Complete Guide To Solar Panel Installation

Our big guide to solar panel installation includes everything you need to know before making a purchase. 

This guide includes:

This is a 15-minute read. So, if you're short on time, read the quick-fire summary below and bookmark this page for later.

Alternatively, jump right in and use our solar panel configuration tool here. 

In Summary: Everything You Need To Know About Solar Panel Installation

Expect a solar panel installation to cost approximately £6,000 without a storage battery and £8,000-£9,000 with one.

There are government solar panel grants available to help reduce the installation cost (or in some cases, get free solar panels). 

However, these are usually limited to those receiving means tested benefits. Popular government grants include: ECO4, HUG2 and Nest (Wales).

In terms of sizing, a 12-panel 5kW system will suffice for most 2-4 bedroom properties. We'd suggest coupling this with a micro or hybrid inverter and a small solar storage battery (as a minimum).

Remember, solar panel systems weigh in excess of 300kg, so you'll need a roof that's capable of holding that weight. And ideally, it's going to be south facing and have a tilt angle of 30 degrees. If you have a flat roof, solar panels can be installed there and we can adjust the mounts to get the most electricity production from your panels. 

After you've got your solar panel installation completed, expect your panels to last decades; high quality manufacturers like LONGi will offer warranties of up to 25-years. 

And if you want to get the most out of your system, use a MCS registered installer. MCS installations will qualify for 0% VAT, as well as allowing you to participate in the Smart Export Guarantee (SEG); you'll be able to sell excess electricity back to the grid. 

All of our engineers are MCS registered so you’ll benefit from 0% VAT and SEG payments. 

You can get quotes on-screen for your solar panel system using our clickable tool here. 

Alternatively, contact our experts here if you have any questions; we'll be happy to help!

Solar Panel Installation Guide

Solar Panel Installation Costs

Solar panel installation costs vary a great deal. A few variables that affect the price include: 

A typical solar 12 panel installation will cost around £5,500-£7,500 without a storage battery. 

Without a storage battery, you'd be selling any excess electricity back to the grid, only to buy it back later at a higher cost…not ideal!

That's why the majority of the systems we install include at least a small solar storage battery. This improves your energy self-sufficiency levels, so you're less reliant on the grid for electricity (and not at the mercy of fluctuating energy costs). 

A typical 12 panel system, including a small solar storage battery, is likely to cost in the region of £8,000-£9,000 from dwellow.

Use our clickable solar panel installation tool to determine the best system for your property in a matter of minutes. 

You'll get fixed prices on-screen and be able to flick between the different battery options to see how it affects the overall installation cost. 

Alternatively, read our big guide to solar panel installation costs here. 

Grants

There are various grants available to help fund solar panels. For those that receive a means tested benefit, there is the opportunity to get not just funding, but in some cases...free solar panels!

The most popular government grants for solar panels include: 

• ECO4
• HUG2
• Nest (Wales)

For those that aren't eligible, you'll get a subsidy thanks to the 0% VAT scheme. This scheme covers energy saving materials (ESMs) and includes the likes of: solar panels, inverters and batteries. 

The scheme is set to last until March 31st 2027. At this point, the government plans to switch to 5% VAT on ESMs. However, it’s likely the scheme would be extended further, to promote the use of green energy in the UK.

If you receive a means tested benefit and think you could be eligible for funding, read our guide to solar panel installation grants here.

Alternatively, use our solar panel configuration tool here. We automatically apply the 0% VAT rate.

Solar Panel Size Guide

If you’ve done some research around solar panel installation, there’s a good chance you’re confused by sizing. 

So, what size solar panel system do you need? 

To get an exact answer to that question, you’ll need to know your household’s energy consumption. For a typical UK property (2-4 bedroom house), it’s likely your consumption sits in the 2,500-4,100 kWh (per annum) range (according to Ofgem): 

However, it's not just the electricity consumption of your household that determines the perfect solar system for your property. 

