What is Radon?
Radon is a radioactive gas found naturally in the environment. It is produced by the decay of uranium found in soil, rock or water. Radon is invisible, odourless and tasteless and emits ionizing radiation. As a gas, radon can move freely through the soil enabling it to escape into the atmosphere or seep into buildings. When radon escapes from bedrock into outdoor air, it is diluted to such low concentrations that it poses a negligible threat to health. However, if a building is built over bedrock or soil that contains uranium, radon gas can be released into the building through cracks in foundation walls or, floors, or gaps around pipes and cables.
When radon is confined to enclosed or poorly ventilated spaces, it can accumulate to high levels. Radon levels are generally highest in basements and crawl spaces because these areas are nearest to the source and are usually poorly ventilated.
How Often Should I Change the Air Filter in my System?
Check it at least every month during peak use, and replace it when it looks dirty enough to significantly impair the air flow through it. Some filters, such as media filters or electronic air cleaners, are washable; others are disposable and must be replaced.
What is the Best Type of System to Meet all Indoor Comfort Needs?
The best system depends on many variables, including family size, house location and design, and utility cost and availability. The optimum indoor comfort system might include high efficiency central air conditioning and heating, a high-efficiency air cleaner, and a central humidifier.
Condensing Gas Boilers
Condensing gas boilers employ either an aspirating burner with an induced draft fan, or a power burner, similar to the units described previously. However, they have an additional heat exchanger made of corrosion resistant materials (usually stainless steel) that extracts latent heat remaining in the combustion by-products by condensing the combustion products before they are exhausted. A chimney is not needed, reducing the cost of installation. Because the flue gas temperature is low, the gases are vented through a plastic pipe out the side wall of the house.
A condensing boiler can have an AFUE rating of 90% or higher. But in practice, condensing boilers in hydronic (hot water) heating systems can have difficulty achieving this efficiency. For the condensing boiler’s heat exchanger to extract all the potential latent heat effectively, the system has to run with the lowest possible return water temperatures, preferably not exceeding 45–50°C (113–122°F). Unfortunately, most radiator systems are designed to operate at significantly higher return water temperatures, which makes it difficult for the flue gas to condense. If the return water temperature is too high, actual operating efficiency may be only slightly higher than that of the better models of non-condensing boilers.
Non-condensing Gas Boilers
Residential gas boilers sold in Canada today are required to have an AFUE rating of at least 80%. ENERGY STAR qualified boilers must have an AFUE rating of at least 85%. The following are some ways manufacturers have improved efficiency levels:
- Elimination of continuous pilot lights. Most boilers on the market today use some form of intermittent ignition device, usually electronic ignition.
- Improved insulation levels. Because boilers store more heat internally than warm air furnaces do, they are subject to greater heat losses, both out through their casing (sides) and up the chimney when they are not being fired. To reduce heat lost from casings, new boilers have much better insulation to keep the boiler water hot.
- Better draft control methods to reduce flue losses. Many boilers use draft hoods. The draft hood is located downstream of the boiler proper. It draws household air into the gas vent along with the flue gases. This stabilizes the airflow through the appliance, isolating the burner from outside pressure fluctuations. But it also continuously draws heat from the boiler and warm household air up the chimney. A vent damper is now usually installed downstream of the draft hood to close off the exhaust when the burner is not operating. When the gas burner turns off, the damper is closed automatically after a short period; before the burner lights again, the damper opens.
Other boilers that use aspirating gas burners have eliminated the need for a draft hood entirely by using a powered exhaust system, usually incorporating an induced draft fan. With no dilution air, high resistance to spillage during the on cycle, and minimal flow up the stack during the off cycle, these units tend to give superior performance to those using draft hoods and vent dampers.
Today, many gas boilers have replaced the naturally aspirating gas burner with a power burner. These use a fan on the burner to improve the combustion process and ensure the development and maintenance of an adequate draft. These burners, similar to ones used in advanced oil-fired equipment, tend to have a high-pressure restriction or even close off the combustion air passage when the burner is not operating. This minimizes off-cycle heat losses without requiring a flue damper. Such units minimize dilution air, or have sealed combustion, and have performance characteristics similar to or better than the aspirating burner with a powered exhaust system.
