⛔ It’s important to be wary of very cheap solar deals

👎 Choosing low quality solar panels will cause you many problems in the long run

⚡ Premium solar panels will look nicer, perform better, and last longer

Solar panels are one of the best ways to reduce your energy bills in the UK, but they’re famously not the most affordable. The average 3 kilowatt-peak (kWp) solar panel system costs around £9,000, which can be a significant outlay for many households around the country - and this is why people are often tempted by cheap solar deals. 

However, solar panels are meant to be a long-term investment - something that you eventually recover the cost of via energy bill savings, and something that will last you at least 25 years. Cheap solar panels might never make it this far. 

We’ll explain exactly why cheap solar panels aren’t worth the risk, as well as give you tips on sensible ways to reduce the cost of solar panels.  

If you’d like to find out how much a solar & battery system could save you, just answer a few quick questions below and we'll immediately generate an estimate for you.

Cheap solar panels are never worth the risk. A cheap price either means the hardware is low quality or the installation is low quality - or both. And this will cause you many problems further down the line (if not immediately). 

If you’re wondering what ‘cheap’ means in the context of solar - speaking very roughly, a 3kWp solar panel system is about £9,000, or £11,000 if you add a 5kWh battery. If you’re seeing prices that fall dramatically under this level, you should start being a little cautious. 

The installation of cheap solar panels comes with a whole host of risks, including:

Let’s delve into these issues in a little more detail. 

If the low price is due to poor quality hardware, you could end up with solar panels that don’t have a very high efficiency rating. In the context of solar, ‘efficiency’ refers to the percentage of natural light that the panels can convert into useable electricity. It’s pretty standard for most residential solar panel installations today to exceed 20% efficiency - anything much lower than this should raise a few alarm bells. 

Similarly, poor quality panels may also have a low power output rating. The power output rating refers to the maximum amount of power that a solar panel can generate in ideal conditions, and the best panels on the residential market today are around 400 watts (W). 

If you cover your roof in solar panels that have low efficiency and low power output, you’ll see much smaller savings on your electricity bills. 

Solar panels are associated with the phrase ‘fit and forget’, which refers to their minimal need for maintenance. You’ll get that if you buy high-quality solar panels from a trusted installer, but not if you opt for something cheap. 

Cheap panels will malfunction more often because of their lower build quality— and that means spending more on repairs. 

Most solar panels start to see decreases in efficiency once temperatures exceed 25°C, and this is completely normal, but cheap solar panels will see more dramatic declines. This decline in efficiency is called the temperature coefficient and it’ll change depending on the quality and type of the solar panel. 

Higher quality solar panels will typically see efficiency reductions of 0.3% to 0.5% for every degree above 25°C. However, lower quality solar panels will see much bigger drops in efficiency once the mercury starts to climb. It’s in the summer months where you would naturally expect your solar panels to be at their most productive, but this won’t be the case if your system is practically wilting in the heat. 

Given that UK summers are expected to become hotter and hotter, it’s particularly unwise to invest in hardware that isn’t built to survive in temperatures above 25°C. 

Unsurprisingly, the best looking solar panels on the market tend to come at a bit of a premium - they’re usually made of monocrystalline silicon, all-black in appearance, and look very impressive on most residential rooftops in the UK. 

In contrast, most cheaper solar panels are made of polycrystalline silicon, which has a distinctly mottled blue appearance, and is often the reason solar panels have traditionally struggled to offer much curb appeal. 

If you’re particularly bothered about having a solar panel installation that looks sleek and stylish, cheap solar panels are unlikely to tick that box. 

Good quality solar panels typically come with a 25-year warranty and are expected to last beyond this point, sometimes up to 30 years or more. This lengthy lifespan is pretty important given how most people view solar panels as an investment that will eventually ‘break even’ and lead to pure profit. 

For instance, the average UK household with a solar & battery system will break even in around nine years. This estimate is based on 40 of Sunsave’s own solar & battery system designs on rooftops all over the UK (every system uses 430W solar panels and a 5kWh battery, and is signed up to the Octopus Intelligent Flux tariff). 

Meanwhile, with cheaper solar panels you might never break even or make it to the 25-year mark, and the panels are unlikely to come with a decent warranty. 

Buying solar panels from a budget installer will likely leave you with poor post-installation customer care. It could even be non-existent, so if something goes wrong with your solar panels you’ll have to spend time finding someone else who can help you. Once you’ve found some assistance, you could then have a pretty expensive time calling someone out to fix your system. 

By opting for Sunsave Plus, you’ll get a 20-year monitoring & maintenance support package, which means you won’t have to worry about extra hassle or exorbitant fees if and when your system needs some attention. 