Other factors include:

• What time of the day you use electricity; solar panels are most productive in daylight hours
• Whether or not you'll use a solar storage battery, and how big it is (in kWh)
• The direction and orientation of your roof (south facing at a 30 degree pitch is the best roof setup)
• The quality and efficiency of your solar panels, and their degradation rate over time

With all that said, a 5kW solar panel system is suitable for a range of properties in the 2-4 bedroom range. 

Expect a 12-panel 5kW solar panel system to cost just under £6,000 without a solar storage battery. This includes the discount applied thanks to the UK government’s 0% VAT scheme. 

If you’re unsure exactly what size solar panel you need, simply use our solar panel configuration tool here. That will suggest the most suitable system for your property.
Alternatively, we’ve written a guide to solar panel sizing here.

Solar Battery Storage

A big decision you'll need to make when booking a solar panel installation, is whether or not you want a solar storage battery. We would receommend that you do, where budget allows.

Solar panel batteries are expensive, with prices generally as follows for the battery alone:

• Small 5kW storage battery: £1,400
• Medium 10kW storage battery: £2,800
• Large 15kW storage battery: £4,200

Using a small solar storage battery, a typical 5kW solar panel system will jump from just under £6,000, to just over £8,000 once you include the additional labour as well.

Solar batteries help to reduce your reliance on the grid for electricity, improving your energy self sufficiency. Put simply, you won’t be as badly affected if electricity prices rise. 

The best way to determine what size solar battery you need, how much it’s going to cost and how self sufficiency ratings change based on battery size?

Use our solar panel tool here. 

You can flick between 4 options to determine which is the most cost effective in terms of both upfront expense and long-term savings: 

• No battery
• Small
• Medium
• Large

For further reading, check out our solar battery guides below:

• The best solar panel battery brands
• SunSynk battery review
• How much solar batteries cost

What Type of Solar Inverter is Best?

Inverters play a crucial role in your system. Before having your solar panel installation completed, it's important to understand what they do, which ones are most suitable for your property and what they cost. 

Put simply, your solar panels generate direct current (DC) electricity, yet your property needs alternating current (AC) electricity. The job of the inverter is simply to convert DC to AC.

There are three types of inverter:

• String: Connect multiple panels, but be warned, if one panel is inefficient, it will affect all panels on that "string"
• Micro: A much better option than string inverters, as a single low efficiency panel won't drop the efficiency of the whole system
• Hybrid: A great option for those using a storage battery or those that are looking to make the most out of Smart Export Guarantee payments 

You can read more in our guide to solar panel inverters here.

Whilst hybrid and micro inverters are much better than string inverters, they're also more expensive. Typically, inverters can cost between £750-£2,250 per unit. 

Read our guide to solar inverter costs here. 

Or, simply use our clickable solar panel configuration tool. That will spec a system that's perfect for your property, including the most suitable inverter.

Roof Suitability

Before forking out £5,000 or more for a solar panel installation, you'll want to check if your roof is suitable.

Firstly, your roof will need to be structurally sound; solar panel systems can weigh in excess of 300kg - the average panel is just over 20kg and then there is the mounting kit. You'll also need a reasonable amount of space on the side of the roof you plan to install solar panels; even a 3kW system is likely to need around 20 sqm of space.

Alongside this, the direction your roof faces and the pitch makes a huge difference. A roof that's facing due south and at a pitch angle of 30 degrees is the best case scenario. 

If your roof isn't facing due south and at a 30 degree pitch, there is another option; fit solar panels on a flat roof. If you have space available on a flat roof, using specialist mounts, the panels can be mounted facing due south and at 30 degrees!

Our solar panel tool scans your roof to determine how efficient your system will be based on both pitch and orientation. And if necessary, we can visit your property to check its structural integrity is good enough to take the weight of solar panels.

Lifespan

To calculate whether solar panels are worth it, you need to know their lifespan. 

Depending on the manufacturer, solar panels should last anywhere from 15-25 years. 

However, it’s worth looking at their “useful” lifespan. As you can see in the graphic below from 8 Billion Trees, after 25 years, your panel’s efficiency is going to have dropped from around 97%, down to approximately 82%. 

