With modern refrigerators, hot water could also be a bigger fraction.
My heating is natural gas, and I have no AC (SF Bay Area). My electricity bill has decreased, but I'm still trying to figure out how to decrease my natural gas bill, especially during the winter months. My theory is that my furnace and hot water heater are very inefficient, so I'm going to look into replacing those next year.
0/3 isn't that bad. Err, yes it is.
If the house is older than the furnace, the problem could also be lack of insulation.
Yes, lack of insulation is definitely a problem for me. I currently have no insulation (including the attic because of a rat problem that was there before I moved in). I do have wireless temperature sensors in various rooms to try to figure out how my house reacts to various weather, and I'm not sure how much adding insulation will actually help me, vs the cost of injecting insulation into the walls, etc. I'm probably going to get attic insulation before summer next year though, but to be honest, the temperature didn't get too crazy this year, despite several days of 90-100 degree weather, so I'm a bit skeptical.