Solar Panels – Pros and Cons
Solar water heating
An average household can save about 50% of the annual cost of hot water using solar panel.
There are two main types of solar water heating panels - flat plate and evacuated tubes (referring to the way in which water interacts with the panel). Evacuated tubes are more efficient than flat plate versions, so are often smaller but generate equal amounts of hot water.
Choosing a solar water heating system
When choosing a solar water heating system, you’ll need to consider a number of factors including your average hot water usage, the area of south facing roof, the existing water heating system and your budget.
You’ll need roughly one square meter of collector area per person in the household. Each metre of panel area will need between 30 and 60 litres of water tank volume.
If you use a less efficient collector (like flat plate solar water heating panels), you’ll need to cover a larger area than if you use a more efficient collector (like evacuated tubes). You’ll also need to select system components (like a hot water cylinder, controls and pipe work) and choose the location for your panels considering shade, pipe runs, roof pitch and future access.
Solar water heating can provide about a third of your hot water needs
Pros
* Solar water heating can provide you with about a third of your hot water needs and about £40 a year off your hot water bills, depending on the fuel replaced.
* Solar energy is free, plentiful and clean.
Cons
* Provides hot water but not electricity.
* An unshaded, south-facing location is necessary to install solar panels.
* Initial costs are higher than conventional electric and gas-heater systems.
* Solar panels can be heavy, so your roof must be strong enough to take their weight, especially if the panel is to be installed on top of existing tiles.
* Solar panels are expensive compared to the amount of electricity they’ll produce in their lifetime.
Photovoltaic (PV) solar panels
PV solar panels generate electricity from the sun’s energy rather than just heating your water. You’re more likely to see these on offices or large developments than on homes.
You can use PV systems for a building with a roof or wall that faces within 90 degrees of south, as long as no other buildings or large trees overshadow it. Less energy will be generated if the roof surface is in shadow for parts of the day.
The are three basic types PV panels: monocrystalline, polycrystalline (or multicrystalline) and amorphous. All are made from silicon, but differ in the way the silicon is cut and treated to create collar cells.
To install a system you need to decide how much electricity you want to generate. After submitting details of your property, a PV installer should help you to conduct a site survey and discuss your options with you.
Pros
* Only daylight is needed to create energy – not sunshine.
* Can cut average household electricity bill by about 30%.
* Solar energy is free, plentiful and clean.
Cons
* A large roof area is needed to generate lots of energy.
* Significantly more expensive to buy and install than solar water systems.
* Solar panels are expensive compared to the amount of electricity they’ll produce in their lifetime.
* The efficiency of solar panels depends on the number of solar light hours and climate.
* Initial costs are higher than conventional electric and gas-heater systems.
* An unshaded, south-facing location is needed for installation.
* Solar panels can be heavy, so your roof must be strong enough to take their weight, especially if the panel is to be installed on top of existing tiles.
