Solar Thermal Hot Water FAQs

How many panels will I need?

The system will be designed around the number of occupants in the property. In some instances if only 2 people are living in a 5 bedroom property, we would still size the system for the size of the house, but tailor the volume of the cylinder to the occupancy size. Panel sizing, rule of thumb, 88 litres per 1 sqm of collector. We will carry out a site survey and design the system for you.

How much will I save on my bills and will I get my initial outlay back?

The savings will depend on how much water you use. If you are a working family you will roughly save about 30% on your hot water energy bill, but during the summer savings should be greater as there will be less requirement to use back- up heat for the water as the solar should provide enough for at least 5 months of the year. During the winter there will be some solar gain, of about 30° so you will need to top up with your back up heat source. It also is changing your habits - bathing more in the evenings and washing in the morning.

The system will pay for itself over a period of time, of up to 10 - 15 years, but grants are available to assist with the costs. Also RHIs are being introduced from April 2011 which will benefit you. A system is also proven to put value on your property should you move.

We recently carried out an installation for a building company that had to meet 25% of the carbon emissions from the properties that they built. They incorporated solar thermal on 8 of the properties - these were the first properties to be sold proving that solar is an attraction.

How much does a system cost?

This depends on volume storage hot water cylinder. A small system should cost no more than £3,600.00 fully installed. All our systems are designed for your requirements, so please contact us to discuss.

Where can I put the panels?

The best position is south facing, at an incline of 45°. There is not much loss if the panel faces 20° either direction of south, and can also be sited at an angle of 30°. Occassionally we will install the system on an East/West split, but this requires two pumps to run the system. Panels can be mounted on flat roofs using A-frames, or inroof, giving the appearance of a Velux window, or mounted on fixings above the existing roof tile.

Will I need a new cylinder?

A new cylinder is always required as the old cylinders do not meet todays building regulations. Also it needs to be twin coil - using one coil for back up heat and the other for solar, unless it is a direct cylinder where only one coil is required. This cylinder will be replaced normally in your existing airing cupboard, and the size of the cylinder will need a dedicated volume of about 25% for solar, which means you will need a bigger cylinder than you have at present.

How does my boiler know not to switch on?

The cylinder stat will be moved higher up on the cylinder, so the solar is dedicated for the bottom of the cylinder, and the solar heat will be stratified to the top part of the cylinder. We have to keep the cylinder set to 60° so not to cause any bacteria build up within the tank, by adding a blending valve within the system we can gain higher temperatures in the cylinder.

How long does an installation take?

in a domestic home the installation should take two days, with minimum disruption and never leaving you for long periods without hot water.

Can I install it myself?

It can be installed yourself but by having a specialist company to install it your VAT charge will be at 5%. It will also need specialist equipment to fill the system, the controller will need setting and it will require commissioning. If you let us install the system, you have peace of mind that it is installed by professionals, and be guaranteed should you have any problems. Also solar collector temperature and fluid can reach up to 200°C which can cause scalding, and extreme care needs to be taken.

What if there isn't any sun?

The system does not require direct sunlight to operate; it only requires daylight and therefore will operate even on cloudy days.

If you have any further questions that we have not covered please feel free to contact us.