Harmonics, they are the source of this dirty power you speak of. DC switching power supplies are some of the worst offenders. These are transients and non 60hz frequencies that are generated by said appliance. The effects and do odd things to protection circuits like your power supply. I don’t know how your heater works but I’m guessing it uses some sort of switching to run on low power.

Should not be plugged into any kind of extension cord/power strip ! Into wall outlet only

How may watts is it??: 1800 watts on a 120 volts system draws 15 Amps

Don’t run 15 amp appliances on a 15 amp circuit it will trip circuit breaker.

It’s not plugged into the power strip, I should add. The power strip is plugged into a different outlet and is where my computer is plugged in. The power strip has an “overload” light on it that is set off when this space heater (it’s 1500 W) goes into “low” mode. Nothing happens when it’s on “high”. There’s something about the low mode that screws with the electronics in the house. This heater affects things in different rooms; it affects the whole house.

@ARE_you_kidding_me What’s a “DC switching power supply?” Sorry, I really know nothing about this topic.

It’s a cheap power supply that converts power to different levels using “on off” cycling. Your computer has one.
Also you said this happens when your heater switches from high to low? That’s probably a “transient” messing with your electronics. When you switch power off of an inductor suddenly you often get a huge voltage spike, especially in a poorly designed circuit. Can you leave your heater in high or low?

Thanks :)

It’s not just when it switches, it’s the entire time that it’s on low. The whole time it’s on low, the “overload” light on my power strip will be on (and the microwave will buzz, etc.) and it will shut off only if the heater goes back to high or if it turns off entirely. If I could keep it on high I would, but the nature of the heater is that it switches from high to low once it reaches the temperature you set. It’s too bad because it heats really well, it’s quiet, and the thermostat is fairly accurate, but I can’t use it if it does this.

Sounds like the “Low” is cycling the heater off and on; maybe on 60 cycle (assuming you are in North America. That would cause a Hum.

From what I understand buzzing can be a sign of bad wiring. Be careful. I don’t really know anything about it though.

Isn’t dirty power the electrical output from coal or oil fired power plants?

So, an update for those of you who were following this thrilling saga:

I sent back the heater. Not going to put up with it messing up the other electronic devices I own. So I bought another heater by the same brand, just cheaper and simpler. No digital climate control, just a mechanical on/off switch. Guess what? It works perfectly. No dirty power, no buzzing on low, no problems with the microwave, just a normal heater. Sometimes the cheaper model is better.