Large, insulated `half-log’ kit homes are super energy efficient

Q. I have seen some very attractive large (over 2,500 square feet) build-it-yourself log home kits. They are super-efficient and designed for free passive solar heating too. How can they make log homes efficient? — S.M.

A. You are referring to insulated “half-log” kit homes. These are super-efficient. Your monthly utility bills will be just a fraction of those for a similar size conventional house.

These home are ideal for the inexperienced do-it-yourself builder/helper. You can dramatically reduce the overall building costs by doing some of the construction work yourself with friends. With the heavy log exterior and insulated studded wall interior, these kit homes are extremely durable.

The half log design uses an insulated 2×6 studded wall behind the exterior half logs. This provides a wall insulation value of up to R-32. The walls of a typical house are less than R-20.

With insulated studded walls, you can finish the interior with log siding for a true log look. Many people finish several rooms differently for variety. Some can be drywall, paneling, stone, heavy beams, etc. The insulated half log design also makes it easy to run wiring and plumbing.

Several of the standard kit floor plans (up to 3,500 square feet) are designed specifically for passive solar heating. These have large south-facing windows with large attractive roof overhangs to block the hot summer sun. A relatively open floor plan with high ceilings and lofts provides a spacious feeling and natural heat circulation.

A large masonry or stone fireplace is often located in the center of a great room with a cathedral ceiling. Not only is this very attractive, it is also efficient. Since the stone chimney is not on an outside wall, more of the heat from a fire is given off to the room.

When you select a log home, choose one with energy-efficient features. The most efficient kits include low-e argon gas windows and an air barrier housewrap under the outer half logs. This housewrap allows moisture to escape, but blocks air leaks through the walls.

You can write to me for Utility Bills Update 362 listing the manufacturers of insulated half-log and full-log kit homes, nine floor plan layouts and exterior diagrams of energy efficient and solar models, specifications, and a complete do-it-yourself kit materials list. Please include $1.50 and a self-addressed business-size envelope. Send to James Dulley, 6906 Royalgreen Drive, Cincinnati, Ohio 45244.

James Dulley studied energy management at the doctoral level at Harvard.