Proper insulation throughout a home or business helps lower energy bills by resisting heat movement through the walls, ceilings and floors. Where the interior of walls and ceilings is fairly easily accessible, adding insulation can be a relatively inexpensive way to get big return on energy savings throughout the year.
Walls, ceilings and floors can be insulated. However, because it is generally covered by finish materials, insulation can be difficult to see. One of the first places to look for missing insulation is up. Inadequate attic insulation can be found in newer homes as well as old ones. As part of a general home inspection, an inspector will examine the type of insulation present and its approximate thickness (R-Value) where accessible.
Provided safe access to the attic is available, the inspector will examine much more than insulation. The attic interior, including: framing, sheathing, insulation, ventilation, chimneys and any signs of moisture intrusion will be noted in the final report.
The inspector will also look for areas of safety concerns such as proper rating and installation of recessed lighting and electrical components to prevent overheating and possible fires.
Being aware of the types of insulation in a home is important, especially when it comes to homes 15 years old or older. These may `have been insulated with vermiculite insulation containing amphibole asbestos fibers. These fibers can cause health concerns under certain, very specific conditions. Of particular concern is insulation produced from ores mined at the Libby Mine in Montana from the 1920’s to 1990. It was sold in Canada until 1984 under the brand-name Zonolite Attic Insulation.
Provided the vermiculite insulation is sealed behind wallboards or floorboards, or sealed in the attic, the health risk is minimal. Health risks occur only when the material is disturbed in some way. Those exposed to significant quantities of airborne asbestos fibers can develop a scarring of the lung tissues, a rare cancer of the chest or lung cancer.
To prevent insulation from sifting through into lower rooms, seal all cracks and holes in the ceilings. Caulk around light fixtures and the attic opening. Before remodeling, call a qualified professional if vermiculite insulation is suspected.
For more information, look for the Health Canada publication “Vermiculite Insulation Containing Amphibole Asbestos,” or call 1-800-443-0395.
Recessed lights, also called can or pot lights, are fixtures recessed into the ceiling. This allows the light bulb to sit flush against the ceiling. These are sometimes considered aesthetically pleasing because they can pinpoint light above specific areas and don’t require large fixtures that trap dust and dirt. On the downside, these light fixtures can allow heat to escape into the attic, or create a safety concern if not installed and maintained correctly.
Only recessed light fixtures rated and marked “Type IC” can be covered with insulation. The acronym “IC” means “insulation contact.” This marking on a recessed lighting fixture means the fixture has been tested and certified to be in direct contact with, or blanketed by, thermal insulation.
Insulation must be at least three inches away on all sides of non-Type IC rated recessed light housings in order to prevent overheating. Overheated lights are a potential fire hazard. Some newer models are equipped with automatic shutoff components if overheating occurs.
The Electrical Safety Authority recommends using only fixtures that have been approved by an accredited testing facility such as CSA or CUL and that they be installed as per manufacture’s instruction.
How much is enough?
Insulation is generally measured using the term R-value or the metric equivalent, RSI-vales. The R-value (RSI) is a measure of the insulation’s “thermal resistance,” or resistance to heat or cold temperatures traveling through the material. The higher the R-value (RSI), the greater the product’s insulating capabilities.
R-values (RSI) are cumulative, so insulation can be layered to create a greater thermal resistance. Compressing certain types of insulation can reduce the resistance to heat transfer. These properties should be considered when factoring current R-values (RSI) or when considering the addition of insulation. Other factors, such as open air space around insulation, un-insulated areas and the presence or lack of an air barrier can also reduce the overall R-values (RSI).
Before replacing or adding insulation, check to see that all openings into the attic are properly sealed. Check all insulation to determine if the material is distributed evenly from wall to wall and maintains a consistent depth. One place that is frequently missed is the area above wall plates. Leaving this area uninsulated can cause cold spots.
For more information on attics and insulation, go to the Natural Resources Canada Office of Energy Efficiency website.