Which are the best solar panels - Solar PV or Solar Thermal.
There are a lot of pros and cons to both solar thermal and solar PV so I have listed the high lights below to give you an idea but the definition of the best solar panels really hinges on your situation. Questions like how many people occupy the building, how much hot water do you use, how much electricity do you use - all influence the decision. So the information below is general and can change depending on the context so it would be great to talk these through to get a better feel of your requirements. Once you have read through this please give us a call to have a chat about your options.
Solar panels for heating water systems are about twice as efficient in producing energy than pv solar panels systems. However the energy produced by solar thermal is of course in the form of heat so has to be used to heat water typically, solar pv produces electricity so can be used to power anything electrical.
Solar thermal energy is typically stored in a hot water cylinder and so the output of the system can be used when required, i.e. you can be out while the sun is shining and come home to use the energy that was collected in your absence. Solar PV can be stored but this is an expensive addition at the moment, the alternative is using the electricity as it is produced which can be difficult of you do not have a constant base load in your house. If you produce electricity that is not used in house it is exported to the grid and donated to the various utilities for free.. There is talk of a Feed in Tarriff coming which will allow for payment in this scenario but it may be a few years away.
The amount of south facing roof space available to you may sway your decision, if small and urban you should consider maximising the amount of solar energy you can produce which will favour solar thermal. So if you have a small roof space the best solar panels would be solar thermal as you get more useable energy from that system. This doesn’t exclude solar pv which can be added at a later stage. If you have a large south facing roof space then there should be enough room for both types of solar panels.
Decent solar panels for heating water can be installed for somewhere between €3500 - €4900 with a grant available from SEAI of €1200 subject to a few conditions, a flat plate system costing €4500 will typically get the grant. Some solar panels prices here. Solar PV systems costs start at about €4500 for 1 KWp but you need to consider 2 – 3 kWp to get value in my opinion. Some prices for solar pv can be found here. Bear in mind that there are a lot of differing prices available out there and the highest price does not necessarily mean you are getting the best solar panels - you may just have met a very persuasive sales person. Get a few quotes is our advice and never be pressured into signing anything.
Solar thermal systems pay for themselves in 7 years approx. (all depending on your current and future water use and future energy prices..) Solar PV systems under the current scenario can take 15 – 20 years to pay for themselves but again it all depends on how the system is used. The best solar panels in this scenario are probably the ones that last the longest as they will continue to produce revenue for a longer period so it can pay to invest more in quality.
I hope this helps. Please feel free to contact us to clarify any of this.