Over the years of running marina house we have seen bills as low as B400 for a full month with a person running the following items:
Floor standing fan (i.e. not using the built-in air-con unit)
Hot water in the shower
It must be noted that this has ONLY been achieved on the 1st floor where the rooms do not heat up during the day.
The average bill for an apartment for a month is closer to B1,000-B1,500 with a person adding in a 3/4 height fridge and using air-con for 4-6 hours a day at 27-28c. Keeping air-con to a higher temperature really does keep the bills much lower.
B5,000-B6,000 This is based of running the following:
Full height fridge/freezer
Mini-kitchen (microwave, hob, steamer, kettle) cooking 2 meals a day
Desktop computer with 22" monitor and a laptop
Air-conditioning at 25c for 12 hours a day
Hot water shower
Fan (to circulate air-conditioning)
It is worth noting that this bill was achieved during April when the average temperature was 40c with a 6 month old baby in the apartment (they just don't cope with the heat as well). This was 3 people as well, all meals cooked at home, 1 person working from home and plenty of luxuries. The same apartment with the air-con at 28c for 8 hours a day would bill closer to B2,000-B2,500 so this high estimate needs to be averaged out over the year as a cost as, in November to February, the air-con can be reduced down to a couple of hours a day at most.