Ensure that your boiler is happy and health with an annual boiler service get in touch to book with us today! Know your rights - home & property. By contrast, our market-leading floor-standing and wall-hung condensing boilers operate at near maximum efficiency - achieving on average % gross calorific value with low nox emissions. We've got loyal clients with great things to say about us! I'd definitely call them again. Combi boilers: is a combi boiler the right boiler for you? The price of your big & bulky delivery will depend on your location and preferred delivery day – see below for details.