To homebuilders, codes can seem a hassle. To new homebuyers, they’re a complexity. “Building codes for new homes exist only to make them safe, healthy and energy efficient,” said Mike Selig, program manager of weatherization and building safety for Clark County.
“By considering only the house envelope in the 1970s, building science missed the mark,” Selig said. “Today, it applies physics and systems thinking to improve home comfort and durability. Today’s building codes reflect that shift and the need for increasing energy efficiency.”
Our state leads the nation in codes yielding highly efficient homes. By 2031, the Washington State Energy Code wants a 60 percent reduction in energy loss from the 2006 code, according to Selig.
“We’re going there in small steps,” said Kent Hegsted, plans examiner for the county. “Defining codes is a cooperative process involving a lot of people looking at what makes sense, what’s cost effective and what technology is readily available.”
From an energy perspective, the new building codes fall into four areas: air sealing and filtration, stopping thermal transfer, duct sealing and energy-efficient lighting.
“Sealing a house makes it energy efficient, but only if it includes engineered ventilation bringing in good outside air,” Hegsted said. That’s not what happened in the ’70s and houses pulled in air from garages, crawl spaces and attics — all places containing particulates or pollutants affecting people’s health, including moisture, mold, dust and, in our area, radon.
Now not only the entire house envelope needs to be sealed, but every hole where wires, pipes or vent tubes enter a house. This means sealing windows, skylights, ceilings, floors, doors, oven hoods and even electrical boxes. State code requires a blower-door test on new homes to find and fix air leaks as well as test for the proper ventilation of five air changes an hour.
Even the home’s wooden frame contributes to an energy loss, known as thermal transfer. Building codes now require wood framing to have a thermal barrier for joists, corners and headers of walls, as well as attics and crawl spaces to reduce energy loss.
In the past builders used duct tape to close duct-work leaks, but eventually tape fails. They now seal ducts with long-lasting mastic to prevent air leaks. They’re also required to pressure test ducts to detect and repair air leaks that can exhaust dust and other particles.
Recessed lights were once culprits of updrafts and air leaks. New code requires placing a gasket inside the visible lip against the ceiling and a sealed and fireproof canister around the recessed fixture in the ceiling. The builder later places insulation around the canister to prevent energy loss. Using CFL or LED lighting only increases the energy efficiency of a home’s lighting system.
Builders can meet the new residential codes by picking and choosing the energy-saving methods they want. “Some opt to go beyond code and also incorporate green building practices to differentiate their homes from others in the market,” Selig said.
These days when buying a new home look for the label on the electrical panel of the home listing its energy efficiencies for everything from air leakage to insulation R-value. If you want to know more about energy-efficient building codes, you can visit the WSU energy website. To learn about a highly energy-efficient home that exceeds code, check out the Emerald House website.
“If you live in an older home and are looking at upgrades or retrofitting to bring the building up to code, you may be eligible for utility incentives,” said DuWayne Dunham, energy counselor at Clark Public Utilities. “Rebates and incentives are available for duct-sealing, insulation, windows and other weatherization measures so be sure to give us a call before starting work to make your home more efficient.”
Energy Adviser is written by Clark Public Utilities. Send questions to firstname.lastname@example.org or to Energy Adviser, c/o Clark Public Utilities, P.O. Box 8900, Vancouver, WA 98668.