Anyone can qualify. If you live in North Lanarkshire, South Lanarkshire or Falkirk anyone who owns their property or is a private tenant qualifies. In other local authority regions if you recieve any form of benefit, you qualify.
Ideally you own the property but a private rented property is still eligible as long as the landlord of the property agrees. This benefits both the tenant and the landlord as the tenant experiences a lower energy bill and the landlord adds value to their property.