Is your house leaking? A leaky house will waste money and energy and isn’t energy efficient. Your energy consumption will increase to offset the heat loss.
Years ago, houses were built as well as we knew how to make them, but since energy costs were low, no one thought much about heat loss. But as fuel prices went up the need for more energy efficient homes grew. That lead to the demand for a tighter building envelope—that’s the thermal and air barrier between your inside air and the outside air. The better the building envelope, the less air leakage.
Air leakage doesn’t just cause heat loss. It also leads to condensation—when hot air meets cold—inside your walls or attic space. And you know that leads to rot and mould.
Test your home
It’s a good idea to have your house tested for airtightness by having an energy audit. And, you can often get a rebate from the government on improvements you’ve made to increase your home’s energy efficiency.
These tests of your home’s energy performance are done by certified energy auditors. The most common test is a depressurization test. All windows and doors are closed, and a special variable speed fan is installed in the front door with a special air-tight seal. Air is blown out of the house, creating a negative pressure inside and the energy auditor monitors the flow of air and the air pressure inside your home.
The fan creates a small air pressure difference between inside and outside. This pressure difference forces air through all holes and penetrations in the building envelope.
A smoke pencil is used to blow puffs of smoke near problem areas like windows and doors. Because the outside air pressure is higher than inside, air from cracks and openings push the smoke around. Because your home’s windows and doors are closed and it has been evenly pressurized, it’s easy to find out exactly where air leaks are-and then you can fix them.
You can caulk and weatherproof as a simple fix when needed, or you can upgrade your windows and doors if budget allows.
You expect to find drafts around windows and doors but a lot of air will leak around electrical outlets and plumbing pipes, vent stacks and recessed lighting fixtures and the sill plate around your home. Think of any spot where there is an opening between the insulted interior of your home and the exterior—that’s where air can escape.
Indoor Air Quality
Your building can also be too tight. If the air isn’t properly exchanged through good ventilation you can have poor indoor air quality and moisture problems, since most of the moisture in your home comes from the people living in it.
If your house is drafty and the windows and doors leak you can bet you are constantly exchanging the stale, moist interior air with fresh outside air, like it or not. You are losing heat and wasting energy, but your air quality might be okay.
If your house’s building envelope is good, there is less air infiltration, so you must make sure you are properly ventilating your home and exchanging the air. I have heard more than once of homeowners who actually turn off the air exchanger in their new home because it’s noisy or they think it’s a waste of energy to run. In an airtight home you must make sure you are exchanging the air—it’s vital to your family’s health.
The ‘Chimney’ effect
Modern high-efficiency heating equipment no longer uses air from the house to feed the combustion air going up the chimney. This "closed" combustion equipment draws the combustion air from the outside of the house. But often other equipment draws air from inside the house.
This is potentially a problem in tighter homes, because negative pressure inside the house from exhaust fans such as the clothes dryer or kitchen and bathroom fans can literally suck air back down the chimney and poison the air in the house.
Make sure your house is airtight, well ventilated and don’t turn off your air exchanger.