Making homes energy efficient

Art Nadler

Tuesday, Nov. 10, 1998 | 11:24 a.m.

Sometimes the problem is as simple as an open space between the garage and the attic, allowing air from the garage to filter into the house. It's not only bad for the power bill, but the carbon monoxide can also harm the family's health.

The solution is equally simple, said internationally recognized home-defects expert Joe Lstiburek: block the opening. Lstiburek (STREE-beck) was in Las Vegas Monday with a message for Southern Nevadans: A properly engineered house can be healthy and energy-efficient too.

Given recent high-profile cases of buildings in Clark County that have caused illnesses among employees -- the Grant Sawyer Federal Building and the Desert Research Institute are among them -- some local home builders now are paying attention to the health of the environments they are creating as well as the cost of keeping them heated and cooled.

Lstiburek, a principal in the Building Science Corp. of Westford, Mass., advises home builders on both of those topics. He is currently advising Pulte Homes Las Vegas on building energy efficient homes in Southern Nevada.

Insulation is an area where energy can be conserved. To get the most out of it, he said, insulation should be applied to the roof line rafters instead of laying it on top of the ceiling in the attic. This allows air-conditioning vents in the attic to sit in an insulated area, improving efficiency.

Rather than using a 5-ton heating and air conditioning unit, Lstiburek said, a smaller and less expensive 2 1/2-ton system is sufficient, because it won't have to work as hard to operate in cold and hot weather.

Another cost-effective measure is to blow a recycled paper fiber product into wall cavities instead of using roll insulation. This creates an airtight seal between the 2-by-6 support studs. The 2-by-6 studs are used because they allow for more installation space than standard 2-by-4 studs.

Windows that filter out heat and allow light to penetrate also reduce air-conditioning costs, he said.

The windows cost $500 to $600 more to install, and the blown-in installation is more expensive, Lstiburek said, but savings on energy bills and a less-expensive heating and cooling system pay for the higher costs in the long run.

"I'm all for any innovative ideas like these," said Paul Wilkins, director of the Las Vegas Building and Safety Department. "It certainly appears to me that this is more cost effective."

Wilkins said electricity is cheap in Southern Nevada, but that may change, and systems like Lstiburek discussed may soon become more popular.

Ken Sheldon, an installation estimator with State Insulation and Drywall in Las Vegas, said homes that are insulated this way show significant reductions in heating and cooling losses.

"Up in the attic, it can get up to 230 degrees" during the summer, Sheldon said. "With this (cocoon system), the air conditioner is in an air- conditioned space."

Properly engineered homes also use air-conditioning units that bring in outside air through vents, Lstiburek said. Traditionally, most home air conditioners only recirculate interior air.

He suggested using air vents to connect rooms with each other. This way, he said, rooms won't build up pressure and try to blow air between rooms via baseboards.

When carpets are black along the baseboards, that indicates that air is trying to escape, Lstiburek said.