Solar panel experts warn nine out of 10 householders won't qualify for government green incentives. 

The government's Feed in Tariff scheme - whereby homeowners are given incentives for installing solar panels in their homes - has proved popular with householders earning up to 15% on their investments.

As of April 2012 the governement proposes only homes with an energy efficiency rating of "C" or above will be eligible for the scheme.

Peter Bladen, Managing Director of solar panel firm BSOLAR, said: "Much of our building stock is older properties, which even if they use the full range of energy saving measures out there, still won't reach the efficiency 'C' rating. It's really only very new houses that can achieve this standard."

Bladen advises homeowners who are considering installing green panels do so before the changes come into effect in April.