The company joins existing members ScottishPower, E-on, British Gas, BP, EDF, npower, Scottish & Southern, Phoenix Gas, Firmus Energy, NIE Energy and National Grid.
Energy Saving Trust chief executivbe Philip Sellwood said: “It would be an understatement to say that since the organisation was set up in 1992 it has grown considerably as climate change has shot up the public agenda.
'In the last five years alone, we have gone from fighting for a voice to being centre stage as we strive to make every home in the UK a low carbon one.
“We have made significant progress over the years, but if we are to hit the 80 per cent carbon reduction target by 2050 then we have to make sure that we are equipped for the challenges ahead.
“Energy company Members will continue to be crucial in helping us deliver domestic carbon savings; however we must broaden our reach and expertise.
'We need to make sure that we are working closely with the very best and co-ordinating our activities in a way that will compel the consumer to take action. Baxi Group has a proven track record as an innovator of low carbon and renewable technologies and can play a major role in helping us bring these technologies to the mass domestic market.”
Baxi Group UK and Ireland chief executive Mark Kelly said: “We are dedicated to offer the best possible advice to industry and consumers.
'Baxi Group is committed to making sure that carbon, renewable and fuel poverty targets can be achieved with full support from the industry.
'We believe that all of these objectives will be enhanced through membership of the Energy Saving Trust as both our organisations work together to promote energy efficiency and sustainable living.”
Over the coming year the Trust will build its membership inviting a select few organisations who share its core values and can add value to its business strategy.
These will include retailers, water companies, house builders, green energy suppliers and micro-generation manufacturers.
The Energy Saving Trust’s strategy sets out its priorities for the next five years with seven areas of focus: energy efficient homes; energy saving behaviour; energy efficient products; low-carbon energy; sustainable travel; efficient use of water; less waste.