If you plug in just one 1200 watt space heater you are using as much power as 20 sixty watt bulbs or 10 amps roughly. The formula is Volts X amps = watts Watts divided by volts = amps roughly. The light bulb issue is a big bunch of boloney fabricated to push more expensive bulbs.
In other words you are only saving a small portion on the least power users in the house to start with.
Here’s an ideal. Light is actually measured in lumens not watts. So a typical 60 watt incandescent has 780 while a 100 watt has 1510. Two 60’s is 1560 but one 100 watt bulb will use less power and give off nearly as much light. But you must have a fixture rated for it. I took out most of my 60 watt fixtures and replaced them with single 100 watt rated ones at a net cost of about $2.00 a piece :>}
A hair dryer will use that much too for the brief time you use it. I never use space heaters. I also don't ever have 20 sixty watt bulbs burning in my house at any one time. I have replaced most of my bulbs with compact fluorescent bulbs and it does save me a few dollars a month, enough that I've more than paid for the new bulbs with what I've saved on my electric bill. I think they are a really good deal if you try to buy them on sale. They pay for themselves in a pretty short time if you replace lights you leave on a lot. I've actually cut my electric bill pretty substantially, but I've done a lot more than just replace light bulbs that have burned out. I found close to three hundred watts of phantom power I was losing with things I left on all the time and things that stay in standby mode and waiting for someone to click a remote control to turn them all the way on. Three hundred watts on 24 hours a day is as much power as you'd burn with a 1200 watt space heater on six hours a day. That's about $20 a month with power going for nine cents a kilowatt hour saved by turning things off and putting other things on power strips that I turn on when I need them. Getting rid of some inefficient light fixtures helped to. The cheesy candelabra in the room I'm in now used to burn 360 watts when it was turned all the way up, and it lit the ceiling a lot better than it lit the room. The fixture we have now burns 69 watts and seems to light the room a lot better. Every little bit helps. It's not that hard for most people to shave $30 or more from their monthly electric bill.