What you need to know about home insulation
TORONTO – While most homeowners don’t give much thought to what’s behind their walls, proper insulation is of key importance to having a comfortable, healthy home. Besides keeping your home warm in the winter and cool in the summer, insulation can help lower your energy bills, prevent mold growth and also keep unwanted noise out.
What insulation does
Insulation helps keep outdoor air from getting inside your home and conditioned indoor air from escaping. This is achieved by trapping pockets of air and slowing down the in/out process.
“In winter, heat flows directly from all heated living spaces to adjacent unheated attics, garages, basements, and even to the outdoors,” the U.S. Department of Energy states on its website. “Heat flow can also move indirectly through interior ceilings, walls, and floors — wherever there is a difference in temperature. During the cooling season, heat flows from the outdoors to the interior of a house.”
The Canada Housing and Mortgage Corporation (CMHC) compares a properly insulated house to dressing for the weather.
“A wool sweater will keep you warm if the wind is not blowing and it is not raining. On a windy, rainy day, wearing a nylon shell over your wool sweater helps keep you reasonably dry and warm. A house is similar,” the CMHC website says. “On the outside, underneath the brick or siding, there is an air barrier that does the same thing as the nylon — it keeps the wind from blowing through. Then there is the insulation (like your sweater) and a vapour barrier, which helps keep moisture away from the house structure where it can do damage.”
How insulation is rated
Insulation is rated based on a measurement of resistance the material has to the movement of heat. This is most commonly referred to as an R-value. The higher the R-value the more effective the insulation is. Local building codes list recommended R-values for each area of your house (these R-values are required for new construction). Improper installation of insulation can lower the R-value of the material you are using so it’s a good idea to follow the manufacturer’s instructions or hire a professional to do the installation.
Signs your home in poorly insulated
Cold floors and walls in the winter and hot inside air in the summer, mold growth, high energy bills and uneven heating or ineffective cooling are all signs of a poorly insulated home, according to the CMHC.
Different types of insulation
There are many different types of insulation available. The type you use depends on where you’re insulating or what R-value you require. Below is a rundown of the most common types of insulation used in homes these days.
Fibreglass: This is the “pink stuff” most people think of when they think insulation. Fibreglass in batts is available at most home improvement centres and is easy to install, offering an R-value of 3.0 – 3.7 per inch, according to the CMHC. Loose-fill fibreglass is also available, but requires to be blown into the space you’re insulating and should be installed only by a professional in order to get the most benefit from it.
Mineral fibre: Like fibreglass, mineral fibre in batts is easy to work with and available at most home improvement centres (this is usually a sturdier material with a brownish colour). While mineral fibre has a lower R-value (2.8 – 3.7 per inch, according to the CMHC), benefits include better fire resistance and sound-proofing capabilities. Loose-fill mineral fibre is also available, but like loose-fill fibreglass, it should be installed only by a professional as well.
Cellulose: Being a loose-fill material, cellulose is mostly used in attics as it’s more dense than loose-fill fibreglass or mineral fibre (which are better used when blown into existing walls). It is highly recommended that cellulose is installed by a professional.
Rigid foam: Rigid foam comes in either expanded polystyrene (EPS) or extruded polystyrene (XPS) and is mostly used on the shell of your home (under your siding) and to line exterior basement walls and to insulate below the basement slab. Extruded polystyrene (XPS) offers a higher R-value (4.5 – 5.0 per inch) and can be installed in wet areas. It can also act as a vapour barrier. Both types are required to be covered due to chemicals used to produce them. Proper installation involves securing the sheets to the surface and sealing all joints with tuck tape.
Spray foam: Thanks to home improvement celebs like Mike Holmes and Bryan Baeumler, spray foam insulation is all the rage these days. There are two main types of spray foam: a low density open-cell polyurethane and a closed cell polyurethane that has a higher density. Closed cell is the more popular choice for attics and exterior walls as it helps to create a stronger, more airtight home, is resistant to mold growth and has the highest R-value (5.5 – 6.0 per inch, according to the CMHC). While there are DIY kits available, it is highly recommended that spray foam insulation is applied by a professional in order to prevent (a potentially costly) improper installation and to get the full eco-benefits of it.
NOTE: While most cans of spray foam, such as Great Stuff brand, is also closed cell polyurethane, these cans are only recommended to be used around windows, doors and to fill cracks. Attempting to fill an entire wall with a can of spray foam is not recommended.
For more details on these and other types of insulation available, visit the CMHC website.
Safely working with insulation
Before knocking down your walls to add more insulation, keep in mind that older homes may have vermiculite insulation in the attic, which could contain asbestos. Old pipes and ductwork wrapped behind walls could also contain asbestos. If you have these materials or are uncertain about what was used, call a professional to come and test or remove them for you. Most municipalities require old fibreglass and other insulation types to be disposed of in a special manner as well. Check with your local waste management facility to get the disposal requirements.
