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Frequently asked questions

  • How much space on my roof do I need for a solar PV installation?
    Our grid connected systems start from around 1kW peak power, this occupies between 5 to 6.6 square metres on your roof.
  • How much electricity does a PV system output?
    For every kW peak power installed on a South facing roof the system will generate around 800 kWh. This reduces by around 15% for an East or West facing roof.
  • How much does a Solar PV system cost?
    Installed prices (including VAT) start from around £1000 to £1500 (inc VAT) per kW peak power depending on the type of panels and inverter and the complexity of the installation. There are no longer any grants available as these have been replaced with the Feed In Tariff (FIT)
  • Will I be eligible for the Feed In Tariff (FIT)?
    Greencap Energy Ltd are approved MCS installers so our installations are eligible for all government incentives. Regulations mean you will also need to obtain an EPC (Energy Performance Certificate) showing your property is a level D or above (including the PV system). We can arrange for this certificate assessment to be carried out.
  • Do I need planning permission?
    Our roof mounted systems do not need planning permission unless the property is listed or in a conservation area.
  • Do I need to inform building control that I intend to install a solar system?
    Greencap Energy Ltd is certified to self-certify the electrical and structural elements of a domestic PV installation, and will notify building control once the system is installed through our certification bodies.
  • Will my roof be strong enough?
    Most roofs are strong enough to take a solar installation without any reinforcement, however we will carry out a full survey of your property and consult our structural engineers if required.
  • Do I need to inform my electricity supplier?
    For systems below 16 Amps output (3.68kw peak power) we will inform them once the installation is complete. For systems larger than 16 Amps we will require permission in advance from the network operator - we will arrange this permission. Larger property's may have 3 phase supply's from the grid and in these cases we can up to 11.04 kw without permission.
  • Can I export any of the electricity I generate?
    Yes, all unused electricity will automatically be exported, your electricity company can fit an export meter or they can pay you based on estimated or "deemed" export rates (usually 50%). Please do not confuse the export meter with the generation meter which we fit as standard on all our installations. Another way Is to fit a diverter which will send all your excess electricity to your hot water tanck. If you do not have an exsport Meter you will still receive the 50% deemed export although you have used it for free hot water threw out the summer period.
  • How much will I be paid for electricity I generate?
    The Feed in Tariff pays up to 4.00 pence for all the electricity generated even if used in your own property.
  • What is a kWh?
    A kWh (pronounced ‘kilo watt hour’) is a specific amount of electricity. 1 Kwh is identical to 1 unit of electricity that is shown on your electricity bill. An electrical item having a rating of 1kW will consume 1kWh for every hour it is on at full power.
  • What does the inverter do?
    The solar photovoltaic panels generate direct current (DC), this is not directly compatible with the 240V alternating current (AC) that is used in your property. The inverter converts the DC power to AC power that can be used in your property.
  • How does the electricity I generate get in to my wall sockets?
    We connect the system to your fuse board (consumer unit). The electricity will automatically flow from there to wherever it is needed.
  • Are solar PV tiles available?
    Yes, PV tiles are aesthetically very pleasing and are becoming more popular, the installation cost will be higher than large ‘on-roof’ panels.
  • Will I have electricity during mains power cuts?
    For the safety of electrical workmen our standard systems do not operate during power cuts.
  • Do I need a three phase electricity supply?
    Systems up to about 7kw peak power can sometimes be accommodated on a single phase electricity supply, however we do need to seek permission from your Distribution Network Operator (DNO). You can expect the DNO to require a 3ph for any systems over this.
  • Does your prices include for Scaffolding?
    We do not include for scaffolding installation in our prices unless there are specific requirements for us to do so.
  • What is the difference between monocrystalline and polycrystalline PV panels?
    Monocrystalline solar electricity panels tend to be slightly more expensive than polycrystalline panels, however monocrystalline panels are regarded as having a higher output per kW peak power installed. Polycrystalline wafer has a dark blue colour, monocrystalline wafer is black.
  • Will PV systems be dropping in price dramatically over the next few years?
    Many developments are taking place in the PV industry and popularity is increasing. However, we would expect prices and performance to change gradually rather than dramatically. The government is interested in maintaining a consistent return on investment for systems installed now and over the coming years.
  • Is efficiency important with solar panels?
    Often not, the efficiency of a panel relates to how effectively it can convert the sun’s light. Given that the sun’s light is free a panel can simply be made larger to offset a lower efficiency. Only when suitable roof area is at a premium does it make sense to choose high efficiency panels, this will maximise the amount of power that can be generated from a roof. Greencap Energy can supply high and standard efficiency modules.
  • Whose panels do you use?
    Typically we use high quality panels from JA Solar and Panasonic but we always try and supply a panel that suits our customers requirements in terms of price, guarantees, manufacturer etc...
  • What guarantees will I receive?
    Panels generally have an output guarantee of between 20 and 25 years depending on manufacturer. Inverters normally have a guarantee of 5 to 10 years. Most other components and labour is usually guaranteed for 2 years and is covered by warranty insurance. Check your quotation for specific details.
  • Are your panels approved?
    We only use the very highest quality of materials. The panels we use meet all the required standards including TUV and MCS approval for government incentives.
  • Will an electrician fit the panels to the roof?
    No, all roof work will be completed by our trained roofing specialists. Many companies use the wrong trades people to fit panels on roofs, we use our electrician for electrical work and our roofers for roofing work.
  • How are the panels fixed to the roof?
    For standard roof we use rigid aluminium brackets that are fixed directly to your roof rafters. The brackets hook out from underneath your existing tiles. We do not drill tiles/slates or use mastic/silicone to weather proof your roof as these techniques do not have a long life span.
  • How long will the installation take?
    Installation normally takes 1-2 days for a domestic system depending on the size and complexity of the system.
  • How much do the solar PV panels weigh?
    Normally about 13kg per m2.
  • Are the solar PV panels fragile?
    Solar PV panels are very robust and can withstand the normal stresses subjected by nature.
  • Can I heat water with solar PV panels?
    Once the panels have created electricity you could connect this to an immersion heater to heat water. Ask us for more information about controllers availlable for this.
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