There are a few pros and cons to both solar thermal and solar PV solar panels so we have outlined the main points below.  These are general comments which can change depending on the context of your solar project so if you would like to talk these through to get a better feel of your requirements please give us a call on 01 5563100.


Solar panels

Solar thermal systems are about twice as efficient in producing energy than pv solar panels systems.  But.. the energy produced by solar thermal is in the form of heat so it 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 solar hot water cylinder or buffer 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 by the solar panels which can be difficult if you do not have a constant electrical base load in your building.  If you produce electricity that is not used in house currently it is exported to the grid and donated to the various utilities for free..  There is talk of a solar Feed in Tarriff coming in 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 your roof is small and urban you should consider maximising the amount of solar energy you can produce so this will favour solar thermal as you get more energy per m2 than solar pv.  This doesn’t exclude solar pv however as the solar panels 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 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 by contacting here


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.

I hope this helps.  Please feel free to contact us to clarify any of this.