Is my site right? 7 Tips to achieving solar pv success

With solar photovoltaics (PV) having become increasingly popular in the UK it won’t take long for one of your close friends to start talking about how much they have benefited and how much electricity they are saving. This will likely be followed by the token “You should look into it! Your house would be perfect”.

As an un-initiated solar energy “virgin” this benign discussion with said frient may be the personal testimonial that finally kick starts you to consider looking into the technology for your home. Here are a few basics things to look out for and consider for your home.

Roof Area

It is critical to ensure you accurately measure your roof to find out how many panels you can install. Using Google Earth or a tape measure this can be figured out pretty quickly.

There are literally hundreds of different sized solar panels, but generally speaking they are 1.6 m tall x 1 m wide. As a result once you have drawn out your roof area you can get a good idea of how many will fit.

You will also need to make sure that there is at least 250mm between any panels and the roof edge or ridge to ensure no detrimental effects from high wind conditions.

Roof orientation

Most people understand that due South is the ideal orientation for solar panels. In the South of the UK an inclination around 35 degrees from horizontal is optimal too. But if you don’t have a south facing aspect all is not lost. Even if you roof is facing due East or West you only lose around 12% output compared to an ideal south aspect.

The big no no is a placing solar panels on a North facing roof aspect.


Make sure the proposed roof area is shade free where possible. Take a look at the roof area at different times of the day and through the seasons to make sure you will get the best output from any array location.

Although some light shade is ok and can be dealt with using string inverter technology and hard shading areas should be avoided even if it means reducing the planned installation size.

Roof structure

Any roof that you are thinking of installing solar panels on should be structurally sound. In fact under the MCs regulations, solar panel installers will have to do a calculation and initial inspection to make sure all is well.

Roof trusses should be solid, dry and not rotten or rotting. If there are any issues with the internal roof support structure these should be resolved before going any further.

Roof covering

The roof covering is also an important consideration when thinking about solar PV. Once again the condition of the tiles and under felt or membrane should be sound and in good condition before proceeding. Also replaced any cracked or damaged tiles before installation begins.

Although there are a large range of solutions for fixing solar panels, flat roofs can sometimes cause an issue as fixing through it may void installation warranties. Alternative ballast methods may have knock on effects on structural reinforcement too.

Planning Permission

Most domestic PV installations are within permitted development as long as the installation does not protrude more than 200mm from the existing roof surface and any higher than the existing ridge height.

If however you are in a conservation area, are of outstanding natural beauty (AONB), within the curtilage of a listed building, etc then you will need planning permission. If in doubt, ask.

If the project seems viable even after considering all these basic points your friend might have be right all along and you too could soon be joining the growing list of households taking control of your energy future.

Your next step… speak to an independent advisor or contact a solar panel installer directly who can help you realise your new system and ensure your getting what’s best for you.

Good luck!

Doug Johnson

Doug is a chartered mechanical engineer and has had the pleasure of being involved in the UK renewable sector since 2008. With wide-ranging operational and design experience in both the domestic and commercial sectors across a wide range of recognised technologies he hopes to be able to share his experience to help enlighten and save you hassle along the way.