Infrared Vs. Convection Heaters
Space heating in a home to augment a central heating system or to provide some extra heat to a particular room without turning up the thermostat is a viable method to reduce winter heating costs, provided the central heating system is turned down and the space heater is only used to warm a small area. Infrared heaters (conduction) and convection-based heaters represent two of the more common approaches used by homeowners. Does this Spark an idea?
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Principle
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All types of electric space heaters use the same basic principle to generate warmth-- the conversion of electrical energy into heat. There are, however, variations in the technology that electric heaters employ to provide this warmth to their surroundings.
The mechanisms by which thermal energy is transported by a space heater are convection and conduction. Convection heaters warm the air and circulate it around the room. Many convection heaters rely upon rising hot air to circulate warmth, while some employ a fan to push the air physically around the room. Infrared heaters transfer thermal energy via electromagnetic waves. Only objects are warmed as opposed to entire areas.
Infrared
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Infrared space heaters for home applications project long-wave infrared radiation which strikes a solid object nearby and converts that radiation into heat. Infrared waves travel through space and are absorbed by people and objects in their path. Infrared is not absorbed by the air through which it travels. With infrared heating, the warmth is directed and concentrated where it is really needed, so infrared heaters are better at targeted or focused heating. In general, infrared heaters are energy-efficient, have no moving parts to wear out, heat very quickly are silent and are unaffected by drafts. If you are sitting in a cold room, a radiant heater projected directly at you will make you feel warm even if you are next to an open window.
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Convection
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Convection heaters warm the air near the heater and, by using either natural or fan-induced convection currents, circulate the warmed air throughout the room. These electric heaters work well for providing overall warmth in a closed space, particularly near the ceiling. They come in a variety of shapes, sizes, configurations and price ranges. Some have a simple heating element, or filament. Some are equipped with fans to help circulate warmed air throughout the room, some have oil-filled reservoirs and look like old-fashioned radiators. In all models, the warmed air circulates into the room, raising the ambient temperature. When the heater's thermostat setting has been reached, the heating element is shut off. When the room air cools again, the thermostat will trigger the unit to turn on again.
Safety
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Space heaters, both infrared and convection, are safe when used according to the manufacturer's suggestions. Most have safety features built-in to protect against the common types of dangers, such as overheating or tipping over. Still, they should never be left to operate if the homeowner is away. Always look for a heater bearing a stamp of approval from an independent testing company, such as Underwriters Laboratories.
Beware of the Claims
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With rising energy costs becoming an increasing greater burden on the family budget, be wary of exaggerated claims from space heater manufacturers which claim extraordinary savings from using their particular product. Do your research. Some are more efficient than others, but none can overcome the laws of thermodynamics. Prices for either infrared or convection heaters vary widely depending upon features and construction. Expect to pay more for well-designed, efficient heaters and those loaded with features, but if it is much more than $100, look carefully.
How to Calculate Your Energy Cost
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Use this formula to estimate a space heater's energy use:
Wattage of heater --- Hours Used Per Day ÷ 1,000 = Daily Kilowatt-hour (kWh) consumptionLook on your electric bill to determine the cost per kilowatt hour in your area. Often, there are different rates for electricity used during on-peak as opposed to off-peak hours. Also remember that heaters equipped with thermostats may cycle off during part of the time, so the calculation is a "worst-case scenario."
For example: Your space heater has two settings: 750 watts and 1,500 watts. You choose the lower setting and fire it up from 5 to 10 p.m.:
750 watts x 5 hours per day usage ÷ 1,000 = 3.75 kilowatt hours of electricity used. If your rate is 8 cents per kilowatt hour, then 3.75 x .08 = .30 (That is, 30 cents for 5 hours, or 6 cents per hour).
If your home is heated by a natural gas furnace, determine the cost per therm of fuel and do a calculation to get an accurate comparison between it and the cost of operating an electric space heater. The result will surprise you.
Be warm this winter. But be smart about it.
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