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Getting the most out of solar electricity

With almost 800,000 installations across the UK to date, it’s clear that there’s something attractive about solar PV

By using the sun’s energy to generate electricity, you can save money on your electricity bills, earn money from the electricity you generate and that you sell back to the grid, as well as doing your bit to cut your home’s carbon footprint. 

The right roof

First and foremost, your roof’s got to be right for the job. South-facing roofs are the best as they get the most direct sunlight throughout the day. East and West can also bring good results, but if your roof faces North, it’s not the technology for you. Whatever way your roof faces, it has to be free from obstructions – this might mean shading from trees or nearby buildings. 

Solar PV on a roof

Eco or economic motivations?

The reasons why people install solar PV vary, but the key divide is probably between ‘green’ rationale, and financial. 

If your prime focus is mainly on reducing the greenhouse gas emissions associated with your electricity supply, then solar will do that. A home solar installation can save up to two tonnes of carbon a year – while offering some useful financial benefits to boot. 

Get your calculator out...

But if looking at solar from purely an economic point of view, there are some key considerations to factor in. A solar panel installation tends to cost upwards of £5,000, so it’s important to do the maths first. 

The average domestic solar PV system, installed in a home with average electricity usage behaviour, is likely to save you around £70 a year on electricity bills. 

The Feed-Tariff (FiT) is a government incentive to encourage people to generate their own energy. It pays for every unit of electricity generated, plus a smaller amount for each unit exported back to the grid. You can make around £200 to £250 a year from this, depending on where you are in the country. 

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Making the finances stack up

With lower rates of FiTs than there used to be, it’s unlikely to be this incentive alone that pushes you to solar investment. But there are a number of contexts where you can get more bang for your buck out of installing solar panels

The more you’re able to use the electricity they generate during the daytime, the better value solar is going to be. So, lifestyle matters.

If you’re retired, or planning retirement, and you’re likely to be around the house a lot, you’re likely to use more solar electricity, and make bigger bill savings. If you work at home or are a stay-at-home parent, a similar logic applies. 

By using a higher than average proportion of your electricity in the day time, when the panels are generating electricity, you could save more off your electricity bills. For example, if you’re able to use 25% of the total electricity that the panels generate, you could save £135 from your annual bill.

Got the builders in already? Consider solar

Installing solar when you’re already taking on other work can also improve the return on investment. 

If you’re undertaking a loft conversion or changing your roof, scaffolding will already be up – an expensive part of installation that you’re likely to be able to deduct from the fee charged by solar installers. Skylights can also be placed in a way to ensure the most panels can be fitted. More panels, more electricity, more benefit. 

If work inside the house is being undertaken too, as part of an extensive renovation, then it might be the time to fit low energy lighting and appliances, to make the most out of the free electricity. 

Beyond the financial implications of adding solar to an existing job, there are clear convenience benefits. Disruption is minimised, and it may well be easier to run electrical wiring and connect to the grid while other work is going on. 

Domestic solar panels

The future of solar power

Global demand means that the cost of solar panels has fallen over the last few years, and is likely to keep dropping in the future. 

The technology itself will also evolve over time. The efficiency of solar cells is improving, and ideas that are currently in the lab may be on roofs within the next few years. 

For those who aren’t so keen on the aesthetics of solar panels, solar tiles could be an option. At the moment, this is a significantly more expensive and less efficient way of doing things, but with tech companies like Tesla jumping into the market, big improvements are expected. There may even be a future role for entirely transparent solar windows.

For now, solar panels can still make sense for many homes. It’s all a matter of having a clear idea of what your motivation for investing is; and once established, finding practical ways to get the best out of an installation. 

Share your thoughts with us in the comments below, or tweet us @EnergySvgTrust.

Gary Hartley is Energy Saving Trust's expert blogger. He has extensive experience researching and writing on a number of topics, with particular expertise in sustainable energy, policy, literature and sport. As well as providing regular blog content, Gary has also been published in numerous magazines and journals.

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Hi, I am thinking about solar pv as I am thinking of retiring in about 5 years. I want to reduce my outgoings as much as possible as I will be living off a pension and not a full wage as I am now. is there any other ways of reducing outgoing ready for retirement?

How does Government measure your generation? At what point is reading taken? at the panel inverter?

Seems to me that installation of a battery storage might allow people to import Economy 7 electricity into battery and then claim extra generation tariffs as well as consuming electricity. I am sure that would be fraud, but what techncially is to stop them?

Just read this blog today. It must be a typo that the expected savings from Solar PV are quoted as £70 per YEAR - it should be per MONTH against the cost of grid electricity, and the export tariff is the highest part of the tariff now - however the tariff is generally not what the main benefits of solar PV is about.

When ours was installed in 2011, our combined direct debit for gas & electricity was immediately reduced by £66 per month from £166 fo £100, for this family of 5 - and we've generally had rising grid tariffs over the past 6 years - so a £70 per month saving is realistic these days.

