When renovating a home following building science principles, there are things to think about:

• How will a renovation change the home?
• Will I be increasing the air tightness or volume of the home?
• How will the renovation effect the current mechanical systems?

All house components should work together, and the main idea of the house-as-a-system concept is to properly control the heat, air, and moisture of a home. Heat, air, and moisture flows all interact.

When upgrades such as installing insulation are completed it is important to consider any repercussions that may occur. For example:

• A renovation may change how heat, air, and moisture flow in a home
• New windows can make a home more air tight, but may also require the installation of a ventilation system to remove moisture from the home or some other form of moisture control
• Adding an addition onto the home may require a larger heating/cooling system or larger ventilation system

Renovating existing homes always present unique challenges. Insulation in older homes may be unknown or non-existent or contain a variety of different types of insulation, such as seaweed, straw, or newspaper. Wall cavities might not be full anymore if the insulation has settled over time or moisture may have degraded the insulation potentially leading to mould issues As a result, most older insulation will have a lower R-value than what is available today.

Insulation, Occupant Comfort, and Indoor Air Quality

Poor indoor air quality results from sufficiently high concentrations of one or more pollutants that can adversely affect the health or safety of occupants.

The indoor air quality of a home is a very important factor when dealing with occupant comfort.The construction of a home can cause a lot of pollutants and air borne toxins/chemicals to enter a home by off-gasing from the products. It is important to ensure that the job is done properly to reduce the pollutants that could potentially enter a home.