When working with new insulation you should wear gloves, a long sleeve shirt and pants to prevent skin irritation. A respirator mask and eye protection are also recommended.
Where to add insulation
Christine Sampson, Marketing Leader at Owens Corning Canada — a major insulation manufacturer — said that “unfinished basements and attics” are the two areas homeowners should focus on first when adding new insulation.
“They can be topped up with insulation in a very cost effective way,” she says. “No demolition required, just add more insulation.”
Owens Corning Canada recommends R-values of 60 in the attic and 20 in the basement for “maximum comfort and savings,” Sampson said.
Once the attic and basement are taken care of, focusing on exterior and interior walls, floors, and around windows and doors is also recommended.
Keep in mind that adding insulation improperly can end up creating issues if not done properly.
“Adding more insulation in wall cavities with high air leakage rates can cause condensation problems in walls,” said Sampson.
Shopping for insulation (or choosing an insulation installer)
Picking the right type of insulation for the area you’re working in is one thing, shopping for insulation is another.
Insulation in batts comes in packages made for either 2×4 or 2×6 framing that is either 16-inch on centre or 24-inch on centre. Also watch that you are getting insulation made for the material your framing is built with (wood or metal).
Sampson said it’s important to use trusted brands that have proven long term performance and durability.
When hiring an insulation installer, ask for a client list to get an idea of their previous work, read online reviews and ask them questions about the types of materials they plan to use. Ask if they have insurance and request a copy of their insurance certificate as proof. When hiring a spray foam installer ensure they are licensed by the Canadian Urethane Foam Contractors Association Inc. (CUFCA).
Other areas of your home you can insulate
Light switches and receptacles on exterior walls can be insulated with special foam inserts that sit between the cover plate and the wall. Insulating hot water pipes with pipe foam will help lower the cost of heating water and will prevent the possibility of pipes freezing in the winter. Caulking around doors and windows and using special weather stripping are all forms of insulating your home as well.
Remember to breathe
Healthy homes need to breathe and by adding more insulation (especially spray foam) you may also need to add extra venting or an air exchanger.
“When a home is airtight it can’t [breathe],” said HGTV’s Mike Holmes. “So you need to bring in fresh air and get rid of the stale, indoor air. If you don’t, you will have condensation issues. That means moisture, which can lead to mold.”
Holmes recommends a Heat Recovery Ventilator (HRV) be added to homes that have been sealed with spray foam.
WATCH: How spray foam is installed
“What an HRV does is that it exchanges indoor air with fresh outdoor air. But it also pre-heats the air that comes in using the air that’s going out. That recovers up to 88 per cent of the heat that’s going out,” he said.
An alternative method of drawing fresh air inside is by installing a passive ventilation system. These are special, non-mechanical vents that can be added to various rooms throughout your home. Fresh outdoor air is pulled in, which in turn forces warmer, stale indoor air into your return air ducts where it will then be exhausted via the furnace chimney.
Passive ventilation systems are great because of the low cost to install them and because they require very little maintenance. They do work better in colder climates though, and will not help remove humidity (meaning you will still need a bathroom exhaust fan).
Future of insulation
In the last 15 to 20 years, fibreglass insulation has become 100 per cent formaldehyde free, Sampson said, and the industry as a whole has changed for the better.
“Third party certifications have become essential to gain consumer and trade confidence, codes have increased; providing homeowners the opportunity for more comfort and savings,” said Sampson. “The trend towards a more sustainable environment is leading us to a complete system solution versus product-based solutions that are tested and evaluated to ensure long term performance and durability.”
Moving forward, the industry continues to evolve and Sampson said it’s not just about R-values now, but how insulation can contribute to the complete building performance.
“The insulation business is now redefined to include heat, air and moisture solutions. This becomes more and more evident as we work towards building net zero-ready and net zero homes by 2030,” she said.
Below are links to websites and articles with more information on what you need to know about home insulation.
- CMHC: Insulating your house
- This Old House: Insulation Education
- DIY Network: What you should know about the installation of insulation
- HGTV.ca: Bryan Baeumler shares tips for installing insulation (video)
- U.S. Dept. of Energy: Home Insulation
- Today’s Homeowner: Dangers of Asbestos Contaminated Vermiculite Insulation in Your Home
- USwitch.com: Home Insulation (UK based)
- HGTV.com: Passive Ventilation
- Ask Mike Holmes: Should I use spray foam insulation?
- Buildipedia.com: How insulation can save you money
- The Canadian Urethane Foam Contractors (CUFCA)
- Net-zero homes: Evolution or revolution
- Is it really worth insulating my pipes?
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