Sensible ways to reduce the cost of solar panels

If you are struggling to cover the high upfront cost of a solar & battery system, there are better ways to keep costs down than simply opting for a low quality installation. For example:

Consider a solar subscription – Sunsave Plus is the UK’s first solar subscription, and it means you can get a top-quality solar & battery system at no upfront cost, and instead spread the payments across 20 years. 

Check if you’re eligible for grants – you might be eligible for the government’s ECO4 scheme, which was set up to help low-income homes make efficiency improvements. If you’re eligible, you could get funding towards a solar panel system, or have it paid for outright.

Consider buying panels through Solar Together – Solar Together is a group-buying scheme designed to help homes install solar panel systems at a reduced cost. This is generally 30% to 35% lower than the average market price.

Can you still get free solar panels?

What is the cheapest way to get solar panels?

Are cheap solar panels any good?

Cheap solar panels: are they worth the risk? | Solar advice

Cheap solar panels: are they worth the risk?

🏠 A property’s EPC score is determined by a physical inspection

🔥 Your home’s heating system has the biggest impact on your EPC rating

☀️ Insulation and renewable energy sources will add to your EPC rating

Apart from a few exceptions, every domestic and commercial property in the UK (that’s available to rent or buy) must have an Energy Performance Certificate (EPC). This means that your home will almost certainly have an EPC rating, even if you don’t know what it is. 

Cutting your energy bills and improving your property’s EPC rating are very closely connected - if you do one, it is very likely the other will follow. And whenever you’re looking to sell up and move on, a property with a higher EPC will generally fetch a better price.

In this article, we run through all the best ways to improve your home’s EPC rating.

An EPC rating is a way of measuring your home’s energy efficiency. In the simplest terms, it refers to how much energy is required to heat your property.

It’s done on a scale of A to G, with A being the highest possible level of efficiency and G being the lowest. This means that an A-rated property needs far less energy to achieve a certain internal temperature compared to a G-rated property (which consequently means the G-rated property will have much higher energy bills).

The A–G scale is colour coded, which gives homeowners a clear and easily understandable picture of their home’s efficiency. Unsurprisingly, bright red is the worst and bright green is the best. 

Your home’s EPC is calculated by an assessor who needs to physically inspect your home. If this hasn’t happened since you moved into your property, it probably will have happened some time before. You can use the gov.uk tool to check your property’s EPC rating. 

The assessor will inspect your property’s energy usage and heat loss, taking into account things like the age and size of your property, whether it has any wall or loft insulation, whether it has double glazing, whether any energy-saving light bulbs are in use, the efficiency of your home-heating system, as well as checking whether you have any renewable sources of electricity (such as solar panels). 

Your property’s assessor will use the SAP (Standard Assessment Procedure) methodology introduced by the government to score the inspection. This score is then converted into an EPC grade. 

Here’s how many points each of the EPC bands count for:

What are the benefits of improving your EPC rating?

The benefits of improving your EPC rating are numerous, and they include:

Warmer winters and cooler summers (if your EPC improvements include insulation / double glazing)

Increased property value (KnightFrank say that increasing your home’s EPC rating could boost its value by up to 20%)

What’s more, it can often be tricky to get a mortgage for a property that has a very low EPC rating and has little potential for improvement, as explained by HSBC.

The average EPC rating for UK properties is D, so there is a widespread, national need for the UK to improve its housing stock. A key problem is that around 1.7 million homes are physically unable to reach above C, according to research by Rightmove.

What are the best ways to improve your EPC rating?

Generally speaking, the most impactful measures you can take are also the most expensive, but there are also a few cheaper steps that can still turn the dial. Here are our top 10:

Looking for a cheap but highly effective way to improve your EPC rating? Insulate your loft with either fibreglass or renewable wood fibre and you’ll immediately add 10 to 16 points to your EPC rating.

Loft insulation works by creating a barrier between your roof and your home, which drastically reduces heat loss. Uninsulated homes tend to lose around 50% of their heat through their roofs, which can lead to hundreds of pounds more being spent on energy bills.

With loft insulation, you can reduce the time (and temperature) of your heating because less of it is escaping out of your house. 

Plus, loft insulation is pretty simple to install yourself, which is something many UK homeowners do. In many cases, you just need to place the insulation between the rafters that support your roof.

A home’s heating system has a huge impact on its overall EPC score, and having an old inefficient boiler can bring your property’s EPC down to the very bottom. 

In some cases, getting a new, efficient boiler can add up to 40 points to your EPC rating.

If you’re among the 15% of UK homes without double glazing, you should definitely consider getting it. Doing so will add around 10 points to your home’s EPC rating and make your home more insulated. 

