I'm in a similar situation, about to buy a house and move in this weekend.
I'm guessing that the will be no gas or electricity on in the house.
I was hoping to start using and then decide which tariff to move on to, is this possible? i.e. a non contractual account for a few weeks to see what usage is, then use those details?
If not what do people normally do?
When you move into a new property normally you have what is called, a deemed supplier (ie existing) -make sure you find out who this is,and ring them on your first day after completion ,with the meter readings.They will set up an account for you on their standard tariffs.You are then free to either change onto a better tariff with the existing company(which should happen instantly) or switch to a new supplier/s,which could take 6-8 weeks to complete. The initial standard tariffs will not have a lock in in terms of either time or cash penalty for leaving - but are usually the most expensive option available.You will also need approximate annual usage figures in KWh when using comparison sites. You should have been supplied with these during the purchase process (or make sure you ask your solicitor/selling estate agent)
If for some reason the utilities have been cut off (eg non payment of accounts) then AFAIA you are free to choose any new supplier BUT they will probably want a deposit up front to reconnect supplies.