Choosing a solar thermal hot water system can be very confusing especially as there seems to so much conflicting information available.
The first step in choosing the correct solar hot water system is to check that the roof in which you intend to mount the solar panels on is facing south, south west or south east if you do not have a compass this can be achieved by typing your post code in to a photo mapping site like goggle earth. You will see a compass in top right hand corner you should be able to determine you roof orientation.
To achieve optimum results for all solar thermal products the solar collector should be mounted on a South facing roof ( Manufactures use optimum conditions to calculate their performance results). if you are not south facing the next best roof direction would be a south west facing roof then south east never north facing.
All chosen roofs must be free from obstruction which may cast a shadow over the solar panel i.e chimneys trees or other buildings if you do have an obstruction such a an adjacent buildings or a tree that cannot be felled, that cast a shadow for large parts of the day then the solar thermal system will not achieve the results expected therefore could be a costly and ineffective system leaving you very disappointed with you purchase.
The next thing to consider is what method of water heating is installed in your property. Do you have a hot water cylinder? if the answer is yes, then a solar installation in most cases will be straight forward. If you have a combi boiler or any other on-demand water heating system then installation may prove more difficult for the following reasons:
- Does your combi boiler accept pre-heated water?. If it is a relatively new condensing boiler the chances are that it will but you must firstly check with the boiler manufacturer. If the boiler is quite old and will not accept pre-heated water, you will need to change it before solar can be installed. although this will add additional costs, by changing to a new boiler you should save up to 30% off your water and heating cost per annum.
- Another thing to consider is do you have an airing cupboard or a suitable location for the pre-heat water cylinder?
More later...