You’ll also reduce the amount of outside noise making its way into your home, which is great if you live on a busy street. 

However, double glazing isn’t the cheapest way to improve your EPC rating, with the cost of replacing all the windows in a three-bedroom home coming in at roughly £2,000. 

Solar panels should improve your EPC rating by around 15-20 points, which will put you up by at least one grade.

A solar panel system capable of powering a three-bedroom home is roughly £9,000 (including installation costs).

It’s worth it if you can afford it, because the benefits of solar panels are numerous. If the high upfront cost is a significant barrier, you should consider Sunsave Plus, which is the UK’s first solar & battery subscription. It enables UK households to switch to solar at no upfront cost, and instead requires fixed monthly payments for 20 years. You can find out more here. 

Other types of renewable energy would also help to increase your EPC, such as a mini wind turbine or a micro hydropower system. 

Replacing your older incandescent light bulbs with halogen bulbs, LED bulbs, or compact fluorescent bulbs is a quick, cheap, and easy way to score two or three points on your EPC rating.

You’ll spend £5 on average for a 12 watt (w) LED light bulb, which is more than the £1 you’ll spend on an incandescent bulb, but it’s worth paying the extra.

An LED light bulb will last 50,000 hours on average, compared to 2,000 hours for incandescent bulbs. So you’ll need to buy 25 incandescent bulbs to reach the same 50,000 hour lifespan of an LED light bulb, which would actually end up costing you around £20 more.

LED bulbs are cheaper to run too – roughly £58 per year instead of the £394 you’ll spend running an incandescent light bulb. 

Smart heating controls are something EPC assessors check for when they inspect your property. Using a smart thermostat allows you to heat your home more efficiently, as you can control the temperature in individual rooms instead of just heating the whole house. 

Smart thermostats usually require a new energy-efficient boiler to work properly and cost between £120 and £220.

Also, some smart thermostats can sync with your phone’s GPS, meaning they’ll turn off the heating when they detect you’re away from home (and then switch it back on when you’re getting near).

Spending just £17 or thereabouts for a hot water cylinder jacket is a small but effective way to improve your EPC rating. With one, you’ll get up to five points on your home’s EPC score. 

These cost-effective jackets can save you up to £35 a year, meaning it’ll usually take only half a year for you to get your money back.

Like loft insulation, insulating your walls is a fantastic way to add to your EPC rating - it can increase your score by up to 24 points. 

However, getting wall insulation is considerably more expensive than loft insulation. For cavity wall insulation, expect to pay around £2,700 if you live in a typical semi-detached property (Checkatrade, 2023).

Meanwhile, solid wall insulation costs closer to £9,000 for a semi-detached house.

Underfloor heating is a highly efficient way to heat your home when combined with good insulation. A typical three-bedroom semi-detached home can add around five points to its EPC score by installing underfloor heating. 

It’ll cost around £120–£135 per square metre for water-based underfloor heating, which is the most efficient. Electric underfloor heating is cheaper to install at £60–£85 per square metre, but is less efficient and actually costs more to run overall. 

Sealing draughts in windows and buying a draught excluder for your door can add a point or two to your overall EPC score.

These are cheap solutions, too — silicon sealant for windows costs just £30 and you can purchase a draught excluder cushion for around £15. 

Alternatively, if you don’t trust the DIY approach then you can spend around £250 to have your home professionally draught-proofed.

Investing in upgrades to your heating and insulation is the best way to improve your EPC rating. For insulation, consider starting with your loft because this is typically the cheapest option and can be highly effective. 

For heating, if you have an old boiler you should think about switching to a new, high-efficiency condensing boiler, as this can add up to 40 points to your EPC score.

SAP (Standard Assessment Procedure) is a methodology used by the UK government to assess and compare the energy and environmental performance of dwellings. Your property’s SAP score directly determines its EPC rating. 

You can improve your SAP rating by installing things like low-energy light bulbs, insulating your home, and switching to renewable energy sources such as solar power.

Double glazing will improve your EPC rating by around 10 points. It’ll keep your home warmer, reduce the amount of noise coming in from the outside, and improve security (double glazing is more difficult to break into). 

Expect to pay around £2,000 to replace all the windows of a typical three-bedroom home with double glazing. 

What is the lowest acceptable EPC rating?

Only landlords need to worry about having an acceptable EPC rating for legal purposes. If you are a landlord, your property must meet an EPC rating of at least an E.

Discover 10 of the best ways to improve your home's EPC rating, from insulation and better boilers to new lightbulbs and smart thermostats.

Tom Gill

Posts from Tom Gill

Cheap solar panels: are they worth the risk?

The 10 best ways to improve your home’s EPC rating