Renewables FAQ
Solar PV
What are the lifetimes of PV products?
Solar modules have a manufacturer’s performance warranty of 25 years, and a working lifetime of 30 years and beyond. Modules of all types usually have a 25 years warranty.
Does the glazed front reflect light away from solar photovoltaic (PV) modules?
No. Solar PV modules constructed with a glass front have two characteristics that reduce light reflection. In order to optimise the electrical yield the glass is treated with an anti-reflective coating which greatly increases the transmittance through the glass to maximise the amount of light reaching the solar cells.
Secondly, the outer face of the glass has a slight granular texture, the result is a matt like finish which maximises yield. These two characteristics greatly reduce reflection from the glazed front face of solar PV modules when compared with that of conventional glazing.
What are the effects of shade?
Shading is critical factor when considering your location. Minor shading can result in significant and a disproportionate loss of energy. This is because the cell with the lowest illumination determines the operating current of the series string in which it is connected. Our modern modules use bypass diodes to minimise any shading effects, but these effects must still be considered. We will tell you about this during the survey and show you the possible effects on a graph, so you are fully aware of any potential loss of power generation.
How is the angle of optimum panel inclination found for different latitudes within the U.K?
The maximum total annual solar radiation is optimised at just east or just west of due south, and at a tilt from the horizontal equal to the latitude of the site minus approximately 20 degrees. For example, 30 degrees is an optimal tilt in Southern England, increasing to almost 40 degrees in Northern Scotland. Our site survey will determine exactly what you are likely to generate and what your returns are estimated to be. If we felt your site was uneconomic we would tell you.
How do the panels perform at different angles and orientation?
If the optimum angle is not achievable, then the performance will fall. These locations can still produce a useful source of generated power, especially when energy prices rise as they are predicted to. Over 90% of the maximum annual energy can be achieved between 10 degrees and 50 degree of tilt. South-facing 90 degree (vertical) facades can still generate around 70% of their maximum yield.
What sort of projects are suitable for solar installations?
The most important aspect to consider is the location of the site. The solar installation must receive as much light as possible. Shadows cast by tall trees and neighbouring buildings must be kept in mind during the design process. The best location for solar PV is on the south-facing roof with a pitch of around 35 degrees. We can give you free advice on your location over telephone, why not call us and together we can see exactly what you might be able generate from the new feed in tariffs?
Planning Consent
It is a requirement to contact your local planning authority and advise them of your intention to install a solar electric system. In most cases the installation will be considered a Permitted Development; however, planning permission may be required. We do all this for you and we will discuss it with you during the survey stage.
Insurance
Our advice with reference to your building insurance is that you should make your insurers aware that you have had a solar array installed. The addition of a solar PV system should be viewed as a “material fact”, and policyholders have a duty to inform insurance companies about “material facts”.
Warranties
Your solar PV system will have the following manufacturer’s performance warranties:
- 25 years solar PV performance warranty.
- 5 years inverter warranty.
- Installation warranty.
The Moral Issue
As global warming increases we all have a moral duty to help the environment.
Solar Thermal Heating
Why install a solar water system?
Installing a solar water heating system has considerable environmental benefits and reduces carbon dioxide emissions caused by burning fossil fuels. It can save you money as well as being a good way of reducing your homes energy demands.
How much does a solar hot water system cost to install?
As a rough guide you would expect to pay from £3,500 upwards depending on the size of your home and your hot water needs.
Does the system on cloudy days?
Yes but with reduced efficiency. The solar panel collectors located on your roof do not need direct sunlight to operate; they work on natural daylight (diffused radiation). It is a common mistake to believe that solar water heating is ineffective in the UK for climatic reasons, whilst it is clearly not as effective as it would be say in Spain, a good modern system will make a significant contribution to your hot water demands. For example, well designed systems by typically provide 50-75% of all annual domestic hot water requirements.
What happens when it’s cold, cloudy, raining or snowing?
