Installing a Solar Hot Water System

The first thing to do in any potential installation is to determine the hot water demand. This will directly influence the system design and is typically considered to be between 40-60 litres of hot water per day, per person. The system can then be designed in conjunction with the building architect in the case of new builds, or in conjunction with the owner and PG Plumbing.

We will supply component specifications as well as a routing plan and talk you through every stage of the project, from the selection of the tank system through to how to operate the heating controls we install. Once fully installed the system will be commissioned and tested by us, with our MCS Accreditation ensuring that you will qualify for any upcoming Government initiatives. The final part of the installation is the sign off for the working system, by which point you will have a fully working and certified solar hot water installation!

Specifying the Collectors

In order to calculate the size of the collector, we need to work out the effective surface area of collector required. The effective surface area talked about in most technical literature is not the absolute size of the flat panel or tube array, but rather the area of the active portion of the collector that collects the heat. For evacuated tube collectors each 58mm x 1.8m tube will give an effective surface area of 0.082 m2, therefore to find the effective surface area of a collector you need to multiply the number of tubes by 0.082 (Numbers stated are for 58mm tubes).

E.G. a 24 tube collector will have an effective surface area of 24 x 0.082 = 1.968 m2

Note: a rule of thumb is that one square meter of collector is installed for each member in the house based on approximately 50L of water used per person per day.

Once the thermal requirements have been established it is then possible to provide a sizing estimate for the amount of roof space required to accommodate the installation. Directly southward facing rooftops are ideal, but due to the nature of solar thermal systems (As opposed to Solar PV panels) they can be installed elsewhere. Do note however that installing on, for example, a North facing rooftop would require a larger array to maintain the same heating output and would therefore result in a more expensive installation.

Planning Permission

Within the UK most installations of solar microgeneration systems are considered to be permitted developments and usually planning permission is not required. However if the system is particularly large, or your property is a listed building, a conservation project or located within an area with aesthetic or local restrictions you may need to apply for planning permissions.

Please contact your local authority to establish as early on as possible whether or not permission needs to be obtained, as we will be unable to offer any refunds for materials or work completed should a planning violation be discovered at any point in the project.

If you discover that you need planning permission to have the installation completed, please obtain it prior to committing to the project to avoid any unnecessary and expensive complications!