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Energy Sources and Equipment Options
Furnaces in forced air heating systems, boilers in hot water systems, fireplaces and space heaters can be fueled by natural gas. It is delivered to your house through an underground pipeline. (It is not available in some areas.)
Most equipment fueled by propane is similar to that fueled by natural gas. In many cases, the only differences are one or two small components that can often be changed by a registered
contractor to convert a unit from one fuel to the other. Propane is delivered by truck and stored in a tank on your property.
Because of their similarities, natural gas and propane heating equipment are discussed together. The term “gas” refers to both natural gas and propane. The cost of the two fuels differs, so remember to check for cost comparisons.
There are three main types of gas furnaces:
- conventional (with a seasonal efficiency range of 55 to 68 per cent)
- mid-efficiency (78 to 82 per cent)
- high-efficiency (90 to 98 per cent)
Gas boilers have similar ranges of seasonal efficiency.
Older conventional gas furnaces and boilers
Some older furnaces and boilers, which are no longer produced but are still in use, require a continuous liner in a masonry chimney or a metal “B” vent chimney. The liner is needed because the combustion gases contain water vapor which condenses on masonry and causes deterioration over time. About 35 per cent of the heat from the fuel goes up the chimney with these models.
Mid-efficiency gas furnaces and boilers
These models remove more heat from combustion gases so that less heat escapes when the gases are exhausted and efficiency is improved. Depending on the circumstances, they might be vented through a wall or through a chimney.
High-efficiency (condensing) gas furnaces and boilers
These models extract so much heat from combustion gases in order to achieve their efficiency, that they can be safely vented through a narrow plastic pipe that runs through the wall.
Gas fireplaces are sometimes used to provide space heating, though they are often chosen for aesthetic reasons. There can be significant differences in energy efficiency from one model
to another, and the effective efficiency of some types can be significantly affected by how they are used.
Oil furnaces and boilers have a burner, a heat exchanger and a blower or pump. Oil is delivered by truck and stored in a tank, which is usually located in the basement.
Older conventional oil furnaces and boilers
Older, conventional oil furnaces and boilers with a standard burner have a seasonal efficiency generally ranging from 60 to 70%. Like older, conventional gas furnaces and boilers, they are no longer produced. However, in an existing model that is working well, the seasonal efficiency can be improved by replacing the burner with a flame retention unit – usually a more cost-effective step than replacing the entire furnace.
New oil furnaces and boilers
A typical new oil furnace or boiler has a seasonal efficiency rating generally ranging from 78 to 86 per cent. Many of these units can be vented through the wall.
There are free-standing oil space heaters with a visible flame now available. There are no efficiency standards for these products.
Electric resistance systems can consist of a central furnace or boiler connected to an air or hot water distribution system, radiant panels embedded in the floor or ceiling or a baseboard space heating system. Electricity also powers heat pumps. When electric resistance heating is used in a new home, including as a back-up for an air source heat pump, the building code requires
the house to be built with higher minimum levels of insulation.
A heat pump is usually an electrically-powered system that can either heat or cool by transferring heat from one place to another. During the heating season, a heat pump extracts heat from
either the air, ground or water outside the house, and transfers it indoors. In the summer the direction of the heat flow is reversed, extracting heat from indoors and transferring it outdoors, to
provide air conditioning. Because they satisfy a substantial part of your heating needs by utilizing already available heat, rather than consuming electricity to generate all of the heat you need,
heat pumps are significantly more efficient than electric resistance heating.
There are three main types of heat pumps:
- air source heat pumps
- earth energy systems
- bivalent heat pumps.
Air source heat pumps
These most commonly-used heat pumps can provide all the cooling requirements of a home and most of the heating needs, but they require an auxiliary heating source during very cold weather. This can be either an electric resistance or a fossil fuel unit.
Earth energy systems
Also known as ground source heat pumps, these systems transfer heat from the ground, ground water or surface water and use it to provide home heating. For summer cooling, the process is reversed. If desired, earth energy systems can be equipped to provide domestic hot water year round. Electric resistance heaters may be installed to provide supplementary heating for the
coldest days.They normally utilize much less electric resistance heat and offer significantly higher efficiency than air source heat pumps.
Some households use wood as their main fuel but even more use it as a supplementary source of heat. Most of these households are outside large urban areas where firewood is usually less expensive than other fuels. The most common approach to wood heating today is a wood stove or high-efficiency fireplace installed in the main living area of the house. If the house is
medium-sized and relatively new, this kind of equipment can provide almost all the heat needed.
If you have an existing masonry fireplace, a high-efficiency fireplace insert could be a good option. And many models offer the pleasure of a visible wood fire.
Older or larger houses may need the additional heating power offered by a wood-burning furnace. If your present heating system is a forced air furnace that uses a more costly fuel, you might want to consider an add-on wood furnace. It is installed beside the existing furnace and the duct work is modified so that it can be shared by both furnaces. Combination wood/oil or wood/electric furnaces are options for new or replacement systems. Stoves that burn pellets made from wood or agricultural crops such as corn kernels are also available. Pellets are automatically fed into the burner and the householder simply dials in the required temperature on the thermostat.
When shopping for wood-burning equipment, visit several wood heat retail stores and discuss appliance selection, location and installation with a knowledgeable salesperson.Always buy wood-burning equipment that is certified for safety. It is also preferable to buy equipment that has been certified as meeting the U.S. Environmental Protection Agency (EPA) or Canadian CSA-B415 emission standards. These certified wood-burning appliances produce one-tenth of the chimney emissions and one-third higher efficiency than earlier units.
“Outdoor” wood furnaces or boilers are also on the market. They may appear attractive, because they will burn low cost material you would not think of putting in an indoor appliance and can burn for long periods between refueling. However, they can be low on efficiency and high on emissions.
Like wood, solar energy is a renewable resource. Solar heating does not involve the combustion of fuels, so it does not produce environmentally-harmful emissions. It can be as simple as south facing windows serving as passive solar collectors. Passive solar heating is free and should be an important consideration in the design of homes. Homes built to high levels of energy efficiency and designed to make the most use of free solar heating can save hundreds of dollars a year on energy bills.
Other energy sources
Residential systems are available to generate electricity from sunlight or wind. In certain situations, such as remote locations, one of these may be the most practical option. In addition, the government is establishing standardized processes and technical requirements which will require electricity distributors to allow customers with qualifying generation equipment to supplement their utility electricity needs with power they generate themselves.