Dear Jim: I want to build an efficient home to withstand the severe weather we are having everywhere. A circular home makes sense, but I do not want to go as radical as a dome. What other circular designs are there? – Connie P.

Dear Connie: You seem to have done your homework on strong, energy-efficient homes. A circular shape is the most energy-efficient design and also one of the most severe weather-resistant.

Just look at nature. Birds and nearly all animals naturally build circular nests and dens to conserve winter heat and to withstand storms.

There are two key reasons a circular house is more energy-efficient than a rectangular one. First, for a given amount of usable floor space, a circular floor plan typically has about 15 percent less outdoor wall surface area. Less wall surface area means less heat loss (winter) or gain (summer) through the walls.

The second reason is a smooth circular wall is more aerodynamic than a rectangular one with corners. When the wind flows smoothly around a circular wall, the air pressure difference on opposite walls is less. Less pressure difference means less air leakage into and out of the home and lower utility bills.

Also, by being more aerodynamic to winds, a circular home can withstand high winds better than a rectangular one. It probably cannot withstand a direct hit by a powerful tornado or hurricane, but circular houses have been left standing when other nearby homes were demolished by high winds. Some circular home manufacturers, such as Deltec Homes, offer high-wind packages with extra-strong strapping.

Choosing a precut panelized building system is your best option for an efficient circular house. There are many standard plans available ranging from small cabins to 5,000-square-foot mansions. These are not cheap prefab kits. A standard 2,500-square-foot model can range in price from $55,000 (slab floor) to $70,000 (truss floor). Efficiency and amenity options can cost many thousands more.

Circular homes are not truly circular. They are made of many flat insulated wall and window panels that create a circular appearance. Some use 4-foot-wide panels and others use 8-foot-wide ones. More panels are used to create a larger home. Another unique option is an octagonal house. The length of each of the eight sides depends upon the size of the home.

Being circular, many windows can be placed in the south-facing walls for free passive solar heating. With the many panels, each room has walls at angles allowing for natural cross-ventilation during summer. The peaked roof, similar to an upside-down funnel, naturally vents the hot air out the center cupola opening. If you have the option, choose 2-by-6 or thicker walls for space for additional insulation.

The following companies offer circular panelized houses: Deltec Homes, (800) 642-2508, www.deltechomes.com; Eagle’s Nest Homes, (800) 579-1079, www.eaglesnesthomes.com; Helikon Design, (800) 323-7863, www.helikondesign.com; Octa-Structure, (800) 448-4062, www.octastructure.com; and Topsider Homes, (800) 941-9801, www.topsiderhomes.com.

Dear Jim: I had an entirely new gas furnace installed in my home. They also installed new ductwork of the proper size. Now, whenever the furnace comes on, I hear a “clunk” sound from one of the ducts. How can I fix this? – Bob J.

Dear Bob: If the “clunk” sound is coming from a duct, it is the result of a duct wall flexing. When the furnace blower comes on, the pressure causes the flat duct wall to move. Have someone turn up the thermostat so the furnace comes on while you inspect the ducts to find the culprit. First try hitting the center of the flexing duct lightly with a sharp hammer. Just a slight dent may stiffen it enough. If not, screw a metal reinforcing strip to it.

Send inquiries to James Dulley, Bangor Daily News, 6906 Royalgreen Drive, Cincinnati, OH 45244 or visit www.dulley.com.