Find Your Home’s Ideal Indoor Humidity Level

Published on March 01, 2019

Find Your Home’s Ideal Indoor Humidity Level

The level of humidity in a house is an often overlooked factor involved in the prevention of health risks due to mould, bacteria, and mildew growth, along with the early deterioration of the building itself, due to continuous moisture build up on various parts of the building’s structure.

Climate change is expected to bring a wide range of dangerous temperature extremes, along with the possibility of longer winters, meaning that the amount of moisture and level of humidity in your house will become more difficult to control while staying at a comfortable temperature.

By combining a few strategies for controlling the humidity and moisture build up in a home, such as: airtightness improvements, a proper ventilation system, and ensuring that your air conditioner is working properly, your home will also become more energy efficient - helping you save on your energy bill and lower your carbon footprint.

A Home Energy Assessment, along with an Airtightness Test, can help you determine the ideal indoor humidity level of your home, and what methods for controlling moisture build up would be the most effective and affordable for you to consider.

A Quick Humidity Definition

Humidity is the term used to refer to the amount of water vapour in the air, but not if the water vapour forms into droplets or rain. Breaking down this humidity definition further would mean including the three different ways that humidity is often measured: absolute humidity, relative humidity, and specific humidity - but the relative humidity measurement is the most important for a homeowner to understand.

Relative humidity is the measurement of how much water vapour is in the air, in comparison to the maximum amount of water vapour the air could hold at that temperature. This means that a room that has a relative humidity of 70 percent at 20 degrees Celsius, is 30 percent away from maximum water saturation at that temperature. The relative humidity measurement is useful in determining weather forecasts, as it often indicates certain weather events such as fog or rain.

Relative humidity can also be used to determine how hot much hotter it feels outside, due to the level of humidity in the air - this is called the heat index. While knowing how hot it feels outside is quite useful for planning day to day activities, it is not much help in determining how humid your home is.

Window Condensation from Indoor Humidity

A Relative Humidity Measurement vs The Dew Point

As warm air holds more moisture, the relative humidity measurement requires adjustments depending on the temperature of the room. That 20 degree Celsius room with a relative humidity of 70 percent for example, would have a much lower relative humidity at 30 degrees, and a much higher relative humidity at 5 degrees.

This is where the dew point comes in handy. The dew point is the lowest temperature where the air in a specific space will retain its moisture; if any air in this space touches a surface that is below its dew point, the water vapour will condense into a liquid and form dew. This means that if you are seeing condensation forming on the windows in your home, the air inside has too much moisture and your home is below its dew point.

Having too much humidity in your house for too long can contribute to a number of adverse health complications over time, as it promotes the growth of bacteria, dust mites, and mould. Those with prior respiratory conditions, the very young, and the elderly are all at an increased risk of humidity related health effects due to poor air quality.

With the dew point, only one number is needed to understand how much water vapour is in a home, and by taking notice of signs such as dampness around windows, a musty smell in certain rooms, or wet stains on walls or ceilings, you can start taking measures to get in control of your home’s humidity before its air quality suffers even further.

Save on Energy While Reducing the Humidity in Your House

Airtightness improvements are an excellent way to reduce the build up of humidity for most of the year, but during the winter, they should be coupled with the proper amount of ventilation to maintain a comfortable dew point. A Registered Energy Advisor is capable of determining how much ventilation a home should have in comparison to how airtight it is, and how it can be achieved in the most cost-effective manner.

An Airtightness Test can determine the location of every air leak in a home, and by having them sealed by professional insulation installer, or by sealing them yourself, you can not only make your home more capable at handling different levels of relative humidity, but you are also improving how energy efficient and prepared for climate change your home will be. This means that while you make efforts to control the humidity in your house, you will also save on your energy bill, improve your home’s air quality, and contribute to lowering greenhouse gas emissions in Canada.

Having a Home Energy Assessment conducted can take your home’s energy efficiency and humidity controlling efforts even further, as our Registered Energy Advisors are able to present you with a complete look at the energy efficiency of your home, along with a list of suggestions for improving your home’s energy efficiency - ordered in terms of their cost-effectiveness.

Our advisors are always happy to answer any questions you may have about the energy efficiency or level of humidity in your house, and they will work with you to find the best options for improving the energy efficiency and humidity control of your home in a way that fits your family’s needs, your budget, and your lifestyle.

The New Home Efficiency Rebate offers rebates up to $5,000.


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