Energy

Solar energy is energy from the sun in the form of radiated heat and light. The sun’s radiant energy can be used to provide lighting and heat for buildings and to produce electricity. Historically, solar energy has been harnessed through passive solar technologies. Typically, these involve the strategic location of buildings and various elements of these buildings, such as windows, overhangs and thermal masses. Such practices take advantage of the sun for lighting and space heating to significantly reduce the use of electrical or mechanical equipment. Solar energy can be harnessed only during the day and only if the sunlight is not blocked by clouds, buildings or other obstacles.

Today, two active solar technologies that involve electrical or mechanical equipment are becoming more common. First, solar collectors or panels are used to heat water or ventilation air for use in buildings. Second, solar photovoltaic technology uses solar cells to convert sunlight directly into electricity.

Source: Natural Resources Canada

Thinking of buying into solar energy? Click here to read an article on this topic published by the Canada Mortgage and Housing Corporation.

What exactly does a heat pump do?
A heat pump can serve as both a heating and air conditioning system. Some heat pumps can also provide hot water for your home. With our cold winter weather, however, a heat pump cannot meet all your heating requirements. It needs to be combined with a supplementary heating system such as a natural gas or oil furnace. The heat pump is an electrical device that transfers heat from one place to another. At a certain temperature, however, the parallel heating system takes over, when the heat pump is not sufficient. In defrost mode, it can release fresh air into your home.

What is the most popular type of heat pump?
The most popular category at present is the air-to-air or air-air heat pump, which is installed in homes that have a hot air heating system. The less common type is the air-to-water heat pump, which is combined with a hot water heating system.

What should I know before buying a heat pump?

• The operational life of a heat pump varies between 10 and 15 years.
• Your electrical entrance panel must be able to support a heat pump hook-up.
• Some heat pumps are noisy. Before making your selection, verify your municipal by-laws regarding heat pump location and acceptable noise levels.
• The heat pump-boiler combination leads over time to increased maintenance costs because your heating system consists of two separate units.
• When you buy a heat pump, look for the ENERGY STAR® Label.

What are the installation costs for an air-to-air heat pump?
The cost of installing an air-to-air heat pump depends on the type of heat pump and your home’s existing heating system. There will be additional charges if the network of conduits needs to be modified or if you need to upgrade the electrical service panel because of increased power demands. The efficient operation and durability of a heat pump depends primarily on good maintenance, which should be done in the autumn. The compressor is the most vulnerable element. A heat pump consumes less energy than a conventional system, but is more expensive to buy.

What sort of maintenance is required?
Heat pump maintenance begins with cleaning the outdoor evaporator coil with a garden hose, and then cleaning or replacing the air return filter in accordance with the manufacturer’s recommendations. Make sure that water, snow and ice on the roof of your house does not fall on the heat pump fan. If the unit is exposed to strong winds, build a windbreak around it.

Does a heat pump consume less energy than other heating units?
Yes. A heat pump consumes less energy than other heating units and costs less to operate. However, it does not produce heat. It extracts air from the outside and pumps it into the house. That’s why it consumes less energy than it displaces. For 1 watt of electricity consumed at an outdoor temperature of 8°C, an air-to-air heat pump releases 3 watts into your house. You therefore get 2 free watts of electricity.

But energy savings in terms of heating are often diminished or cancelled by the additional energy expenditures required for air conditioning during the summer. The rigours of our climate also significantly reduce the performance of heat pumps. If they are installed in homes that are not airtight or are poorly insulated, the energy gains will be even more limited.

Cautionary Note
Expectations about the greater energy efficiency of a heat pump and the money that will be saved must be realistic for certain points have to be taken into consideration:

• climate and geographic location;
• the house envelope;
• the surface area to be heated;
• your consumption needs;
• saving energy is not synonymous with saving money;
• other costs entailed in the purchase of a heat pump;
• the supplementary heating system required.

Source: Agence de l’efficacité énergétique du Québec

A house that is not airtight can raise your heating bill by up to 15% per year, and can cause premature deterioration of the house due to humidity and dampness. Doors, windows and cracks and fissures should be properly sealed. Caulking and weather stripping are low-cost remedies to such problems.

Draw up a list of air infiltration sites
If you take the time to detect and list places where outside air infiltrates your home, it will help you effectively solve the problem. The inspection service provided by the Agence de l’efficacité énergétique (AEE) du Québec includes a blower door test that pinpoints and measures air entering from the outside. The test also indicates any leaks to the outside, i.e. warm and humid air leaking out of the house.

