Having a solar heater system installed by a professional will take less than a day but these systems can be fitted by a competent DIYer. This option can work out cheaper but will take longer and requires a certain level of skills.

No planning permission is needed for Solar Thermal systems as they typically fall within what is known as "permitted development rights". However, it is best to check with the Local Authority. Especially if the building is divided into flats, is listed or is in a conservation area.

However, building control should be informed of the work being carried out so that it is deemed safe. There is a useful booklet on the ODPM website entitled "Building Regulation Explanatory Booklet". It is a good idea to consult this booklet to check whether building control need to know of your completed work as in most cases they will.

There may be an issue due to the extra weight load on the roof and this should be assessed by a structural engineer.