On What Heating and Cooling Products Would I Find the EnerGuide Rating?
The EnerGuide Rating label on heating and cooling products sold in Canada can be found at the back of product brochures for: gas and propane furnaces residential air conditioning systems air-to-air heat pumps.
Can Homeowners Repair their Own Air Conditioners?
In most cases, definitely not. Cooling systems today are more complicated to service and usually require expert attention in order to comply with federal regulations, such as the Clean Air Act which prohibits releasing refrigerants into the atmosphere. An EPA-certified air conditioning contractor or service technician should be called at the first sign of trouble.
What is the Average Life of a Central Air Conditioning System?
It can vary, depending on how much the system is used and how regularly it is checked or serviced. Generally, the average life of cooling units built in the 1970s and 1980s is about 15 years, but individual units may vary and last much longer, depending on use and how well they are maintained. Heat pumps have about the same life span– an ARI survey showed average heat pump life to be about 14 years when recommended maintenance procedures were followed. Newer units are expected to last even longer.
Higher Energy Efficient Furnaces and Air Conditioning Systems Often Cost More to Buy
Why Would I Want to Buy One?
Buying a high-efficiency furnace, heat pump or air conditioner is an economically and environmentally responsible decision. Equipment with high energy efficiency ratings:
- use less energy, which helps conserve non-renewable resources and contributes to reducing greenhouse gas emissions;
- accumulates savings over its lifetime from lower energy use
- has other advantages: they can cost less to operate, have more efficient motors and fans than standard efficiency systems
- sometimes has a longer and more comprehensive warranty
How are EnerGuide Ratings Determined and who decides what number goes on the rating label?
Like the EnerGuide appliance ratings, the numbers are the results of product testing using energy standards specified by Natural Resources Canada in the Regulations of Canada’s Energy Efficiency Act, and then verified by agencies such as the Canadian Standards Association (CSA).
Why is the EnerGuide Rating for Heating and Cooling Products on the Back of Manufacturer’s Brochures?
Unlike major household appliances, which are usually purchased after the customer has personally examined the various models on the retail floor, furnaces, heat pumps and air conditioning systems are usually sold from brochures or product literature. Therefore, the brochure is the most suitable place to help consumers looking for energy efficiency ratings.
What Does the ENERGY STAR® Logo Mean?
The ENERGY STAR® logo, found on packaging, literature, product advertising and in some cases, products themselves, means that the products are significantly more energy efficient than required under current federal standards. For example, central air conditioning systems with ENERGY STAR® endorsed logos exceed existing federal standards by a minimum of 20 percent, and furnaces with the logo, exceed minimum standards by 15 percent. This means that the products have a higher level of energy efficiency than standard products found on the market today.
By choosing ENERGY STAR® qualifying products, homeowners can use energy more efficiently, save money on utility bills, help make their homes more comfortable and reduce air pollution without sacrificing the features, versatility or style that they expect from high-performing products.
How Much Humidity Should You Have in Your Home?
Humidity levels above 20 percent help prevent dry, sore throats and make the air feel warmer and more comfortable. Moist air also eliminates static electricity in the house and helps to protect plants and preserve your furniture.
On the other hand, humidity levels over 40 percent can cause frosting and fogging of windows, staining of walls and ceilings, peeling paint, mould growth and odors. When relative humidity is over 50 percent, airborne diseases become more difficult to control. Condensation on your windows can provide a good indication of the relative humidity. You may, however, want to install a humidity sensor or humidistat to keep more accurate measurements of humidity levels.
How Do I Keep My Housing Structure Dry?
Use four strategies to keep the structure dry:
- Provide exterior weather and moisture protection. Use building paper, siding, flashing, gutters and other construction techniques to shed water and repel wind-driven rain. Pay attention as well to below-grade measures. Proper drainage, grade slope and damp-proofing can protect the foundation from ground-water leaks or from moisture movement by capillary action.
- Reduce moisture at the source. This means producing less moisture in the first place and exhausting moist air and bringing in drier air.
