What is the difference between a condensing boiler and a non-condensing or conventional boiler?

The main difference between a condensing boiler and one that does not use the condensing principle or a conventional boiler lies in the type of combustion. Indeed, the combustion of natural gas or methane produces heat, and since the CH4 methane molecule contains hydrogen H, the same combines with the oxygen to produce water which, considering its high temperature, is in the steam state. The combustion of Carbon C produces carbon dioxide CO2.

In condensing boilers, a special heat exchanger also acts as a condenser. Indeed, the heat exchanger is capable of cooling the fumes which are saturated with steam and which condense into water in the liquid state, using the water from the heating system at low temperature (approx. 50°) circulating through it. The fumes are expelled through purpose-designed disposal pipes which are normally connected to the heating system drain outlets.

The heat which the fumes transfer to the boiler heat exchanger in turn heats the water in the heating system which therefore benefits from this value which is normally lost. This operating mode reduces NOx and CO emissions (Nitrogen oxide and carbon monoxide) thanks to the use of particularly sophisticated combustion technologies.

How much heat is recovered with a condensing boiler?

Depending on the type of heating system, a condensing boiler makes it possible to recover up to 10-11% more than a conventional boiler, but also with respect to the lower calorific value of methane, which is also known as natural gas.