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Open your windows in winter for the good of your family's health

Jan 09, 2019 05:17PM ● By Editor

By Mike Holmes from - Posted January 9, 2018

Winter is heating season, and when we run the heat in our homes we tend to keep our windows and doors shut, to help keep the heat in and the cold out. (Makes sense.) But what we’re also keeping out is fresh air.

Keeping windows and doors shut over winter helps save energy, not to mention money, too — all pluses. But if you never exchange the air inside your home for fresh air, it can get stale and potentially lead to health issues. Have you ever heard of sick building syndrome, or SBS for short? That’s when you spend a lot of time inside a space that is tightly sealed and with little ventilation.

Not only can keeping openings closed cause condensation issues inside your house (i.e. weeping windows), which we know can lead to mould, it also allows toxins already inside the home to build up. That includes volatile organic compounds, mold spores, dust, smoke, radon, viruses and bacteria. Breathing these in over an extended period of time isn’t good for your health. It can make you feel sick, tired and drowsy, it can cause headaches, dizziness and nausea, and can irritate your eyes, nose and throat. It can even lead to building-related illness, or BRI. Symptoms of BRI include fevers, coughing, muscle aches and tightness in your chest.

You might think that the furnace is bringing fresh air into your home, but that’s not always the case.

A furnace has two vents: One that exhausts old air inside the house outdoors, and the other for air intake. Older furnaces — say about 12 to 15 years old and older — don’t bring in fresh air from outside. The air intake is located inside the house (usually a vent sticking out of the furnace) so it’s actually drawing air from inside the home.

You don’t need to do this for hours; 15 to 20 minutes is enough to make a difference. 

And ceiling fans also circulate the air already inside your home; they don’t bring fresh air in. As hot air rises, a ceiling fan can help push down the warm air that tends to hang around your ceiling, which can help save energy — but they don’t bring fresh air into your home.

The best way to get fresh air inside is a heat recovery ventilator (HRV). Some reputable home builders nowadays install HRV units in their new homes because they’re building them to be more airtight and energy-efficient. So to prevent problems such as condensation, mould and poor indoor air quality, they install a HRV.

HRVs brings in fresh air from outside, preconditioning it to the interior temperature using the air that’s going out. This system recovers up to 88 per cent of the heat, and, thanks to an electronically commutated motor (ECM), it uses a minimal amount of electricity to do it.

If you want to bring in fresh air over the winter but you can’t invest in an HRV, don’t be afraid to open your windows a bit during the day. But do it on warmer winter days, like when it’s a balmy 5 C outside. And while you have the windows open, run the main exhaust fan in your home, which is usually located in the main bathroom, to help pull out old, stale air.

You don’t need to do this for hours; 15 to 20 minutes is enough to make a difference. It’s also a good solution for homes that don’t have forced air. Yes, you will be losing some energy, but the health benefits you get from bringing fresh air into your home can offset this energy loss.

Remember to change your furnace filter at least once every three months — and once a month during the cold season. And if you and/or your family are experiencing symptoms related to poor indoor air quality, such as SBS or BRI, get a healthy home inspection that includes indoor air sampling, because when it comes to the air you breathe, you shouldn’t take any chances.

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