Getting a system installed is a quick and simple process, which takes very little time at all. Solar panels can be installed on your roof, and fully wired so they are feeding the electricity into the main grid within one or two days depending on the company you choose. Scaffolding is usually necessary unless your home is a single-storey property. Once the modules are on your roof, they will get bolted in place and finally the wiring into your home will be completed - again, this is a very simple task. Once this has been done, the installer will inform your District Network Operator to gain permission to connect the system to the national grid. The system also will be registered by the solar installer with the MCS, you'll then receive an email to confirm, and then the Feed in Tariff payments will start!
The ideal site for the installation is a roof tilted at approximately 30 degrees and facing as close to directly south as possible. It's still worthwhile getting quotes even if your property's roof isn't perfect - it should still be possible for the company to provide you with an estimate of how much it will affect the potential earnings and quantity of electricity generated. In terms of the amount of roof space required, as long as you've got a space of at least 2 metres by 2 metres - about the area required to park a small car - you should be fine. The average system is somewhat larger; a 3kW set up would occupy about 20 square metres.
Planning permission is not necessary in England, Wales and Scotland for nearly all home solar, as long as they're below a certain size. It is important to double check with your local planning officer, however, particularly if your home is listed, in a conservation area or on a World Heritage Site.
Minimising the shadows being cast onto the solar panels is very important. All the individual solar modules are connected through a single inverter usually, which means that if just one module is in shade, then it will affect the performance of the entire system. A small amount of shading at times is ok, but if the panels are shaded between 10am and 4pm, the loss is likely to be large. The most common items causing these issues are nearby trees, lamp posts, chimneys and aerials.
The weather obviously will change how much output your solar panels provide, but remember that they will still work well even when it's cloudy. Here is a useful diagram of how much electricity a 3kW system (average size of a domestic system) would generate if it were facing due south over the course of a year.
Choosing a reliable firm is very important - solar panels are a serious financial investment, and will earn you a lot of money over time. It's therefore vital that your installers can give you accurate and realistic figures for the cost of setting up the system as well as the potential earnings.
Important Tip: Make sure any companies that you decide to get quotes from are MCS accredited. This is a government scheme (the Microgeneration Certification Scheme) which regulates the installation process. Once the panels are installed, then for the system to receive Feed in Tariff payments, or the Renewable Heat Incentive (the two official schemes for solar panels which pay you back over time), the firm must be MCS accredited.
The way the potential company makes you feel at the appointment is a good indication of what they may be like; if they're using pushy sales tactics, such as telling you they can give you a great discount but only if you sign the paperwork there and then, just take a minute to ask yourself why they would be doing something like that? The answer is that they are desperate for your business - certainly not the sign of a reputable installer. Do not let yourself sign anything on the day.
If you went shopping for a new car, you'd certainly compare a few dealerships before buying. Purchasing solar power for your home is very similar - they are a great investment, but spending several thousand pounds on something that doesn't offer good returns because it's set up incorrectly for your property isn't a good idea. Speaking to multiple installers also gives you a great chance to get a feel for several companies before you sign a cheque - it's usually quite obvious who is reliable and who isn't; ask for a couple of references from previous customers of theirs nearby to you... any decent company should be happy to provide them. Finally, getting several solar quotes means that you're likely to save a lot of money - companies will offer better deals if they're competing with others, but remember that the lowest cost product may not offer the best returns.