At this point, it’s probably worth upgrading your panels to new and much more efficient units.

You’ll want to ensure you're purchasing the most efficient solar panels possible. And we’re not just talking about their efficiency on day 1.

Degradation rate is important, so heading for a brand that offers a 25-year warranty that covers a maximum degradation rate is key. 

As you can see in our review of LONGi, they offer a 25-year warranty. More importantly, this covers a max degradation rate of 1.5% in year 1, and an average maximum of 0.4% from years 2-25. 

Read more about how long solar panels last here. 

Alternatively, go ahead and get a quote on solar panel installation with a 25-year warranty (which covers a max degradation rate) here. 

Finding Solar Panel Installers Near You

If you've made the decision to book a solar panel installation, you'll need to find a qualified installer. 

Remember, you need an installer registered with the Microgeneration Certification Scheme (MCS). If you don't use an MCS installer, you'll lose out on: 

• The government's 0% VAT scheme
• £100s per year if you're able to generate excess energy; to register with the Smart Export Guarantee scheme your system needs to be installed by a MCS professional 

All of our solar panel installers are registered with MCS, so you'll benefit from 0% VAT and SEG payments. 

You can get a quote on your solar panel installation using our clickable quote form here. 

Or for further reading, check out our guide to solar panel installers here. 

Advantages & Disadvantages

Advantages

Whilst solar panels have some drawbacks (which we'll discuss below), the advantages by far outweigh any disadvantages.

By having solar panels installed you'll benefit from: 

• A huge reduction in your energy bills
• Payments via the Smart Export Guarantee scheme, as long as you have your system installed by a MCS registered installer
• Protection from fluctuations in energy costs thanks to having some level of electricity self sufficiency
• Low maintenance costs
• The production of green energy, helping to combat global climate change!

Disadvantages

One of the biggest disadvantages of solar panels is the high upfront cost. 

Expect to pay somewhere in the region of £6,000 for a basic system, without a solar storage battery. However, this cost is offset over time thanks to SEG payments, and a reduction in your energy bills from the electricity your system creates. 

Other disadvantages include roof suitability. To get maximum efficiency (and therefore, energy bill savings), you'll need a roof that's pitched at 30 degrees and facing due south. 

We've written a complete guide to the disadvantages of solar panels here. 

Solar Panel Installation FAQ

How long does it take to install solar panels?

Expect a solar panel installation to take between 1-3 days, including mounting panels and hooking up the system to the grid. 

Do I need planning permission for solar panels?

Generally, you won't need planning permission to have solar panels installed, unless you plan to install them on a listed building, or want a large system on a commercial property. 

Feel free to contact us for advice if you think you might need planning permission.

How long do solar panels last?

The lifespan of solar panels varies depending on the manufacturer. However, if we take the LONGi Hi-Mo X6 Guardian as an example, expect a 25-year lifespan.

If they drop below a 1.5% degradation rate in year 1, or an average of 0.4% in years 2-25, they’ll be covered by their 25-year power warranty.

How efficient are solar panels?

Efficiency depends on quality. High quality solar panel brands will offer efficiency levels of 20% or higher. For example the Hi-Mo X6 Guardian has an efficiency level of 23.2%, according to LONGi.

What are the biggest advantages of solar panels?

• Energy savings
• Self sufficiency (you won’t be at the mercy of fluctuating energy prices)
• Income (you can earn money by selling excess electricity back to the grid via the SEG scheme)
• Clean energy

What are the biggest disadvantages of solar panels?

• High upfront costs
• Dependant on sunlight 
• Panels will need to replaced after around 25 years to ensure your system is efficient
• Requires a roof space that has reasonable structural integrity

Can I install DIY solar panels?

Whilst you can fit solar panels on a DIY basis, remember any materials will be subject to the normal VAT rate, and you won’t be able to sell excess electricity back to the grid. 

All of our solar panel installations are completed by our MCS installers. You’ll qualify for both 0% VAT and the SEG scheme. 

Get quotes on your solar panel installation using our clickable tool here.