When it comes to picking a residential boiler, it’s usually fairly easy to estimate the size you need based on the number of residents and bedrooms. Picking the right size for a commercial building, however, is a little more complicated as there are other factors to consider.
Commercial boilers typically have an output of 70 kW or greater, although the distinction is not always clear cut. Here’s a quick guide to choosing the right size boiler.
What determines boiler size requirements?
The first thing to consider is the area of the commercial space. A common rule of thumb is to allocate 50-60 watts of output for every square metre that requires heating. If you prefer to work in imperial measurements, that’s about 5–6 watts per square foot. This means, for example, that a smaller commercial space of 300 square meters would need at least a 15 kW boiler, while a 30 kW boiler or better could be appropriate for a medium-sized space of 600 square meters. When you get to larger commercial spaces, you’re looking at the higher outputs that are typical of commercial boilers.
While this provides a useful initial guide, the precise requirements can vary based on a number of other factors. For example, what sort of building is it? Factories and warehouses tend to have higher ceilings than office buildings, for example, suggesting a need for greater heating. Nevertheless, an office may be split over multiple floors and separate rooms with a greater number of heating devices. Once you factor this in, an office building may need a larger boiler than a similarly sized warehouse.
Next, the boiler needs to be able to handle a reasonable worst case in the depths of winter, so the local climate is a factor. The bigger the difference between the internal and external temperature, the faster the building will lose heat. This means more heating is needed to maintain the required temperature. Related to this is the building’s insulation. Good insulation restricts heat loss to the environment, so the better a building is insulated, the less power a boiler will need to output.
It’s also worth considering the type of activities taking place in the building. For example, physically active employees on a factory floor may be more comfortable with a moderate temperature. In contrast, office workers or patrons in a restaurant may prefer a warmer environment.
Finally, the level of demand for hot water also needs to be considered. If your business uses large volumes of hot water, you need a boiler powerful enough to provide this while still heating the building on a cold winter’s day.
Some final recommendations
Installing a commercial boiler is a substantial investment, so you should also consider your potential future needs. For example, if you expand your operations, you ideally don’t want to pay for a whole new boiler as well. A well-maintained and regularly serviced commercial boiler could last 15–20 years or perhaps even longer. It’s therefore worth considering how your demands might realistically grow over this time.
When making the decision to install a commercial boiler, it’s also a good time to consider the wider subject of energy efficiency. For example, as insulation partially determines your boiler needs, upgrading insulation at the same time may mean you need a smaller boiler while reducing your business’s long-term energy costs. In addition, not all boilers are created equally, so some require more energy to achieve the same output heat. Choosing a more efficient boiler can therefore also reduce energy costs and the carbon footprint of your business.
As you can see, choosing the right size boiler is not a simple matter. While the above steps can help give you an idea of what boiler size you need, it’s best to get the opinion of a qualified heating engineer. An underpowered boiler may not function adequately under the most demanding conditions, while getting an overly large one can be an excessive investment. Xgas provides commercial heating solutions that fit with specific needs through a transparent process that helps you understand the work involved and the associated cost. Get in touch to arrange an initial consultation and learn how the team at Xgas can develop a solution that caters for your budget and unique requirements.