Your bills are okay. Spanish electricity services have increased the standing charges for normal rates but tye charges for tariff Noche ( similar to Economy 7) have stayed the same. If you dont rent out and are willing to stick to the cheap electric hours, approx midnight to noon, depending on season..the tariff Noche is great. Rates are approx 5 c at night and 20 c in day. Normal metres are about 15 c per unit.
We live here and I organise my cooking, washing, water heating around these times. If I were a visitor i would still use it.
If I was loaning my apartment to family, without the use of a card metre installed, I wouldnt be comfortable asking family not to use water heating etc during the day. Asking them only to use the aircon midnight to 1200 wouldn't be great either.
I hope this helps,