Relative humidity refers to the percentage of water vapor present in the air at a given temperature. For example, when the relative humidity is 50 percent, the air is holding half the moisture it’s capable of holding. The air’s ability to hold water decreases as the temperature goes down and increases as the temperature goes up.
Humidity in Action
On a cold winter day the outside temperature might be 10° F with 70 percent humidity. When the cold outside air creeps into your home, and your furnace heats it to 72° F, the air expands. While the moisture in the air remains the same, the relative humidity is significantly reduced. This means that the outside cold air with 70 percent humidity has an indoor relative humidity of only 6 percent. That’s more than four times drier than the Sahara Desert!
The dry interior air will steal moisture from wherever it can find it, including your body. As moisture evaporates off your skin, you feel cooler. When you feel cooler, you tend to turn up your thermostat and the cycle continues, which becomes an expensive habit given the high cost of heating.
How to Protect Yourself
To combat this problem it becomes essential to maintain indoor relative humidity at a comfortable 35 to 45 percent range. This minimizes the air’s need to replenish moisture and little or no evaporation from your body takes place. As a result, you can actually turn down your thermostat about three degrees and still maintain your former level of comfort and warmth, all while saving on energy costs.
There are many ways to humidify the air in your home. You can use a single room humidifier or you can install a whole home humidifier connected directly to your HVAC system. These humidifiers work automatically to ensure the air in your home is at peak humidity levels to keep you comfortable. Typically, these whole home systems cost between $300 and $600, but the energy savings year over year make it a smart investment. It is also recommended to use a more accurate digital thermostat with humidity control to automate the process and keep your system at peak efficiency.
In addition, consider upgrading to a system with a variable speed or modulated compressor. These compressors are able to adapt to the cooling demand of your home by running on more or less power as the situation demands. They use less energy and because they run for longer periods of time, albeit at a lower speed, they are able to do a better job of controlling relative humidity within the home.
Ask your contractor about humidity in your region and the best way to protect yourself.
Do you feel extra thirsty during the winter months? What other ways do you notice humidity affecting your comfort at home?
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