"Cut Your Heating Bill By Up to 50%" is a claim made regarding some quartz infrared (radiant) portable heaters. Is this true?
This issue boils down to three questions:
- Can this claim be justified?
- Do radiant heaters have advantages over other electric space heaters?
- Are quartz heaters really enough better to justify their higher cost?
Can this claim be justified?
The "up to" phraseology, which so many manufacturers use, is very convenient. All they have to do is find one specific situation where they can achieve the savings claimed, even hypothetically, and they can justify the claim. This way they give the impression that everyone will save 50%, or whatever their magic number is.
So—for people with a certain living space, heating system and lifestyle—I believe the claim can be justified. It’s all in what you compare it to. Compare this to central heating with an electric resistance furnace. The actual production of heat will be the same efficiency (100%). It is not unusual, however, for ducted central heating systems to lose 30% of their heat through the ducts. In addition, heat is often wasted in overheating unused rooms. If the space heaters are used judiciously—where people are located—they can save substantial energy. In the extreme case, if there is only one person in the house and they spend much of their time in one location (sitting at a desk or couch, for instance) and they use the heater only where they are, it would save significantly over central heating where you are heating the whole house. This alone could save "up to 50%."
For a related article, go to The Home Energy Saver Answer Desk and click on the question, "Should I use portable room heaters to lower my energy bills?" Another resource on Space Heaters is from the Missouri Energy Center.
Do radiant heaters have advantages over other electric space heaters?
In terms of efficiency, in a technical sense, all electric heaters are exactly 100% efficient, so radiant heaters are no more "efficient" than other heaters. In some situations, however, you may be able to get by with supplying less heat to achieve the same level of comfort, making your energy costs lower.
Many of the articles above compare the different types of space heaters. In brief, some of the advantages of radiant heaters are:
- They heat a small area quickly. For example, if the application is to heat one person who stays fairly stationary, this may be a good choice.
- The effect of the radiant heat is nearly instantaneous when you switch it on.
- They heat objects and people, not air. This may allow you to supply less heat to achieve the same comfort level. Eventually, however, the warm objects and people heat the air, and your actual air temperature may be as high as any other heat. Even if the lower air temperature is only for part of the day, however, you still save some energy.
- Radiant heat is a pleasant form of heat. Many people prefer the feeling of the warmth of a radiant heater to having warm air.
The potential disadvantages and limitations of radiant heaters include:
- Radiant heat travels in a straight line, so they will only heat objects and people in a clear "line of sight" from the heater. If the heater is located above you, for instance, and you are sitting at a table or desk, your legs may be cold. If you are moving around a lot, and the heater has a reflector that directs the heat to a small area, you will only get the full benefit when you enter the area it is directed to.
- The effect of the radiant heat requires the appliance to be warm or hot. In the case of electric element radiant heaters, such as quartz heaters, the heater must be turned on to get its full effect. If you have turned the thermostat down to take full advantage of the radiant heater, as soon as it goes off, you may feel cold.
- Electric element radiant heaters, and quartz heaters in particular, can pose a significant fire hazard because of their high temperature. Make sure any electric element radiant heater you get has a safety switch that will turn it off when it is tipped over, and never leave them unattended when on.
Are quartz heaters really enough better to justify their higher cost?
When quartz heaters first came out in the 1980s, they made a big splash, and there was some controversy about whether they were really as efficient as advertised. The Annual Report of the FEDERAL TRADE COMMISSION 1981 p. 6 reports that a manufacturer and distributor were forced to retract efficiency claims in 1981. Certainly, in a technical sense, they are no more "efficient" (i.e., provide more Btus per watt) than any other electric heater. But do they provide more effective radiant heat somehow? The effect of radiant heat is dependent on the temperature difference between the heater and the object being heated. I don’t know the precise temperatures, but apparently the temperature of the quartz heaters is somewhat higher than other radiant heaters, making the radiant effect stronger. Whatever advantages you obtain by using a radiant heater, the effect with quartz would be more so. If you are able to lower the thermostat setting in the room, for instance, you may be able to lower it even more with a quartz heater.