Solar Heating Panels for a house extension - should you be including them?

Just like PV solar panels, solar hot water heating panels have improved enormously over the last 5 years. Many of the original systems even installed up to 8 years ago are now defunct, broken or taken out of use simply because they had so many problems. This was mainly due to a lack of understanding, poor design of the units and lack of controls for the whole system.

The solar heating panels and controls now built and installed are far far better and most are fit for purpose in my opinion but it has been a long awkward journey to get to this point. So, should a home owner having a house extension built be having solar hot water heating panels built into the roof design?

Quite likely the answer would be yes and at this current time possibly in preference to PV solar panels as I see the longer term use and reliability of more value to the householder than PV. The most efficient of these solar hot water panels are the glass vacuum tube systems. These are far more suitable for the UK overcast climate that we always seem to have although they are probably twice the price of the alternatives.

However, some of the questions a homeowner should be asking any supplier or installer of solar hot water heating panels are:-

1 - What is the life span of each solar hot water heating panel - some manufacturers are only guaranteeing 5 years - that’s no good at all.

2 - What are the strengths of these solar hot water heating panels and can they withstand a heavy firework dropping out of the sky?

3 - Should one solar panel break or fail how easy is it to replace and will the same type and size of solar panel be available from the same manufacturer. The design shapes and interconnectivity seem to be evolving very quickly so you could be faced with having to replace the entire panel set all over again. Roofers have this problem with most of the dry fix hips, ridges and verges - they are virtually impossible to repair or replace because the design of the fitting has changed even within 5 years and manufacturers do not keep lots of redundant design stocks.

4 - Can they withstand the odd gale force winds we have in the UK and what code of fitting are the installers working too. I foresee a lot of problems highlighted on this issue given the rapid expansion of the solar hot water systems and the clamber by certain companies willing to leap onto the current carbon reducing band wagon.

5 - Given the UK’s lack of direct sunshine for most of the year how efficient are they compared to the optimum sunshine levels for maximum production of hot water. Here in the UK most hot water solar panels only act as a pre-heat function and still require top up heating from conventional sources. I fear that you may only be getting around 50% of their capability levels and much of the theoretical proving calculations are based upon higher efficiencies - rather like those old style pension growth forecasts that never ever lived up to the reality of their suggested performance leaving most of the people very disappointed and let down.

6 - What are the safeguards and control measures to prevent overheating of the system during unoccupied periods of the home where no hot water is being used? I have heard that ‘drain down’ is often required and that failures or breakdowns of the system due to overheating are quite common.