You can get a new gas furnace with a variable speed blower that will use less energy than a 100 watt light bulb. If the neighbor has one and you're still using an old 50-60% gas furnace that old blower motor could account for most of that 27%.
I use a 24k btu space heater mounted on the wall in my garage to keep it comfortable out there. I'm not allowed to smoke in the house. Here's a side rant about that. I maintain 70 degrees in the garage, last winter we had a morning that got down to -19 (that's rare in my area) so anyway my wife pulls her suv out to go to work. That night I notice that "chrome" grill was all wrinkled and fucked up looking. I guess the instant 90 degree temp swing was more than the chrome tape on that plactic grill could handle. Color me pissed that day.