This family have learned much from generating electricity, having a solar generation monitor installed too, and a few years ago also the addition of another simple meter to measure how much of our own on-site energy was not being used (a very wise step to take, at minimal cost, if presently trying to work out whether viable and cost-effective to have a retrofitted energy storage system installed). Anyway, knowing your own data is key, and has been the pre-requisite for us, to make a decision on how best to use all this on-site generated energy available for this family to use. For us it has become the fuel for this family's plug-in cars - helping fuel 2 x battery electric vehicles, and 1 x hybrid electric - and what has astounded us is that we still have 6% surplus available, which exports to the grid simply because we have no further way of using it.

The annual savings that solar pv has made to this family? > £3,000 per year! 42% energy bill reduction. Solar PV has been key for helping power our home, heat water, fuel the cars, and power nextGenergy's little home-based office.

What I'd like to encourage is that any size of solar PV system does a job for every household using grid electricity - there are ways of making it really work for you, without very much effort - it certainly does not mean that you need a 'typical' 4kw large domestic system, eg 16 solar panels, and they don't have to be fitted to the house roof - even a small 1kw system of 3-4 panels on a limited space, or much lesser occupancy, will work.

Also, if the tariff is important, be aware that foe new installations, the tariff is set to cease entirely from 31/03/19 - so if you would like the added benefit of a 20-year incentive income, your solar panels need to be fitted, commissioned and your feed-in tariff applied foe before then.

Hope you can make it along to the @HES_SE events this week coming - we may get a chance to have a chat - some photos and data, sharing my learning, will be in display.

Events: Electric Cars, Solar PV, Car Charging, Energy Storage

Wed, 27th Sept - 5-8pm - Cumbernauld New Town Hall

Thu, 28th Sept - 5-8pm - Livingston Football Club

Shirley Paterson
Domestic Energy Assessor & Green Deal Adviser
nextGenergy

Hi Shirley,

Thanks for getting in touch. We spoke with our Data and Insight experts, who have replied to your query:

"It is impressive to hear about the savings that you are making with your solar PV system.

Our estimate that the average domestic solar PV system is likely to save around £70 a year is the electricity bill saving only. This is separate to any income from the Feed-in Tariff (FIT) and Export Tariff. The electricity bill saving is based on the assumption that 25% of all electricity generated by the panels is used in the home, up to a maximum of 500kWh. The assumption comes from the best available data which we believe represents a home with average electricity usage behaviour. The data sources are the results of a field trial of houses with PV systems, and the National Energy Efficiency Database.

Of course, it is likely that some householders can obtain higher electricity bill savings by using more of the electricity when it is being generated, such as by using home appliances in the daytime."

We hope this helps.

-

EST Team

I think we must can take this claim with a large pinch of salt: "The annual savings that solar pv has made to this family? > £3,000 per year! 42% energy bill reduction."
My experience with an East: West 4 kWh rooftop rig installed in 2013 has been that I generate around 2500 kWh per annum, mainly during the six months between April and September, and mostly between 9am and 6 pm. The historic feed in tariff of around 20 pence per unit made that a cost-effective investment.
But even at savings of 15 pence per kilowatt hour, that is say £375 worth of electricity per annum, of which I might be able to use half, though that is not easy to estimate when the rate of sunshine and cloud is highly variable.
Smart meters and batteries are the way forward if we are to make best use of the technology, and at present it is not convenient to leave a car plugged in outside just in case the sun shines, because it charges at 3 (or 6) kW per hour, which is more than the sun provides. Some kind of controller would help to ensure that only surplus solar electricity was used for car charging, else it is far cheaper to charge up overnight .

I sent in a reading of my solar meter on August 1st of 1506, and I have not had any reply, why is that.

R. P. King Fit ID: FIT00010682 Vendor ID: 1173049 Name: Mr Reginald King

Hi Reginald,

Thanks for getting in touch. It appears your query relating to Feed-in Tariffs (FITs) was intended for your energy supplier or Ofgem. We recommend contacting them directly in order to have your questions answered.

In the meantime, our guide to FITs may be of use.

We hope this helps.

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EST Team

I have 10 PV panels on my roof (installed in 2011) and have recently acquired an electric car. In order to be able to charge the car more cheaply, we have switched to Economy 7 and charge the car at night. However, I am wondering if I would save more money by charging the car during the day when the panels are generating? I understand savings on electricity bills is related to the amount of electricity being used "when it is being generated" but the amount generated varies considerably according to weather, time of day, season etc.

Hi Andy,

Thanks for getting in touch. We have spoken with our Data and Insight experts, who have advised the following:

"It's difficult to calculate whether this strategy would save money or cost more because although some electricity will come from the panels, if there isn't enough being generated the rest will come from expensive peak-rate electricity.

Without a special system that will charge the car using only the pv generated, your bills could go up rather than down."

We hope this helps.

-

EST Team