Jason Hobson, Divisional Director at McDonald Water Storage, explains some of the advantages that thermal stores can provide over alternative forms of hot water storage.
Thermal stores have been an effective and highly efficient hot water solution in the UK for almost 40 years, however, it’s a solution which many installers tend to shy away from in favour of unvented cylinders.
It’s no surprise really – sometimes it’s easier just to go with a straight replacement of what’s there, or simply revert back to what you know best.
However, the popularity of thermal stores are on the rise, particularly as they overcome many of the frustrations installers have with unvented cylinders, as well as the hidden costs of installation that are seen as ‘just part of the job’.
So, why are installers looking at installing thermal stores to simplify the installation process and improve the finished solution with a fit and forget hot water solution?
Sometimes it is out of necessity. For example, in projects where commercial offices are being converted into private apartments, you need to deliver a mains pressure hot water solution but it’s almost impossible to install the discharge pipework to comply with G3 of the Building Regulations necessary for unvented solutions.
Other times, it’s because it is just the best solution for the project, such as when incorporating renewable energy inputs, or the cylinder needs to be located in a specific part of the home, for example, the attic space.
Other reasons why installers are looking to this solution are that it’s a fit and forget solution that’s easy and quick to install and requires zero maintenance.
The big tick in the box for end-users is the thermal store’s ability to provide mains pressure hot water, without the need for ongoing annual maintenance, making them a perfect alternative to the unvented unit. This is achieved by reversing the traditional approach to hot water.
So, instead of storing hot water in the cylinder under pressure, which is then used for taps and showers when required, the thermal store acts more like a battery, storing the energy from any fuel source when it is cost effective, then providing hot water and heating when it is needed in an inherently safe vented store. The mains pressure hot water is generated by passing the mains pressure cold water through the highly efficient internal coil, and the heating by sending the stored water around underfloor or radiator system.
A further benefit of the thermal store is that the heated water is then blended to achieve the optimum temperature of approximately 52°c to avoid scalding, and is then supplied to the taps and showers. As the hot water is produced instantaneously and is not stored, there is a lower risk of legionella.
As the system is not pressurised, it acts much like a vented cylinder, therefore offering additional benefits to installers to simplify the install process.
The first big benefit is the ability to site the thermal store anywhere in the property, with no need for complicated discharge pipework. That, in turn, avoids the implications of screeding the pipework under the floor, which is required to allow the fall necessary prior to discharging into a high temperature soil stack.
This means installers can virtually guarantee they can install a thermal store in the existing space, or enable homeowners to move the hot water solution to the attic to free up cupboard space. In addition, the thermal store can be manufactured in a tall, short, fat, thin format, or even as a cube, which can reduce the size by 25%.
As thermal stores are not pressured, they do not fall under the G3 of the Building Regulations and do not require installers to be G3-accredited.
This makes them a suitable solution for apartment blocks or in projects where commercial office blocks are being converted into private apartments, enabling mains pressure hot water to be delivered throughout the building.
The thermal store is widely recognised as an optimal solution for incorporating renewable energy inputs, thanks to its ability to harness the energy as it is generated, store it until it is required, and then transfer the heat into heating and hot water on demand.
By incorporating multiple renewable energy sources, you can create a truly efficient solution using, for example, solar to capitalise on the energy generated in the summer months, with a solid fuel stove generating the power during the colder winter months.