Are in-roof solar panels better than on-roof?

Not necessarily. In-roof panels look sleeker but cost 20–30% more and produce 3–5% less electricity due to reduced cooling. On-roof panels offer better value per pound spent. In-roof is better for new builds, re-roofs, and conservation areas.

How much more do in-roof solar panels cost?

In-roof panels cost approximately 20–30% more than standard on-roof installation. For a 4kW system: on-roof costs £5,500–£8,000; in-roof costs £7,000–£11,000. The premium covers the flashing system, waterproof trays, and more complex installation.

Do in-roof solar panels leak?

Not when properly installed with the manufacturer's flashing and tray system. The waterproofing is designed to replace tiles entirely. However, incorrect installation can cause leaks — use an experienced MCS-certified installer with in-roof experience.

Can I convert on-roof panels to in-roof?

It is technically possible but rarely cost-effective. You would need to remove the existing panels, remove tiles underneath, install the in-roof tray system, and remount the panels. The labour cost often exceeds a new in-roof installation from scratch.

In-Roof Solar Panels: Integrated vs On-Roof

Last updated: 18 March 2026

Independently written

Solar panels integrated into UK home roof for a flush appearance — In-roof panels sit flush with the roofline — sleeker, but at a premium cost.

What are in-roof solar panels?

In-roof (integrated) solar panels replace your roof tiles entirely, sitting flush with the roofline for a sleek appearance. They cost 20–30% more than standard on-roof panels (£7,000–£11,000 vs £5,500–£8,000 for a 4kW system) and produce slightly less electricity due to reduced airflow cooling. They are best for new builds, re-roofs, and homeowners who prioritise aesthetics.

In-Roof vs On-Roof: The Key Differences

On-Roof (standard): - Panels mount on rails above existing tiles - 100mm+ gap between panels and roof surface - Tiles remain in place underneath - Most common installation method (90%+ of UK installs) - Cost: £5,500–£8,000 for 4kW - Output: 100% (good airflow keeps panels cool)

In-Roof (integrated): - Panels replace the tiles in that roof section - Sit flush with surrounding tiles - Requires a flashing kit and waterproof tray system - Used in 5–10% of UK residential installations - Cost: £7,000–£11,000 for 4kW (20–30% premium) - Output: 95–97% (reduced airflow = slightly warmer panels = slightly lower efficiency)

Source: MCS installation data; GSE and Viridian in-roof system specifications.

Solar panels on UK home — standard on-roof mounting visible — Standard on-roof panels are visible above the tiles — functional but not as sleek as in-roof.

Advantages of In-Roof Panels

Aesthetics — flush with the roofline, more visually appealing. Important in conservation areas or for design-conscious homeowners.
Weatherproofing — in-roof panels replace tiles, providing a dual function (generation + weather protection). Can reduce total roofing cost on new builds or re-roofs.
Planning — more likely to receive planning approval in conservation areas or on listed buildings (less visual impact).
New builds — increasingly specified by housebuilders as standard. Easier to install during construction than retrofitting.
Wind resistance — flush mounting eliminates wind uplift risk. No brackets or rails protruding from the roof surface.
Longer-term durability — no mounting brackets penetrating tiles means no potential for bracket-related weathering issues.

Disadvantages of In-Roof Panels

20–30% higher cost — the premium comes from the flashing system, waterproof trays, and more complex installation labour.
Slightly lower output (3–5%) — flush mounting reduces airflow behind the panels. Hotter panels = lower efficiency. A 4kW in-roof system may produce 3,700–4,050 kWh vs 3,800–4,200 kWh on-roof.
More complex installation — requires roofing skills as well as electrical, so the installation team needs dual expertise or a roofer on-site.
Harder to maintain — accessing or replacing a panel means disturbing the waterproofing system, which is more involved than unclipping an on-roof panel.
Warranty complexity — the waterproofing warranty is separate from the panel warranty. Ensure both are clearly documented.
Not suitable for all roofs — the roof structure must be compatible with the in-roof tray system. Older roofs may need additional work.

Solar panels on semi-detached home — comparing on-roof and in-roof options — On-roof panels are more common and cost-effective; in-roof panels are sleeker.

When Are In-Roof Panels Worth It?

Best case for in-roof panels:

1. New build — installing during construction eliminates the retrofit cost premium. The panels replace tiles you would have bought anyway, so the effective premium is much smaller.

2. Full re-roof — if you are replacing your roof tiles anyway, in-roof panels save on new tile costs for the area covered by panels. This reduces the effective premium to 5–10%.

3. Conservation areas — where standard on-roof panels might face planning objections, in-roof panels may receive approval due to lower visual impact.

4. Aesthetic priority — if the look of your home is very important to you and you are willing to pay a premium for sleek integration.

Not worth it if: - Your existing roof is in good condition and you do not plan to re-roof - Budget is your primary concern - You want maximum output per pound spent - You are in an area where on-roof panels face no planning issues

Source: NHBC new build solar guidance; MCS installer recommendations.

Cost versus savings comparison for in-roof vs on-roof solar — In-roof costs more upfront with slightly lower returns — but aesthetics may justify the premium.

In-Roof Solar Panel Brands

Leading in-roof systems available in the UK:

GSE In-Roof System: The most widely used in-roof mounting system in the UK. Compatible with most major panel brands. Flashing kit + waterproof trays provide proven weatherproofing.

Viridian Solar Clearline Fusion: Purpose-built in-roof system with integrated panels and trays. Available through approved installers. Clean aesthetic with minimal visible framework.

Marley SolarTile: A solar tile system that replaces individual tiles with PV-generating tiles. More expensive per watt but creates a truly seamless roof appearance.

Tesla Solar Roof: Available in the US; UK availability has been repeatedly delayed. Not currently a practical option for UK homeowners.

Note: The panel technology itself (monocrystalline cells) is the same whether mounted on-roof or in-roof. The difference is purely in the mounting and integration system.

Source: Manufacturer product listings; UK distributor availability.

Solar panels on bungalow — in-roof option available for low-pitch roofs — In-roof panels work on most roof types — but check compatibility with your roof pitch and tile type.

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