A good choice for a radiant electric heater
Quartz space heaters are a good choice if you’re looking for an electric space heater to warm a particular area of a room. As I explain in Energy efficient electric heaters, there are three types of electric portable heaters: convection heaters without fans, convection heaters with fans, and infrared heaters. Quartz heaters, along with parabolic ceramic heaters, fall into this last category.
An infrared space heater such as a quartz space heater uses direct infrared radiation to warm the objects it is pointed at. (Don’t get alarmed – that just means light waves in the spectrum that produces direct heat, similar to how french fries are kept warm in the school cafeteria.)
These heaters are also called radiant quartz heaters. Quartz heaters are great for situations where you are sitting in one place (for instance, a couch or a desk) and you only want to warm that one area.
The air between the heater and the solid objects it is pointing at (you, your couch or desk) are not directly warmed by the electric heater; only solid objects in a direct line of sight to the quartz heater. Air is only warmed to the extent that solid objects warmed by the heater then let heat off into the air.
Quartz heaters lose their effectiveness at around 10-15 feet from the object or person being heated.
The net of this is that a quartz heater can be ideal for a drafty room, where you want to stay warm but you don’t want to let all that heat outside. On the other hand, quartz heaters are not suitable for keeping a bedroom warm at night, since they generally point across a room, which means you would be warming the side of your bed but not the top where you are sleeping. For this type of application a convection heater will do a better job.
Quartz space heaters can also lead to a ‘warm side, cold side’ effect, if the air temperature is substantially lower than your comfort level, because the radiant heat warms the side of you facing the heater, but not your other side. If you’re sitting in an armchair or couch this isn’t a problem since the furniture is probably keeping you warm behind. But if you’re working at a desk with the heater pointing at you from behind, you’ll have a warm back and neck and head (and a warm chair), but your chest, legs, and feet may be a little cold.
Are quartz space heaters energy efficient?
Quartz space heaters have exactly the same energy efficiency as other electric heaters: they convert 100% of the electrical energy they use into heat. Of course, if your electricity comes from fossil fuels such as coal or natural gas, the total system efficiency is really only 30%, since coal and gas fired electricity plants are only about 33-35% efficient and there are power line transmission losses as well. Still, careful use of an electric heater such as a quartz space heater can cut your overall energy used for heating, if you use them to heat just a small area rather than heating your whole house with natural gas or heating oil.
Quartz space heaters can really be considered more energy efficient than other electric heaters, such as convection heaters or oil filled radiators, when used to heat only a small part of a drafty space. To be accurate, we could say that they are more effective at distributing the heat primarily to the people in a room, rather than to the room as a whole, when they are properly set up (and the people are staying still).
Fire and burn hazards with quartz heaters
The other thing you need to be careful about with quartz space heaters is that you don’t point them directly at a nearby solid object.
If their heat is distributed over too small an area – which happens when they are pointed at something very close to them – the heat becomes concentrated and can cause discomfort or even burns on people or animals, can cause your plants to wilt, and can damage or even set fire to fabrics, paper, and other flammable items. Damage to fabrics and other materials may be immediate or may build up over time, depending on the heat sensitivity of the material and how close it is to the source of infrared radiation.
For safety reasons, quartz space heaters should also come with some kind of anti-tipping or tipover shutoff device, because if the heater is tipped over and continues operating while pointing at the floor it could set wooden flooring, carpet, or other flammable floor materials smoldering. The three models pictured on this page all have tip-over or anti-tipping capability.
This is a very useful article and has provided key information in deciding which heater type to purchase. Thank you.