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Before investing in your own rooftop energy system, it’s wise to do your research. That’s why we’ve asked an expert to answer some of the internet’s most-searched questions on solar panels
The way solar panels work is pretty simple – they absorb energy from solar rays and turn it into the kind of energy we can use to power our homes. But when it comes to actually getting your own rooftop solar panels, things might seem a bit more complicated. That’s why we put some of the UK’s most-searched solar installation questions to an expert.
Carl Hogg is managing director for services at Good Energy, an energy company dedicated to helping customers power their homes and businesses renewably. An important part of its work is solar power, guiding customers through everything from installation to selling energy excess back to the grid. That makes Hogg the ideal person to answer the internet’s most pressing questions about all things solar. Here’s everything you need to know …
Hogg’s answer to this is essentially that it depends. But he recommends that homeowners budget between £6,000 and £14,000 for a “solar array”. What’s a solar array, you ask. An array includes the panels and also the devices that transform the solar rays they absorb into usable power. It might include a battery, too, to store excess energy produced.
The reason it’s hard to be more specific is that, as Hogg notes, any good installer should look to understand your needs and design a system to match them. “We typically go out to every single property and do a full survey. We sit down with a customer, we have a really in-depth discussion with them. Then we design a bespoke solution,” he says.
Once again, the answer to this isn’t the same for everyone. “It depends on the size of the house, the energy consumption, how many people live there and how they use electricity,” says Hogg. It also depends on your solar generation goals. He says that “10 panels will normally supply 30-50% of a household’s electricity use” – “essentially free energy from the sun”. However, with a solar battery that figure can be much higher – you can expect about 80% of your household energy usage to be covered by your solar panels, thanks to the battery’s ability to store excess power.
Solar panels it seems, are a bit like parties – better when it’s sunny and the more the merrier. “Our advice is always, if you can, you should maximise and put as many panels on your house as possible,” Hogg says. “It’s all about trying to make the most of your roof space to get as much energy output as possible.”
“It’s a common myth that it has to be a really bright sunny day. It doesn’t, panels just need daylight,” says Hogg. Of course, panels do work optimally in bright sunshine. But Hogg notes: “Even on a bleak winter’s day, as long as there is daylight, they will still generate.”
The answer is yes. Hogg says: “The roof angle, the direction the house is facing and the shading of the house do affect things. Our recommendation is minimal shading and south-facing where possible.” But he emphasises that the house position isn’t “the be all and end all”. What matters most is “making sure that you design the right solutions for the condition of the roof to maximise the daylight coming into those panels”. So, for a house where the front faces east and the back faces west (or vice versa), that might mean putting panels on both sides to maximise the absorption of solar rays throughout the day.
This is the big question for most people considering solar panels. Hogg advises that you look at the wider picture. “The important thing is that you are investing in your home. While it’s an initial outlay of cost, you will see the reduction in your bill straight away. Literally the next day.”
Once again, maximising your solar system’s potential will help make it worth your while long term. “By choosing the right system for your house, getting the maximum amount of panels you can, you generate as much as possible,” says Hogg. As well as getting a battery, which stores excess generated power and also gives you the flexibility of charging it overnight “when the cost of energy from the grid is at its cheapest”, Hogg recommends getting an export tariff from your energy provider.
With an export tariff, he says: “Any excess energy that you have, you can sell it back to the grid. Then that brings your bill down.”
Overall, Hogg suggests thinking about solar installation as you would other home improvements – as a long-term investment. “You wouldn’t cut corners with your boiler, so you shouldn’t cut corners with solar,” he says.
Because solar panels are a win for everyone, the government does offer incentives to help encourage people to put them on their roofs. The most important one from Hogg’s perspective is the fact that all solar equipment and its installation is VAT-free. “VAT is 20%, so it’s quite a chunk,” he says. He also advises taking advantage of it as soon as possible, because it may not last forever.
It’s also worth looking into green loans offered by some mortgage providers. Good Energy is exploring a finance package for its customers and Hogg also recommends keeping an eye out for a government-backed financing scheme expected to arrive in the next year or so. Essentially, before you pull the trigger on getting panels installed, do some research into the grants and financing options available to you. Speaking of installation …
First things first, “find a reputable installer” such as Good Energy, says Hogg. Good Energy is one example, but whoever you choose should be fully accredited. “All domestic solar installers have to be MCS accredited, that’s the standard. You could also look for them to be an NICEIC-accredited installer as well, so electrically certified,” he adds. As well as the people doing the installing, “you want to make sure that the products they’re installing have at least a 25-year guarantee. You should also be looking for an installer that provides a third-year performance guarantee [guaranteeing that the actual total energy generated (kWh) matches initial quotes] as well,” says Hogg.
As you would with any home improvement work, gather a few quotes from different installers. Hogg recommends not choosing “the cheapest quote out there. You get what you pay for. If you go cheap, and you get a poor installation, it can actually cost you more in the long term.”
He cautions against buying an off-the-shelf power system or settling for a desktop survey (by computer rather than in-person). “You should choose an install company that comes out and does a physical survey,” he says. “They should have a look at your roof, have a look at the conditions and come and speak to you about what you want. That’s always our recommendation, and it’s what we do.”
Hogg says that most homeowners don’t need planning permission, because solar panels are considered permitted development. However, it’s always wise to check. “There are certain types of homes – listed buildings or if it’s in a conservation area – where there may be some restrictions, so you may need some permissions,” he says. This is also a good thing to discuss with your installer. “They should help the homeowner through this,” Hogg says. “They should deal with a lot of these permissions, if not all, as we do at Good Energy.”
If you’re daunted by the potential admin associated with selling your excess power, don’t be, says Hogg. “It sounds a lot more complicated than it is.” In fact it’s as easy as choosing the right energy tariff. “The simplest thing to do is get on an export tariff with your provider,” he says. “At Good Energy, our export tariff pays 12p per kilowatt. If you install solar and a battery with us, we can pay up to 25p a kilowatt. Get on an export tariff, and the rest of it will be taken care of. Any excess you’ve got automatically goes back to the grid, and it will come off your energy bill.”
Hogg reckons plug-in solar has its place. “It’s important to have a range of options to best suit people’s situations,” he says. “For someone who’s renting a property, they’re not going to invest on the roof. Get the solar panels, plug them in and help reduce some of the costs. If you live in an apartment block and you’re going to put them on your balcony, potentially there’s another good option as well.” However, he’s clear that they don’t compare with built-in panels in terms of energy generation and cost-saving potential. “They’re not going to generate as much as a built-in system because there simply won’t be enough panels,” he says.
It all comes down to the installer, says Hogg. “Speak to a trusted installer. Look for the accreditations I mentioned earlier. If you find the right installer, they will speak to you in plain English. They will manage the whole process end to end and support you afterwards as well. Find the right installer and they will take care of everything else.”
Find out more about solar panel installation with Good Energy

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