Almost all plug-in type heaters use the same amount of electricity - around 1,500 watts - including the oil-filled ones. A plug-in heater usually will draw the maximum amount of power available on a 15amp circuit, so no more than one per circuit would be good advice (be aware that it is common that more than one receptacle can be on the same circuit). Heaters usually draw more power than air conditioners - especially the newer A/C units.

Technically, any receptacle in your home should be able to handle a minimum of 1,440 watts of continuous use without any negative effects. If you noticed a problem using a plug-in heater (and you were not using it with an extension cord or a power strip), then you should contact a licensed electrician as you may have a problem with the wiring in the house. When we are called in for these types of problems, the issue is almost always either loose connections, or too many heaters on the same circuit. In either case it’s usually a simple fix, but left unchecked could cause a fire.

I have a 200 amp service and am getting central AC installed which requires two 2-pole 15 amp breakers. Is there a benefit in installing a sub panel for the air conditioning instead?

That depends. Usually a sub panel is only necessary if the main panel is full, or if more than just a couple of circuits are needed at a distance away from the main panel.

Can I move my thermostat to a wall that contains plumbing?

I don't see any reason why not. The only thing you should avoid is installing a thermostat on an outside wall, as this may affect the temperature readings.

The plug on my small window air conditioner keeps getting hot. What can I do about it?

If the plug is not securely in the receptacle, it can get hot when under a heavy load. Also, if the plug doesn’t stay firmly in the receptacle, it may be that the prongs are worn out. You may want to have a licensed electrician replace it.

I installed a window air conditioner and now the circuit breaker keeps tripping. Can I install a larger breaker to make the outlet stronger?

The only safe way to do this is to install a new receptacle circuit wired from the service panel on its own circuit breaker sized appropriately for the A/C. This way, there would be no overload worries. By putting a larger breaker on the existing wire, you run the risk of a fire starting due to a possible overload.