Insulation and Draught-Proofing

Where to Insulate

Knowing where to insulate your house can help you successfully manage your energy efficiency budget. Parts of the house that require the most insulation are as follows: the roof and loft, walls, floors, basement or crawlspace and the foundation or concrete slabs. In addition, hot water tanks and radiators need specialty insulation that helps to prevent heat loss.

The insulation level of your home's air duct system should be inspected by a professional. The duct system is an extensive network of metal tubes throughout your home's walls, floors, and ceilings that delivers heated or conditioned air to the living spaces. Inadequate ductwork insulation leads to considerable heat loss and uneven ventilation of your home.

In addition to poor insulation, air leaks in your home also contribute to heat loss and overall energy waste. Outdoor air leakage usually occurs around corners, outside taps, the space between sidings and chimneys as well as around areas where the foundations and the bottom of exterior bricks meet. Within your home, air leaks may emerge around electrical outlets, sockets, light switches, door and window frames as well as electrical and gas service entrances. In addition, entry ports for internet, phone, and cable television wires may be potential areas of air leakage. Other common places where you could find interior air leaks include fireplace dampers, baseboards, loft doors, dryer vents, exhaust fans, and window air conditioners.

Insulation Materials and Types

There are many insulation options available on the market, each with its own advantages. Installation methods also differ based on the type of material used. Types of insulation that require professional installation include concrete block insulations, foam boards, loose fill, fiber insulation, sprayed foam, and structural insulated panels.

Concrete blocks are used in foundations and walls. They may be filled with insulation, but it is more effective to install insulation across the surface of the blocks. This type of insulation is applied during new building construction or major renovations. Foam boards, on the other hand, are used on walls, ceilings, and lofts with a low slope. The boards can be made of polystyrene, polyisocyanurate or polyurethane and must be covered with gypsum for fire safety. They offer high insulating value for little thickness.

"Soap research" by University of Salford Press Office on Flickr, licensed under CC BY 2.0

The installation of loose fills requires specialized blowing equipment. It is typically used in walls and lofts as it works well for hard-to-reach and irregularly shaped spaces. The loose fill may consist of cellulose, fiberglass or mineral wool. To insulate air ducts, professionals also use fibreglass or mineral wool in the form of rigid fibreboard insulation.

Sprayed foam is a liquid that cures once it is exposed to air. Made of cementitious, phenolic, polyisocyanurate or polyurethane materials, this type of insulation has the highest thermal resistance (R-value) of all types of insulation. It must be professionally installed and can be used in walls, floors, and ceilings.

Structural insulated panels differ from all other insulation types. These panels are manufactured in factories and shipped to construction sites, where they are assembled and used to construct a house. The panels might be costly, but they offer superior insulation and can significantly decrease the construction time.

"Jo's new best friend: an electric screwdriver" by Phil on Flickr, licensed under CC BY-ND 2.0

Some insulation types can be installed by homeowners themselves and do not require specialized equipment. Blanket insulations are the most common type that comes in the form of batts or rolls. Made of fibreglass, mineral wool or natural fibres, they can be easily rolled out and attached to walls, floors, and ceilings with staples.

If you have unfinished walls, ceilings and floors, consider installing reflective insulation systems such as highly reflective aluminium foil or plastic films. These DIY solutions reflect radiant heat away from the living area and work best in hot climates. They are usually installed in lofts and can reduce cooling costs up to 10%.

Testing Home for Air Tightness

Testing home for air tightness is generally conducted during the home energy audit process. You can perform your own building pressurization test, but for more accurate results, consider having professional auditors conduct a blower door test.

A blower door is a large and powerful fan that sucks the air out of a structure. With higher outdoor air pressure, the outside air will flow into your home through air leaks. The tester can get a precise measure of your home's air filtration rate. Also, you will be able to detect the areas of air leakage in your home.

Tips for Sealing Air Leaks

After detecting air leaks, it is important to seal them properly. Air-sealing methods may include caulking, weatherstripping, and draught-proofing. Caulking is the use of thin strips of silicon or plastic to fill small crevices, while weatherstripping is usually applied to doors and windows. Similarly, draught-proofing refers to blocking air leaks with strips of plastic, foam or metal around doors, windows, and fireplaces. Some simple actions that you can take to seal air leaks include:

Caulking around leaky door and window frames
Sealing entry areas at plumbing, air duct and electrical entries in walls, floors, ceilings, and soffits
Placing foam gaskets behind wall outlets and light switches
Covering uninsulated windows with storm windows or replacing them with double pane or low-emissivity windows
Sealing gaps around windows and baseboards with a foam sealant spray
Closing exhaust fans when they are not in use
Making sure that your dryer vent is not obstructed with lint
Replacing door thresholds with ones that have pliable sealing gaskets
Closing fireplace dampers when there is no fire burning
Sealing leaks around all gas fired and wood burning flues with fire-resistant sheet metal or gypsum
Recessed lights usually have vents that open into the loft. Insulate around recessed lights to prevent air leakage

Stains and dirt may also be indicative of air leakage. Look for any dirty areas on your insulation. If there are noticeable leaks, use a handheld can of spray foam made for this purpose to seal the leaks. In addition, inspect the paint and carpet in your basement and any rooms where steam is generated. Use masonry caulk to seal the leaks at wall and floor joists as well as any ceiling cracks.

Indoor Air Quality and Ventilation

Good indoor air quality is crucial for your health and it contributes to a more comfortable living. Indoor air quality is often compromised by various internal and external pollutants. Indoor air pollutants include fuel-burning appliances such as gas-fired or oil-fired furnaces, water heaters, gas stoves, kerosene and gas space heaters, fireplaces, clothes dryers. These appliances should be maintained, checked regularly and properly vented to prevent the release of harmful pollutants.

Volatile organic compounds (VOCs) can also negatively affect indoor air quality. These compounds are emitted as gasses at room temperature from certain products including building materials, furnishings, paints, cleansers and disinfectants, pesticides, adhesives. You can minimize your exposure to VOCs by following the warnings on product instructions, maintaining proper storage of hazardous materials and using adequate ventilation in your house.

Mold and moisture are the most common indoor air pollutants. Moisture usually gets into your home with air currents. Three general moisture control steps include damp-proofing your basement with polyethylene, sloping the ground away from the foundation and installing a continuous vapour barrier. Proper insulation also helps prevent moisture from entering your home. Correcting more serious moisture problems, such as water leakage, should be left to professionals.

"Day 66" by orangefan_2011 on Flickr, licensed under CC BY-ND 2.0

Excess moisture levels promote the growth of mould, which may be toxic. Usually, mould can be cleaned with mould removal products, but if it is caused by contaminated water, get a professional to remove it. If you chose to remove mould yourself, use goggles, gloves, and a mask.

The best way to maintain good indoor air quality is through ventilation. Outdoor air can enter a home by means of infiltration, natural ventilation, and mechanical ventilation.

Air infiltrates through cracks and naturally gets in through opened doors and windows. Mechanical ventilation is achieved through your heating and cooling system as well as through loft vents.

Ventilate your house regularly by opening doors and windows. Use spot ventilation (e.g. extractor fans) to remove pollution and moisture at its source. A whole house ventilation will provide you with uniform air quality throughout your entire home.

By increasing your property's air quality, improving the insulation and sealing air leaks, you will create a home that is highly energy efficient. This will consequently reflect in lower utility bills and increased comfort level within your home.