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Fall is here. The air is getting colder, and that little bar representing your natural gas consumption on the monthly utility bill is about to start growing like a weed. But, there are ways to stop it.

One way is to change your lifestyle, like turning down the thermostat on your furnace and water heater, and wearing sweaters at home. But for many, taking a cold shower in the winter is the definition of insanity.

Instead, we want cushy, warm comfort and low energy bills, which means we need to talk about insulation.

A recent industry-backed study showed 90 percent of existing detached single-family homes are under-insulated and wasting money.

“If all U.S. homes were fitted with insulation based on the 2012 International Energy Conservation Code, residential electricity use nationwide would drop by about 5 percent and natural gas use by more than 10 percent,” said Dr. Jonathan Levy, Professor of Environmental Health at Boston University School of Public Health.

Some homes have more to save than others

A professional energy audit can help homeowners understand the types of insulation issues they face, explained Ben Cichowski, director of the Montana Weatherization Training Center in Bozeman.

Cichowski oversees the certification of specialists who work for contractors like Big Sky Insulation and are hired by the Human Resources Development Council for the federal Weatherization Assistance Program.

At the training center on Frontage Road, his students learn to install insulation, lead a crew and audit a home. The goal is to make them able to give advice on increasing energy efficiency in situations that might not fit well on a checklist.

“You really have to assess a home on an individual basis,” he said. “Alot of people want to go straight to windows and doors. They can save you some money but new windows are really expensive.”

For this story, Cichowski reluctantly agreed to categorize homes by their age, pre-1960s, the middle ages, and recent builds.


Homes built before the 1960s are often well constructed, he said, but have terrible insulation.

“In a lot of those houses there’s nothing in the walls. Newspaper is common, compacted wood chips, they would dump all of the garbage from the construction site into the walls and assume that it’ll do something,” he said. “But it doesn’t do anything, almost zero insulation properties out of it.”

Residents of homes built pre-60s, like the beautiful homes near downtown Bozeman, should think about air sealing.

“They’re usually pretty leaky. They’ve been around for a while,” the weatherization expert said. “Wood shrinks over time, and so you get cracks and cold air blows in.”

This era of homes were built without an air and water barrier, like Dupont’s Tyvek home wrap. So cold air can blow in around doors, windows, and the home’s siding and find its way into the living space through electrical outlets, light switches or drywall seams.

Much of the air infiltration can be addressed at the ground and at the roof, where the angles of framing meet and builders had a hard time making it tight. Older homes were also built using a technique called “balloon framing” which leaves walls with no top or bottom, which allows them to leak heat. Inserting foam blocks at the top and bottom of wall studs is the fix.

It’s the same story in the attic of older homes.

“Hot air is rising and if you don’t have something to slow it down it’s just gone and you just keep cycling your furnace on and on,” Cichowski said.

The new standard for attic insulation is known as “R-49.” Loose insulation has an R value of about 2 per inch. Fiberglass “batt” insulation, which is sometimes attached to paper on one side, has an R value of about 3 per inch.

The middle ages

In the 1960s, carpenters began putting insulation in the walls and attic, but there still wasn’t much in the way of building regulations.

Instead of worrying about insulating walls and attics, energy conservation gains come again from looking for leaks in the home and the heating system.

The best way is to de-pressurize your home.

“The way we do it is with a blower door,” Cichowski said. “It simulates a 20 mph wind on all sides of your house.”

Gauges measure how much air is being sucked into the home through the cracks. Exaggerated by the de-pressurization, an auditor might also use a “smoke pencil” or infrared camera to clearly see where the cold air is coming in.

New construction

With new construction, homes are much tighter. Not only are there building standards but often post-construction audits to enforce them.

But mistakes are still made. Even in the weatherization training center, the builder did not install insulation in a large wall section. Cichowski said his kids found it while they were playing with the infrared camera.

Most houses will have an area like that, he said. There might be a window creating an awkward space which was difficult to insulate. Similar problems in a home would be difficult for laymen to detect, which is why a $400 audit might be money well spent.

And an important part of an energy audit is the return on investment calculations which allow homeowners to understand how long a energy conservation investment, new windows, more insulation, will take to pay for itself.

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Troy Carter can be reached at 582-2630 or He’s on Twitter at @cartertroy.

Troy Carter covers politics and county government for the Chronicle.

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