As more homeowners look for sleek, high-performing renewable energy systems, Viridian Solar has emerged as a leading choice for in-roof solar. Unlike traditional on-roof solar systems that sit above the tiles, Viridian integrates directly into the roofline, creating a neat, efficient, and cost-effective solution.
In this blog, we’ll explore how the Viridian system works, its advantages and disadvantages, and why it is increasingly specified in both new builds and re-roofing projects.
A Viridian in-roof installation begins when the roof is felted and battened but before tiles are laid. Unlike many systems that require trays or pods, Viridian panels are fixed directly onto battens. Each panel is 70 mm thick, with an integrated frame that allows secure mounting and built-in gaskets for weather protection.
Flashings are then installed around and between the panels to create a watertight seal. The system is tailored for each project, whether it is a simple rectangular array or a more complex design with skylights. Once installed, roofers complete tiling around the array for a clean, integrated finish.
Retrofit projects follow a similar process, with tiles stripped back before fitting the in-roof system.
If you would like to see the full installation process click on the video below:
While solar panels are inherently safe, DC connectors such as MC4s can present fire risks if not fitted correctly. To enhance safety, Viridian developed the ArcBox. This hinged enclosure houses MC4 connections, keeping them ventilated, dry, and isolated from combustible materials. If an arc fault occurs, any fire remains contained within the ArcBox, protecting the system and the property.
At Spirit Energy, we install ArcBox as standard with every Viridian in-roof system.
Choosing an in-roof solution like Viridian Solar brings several benefits:
- Cost savings on tiles and labour: Every area covered by panels reduces the need for costly roofing materials, especially premium options like slate. We estimate that by installing 8 kW of in-roof solar, you save over £2,500 on roof tiles and tiler labour.
- No bird protection required: Unlike on-roof systems, pests cannot nest beneath in-roof panels, eliminating the need for mesh or premium guards.
- Reduced wind uplift risk: In-roof panels sit flush with the roof, making them naturally resistant to wind forces, particularly in exposed coastal or hillside locations.
- Structural benefits: Lighter overall weight compared to on-roof systems, especially when tiles are replaced by panels.
In-roof solar does come with trade-offs compared to on-roof alternatives:
- Less flexibility in layout: Viridian panels cannot be mixed in portrait and landscape within the same array.
- Limited panel choice: Viridian currently offers only the 445 W panel, whereas on-roof systems support a wider range of modules.
- Slightly lower efficiency: In-roof panels run hotter due to reduced airflow, which can marginally reduce performance in summer. However, the difference is minimal over a year.
For one recent project, Spirit Energy installed 22 Viridian 445 W panels alongside a 32 kWh battery system. The array is expected to generate 9,594 kWh per year, saving the homeowner nearly £2,500 annually.
Key benefits included:
- 35% of solar generation used directly in the home
- 36% stored in the battery for later use
- 29% exported to the grid for profit
With an estimated return on investment of 11% and a payback period that improves as household electricity usage grows, the system combines financial security with environmental responsibility.
Viridian Solar is ideal if you are re-roofing, building a new home, or seeking a visually integrated system. The panels reduce roofing costs, deliver long-term energy savings, and look as though they are part of the roof itself. While they are less flexible than on-roof systems, for many homeowners the aesthetic and practical benefits far outweigh the limitations.
Viridian Solar offers a forward-thinking solution for homeowners who want more than just solar panels on their roof. By combining performance, safety, and style, it delivers an energy system that works as well as it looks.
At Spirit Energy, we specialise in Viridian in-roof solar installations across the UK. Whether you are starting a new build or considering a re-roof, our team can design, install, and commission a system tailored to your home.
Contact us today to discuss how Viridian Solar could transform your roof into a clean energy powerhouse.