combine this benefit with proper sitting, porch placement, a natural western screen, extended roof overhangs, and you can increase those savings even more.
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