Detecting air infiltration
By slowly moving a lit candle, a smoke pen or a thin piece of paper along the edges of the walls, floors and ceilings along the perimeter of the house, you will notice an air leak whenever the object flickers. This simple method will give you a good indication of the work to be carried out. Turning on all exhaust fans (kitchen range hood, dryer, central vacuum cleaner, bathroom exhaust fan) will help locate the leaks more quickly and accurately.

Seal leaks from attic to basement
Air that is leaking to the outside can cause condensation problems and damage the insulation and wood framing of the house. Since air leaks tend to rise upward, start by caulking and sealing the top of the house and rooms with the highest moisture content such as the bathroom.

Caulking requires a clean surface
For best results, the joint to be sealed must be clean. Remove any paint, dust and old putty using a putty knife or screwdriver.

Strategic points to inspect when making a house airtight:

• attic access hatch (trapdoor) and ceiling voids;
• entry points for components that run from the ceiling to the attic (wiring,
• plumbing pipes, ventilation ducts, etc.);
• doors;
• exhaust fans (such as kitchen range hoods);
• letter slots;
• the joint between the wall sole plate and the end joists at the outer edge o
• the floors;
• inlets in exterior walls for conduits, wiring and pipes;
• the area drain;
• cracks in the foundation;
• electrical outlets;
• windows;
• chimney.

What can happen if a house is not airtight?
Infiltration of cold, outside air greatly diminishes the comfort of your home and increases your heating costs. As for warm inside air escaping from the house, it is humid air that can create condensation problems inside the envelope. It can damage the insulation, produce mold and cause the wood framing to start rotting.

Air tends to leak through the following weak points in the envelope:

• the joints where the exterior walls meet the foundations, the floors, the ceilings and the brick wall backing tiers;
• the joint where the backing tiers meet the insulated ceilings;
• the joint where a door or window frame meets the exterior wall, and the joint between the glass and the window frame;
• wherever wires or pipes run through exterior walls and insulated ceilings (ceiling lights, electrical outlets, light switches, exhaust fans, fresh air intakes, plumbing pipes or the main electrical service panel).

How can I detect air leakage?
Hear are two methods for detecting air leaks.

Flicker test
This simple method consists of slowly moving a lit candle, smoke pen or a thin piece of paper along the inside walls at the weak points mentioned above. The flickering flame or smoke, or the trembling sheet of paper, indicates an air leak.

Blower door test
This is a more sophisticated method. A blower door panel is used to create artificial depressurization inside the house so as to simulate high wind conditions. The air penetrates through holes and cracks in the house, which makes it possible to identify the specific points of air infiltration.

What are the rules to follow to ensure an airtight house?
Install the air barrier material in seamless, continuous fashion to prevent any passage of air through the building envelope. A lack of continuity in the air barrier will allow cold air to penetrate the insulation, which will diminish its insulating capacity.

Install the vapour barrier material in continuous fashion on the warm side of the insulating material. The vapour barrier prevents humid air and moisture from penetrating colder zones. Without the barrier, the humidity could cause condensation and mold to form.

Seal the perimeter of any object (ceiling lamp, electrical outlet, light switch, fan, dryer outlet, fresh air intake, electrical entry conduit, plumbing entry pipe, etc.) that runs through either the air barrier membrane or the vapour barrier membrane to ensure their integrity.

When choosing a sealer, keep the specific nature of the site to be caulked or sealed and the climate conditions in mind. Also take into consideration the cost of the sealant, as well as its resistance, adherence, elasticity and ease of installation.

Start by caulking and sealing the interior in order to stop leakage of warm air to the outside. Then continue sealing leaks from the outside to prevent rain water from infiltrating into the exterior walls.

Install weather stripping around doors and windows.

Improving air tightness of foundation walls
A cracked or damaged joint between the concrete foundation walls and the wood framing is often the cause of direct infiltrations which increase heating bills and reduce the comfort of your home. During construction, it is relatively easy and inexpensive to place a compressible sheet under the foundation sill to prevent the entering of cold air from underneath the ground level floor.

It is possible to correct that shortcoming in an existing house, but it calls for careful attention. Start indoors by sealing each joint with foam insulation. If you are doing major repairs to the exterior cladding of the house, seal the cracks between the concrete and the wood with the same type of sealing product before installing the new siding.

Once your house is airtight, it’s time to insulate the top part of the concrete wall and the edge beam to prevent any direct contact between cold air and the wood framing. A range of different materials provides satisfactory results. Glass fibre batt insulation is the easiest to apply. Cut the insulation to the exact size required and place the pieces into position loosely, without packing them too tightly. Cover the insulation with a polyethylene vapour barrier and seal the joints of the membrane with the appropriate adhesive tape. You can also use styrene foam insulation, but it must be covered with a fire-resistant material.

Source: Agence de l’efficacité énergétique du Québec