Both organisations are responsible for ensuring that their member companies – which are involved in the installation of windows and doors in the UK – comply with government Building Regulations. Both also assess members annually to ensure they are competent in their trade. Certass is the more recently-formed of the two and, as such, is a Green Deal Approved Certification body. It also has the industry’s TrustMark accreditation and a tailor-made dispute resolution service which both the member and their customer can access. Here at Sovereign Home Improvements we have opted to go with Certass due to its green credentials, which we find more customers are interested in these days.