ENERGY EFFICIENT Space Heaters
There is an amazing variety of space heaters. They vary in their types, models, designs, capacities, prices, goals, features and… efficiency.
The efficiency of the different space heaters, though important, is only a small part of the whole issue. Their global efficiency depends also on how they are used, and on the intrinsic goals of each type of heater. You shouldn't use a radiant electric space heater to heat an entire room, or a couple of electric oil-filled radiators to heat a large home in a cold climate. It would be too expensive, too energy-inefficient. That’s not their goal...
Types and designs
There are now new heaters, with new designs, new features, and new technologies. Ancient electric infrared heaters, for instance, where mainly metal sheath heaters, but they are now mainly quartz and ceramic (and much more energy efficient, and safe, and cheap...). 
And the same happens with new “radiators” like the electric oil filled heaters or the wall-mounted heaters (whether wall electric furnaces or gas-wall vented heaters…)
And all these type of heaters and models come in a wide variety of designs: baseboard, tower, panel, radiator, compact, fixed, portable…
See:
Small fan heaters
Types of infrared heaters
Ceramic electric heaters
Oil-filled electric heaters
New direct vent furnaces
Baseboard electric heaters efficiency
Electric wall heaters
Electric thermal storage heaters and solutions
New electric furnaces
Radiant vs. Convection Heating
The radiant vs. convection heating is still a major dividing in what concerns space heaters. Though most modern models of space heaters are a combination of convection and radiant heaters, the divide remains.
Some space heaters are mainly radiant, that is, they aim to heat people and not the air in the room. They are personal, spot, directional heaters for specific uses.
And, on the other hand, there are the convection heaters: those aimed to heat an entire room, demanding time to achieve it, but providing a more even and comfortable heating, for longer periods…
See, for details:
Convection vs radiant heating
Electric, gas or kerosene?
The type of fuel used by the space heaters is another divide. Gas heaters (natural, propane…) can be very efficient and they have a higher capacity, but they pose some concerns about safety (only wall-mounted vented gas units are truly safe).
Kerosene space heaters are another alternative, largely used in countries like Japan, due to their prices and capacity. But – more than gas heaters – they pose yet more concerns about their safety.
See:
Electric vs gas space heaters
Kerosene heaters: indoor and outdoor uses
Gas space heaters: vented and ventless
Radiators and hot water heating systems
Hot water heating systems (steam radiators, baseboards, hot water radiators) are a category of their own. They are often central systems, not room-space heaters. The only radiators that are truly space heaters are the oil-filled radiators, but they are electric units, not hot-water units...
See:
Hot water baseboard heaters
Hot water radiator systems
Steam radiators
Supplemental heating and Zoning
Space heaters can both be a source of supplemental heating and energy savings. Using zoning ( the division of a building in separated areas, with different heating charges and schedules) and space heaters is one of the most interesting ways of getting energy savings.
See: Heating and cooling zones for your home
Top Manufacturers and Brands
Top manufacturers and brands of space heaters aren't equally well rated in the several categories of space heaters.
See:
Top manufacturers of small space heaters
Best of Space Heaters
Safety
When shopping for a space heater look for the UL (Underwriters Laboratory) label, or the Intertek, the National Electrical Manufacturer's Association (NEMA), the Canadian Standards Association or other independent entity label. They are a guarantee of safety and performance standards.
See, for details:
Gas, kerosene and electric heaters safety
See also:
Space heater wattage & BTU
Room heaters efficiency
Energy efficient space heaters
Small fan heaters
Ceramic electric heaters
Oil-filled electric heaters
Convection vs radiant heating
Types of infrared fan heaters
Radiant Convection Heaters
Radiant Space Heating
Convection heating
New direct vent furnaces
Kerosene heaters: indoor and outdoor uses
Gas space heaters: vented and ventless
Baseboard electric heaters efficiency
Electric wall heaters
Electric thermal storage heaters and solutions
New electric furnaces
Hot water baseboard heaters
Hot water radiator systems
Steam radiators
Electric vs gas space heaters
Gas, kerosene and electric heaters safety
Space heater wattage & BTU
Room heaters efficiency
Top manufacturers of small space heaters
Heating and cooling zones for your home
Cooling zones
Zone heating with furnaces, ac and central systems
Zone heating strategies with space heaters
Best of space heaters
See also:
Combustion vs. electric space heaters
Fan electric heaters
Ceramic Space Heaters
Oil-filled heaters
Convection vs. radiant electric heating
Direct vent gas furnaces
Kerosene and other liquid-fueled heaters
Gas and Propane Heaters
Gas stoves
Pellet stoves and inserts
Space Heaters and Safety Concerns
Zone heating basics
Zone heating strategies with space heaters
Electric portable heaters
Heaters capacity
Pellet stoves and inserts
Air-source heat pumps
Home steam radiators
Wood stoves
Hearth Mount Heating
Fireplace inserts
Electric fireplaces
New efficient fireplaces
Direct-vent heating
Radiant heating
Boilers Basics
Furnaces Basics
Air conditioning Alternatives
Wall Gas Furnaces
