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Electric Forced-air Heating Systems

Buying a forced-air furnace

When a electric furnace delivers heated air blown by a fan through a network of ducts, it is called a forced-air system. Because the fan forces air into each room in the house, this type of system does not depend on natural convection to distribute heated air evenly throughout your house.

Heating with Electricity

Electric forced-air systems come in a wide range of capacities – generally from 10 kilowatts to 50 kilowatts. The heating elements, circulation fan, air filter, and control devices are contained in a compact cabinet.

Electricity can be used as the sole heating source or in combination with other sources in a home heating system.

The five basic types of electric heating systems available in Canada are as follows:

  • forced-air systems (which can be electric resistance heating, a heat pump or a combination of the two)
  • hydronic or hot water systems
  • room heaters
  • radiant systems
  • combination systems with plenum heaters in the hot air plenum.

An increasing number of homeowners with electric baseboard heating are switching to other energy sources, such as natural gas, oil or heat pumps, because of the high cost of electric heating. While a major constraint is the lack of a distribution system, many homeowners find that air ducts for a central forced-air system, or pipes and radiators for a hydronic system, can be installed at a cost that still makes the whole conversion financially attractive. Fuel-fired space heaters, wood stoves, and advanced, energy-efficient wood-or gas-fired fireplaces can also be effective.

If electricity is your only energy source, unused chimney flues can be closed off, insulated, and sealed. Closing off the chimney flues can have an effect on drafts and humidity levels in the house, and will reduce heat loss.

If you replace your forced-air furnace with a new electrical furnace, you can usually use the existing ductwork with very few modifications. However, If the energy efficiency of a house is improved, it will have a smaller heating need than it had before the retrofit. This could mean that the furnace is now oversized. If so, you might end up with large temperature fluctuations and the potential for rapid on-off cycling.

In addition, the balance of the heat distribution is likely to have changed. Insulation and air sealing could make some hard-to-heat rooms easier to heat, while other rooms may overheat. This may require a re-balance of the system by adjusting the dampers in a ducted system or adjusting valves in a hot water system.

CAUTION: Any additions or alterations to an existing furnace involving installation of an electric plenum heater must be done by a qualified contractor. The furnace must then be inspected, usually by the local electric utility representative.

Electric hydronic systems

Electric Thermal Storage

Electric thermal storage (ETS) heating was developed in Europe in the 1940s and was introduced to the United States market in the 1980s. This type of space-heating system is capable of providing a home's heating requirements by storing heat produced during the night, when utilities generally offer lower off-peak rates. Most ETS systems now available can provide 16 hours of on-peak heat from as little as eight hours of off-peak charge.

How it works - The ETS central furnace consists of a storage medium (usually called the core) and controls, which detect when it is necessary to accumulate a charge during the off-peak period. Elements within the storage core heat ceramic bricks, crushed rock, water, or paraffin wax to a high temperature to provide the heating requirements for the on-peak period. Room storage units are smaller versions of central ETS furnaces. They come in a variety of sizes, from 2 kilowatts to 7 kilowatts, and supply the heating for individual rooms. Larger rooms in the home may sometimes require more than one storage heater.

These systems can offer savings on heating costs if there are significantly lower off-peak (night) electricity rates.

Certification and Standards

All electric heating equipment, heating elements, and electric baseboard heaters sold in Canada must meet strict manufacturing and installation standards for safety. The standards fall within the purview of provincial safety codes and the Canadian Standards Association (CSA). Before purchasing your heating equipment, be sure it carries a CSA, CGA, IAS, ULC or Warnock Hersey certification label.

Federal and provincial energy efficiency standards are now in place for space heating equipment. No energy efficiency regulations apply to electric resistance heating equipment; only heat pumps are affected.

Improving the efficiency of an existing electric heating system.