The Energy Saving Trust are an impartial and independent organisation giving a source of free advice and information for those people across the UK who are looking to save energy, conserve water and reduce waste.

MCS:

The Microgeneration Certification Scheme (MCS) is an independent scheme that certifies microgeneration products and installers in accordance with consistent standards. It is designed to evaluate microgeneration products and installers with robust criteria helping to provide greater protection for consumers.
http://www.microgenerationcertification.org/

 BRE:

The Building Research Establishment is the governing body that deals with PowerNaturally's MCS accreditation. This page gives even more information on the MCS scheme.  
http://www.greenbooklive.com/page.jsp?id=4

 REAL Assurance Scheme:

The REAL Assurance Scheme has been set up by the Renewable Energy Association. It aims to guarantee a high quality experience for consumers wishing to buy or lease small generation units for their home, for a community building or for a small business. REAL membership is a sign that the supplier has agreed to abide by the high standards as set out in our consumer code. The REAL logo is a symbol of professional excellence.
http://www.realassurance.org.uk/

The Energy Saving Trust:

The Energy Saving Trust are an impartial and independent organisation giving Aa source of free advice and information for those people across the UK who are looking to save energy, conserve water and reduce waste.
http://www.energysavingtrust.org.uk/