@Mike-And-Jane0
The way my accountant works it out is on number of rooms basis, so the guest bedrooms but also the areas that they have access to (which in my case is basically the whole house, minus my bedroom).
If, like @Andrew2387 , I had an annexe or similar, I would seriously think about putting in separate meters for gas and electricity, but I have no idea what that costs. For hallways, you could think about lights that are activated by sensors or those operated by a push button that automatically turn off after a while. I think my mother paid around £40 for a set of two of these for a rental unit, but I don't know how much the electrician charged her.
As to a clever way to incorporate rising fuel costs into the Airbnb rates, I haven't figured anything out. My rooms are pretty much booked until July or August, but I'll have to increase them for next winter. If other hosts in the area are doing the same, then the prices should still be competitive.
Although it's a pretty energy efficient household, it's a big, old property that already cost a fortune to heat in the winter before the fuel prices shot up. The summer months should at least be a respite but we have good water pressure and I find that guests tend to whack the showers on full and many of them seem to take scaldingly hot. It's just not going to be worth me doing Airbnb if I have to shoulder all of the extra cost.