Yes, everyone is entitled to a subsidy and some people can even have free installation. Why? Because the UK Government is obligated to reduce greenhouse gas emissions by 2012 as part of the Kyoto Protocol. One of the easiest ways to achieve a large reduction in greenhouse gas emissions is through increased home energy efficiency. The Government has stated that cavity wall insulation and loft insulation are the most effective methods which is why they have legislated for power/energy utilities and power companies to provide subsidies.
Yes, people living in rented property can get their homes insulated, but you must get the permission of the owner or landlord.