The ECA scheme is well worth taking up if you are a business user of Air Conditioning equipment as on certain equipment they will give you 100% capital allowance in the first year, follow this link to find out more.
www.eca.gov.uk. Other sites that may be of interest are
www.thecarbontrust.co.uk as you may be able to get an interest free loan, obviously their are terms and conditions related to this, another is the inland revenue as they will discount the VAT on some domestic installations
www.inlandrevenue.gov.uk