Frequently asked questions

If you can't find the answer to your question here, please contact us.

Is my roof suitable?

Large, sloping, south facing roofs with no shade generate the most amount of electricity.  However, many people are surprised to learn that panels facing east or west only lose about 15% of the output they’d achieve if they faced due south.

Shading has more impact on solar energy generation than either orientation or roof pitch.  Please see our Technical page for more information about shading.

Your roof will need to be in a good state of repair (eg no loose ridge tiles) before we install solar panels. We will inspect your roof and if necessary recommend remedial work, which we can undertaken with the installation if required.

Do I need planning permission?

Installing PV solar panels on a domestic property with a sloping roof is likely to be considered ‘permitted development’, which does not require planning permission, as long as certain conditions are met.

You no longer require planning permission to install Solar PV on a non-domestic / agricultural building, or as a ground mounted system either, as long as certain conditions are met.

To be installed as 'permitted development', the panels must not protrude more than 200 mm from the roof surface (our installations would always comply with this).  We recommend that you consult your local authority planning department to check if you need planning permission.  For a small charge they can normally send you a letter confirming that your installation is a ‘permitted development’.

Installations on listed buildings, flat roofs, and properties in conservation areas would need planning permission.

What does a site survey involve?

A site survey will last no longer than 2 hours and involve:

Making written notes of all the measurements, in particular the orientation of the roof.
Looking at the roof structure and condition – from both inside and outside.
Using a ladder for closer inspection where roof quality can’t be seen clearly from the ground.
Noting any possible risk of shade on the roof from trees, neighbouring buildings and chimneys.
Examining the loft and measuring the tilt angle of the roof.
Looking in detail at your consumer unit (fuse box) and metering.
Identifying your main electrical appliances and when you use them.
Looking around your house to discuss where to locate cables and equipment.
Explaining what our quote covers including scaffolding costs, panel/module information, details of warranties, details of the inverter, our terms and conditions, and information on how we calculate the payback, rate of return and savings.
Answering your questions about the technology, or any other aspect of the proposed installation.

How long will my solar panels last?

Solar panels are designed to last a minimum of 25 years, although they are likely to last longer.  There are examples of panels built 40 years ago which are still performing well.

Are there any maintenance or ongoing costs to consider?

PV solar panels - have no moving parts to wear out, and if they are installed at an angle of 20 degrees or more, are self cleaning in most locations.  Most panel manufacturers recommend a periodic inspection to check if there is any build up of grime and if there is, it should be cleaned off.  Be aware of any shade cast by trees as they grow, and get them trimmed if necessary.
Inverter – although solar panels are designed to last a minimum of 25 years, within this time you may need to replace the inverter.

What guarantees do you give?

Our panels are guaranteed by the manufacturer for 10 years against defects, and 25 years for performance (guaranteeing a minimum of 80% of original performance after 25 years).  All the panels that we supply are MCS accredited – this is essential for you to be able to claim the Government’s feed in tariff.

We typically use SMA or SolarEdge inverters, because they have a reputation in the industry for being the best.  SMA inverters have a 5 year manufacturer’s warranty, and SolarEdge inverters have a 12 year waranty.  Both manufacturer's warranties can be extended for an additional charge.  Our mounting systems have a 12 year manufacturers warranty.

We are so confident in the quality of our workmanship that we provide a 2 year warranty on all workmanship carried out as part of your installation.  This runs for 2 years from the date of commissioning and means we will correct free of charge any fault arising from the system due to faulty workmanship by Greenwire Solar.

Do you offer an independent warranty?

Yes, we register all our installations with QA National Warranties, via the Renewable Energy Consumer Code website.  In the unlikley event that we cease trading before completing your installation, QA National Warranties (QANW) will arrange for your installation to be completed, and you pay only the balance due on the contract.

Also, if we were to cease trading within the guarantee period, the warranty covers the cost of any work that would have been covered by our guarantee.

QA National Warranties specialise in this service,  and have been operating for over 20 years.  You can find out more about our independent warranty here. Read More

What manufacturer do you use for panels and inverters?

We only use top quality panels, inverters and mounting systems.  We are totally independent, and not tied to any one manufacturer for panels or inverters, so we can use whichever parts are best for your installation.  This is especially useful for smaller and more unusual shaped roofs as many installers buy standard size panels in bulk, which cannot always maximise the available roof space.  Many customers prefer panels with a darker, more designer finish eg LG NeON 2, or JA Solar mono all black, while other customers are happy with the value for money offered by silver and black panels.

We use market leading inverters, for example SMA and SolarEdge, which have the best reputation in the solar industry.

We’ll talk to you to find out your preferences.  As with any other purchase, there are many choices depending on your budget and personal preference.  

Where do you fit the inverter?

The inverter is the ‘box’ that converts the energy from sunlight into electrical energy you can use in your home.  Many solar companies only put inverters in your loft, because it’s the easiest and quickest place to fit it.  However inverters work most efficiently, and will last longer, when they are cool.  We like our customers to get maximum benefit from their PV system, so wherever possible we fit inverters in a utility room, outbuilding or garage, or even on an external shaded wall.

Will I need an Energy Performance Certificate (EPC) to apply for the feed-in-tariff?

To receive the most beneficial FIT rate, your property must have a level D or above Energy Performance Certificate (EPC). Your FIT application must include a copy of the EPC showing the rating for your property.

The EPC certificate date must be before (or the same date as) the commissioning date of the system.

Our installations include a pre-installation assessment of the property's current EPC rating.  If this is below level D we will advise you, then reassess the property once additional energy saving measures have been installed.

How much energy can I expect to generate each month?

You'll generate the highest amount of energy from May to August, with only 10% output from November to January.