Energy Efficient Log Homes
Everyone loves their natural beauty, but is a Log Home the energy efficient? How can a stack of logs keep out the cold? Won't I be wasting my hard-earned money trying to keep the house warm.
First a little bit about R-values and insulation. The R-value of a material refers to its resistance to heat flow and was adopted in the 1970s during the first energy crisis as a simple factor to compare energy efficiency.
So we commonly see R-value ratings for things like Glass-fibre insulation, where 90mm designed to fill a 2 x 4 wall is rated at R-13, and 140mm designed to fill a 2 x 6 wall is rated at R-19. But in the laboratory where they do the rating, the Glass-fibre is actually enclosed in plastic completely stopping any air flow (unlike the real world) and the difference in temperature that is measured is only 10 degrees (again, vastly different from comparing outside and inside temperatures of a house in Finland in the winter where the temperature differential might be 70 degrees or more). This is a complex issue.
Logs take advantage of what is referred to as "thermal mass" effect, using the heat capacity of the wall. That is, the mass of the solid wood absorbs and holds the heat and slowly releases it over time. Studies done in the US by the National Bureau of Standards compared energy costs between houses insulated with Glass-fibre to a value of R-13 and log homes built with 170mm thick square logs. They showed that the two homes used the same amount of energy, even though the timber-framed house had a nominal R-value 17% higher.
The energy efficiency of log homes can be as much as 15% more than conventional timber-framed homes.
This will reduce your monthly energy bill, since the DOE estimates that 44% of your total utility bill pays for heating and cooling of your home. Your log home will feel more comfortable and long-term maintenance will be reduced.