Condensing boilers in commercial premises

A variety of commercial boilers have been tested to determine their full- and part-load efficiencies under operating conditions. These tests have shown that there are three distinct classifications of boiler- 'traditional', 'high-efficiency' and 'condensing'. Condensing boilers differ chiefly from traditional and high-efficiency boilers in their ability to recover and use some of the latent heat produced when the moisture within the flue products is condensed. Although condensing boilers can benefit from recovering this latent heat, it does not follow that condensation will always occur within the boiler. Although other fuels produce water vapour during combustion, natural gas has a particularly high proportion of moisture in its flue products. This fact, plus a low sulphur content (and hence a less acidic condensate), makes natural gas the ideal choice of fuel for condensing boiler design. A payback analysis is presented.