It will still make a contribution to your water heating even when it is cloudy, raining or snowing, because the system uses diffused radiation as well as direct sunlight. The only time it may not work is if the panels are covered in a layer of snow for any length of time.
How much hot water will they provide?
A well designed system should provide most of the hot water needs of an average household for the sunniest four or five months of the year. The rest of the time they will contribute to the overall requirements, so typically between 50 and 75% of the hot water demand can be met by a solar hot water system.
How many panels do I need?
Industry professionals say you will need about 1 square metre of panels per person, and approx 50 litres of cylinder storage per person.
How will using solar energy help the environment?
A standard size house in the UK using a solar thermal system would save in the region of ½ tonne of Co2 emissions per year. Multiply this by the millions of houses in the UK and this is a significant reduction on the amount of co2 we all dispel into the atmosphere.
Air Source Heat Pumps
How much does an Air Source Heat Pump cost?
Air source heat pumps are now supplied by an increasing number of manufacturers and have different capabilities. They come in a variety of capacities to suit different types and sizes of properties. Therefore, it is difficult to determine an exact cost for a full installation due to the number of variables. We will give you an individual fixed price free estimate based on your specific property.
What sort of properties are suitable for an Air Source Heat Pump?
Air source heat pumps are a suitable for a complete or even a partial solution for the majority of existing properties. Most properties that have a reasonable level of thermal insulation could be suitable for an air source heat pump.
Will an Air Source Heat Pump work with my existing radiators?
For a retrofit application in newer homes the existing radiators are likely to be of a suitable size and performance to cope with the lower flow temperature provided from the air source heat pump. This may not be so with older properties where additional or larger radiators may be required. We always conduct a heat loss calculation on the property and we will discuss these findings with you.
Can an Air Source Heat Pump be used in conjunction with other technologies?
Yes, with suitable control systems an air source heat pump can be operated to act in either a lead or support mode with any other fossil or renewable heating technology.
Are Heat Pumps noisy?
Some heat pumps make more noise than others. The older technology was relatively noisy compared to the new generation of inverter driven heat pumps. We have some already installed that you can visit and see working and chat to the owners who have used this technology for some time.
Would the homeowner notice anything different in using an Air Source Heat Pump to a traditional boiler?
You will experience a gentler more consistent heat within the room. Not like the pulses of high temperatures to the radiators that occur with the traditional boiler, otherwise the radiator and system controls work in exactly the same way.
Will an Air Source Heat Pump work when it is cold outside?
Yes most air source heat pumps work at temperatures as low as -20 degrees centigrade which would be very unusual for the U.K. Most air source heat pumps are designed to operate at the optimum efficiency level at any time of year. The technology will automatically regulate the system so that it never uses more energy than is needed at any given time. Air source heat pumps are one of the most energy efficient ways to heat your home.
How can Air Source Heat Pumps help alleviate fuel poverty?
Purchasing energy for our homes is expensive and will continue to rise as fossil fuels become more difficult to find. Because of the energy conversion efficiencies within an air source heat pump, the running costs against mains gas, oil, LPG and electric heating systems will help fuel poverty, by reducing energy bills.
Can I reduce my Carbon footprint by using an Air Source Heat Pump?
Carbon footprint is a measure of carbon emissions based on energy consumption per Kwhr and the fuel type used. An air source heat pump can save approximately 45% of an average yearly Co2, based on a gas fired boiler, even more when coal, oil and electric are used as the primary energy providers for heating.
Is this a renewable energy system and can I get a feed in tariff?
Yes this is to be introduced in April 2011 and is referred to as the Renewable Heat Incentive tariff (RHI). This tariff is still being finalised, however, this payment is made by energy companies and not the government, so should be immune from any spending cuts. The Micro generation Certification Scheme (MCS) underpins the Department for Energy and Climate Change (DECC) feed in tariff scheme. All the feed in tariffs will only be applicable to domestic applicants that use both products and installers who are certified under MCS. For more information please call us to discuss your particular circumstances.