- Prevent moist indoor air from getting into the envelope.A vapour barrier will reduce moisture movement by diffusion, and an air barrier can prevent moisture movement by air leakage. Although less moisture can be moved into the envelope by vapour diffusion than by air leakage, it is still important to provide a vapour barrier. An effective vapour barrier must be the following:
- resistant to vapour diffusion
- installed on the warm side of the insulation
A number of building materials resist vapour diffusion well enough to be used as vapour barriers. These include polyethylene, oil-based paints and special vapour-barrier paints, some insulation materials and exterior-grade plywood. Different materials may act as the vapour barrier in different parts of the house.
The same material may work as both an air barrier and a vapour barrier, provided it meets both requirements and is properly installed. Polyethylene sheets and foil-backed gypsum drywall can both combine these functions. To avoid confusion of terms, we refer to a material doing both jobs as an air and vapour barrier.
As a general rule, the vapour barrier should be on the warm side of the insulation. In some cases, however, the vapour barrier can be located within the wall or ceiling assembly, provided that at least two thirds of the insulation value of the wall is on the cold side of the vapour barrier. Because this ratio should be adjusted for houses with high interior humidity or for homes in extremely cold climates, it is recommended that you consult a professional builder-renovator, who will apply the specifications outlined in the National Building Code of Canada.
- Let the envelope “breathe” to the outside.This will allow the house to deal with seasonal fluctuations in humidity and to release any moisture that does penetrate the envelope from the interior or exterior. The materials of the envelope are layered, with those most resistant to vapour diffusion located on the warm side of the envelope and the least resistant (such as building paper) located on the outside. In this way, any vapour that penetrates the envelope can escape to the outside.Some wall systems work well with a relatively impermeable insulated sheathing because the interior wall-cavity temperatures are kept high. As a precaution, when retrofitting a wall, always ensure that the interior surfaces are vapour-resistant.Some siding applications have an air space immediately behind the exterior finish to promote drying out of materials that have been soaked by rain or dampness. This air space also provides an escape route for any moisture that has penetrated the wall cavity from the indoors. This type of installation should not be used with insulated siding, as convection in the air space will negate the effect of the insulated backer board on the siding.
What are Sources of Moisture in the Home?
Even if your house has no leaks in the basement or roof and is apparently dry, it can have moisture problems. Where does all the moisture come from? There are a number of major sources that are not always obvious:
- Occupants and their activities: An average family of four will generate about 63 litres (20 gallons) of water a week through normal household activities.
- Wind-blown rain in walls: Where basement damp-proofing is inadequate, ground water in the soil can migrate through the foundation by capillary action and evaporate on the surface of the wall or floor.
- Damp basements
- Moisture stored in building materials and furnishings: Building materials and furnishings absorb moisture from the air during damp, humid weather and then expel it during the heating season.
Despite all this water produced each day, most older houses have “dry” air in winter to the point where they have to have humidifiers installed. Why?
Cold outdoor air cannot carry much water vapour. In older homes, uncontrolled airflow brings colder, drier air indoors and forces the warm, moist household air out through openings in the upper walls and attic. The air quickly escapes through the un-insulated envelope without cooling down enough to cause condensation.
When insulation is added, the building exterior becomes much colder. Unless additional protection is provided, water can condense in the building structure.
How? Remember that cold air is able to hold much less moisture than warm air. As the warm, moist air cools in the cold outer layers of the building, the water vapour it holds may condense as liquid or, if it is cold enough, as frost. This can reduce the effectiveness of insulation and even cause rot, peeling paint, buckled siding, mould growth and other problems.
Why You Should Control Moisture Flow?
We must control moisture in all its forms to keep our homes durable and comfortable. Building components and practices such as flashing, roofing and basement damp-proofing successfully protect the home from liquid water.
It is equally important to control the movement of water vapour, providing added protection for the house structure and helping to maintain indoor humidity at a comfortable level.
Controlling moisture involves three strategies:
- using construction techniques that keep moisture away from the structure
- producing less moisture
- exhausting excess moisture