There is essentially no difference in efficiency. All electric resistance heaters are 100% efficient at converting electrical energy to heat energy. There are some big differences to consider when you shop for products to keep your home warm in the coming heating season. The two biggest differences are safety and comfort.

Safety should be on the top of your priority list when shopping for a heater. Remember, portable electric heaters should never be used as a permanent heat source. They should not be used with extension cords. Portable heaters do have safety switches designed to turn off the power if they are tipped over or accidentally covered or blocked, but these safety switches are simple devices that can and will fail!   Do not rely on them. Always unplug them when you leave the room they are in.

How comfortable you are in a room depends on how a given heater moves heat into the space. Some rely on the convective currents of warm air rising, some are radiant panels, while still others use a fan or a combination of these methods. This is largely an area of personal preference, but it bears some serious consideration. Some fan forced models can become noisy after a few months of run time. Also sometimes the fan blows too hard and actually moves most of the heat past you and into the opposite wall. I recommend trying one in a showroom before you buy if possible.

CPC sells a complete line of high quality electric heaters called ConvectAir that may be a viable choice for you. They mount to the wall so they can’t fall over and can safely be used as permanent heat source. They have electronic thermostats for greater accuracy and each heater has an on/off switch which is important for making sure the heater is coming on when you don’t want it on. They have an excellent warranty and come in both plug-in 120v and hard-wired 240v models.