A condensing boiler it has a higher efficiency but also costs more than a traditional boiler to meet the thermal needs (heating and domestic hot water production). Let's try to understand if the greater investment is always convenient.
If you look at the economic convenience taking into account the payback time net of incentives (the so-called pay-back), the condensing boiler it is considered an optimal technology for satisfying the thermal need in a residential environment, that is when it is installed in buildings intended for residential use.
If, on the other hand, we move to the industrial and part of the tertiary sector (supermarkets and banks) - according to the Politecnico di Milano which has studied the pay-back of technological solutions for energy efficiency - the condensing boiler it is less convenient than cogeneration (for the industrial sector) and the heat pump (for large-scale distribution and banks).
In other situations of the tertiary sector, for example hospitals and hotels, the optimal technology for thermal needs is still cogeneration (with which electricity can also be produced) while in schools the traditional natural gas boiler is preferable in consideration of the downtime system due to the discontinuous use of buildings. The economic convenience of the condensing boiler in short, it depends on the scope of application.
Even for residential buildings, however, distinctions must be made. The technology of condensing boiler it has the characteristic of functioning well at relatively low temperatures (lower than the traditional boiler) and this makes it particularly suitable for situations in which radiant panel heating systems are installed in the floor (underfloor heating) or in the walls ( wall heating). Less so when it comes to heating systems with traditional radiators.
Always for the characteristic of having a high efficiency at low temperatures, the condensing boiler it is optimal in buildings well insulated from the thermal point of view. Well insulated walls and roofs and the absence of thermal bridges maximize the yield of the condensing boiler which, conversely, is penalized in the presence of high dispersions.
Other parameters on which the economic convenience of one depends condensing boiler are the local climate, the size of the house and the actual use of the same. There condensing boiler it is optimal when you spend so much on heating, which occurs in a house is great in a cold climate. For a small house in a temperate climate zone, a traditional boiler may be more convenient. Even when the house is little used during the day (and the boiler remains off for a long time), or in a house used only for holidays, the economic convenience of the condensing boiler.
Given these considerations, the validity of the technology is indisputable in terms of performance condensing boiler which today in Italy represents about 20-30% of the approximately 19 million heating systems installed, between autonomous and centralized. The high yield of the condensing boiler (variable between 105% -109% compared to 90% -93% of the traditional boiler) depends on the fact that this system is designed to exploit a good part of the latent heat contained in the exhaust gas.
Perhaps you are also interested in our article: How a condensing boiler works