How many square feet was the house? I don't know if that's compatible to heating a McMansion though.
I just did the math with my past bills and, amortized, I spend about $200 total on utilities a month. That's water, electricity, and oil. I have no special upgrades to my house. It gets fairly cold here. I have the aforementioned 2000 square foot (which I consider big) 75 year old house. I keep the heat on 68 when we are home. It gets hot in the summer and we use window air units.
I just looked up the realty listing and it says it's 2100 sq ft.
In the summer the bill was < 100. We get a lot of snow up here and I am betting that even though they added insulation the roof leaked ridiculous amounts of heat. I don't live there anymore luckily.
In climates with seasons you really have to do a yearly amortization to get a true idea of utility costs. A lot of oil and propane companies around here actually let you sign up for a plan that lets you pay them your amortized costs year-round. A few friends of mine love those plans, I prefer to pay the upfront cost to fill the tank and not bother.
My grandma's house had exactly the same problem, the roof was rotted and actually had a hole in it, you could see the outside from the inside. She didn't have the wherewithal to get it fixed though, unfortunately. She would just put down buckets to catch the water when it rained.
I just did the math with my past bills and, amortized, I spend about $200 total on utilities a month. That's water, electricity, and oil. I have no special upgrades to my house. It gets fairly cold here. I have the aforementioned 2000 square foot (which I consider big) 75 year old house. I keep the heat on 68 when we are home. It gets hot in the summer and we use window air units.