I was prompted by a message on the tenants' forum to look up information about energy performance certificates for rental houses.
According to the following link:
Energy Performance Certificates (EPCs) - Planning, building and the environment - Communities and Local Government
You will need to get a certificate when you rent out a house after 1st October 2008.
As with HIPS, prospective tenants are allowed to see it when they ask for particulars or view the property (with certain exceptions - eg. if you don't think they can afford the property, or if you have a lawful reason for not wanting to rent to them).
Certificates will remain valid for 10 years - as far as I can see you don't have to get a new one when you get new tenants.
The exception is that if you sell the house, the certificate has to be less than 12 months old.
Can this thread be stickied (assuming I have the correct information)?