Insulation in the roof and walls is clearly beneficial for its ability to reduce heating and cooling losses and costs. The savings achieved by reducing heat transfer by conduction justifies the cost of adequate insulation.
But don’t forget that convection is another source of heat transfer when air moves between two spaces. Minimizing or controlling losses via convection is desirable but requires more consideration. Adequate outside air is necessary for breathing, and sufficient air transfer is required to ventilate other gases and odors from interior spaces.
Most homes are so leaky that there is plenty of opportunity for air to intrude and be enough for the occupants. However, as structures become more air-tight and interior materials become more synthetic, there is the possibility that the indoor air quality is compromised.
Controlling infiltration of outside air is important. Not only is uncontrolled air infiltration wasteful of energy it can also carry outside pollutants such as fumes and dust. Inadequate exhaust of indoor pollutants can cause allergies, respiratory distress and ‘sick building syndrome’.
Expanding foam insulation applied to walls and roof voids fills small spaces and gaps that allow air to flow between the interior of a home and the outside environment. Eliminating these gaps prevents air convection from carrying heat between the interior and exterior of a home, which results in lowering the expense of heating or cooling a space.
Minimizing air from entering from the outside into the house means that expanding foam insulation can improve the quality of air inside your house. With proper permeable filters and especially electrostatic filters installed with your air-handler, circulating inside air can be controlled and cleaned of allergens, particulates and pollutants within a building’s interior. By using expanding foam insulation to reduce infiltration of outside contaminates, the inside air is a higher quality. This may be an even more important consideration if a resident suffers from allergies or respiratory conditions.
A more sophisticated installation that is used in commercial buildings and may be justifiable in homes is the use of an ‘economizer’ air handling system. By using an arrangement of ducts and dampers in an ‘H’ pattern outside air and exhaust air can be controlled to allow recirculation and proper ventilation. Depending on the sensible heat and latent heat outside, controllers move the dampers to allow the desired air flow in and out of the building space, which maintains adequate fresh air and takes advantage of the energy of the exterior for cooling or heating. This is especially effective for ‘air-tight’ structures and locations where day and night time temperatures and humidity vary significantly.
Expanding foam insulation is extremely useful to address multiple issues of conduction and convection. Whether it is maintaining the temperature of a home, controlling air infiltration, soundproofing a space, and minimizing energy consumption, almost everyone will enjoy the benefits of expanding foam insulation.