My bill was $515 this month. We've lived here 12 y...

My bill was $515 this month. We've lived here 12 years & its never been anywhere near that high. The heat was off & we had a fire going everyday last month(which we hadn't done much in previous yrs). We only had a Christmas tree lit but we usually have the whole house decorated & a few in the yard. Plus to top all that off, we bought a brand new heat pump last year. There's no good reason why it should be that high when we did so much to lower it.