Viessmann urges domestic installers to consider lower output boilers

31st January 2024

With the cost of living and energy crises deepening and as the country hits much colder winter temperatures, UK homeowners facing boiler replacements are looking for ways to reduce the cost of a new boiler, increase efficiency and lower their bills.  

One way in which heating installers can help is to check, in the case of system boilers, that the output of the proposed model matches the heat demand of the home. It is often the case that installers replace a boiler like-for-like when it comes to output. This often results in boilers being specified with a higher output than actually needed. Viessmann is urging installers to consider fitting a lower output boiler if possible.

“The majority of homes do not have a heat load of more than 10 kW, yet most system boiler ranges start at an output of around 19 kW. This means that the majority of system boilers in the UK are oversized,” explains Viessmann marketing director, Darren McMahon. “Homeowners are buying larger and more expensive boilers than they need and once installed, the boiler cycles more than it needs to, increasing running costs and wear and tear. A correctly-sized boiler will be more efficient and last longer.”  

Viessmann’s Which? Best Buy-awarded Vitodens 100-W and 200-W range of domestic gas-condensing boilers all include a low, 11 kW output model.  

Choosing a lower output model makes life easier for installers too:

“The Vitodens 11 kW models mean installers no longer have to range-rate larger boilers to reduce their maximum output for heating. System boilers can now be fitted where heat-only models may have been chosen previously. The boiler has a higher output rating of 17.5 kW for the generation of hot water, so there is no trade-off between space- and domestic hot water- heating,” continues McMahon.