Is My Boiler Domestic or Commercial?

What are the differences between a domestic and commercial boiler system?

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a commercial boiler unit inside a boiler plant room

Commercial Boilers

Most commercial boiler systems are installed in commercial businesses where the units are solely intended for commercial purposes such as offices, factories, hotels and care homes to name a few. Commercial boilers often comprise of either one large boiler capable of outputs above 60kW or a series of smaller boilers in a cascade system designed to collectively output over 60kW.

Commercial boilers can also be used on a domestic premise, this is implicated when the domestic dwelling exceeds the size of an average home e.g. residences with a higher than average square footage, 7+ bedrooms or multiple living areas and bathrooms. In these circumstances a domestic boiler will not suffice and a commercial boiler will need to be installed to provide the correct output. Despite the domestic setting, a commercial engineer will still be required to install, repair and maintain the heating and hot water system.

Commercial boilers may also require additional components such as low loss headers, compensated mixing circuits and flue fan dilution systems. These are implicated so the boiler system can withstand a higher flow rate as a result of larger heat exchangers and for additional heating appliances (such as radiators) to be added to the system without leading to circulation issues.

Wall mounted boiler

Domestic Boilers

Domestic boilers typically output 10 to 60kW of power and are intended for use in the average domestic family house or apartment. These can often have upwards to 12 radiators and 6 or fewer inhabitants within the home.

Domestic heating systems will not regularly require the components mentioned for commercial systems as they will only have to provide heating for a low amount of heating appliances and hot water for 1 or 2 bathrooms, as well as a kitchen.

Another difference between domestic and commercial boilers is the lifespan and warranty period of each. As a general rule of thumb domestic boilers normally come with a warranty spanning 5 – 10 years and are expected to have a lifespan of 10 – 15 years. Commercial boilers will have a much shorter warranty duration ranging between 2 – 5 years, this is dependant on the manufacturer as some offer a longer warrant such as Vaillant pure which offers 10 years. The lifespan of any boiler entirely depends on how much it is used and how well it is maintained but the lifespan of a commercial boiler in general tends to be shorter spanning between 5 – 15 years as they meet a much higher demand than domestic boilers.

Please bear in mind that the guidelines we have provided for domestic and commercial boiler outputs are not definitive as you can have commercial boilers smaller than 60kW  (such as the Potterton Gold WH 46) and domestic boilers larger than 60kW. The deciding factor relies solely on the manufacturers who will normally indicate whether the boiler is for commercial or domestic use.