Electric heaters have been around for decades as a source of heat in homes to provide warmth to us. One of the reason for their popularity is because of lower cost to purchase and easy maintenance compared to other sources of heat. They are usually powered by electricity though a small percentage are still using propane or kerosene as fuel.
They work by converting electricity into heat using metals as heating elements. The metals have high resistance that permit a certain amount of current to flow though them to provide the required heat. Electrical energy is changed into heat energy and the the relationship between the wattage and Btu/hr is:
1 Watt = 3.415 Btu/hr.
There are three types of electric resistance heating wires that are in used today:
- Open Wire consists of nickel chromium resistance wire which is mounted on ceramic or mica insulation. For safety reason, they must be protected and should not be contacted by users or metal objects. This protection is vital to prevent the danger of electric shock.
- Open Ribbon is similar in material to the open wire type but has more surface area that are exposed for air contact. It too must be protected to prevent the danger of electric shock to the users.
- Tubular cased wire uses nickel chromium resistance wire that is surrounded by a magnesium oxide powder which are then enclosed in a heat resistance steel tube. This tube protects the users from the danger of electric shock.
One of the commonly used natural convection heating equipment is known as Baseboard Heating Unit. This unit has electrical resistance mounted in a casing which is designed to move air over the elements naturally. They are usually mounted under the window on the wall.
When purchasing units, make sure that they have safety features such as wire grills, automatic shutoff controls in the event of overheating, tilt switches and good thermostat controls. Look for certification on the units such as UL or CE Mark.
Pro and Cons of Using Electric Heater
The advantages of using electric HTRs are:
- Initial Low Cost Investment. The units are usually lower in cost compared to other types of heating sources.
- Clean Operation. There isn’t any need for refrigerant or oxygen, hence the operation is neat and clean.
- No Toxic Gases. Since no combustion is needed, there is no danger of toxic gases that may leak in the event of faulty units. No chimney is needed unlike the traditional coal or wood source of heating.
- Smaller in Size. They take smaller space compared to other systems.
- Ease of Control. Individual unit temperature can be controlled more precisely using the thermostat mounted on the unit.
- Ozone Friendly. Since no refrigerant is involved, this type of heat source is more ozone friendly.
The disadvantages of using electric HTRs are:
- Humidity control may be a problem.
- Higher Cost/unit of heat compared to other fuels.