Baby, it’s Cold Outside!
8 Dec 2016

Baby, it’s Cold Outside!

By Corey McCloskey, Response Team Representative

Brrrrrrrrrrrrr! Our honeymoon with fall came to an unceremonious screeching halt this week, and it’s frosty nose hairs for all. We’ve been spoiled with pretty mild winters the last couple of years, but Jack Frost is back, and he’s making up for lost time.

The single most common thing we Response Teamers hear from our homeowners when the mercury plunges relates to condensation and ice build-ups on windows and doors. This is common and very normal, but it can cause issues, from patio doors frozen shut to cracked casing lacquer. The first step is to bring down the humidity in your home.

If you read this and find yourself thinking “I should have turned down my humidity already,” it’s probably too late for this cold snap, but you’ll know better for next time. When you’re hanging around the water cooler at the office talking about how cold it’s going to be next week is when you should be thinking about turning your humidity down, as it takes time for your home to acclimate. The chart below is a good guideline to follow.

Outdoor Temperature, ⁰C Recommended Interior Relative Humidity @ 20⁰C
-30 or lower 15%
-30 to -24 15% to 20%
-24 to -18 20% to 25%
-18 to -12 25% to -30%
-12 to -6 30% to 35%
-6 to 0 35% to 40%

Recommended Humidity Chart, courtesy Durabuilt Windows and Doors.

Why does it take time, you ask? Your humidifier starts or stops supplying water vapour to the air running through your HVAC system immediately, but the moisture added to the air is absorbed by every porous material and surface in your home. That means your hardwood floor. That means the drywall. The floor joists. The studs in your interior walls. Even your couch and the clothes in your closet. They all absorb the moisture in the air, and contribute to the overall humidity levels in your home, and they all have to dry out to lower your humidity levels.

We also add moisture into the air in our homes from a variety of other sources, every single day. They include:

  • Bathing
  • Cooking
  • Hang drying laundry
  • Plants and pets
  • Breathing

Breathing? Oh yes, even breathing. One of the most common locations we hear about excessive condensation build-up is in the master bedroom. You know, the place you and your significant other sleep for a few to several hours every night, quite possibly with the door closed and your blinds down. If this sounds like you, check your window tomorrow morning, and I’d be willing to bet you could turn it flat and play hockey on it.

The good news is we’ve already given you the tools you need to manage condensation. Here’s how and when to use them.


The brain of your HVAC system, your Emerson thermostat commands your furnace, HRV, and humidifier, and ensures all are working in harmony. These units are great, in that they don’t require constant adjustment, but a 30-degree swing in the wrong direction is simply too drastic for your home to acclimatize to organically. Watch our Site Supervisor, Kyle, work through the programming on our YouTube page!

Bath Fans

These handy little units are your way of combating the odiferous evidence of the double serving of chili you crushed at dinner last night, but they’re also incredibly important in managing humidity, resulting from bathing.

Most of us know that we should run the fan during our shower, but it’s ideal if you can run the fan before and after, as well. Consider this: your upper floor bath fans connect to the exterior of your home via a 4” insulated duct, which runs through your attic. If it’s -30 outside, it’s -30 in your attic, and it’s not much warmer than that inside the duct, which will result in a whole lot of condensation when you pump a bunch of hot, moist air into it.

Try this, instead. When you roll out of bed in the morning, head straight to the bathroom and flip on the fan. Head back to bed for a few minutes, figure out what you’re going to wear, do a few push-ups…whatever gets your day started. When you’re done that, jump in the shower, do your thing, get out, dry off, and let the fan run. When you’re ready to head out and take on the day, click the fan off.

Better yet, replace your fan switch with a timer switch in each bathroom you use for bathing. Digital timers are fancy, but for around $15 at your local big box store, you can buy a spring wound timer switch, which will run your fan for an hour. Crank the dial, warm up the vent, have a shower, head to work, fan turns off.

Range/Cooktop Vents

Next to bathing, the most common source of additional humidity is your kitchen. This one is pretty straight forward: if you turn on your cooktop or oven, run the fan. In most instances, your range fan ductwork is a quick shot straight out the wall to the exterior, and the majority of added moisture will vent straight to the outside. It’s also a good idea to clean or replace the screens on that hood as well, as they tend to get gummed up quickly.

Laundry Dryer

Saving energy is very en vogue these days, and some stuff just doesn’t go in the dryer, but you’ll want to plan accordingly when hang-drying your laundry. A couple shirts you’d like to have ironed for Monday, not a big deal.

This, here, is a big deal. Don’t let your friend from Vancouver convince you otherwise, either; the day a Vancouverite needs to plug in a vehicle to ensure it will actually start in the morning is the day we can compare notes on interior climate management. You can hang dry your laundry around 300 days a year to your heart’s content, but you’d do well to use your dryer when it’s breathtakingly chilly out.

Good Ol’ Elbow Grease

If this message is not as timely as you might have liked, don’t fret! Condensation is normal, and it’s how it’s dealt with which is the key. If you missed your chance to be proactive, be reactive…as proactively as possible!

If it’s already there, it’s already there. Lift your window coverings from the sill, tilt planks, whatever you need to do to get air moving across the glass, and make sure they stay that way, day and night, until it warms up.

Make sure your heat registers and return air ducts are open and clear of obstruction; if that means pulling a couch out from a wall for a week, it’s worth it. Change your furnace filter! Air flow is the best way to combat condensation, and your furnace works best with a clean filter.

Worst case scenario, grab a rag and wipe the water up. 10 minutes going around your house will save you hours of paint repairs on your casings. And I say ‘you’ because I mean ‘you’: damage resulting from inadequate condensation management is not a warrantable defect, and I don’t want to be a bad guy. Clean it up, and stay warm!

Have a great weekend,

Cedarglen Homes