Back when gas fired water heaters were first launched in the seventies, estimates from reference guides and manual calculations were used to specify a suitable product. How times have changed, says Chris Meir, sales director at Andrews Water Heaters, as he reflects on how sizing practices have evolved over the years.
Traditionally, water heaters were selected based on the demand of the building they would be installed in, with the flow rate calculated based on ‘demand units’, i.e. basins, showers, baths etc. Long-winded calculations based on reference points from CIBSE guidelines and the original Andrews Water Heaters Sizing Guide were used. There wasn’t as much diversity in system specification as there is now and many systems were oversized. After all, end users were unlikely to complain about having too much hot water, and energy efficiency was not as high on the agenda as it is today.
But oversized systems are problematic, even if end users don’t realise it. The capital outlay is greater on larger plant, more energy is used in operation, and, if the demand for hot water is not there, it will cost the end user more in energy bills. This is all before we consider that larger plant takes up more space, and can therefore cause installation issues if a very limited area has been allocated for housing equipment.
Andrews Water Heaters saw the issues of oversizing in the industry and launched its Size-it tool in 1996. The way it worked was simple – users just inputted their hot water requirements depending on property type to determine appropriate products that would meet their needs. Since its launch, a handful of other sizing tools have come onto the market as more manufacturers aim to combat the issue of oversizing. Technology has since moved on leaps and bounds, which is why we revamped our Size-it tool to make it more user-friendly, informative and accessible across multiple devices.
Complex calculations need to be made straightforward so that busy specifiers can get the required information, and match the right product to the right job every time, no matter which sector they are working in. This approach benefits all parties – specifiers, installers and end users – and from a manufacturer’s point of view it ensures that our products are chosen for applications where they can deliver hot water in the most efficient way.