You are stumbling across the bedroom carpet one early winter morning, still in your pajamas. As you reach for the doorknob, your fingers are zapped with 20,000 volts of static electricity. Now you are awake! Does that sound familiar? If so, your home might be suffering from low relative humidity.
Beyond those annoying shocks, you or your family might notice dry skin, chapped lips, scratchy eyes, or frequent colds. Dry mucous membranes make it easier to catch viruses and irritate airways. Dry air also stresses wood furniture, houseplants, and even pets. The culprit is your furnace. Here’s why and what you can do about it!
Humidity describes how much water vapour is in the air. Cold air holds less moisture than warm air. “Relative humidity” compares how much moisture is in the air currently, to how much it could hold at that temperature. For example, air at 50 % relative humidity holds only half the maximum moisture possible at that temperature.
Here’s the catch: when freezing winter air enters your home and gets warmed by your furnace, the moisture content doesn’t increase, but the air’s capacity to carry moisture does. That causes the relative humidity to plummet. For example, air at –18 °C with 75 % relative humidity, when heated indoors, can drop to as low as 5–10 %!
When it’s cold outside, the air naturally holds very little moisture. Your furnace pulls in that dry air and heats it but it doesn’t add any moisture on its own. Warmer air can hold more water, so when it's heated without adding humidity, the relative humidity drops sharply. That means it feels even drier than the cold air with the same water content.
That dry, heated air then circulates through your home, leaving everything your skin, your sinuses, your furniture and even your clothing feeling parched.
So even though your home feels warm, the air is far drier than in summer and that’s what causes all the associated cold‑weather discomforts.
Most experts recommend keeping indoor humidity between 30% and 50 % during winter. Staying within that range helps protect comfort, health, and your home’s structure. Go too low and you get dry air; go too high and you risk condensation, mold, or damage to wood surfaces.
If your air feels dry, here are common ways to bring humidity back to healthy levels:
When humidity is balanced, you’ll notice softer air, fewer static shocks, less irritation to skin and airways and better care for your furniture and plants.
If winter dryness is bothering your household, we can help. Our team at Appleby Systems can assess your needs, recommend the right humidification solution, and install it correctly so your home stays warm and comfortable all season long. Just reach out, and Appleby Systems will help you get ahead of winter dryness before it starts.
