Rant Alert !

This seems appropriate with the climate conference kicking off. 
As well as gardening, we look after 2 gîtes - clean, change and do the laundry between guests - and the owners of one have told us not only to leave both the empty fridge freezers running, but to leave the heating set to 20 degrees,  day and night. They have nobody booked before summer next year. 
Although we need the income,  I personally would rather not work for them. Am I being too sensitive?!

Don’t get the fridge freezer bit PP but kind of understand the heating during winter as left without heating buildings do start to deteriorate very quickly, although I’d say 20 degrees was a bit warm.

I have worked for people like that. Do the owners live near by? If not I’d turn the heating down to frost free setting & turn fridge freezer off. Leaving door propped open. What they don’t know won’t hurt them. Turn it all up again a couple of days before their next visit.

Don’t get the fridge freezer bit PP but kind of understand the heating during winter as left without heating buildings do start to deteriorate very quickly, although I’d say 20 degrees was a bit warm.

Our other place is a 200 year old farmhouse and converted barn half set into the mountain side; all the power is turned off when empty and it is fine. A low or even frost setting should be all that's needed, not 20 degrees, 24 hours a day  That's warmer than our house! The advantage of summers in the high thirties is everything dries out. And I mean everything 
Plus the place gets a monthly airing right through the winter, and it's a modern building.

Could you have a blown fuse that stops them running - that you won't notice until next time you have to clean it?

I have worked for people like that. Do the owners live near by? If not I’d turn the heating down to frost free setting & turn fridge freezer off. Leaving door propped open. What they don’t know won’t hurt them. Turn it all up again a couple of days before their next visit.

They don't let us know when they're turning up or I would 

They have more money and sense and no social responsibility, such a waste.

We have a little countryside cottage and in the good old Scottish winters if heating is not left on (frost setting on electric radiators) it’s amazing how quickly the damp takes over. It’s an old stone building. As I said I understand leaving a bit of heating on but 20 degrees is a bit much.

Turn down you're own heating and move into the one with the heating on

It's a thought, Spec   althouh we haven't actually lit the fire yet this year!