If I move house do I have to buy a new system?

No. Wiser can be taken with you when you move house and re-installed in your new property. Insights+ will only work if your new home has a compatible smart meter. You can take your IHD with you to a home that has smart meters, the IHD from your previous home will not connect to the meters in your new home – you will need request re-connecting it to the new meters at your new address.