How Many Solar Panels Should I get?

When homeowners start looking into solar panels, it's natural to focus on the cost of the panels themselves. However, one of the most important things to understand about solar is that the panels are often only a portion of the total project cost.

A significant proportion of the investment goes towards scaffolding, installation labour, electrical works, design, testing and commissioning. Because many of these costs are fixed, a well-designed solar system will usually seek to maximise the amount of solar generation your property can support whilst ensuring compliance with structural and installation requirements.

The result is often a better return on investment, greater energy savings and a shorter payback period.

Understanding the Real Cost of Solar Installation

A typical solar installation includes:

• Solar panels

• Mounting systems

• Inverter and electrical equipment

• Scaffolding

• Installation labour

• Electrical testing and commissioning

• Certification and administration

  
  

Many homeowners are surprised to learn that once scaffolding is erected and installers are working on a particular roof elevation, adding extra panels to that same roof face often represents a relatively small increase in overall project cost.

This means that the cost per additional panel can be significantly lower during the initial installation than if those panels were added later.

Why Roof Elevations Matter

When discussing solar panel layouts, it's important to distinguish between adding more panels to an existing roof elevation and installing panels on additional roof elevations.

Maximising a Single Roof Elevation

Once scaffolding is in place and a roof face is being worked on, many of the installation costs have already been incurred.

Adding additional panels to that roof slope typically requires:

• More panels

• Additional mounting rails

• Slightly more installation time

  
  

As a result, the cost per additional panel is often very attractive, making it one of the most cost-effective ways to increase solar generation and improve your overall return on investment.

Adding Additional Roof Elevations

Installing panels on a second or third roof elevation can involve additional costs, including:

• More scaffolding

• Longer cable runs

• Additional mounting equipment

• More installation time

• Greater design complexity

  
  

This means the cost per installed panel may be higher than on the primary roof elevation.

However, this does not automatically mean those panels are poor value.

The Most Important Question: What Is the Return on Investment?

A common mistake when comparing solar designs is focusing solely on installation cost.

The more important question is: How much additional energy will those panels generate over their lifetime?

Even when an additional roof elevation increases the installation cost, it can still improve the overall financial performance of the system if it generates enough additional electricity.

For example, a west-facing roof may generate less energy annually than a south-facing roof, but it often produces electricity later in the day when many households are using more energy. This can increase self-consumption and reduce electricity imports from the grid.

Similarly, an east-facing roof can generate useful electricity during the morning period when household demand begins to rise.

The objective is therefore not simply to install the cheapest system possible, but to identify the system that delivers the greatest long-term value.

More Generation Can Mean Faster Payback

Every solar installation should be assessed as an investment.

If adding an extra roof elevation increases the project cost by £1,500 but generates an additional £300 of electricity savings each year, the extra investment may pay for itself in around five years while continuing to generate savings for decades afterwards.

This is why a good solar design considers:

• Additional installation cost

• Expected annual generation

• Self-consumption opportunities

• Future electricity prices

• Overall system payback

• Lifetime return on investment

  
  

In many cases, additional generation capacity can actually improve the overall economics of the installation.

Future-Proofing Your Home

Your electricity consumption today is unlikely to be the same in ten years' time.

Many households are planning for:

• Electric vehicles

• Heat pumps

• Home batteries

• Electric heating

• Air conditioning

• Home offices

  
  

All of these technologies increase electricity demand.

By installing the right amount of solar generation now, homeowners can better protect themselves against rising energy costs and future increases in household consumption.

A system that feels generously sized today may become perfectly matched to your energy needs in the future.

It's Not About Filling Every Available Space

It's not simply about trying to fit panels wherever they physically fit.

Every roof should be assessed for:

• Structural Capacity: The roof must safely support the proposed installation.

• Roof Edge Clearances: Appropriate clearances must be maintained around roof edges, ridges and verges.

• Roof Windows and Obstructions: Velux windows, chimneys, vents and other features must be accommodated within the design.

• Shading: Trees, neighbouring buildings and roof features can all affect performance and must be considered.

The goal is to maximise practical solar generation whilst ensuring every panel contributes positively to the overall economics of the system.

Why Ulex Energy Recommends Maximising Economically Viable Solar Capacity

As scaffolding and installation costs make up a significant proportion of the overall project cost, it is usually sensible to maximise the solar generation available from each roof elevation being worked on.

When additional roof elevations are available, we assess whether the additional generation justifies the extra installation cost. In many cases, the answer is yes, and the increased generation can improve both annual savings and lifetime return on investment.

Rather than designing systems around an arbitrary number of panels, we design around long-term financial performance.

The best solar system is not necessarily the cheapest or the largest. It is the system that delivers the greatest value over its lifetime.

Contact us today to find out how much solar generation your roof could support and what system design would deliver the greatest value for your home.