Landlords are being urged to make sure they install cavity wall insulation to help reduce energy bills.
Mike Malina, an energy efficiency expert, has suggested that installing good insulation is better than replacing double glazed windows.
"There is a myth about this; it's a cosmetic thing. If your windows are in drastic need of replacement then fine, you should invest in it," he commented.
"But to go out and change your windows if they're sound is not a good idea because there are a lot of better things you can do first that you can get a much better financial return on."
Other measures suggested by Mr Malina include the installation of draft stripping and individual thermostatic radio valves for radiators.
Making such changes can dramatically reduce energy bills, especially in homes that are let to the likes of students who often have bills included in rent.
The Department for Communities and Local Government say that the average new build home emits 0.7 tonnes less carbon emissions than older properties.
