Here's something else you need to know about heaters.
There are three ways a heater can heat things, including you.
Conduction requires direct physical contact and we can ignore it for electric heaters (though a hot cup of coffee warms the hands nicely).
Convection warms the air in the room, some of the air warms you.
Radiation warms the surfaces in the room, including you.
Radiation is much quicker, since there is no intermediate air, and more effective, since it warms you directly. Radiation is what you feel when you hold your hands up to a fire. A low power radiator (or even better a pair, one on each side of you) will warm you up as soon as they are turned on and do a much better job than a much higher powered convector, which has to warm the air in the room and most of the surfaces before it has much effect.
How do you tell a radiator from a convector? Easily, radiators glow. If it's not glowing it is a convector not a radiator. Now a glowing red heater can be a fire hazard so there is a trade off, but you should at least know what it is.