BIPV for Commercial Buildings: Solar Facades, Glass and Roofs
Updated 23 October 2026 · SEO Dons Editorial
What is BIPV, and how does it differ from rooftop solar?
Building-integrated PV (BIPV) replaces part of the building envelope with modules that also generate power. BSI describes it as photovoltaic materials "used to replace traditional building materials in areas such as the roof, skylights, or facades". Panels clamped onto a roof or bracketed to a wall are building-attached PV, which is outside the scope of the BIPV system standard: BS EN 50583-2 "does not apply to concentrating or building-attached photovoltaic systems".
The distinction changes who is responsible for what. BS EN 50583-1 applies to PV modules used as construction products, and BSI notes that integrating PV into a construction product "necessarily changes the properties" of the original product, so a building owner must take the requirements into account. BSI lists Part 1 as current and under review. A BIPV package is therefore both a building element and an electrical system. Bracketed wall arrays are covered in the wall-mounted solar guide.
Which BIPV types exist, and what do makers publish?
The figures below are each maker's own claims for its own products, read on 22 October 2026. They are not independent test results or a ranking.
| Type | What it replaces | Mainly generates, or forms the envelope? | Maker's published figure |
|---|---|---|---|
| Crystalline silicon laminated glass (Onyx Solar) | Canopies, skylights, spandrels, solid walls | Both: glass first, with power set by cell density | Efficiency up to 16%; 100 to 180 Wp/m²; light transmittance from almost 0% to 75% |
| Amorphous silicon glass (Onyx Solar) | Glazing that needs daylight | Envelope and daylight first | About one third the generation of crystalline silicon glass; light transmittance up to 30% |
| Ventilated facade and rainscreen cladding (Onyx Solar) | Conventional facade materials | Cladding that also generates | No output per m² on the page read |
| Frameless glass-on-glass in-roof system (Megasol, 19 August 2026) | Tiles or slate | Roof covering with power | Over 200 Wp/m²; rain tightness to CEN/TR 15601 |
| Solar slates and glass roofs (GB-Sol) | Roof covering | Roof covering, which the maker says provides the waterproofing | Slates about 80% of the output per m² of larger panels; no Wp/m² on the pages read |
How much yield does building integration cost?
Some, because a module with no air behind it runs hotter. PVGIS describes its building-integrated option as modules "completely built into the structure of the wall or roof of a building, with no air movement behind the modules", and notes that restricted air movement can make modules "considerably hotter". The table compares annual kWh per kWp for a south-facing crystalline silicon array in PVGIS 5.3 (SARAH3 radiation data, 14% losses), changing only the mounting option.
| Location | Slope | Ventilated mounting (kWh per kWp) | Building-integrated (kWh per kWp) | Difference |
|---|---|---|---|---|
| Plymouth | 35 degrees | 1,122 | 1,088 | -3.0% |
| Plymouth | 90 degrees | 795 | 776 | -2.3% |
| Birmingham | 35 degrees | 968 | 940 | -2.9% |
| Birmingham | 90 degrees | 710 | 693 | -2.4% |
| Glasgow | 35 degrees | 853 | 829 | -2.8% |
| Glasgow | 90 degrees | 633 | 618 | -2.3% |
Integration costs about 2% to 3% of annual yield in these runs. The wall-mounted guide covers the larger loss from facing a vertical wall, and Onyx Solar says its glass must balance "natural light transmission and nominal power". Use the maker's Wp/m² for the actual build-up, because PVGIS models a standard crystalline silicon module, not tinted or spaced-cell glass.
What do the Building Regulations add when the module is the wall or roof?
This section covers England. Wales has a separate version of regulation 7, and Scotland and Northern Ireland have their own building regulations. An integrated element has to meet Schedule 1 as a building element, not only as an electrical product:
- Fire spread. B4(1) says external walls "shall adequately resist the spread of fire over the walls and from one building to another", and B4(2) sets the same test for the roof.
- Weather-tightness. C2 requires walls and roof to protect against "precipitation including wind-driven spray".
- Cladding on taller buildings. Regulation 7(2) requires materials that become part of an external wall of a relevant building to be Class A2-s1, d0 or A1. A relevant building has a storey at least 18 metres up and contains dwellings, an institution or a room for residential purposes. An office or warehouse with none of those uses is not a relevant building, but B4 still applies. Regulation 7(3) exempts "window frames and glass" and electrical installations. Whether a laminated PV glass unit counts as glass is for the designer, the classification evidence and building control to settle.
Approved Document B's gov.uk page was last updated on 16 September 2026, and the update it lists introduces guidance on second stairs and evacuation lifts in taller residential buildings. Its FAQs, last updated on 21 February 2025, tell designers to consider materials used for the external wall "in relation to buildings of any height or use".
MCS adds evidence rules for the systems it covers, which stop at 50kW for electrical technologies. Its MIS 3002 clause 5.5.5, which applies where no mounting system is certified under MCS 012, was updated on 18 March 2026 and is mandatory for MCS installers from 18 June 2026. It asks installers to show how fire performance and weather-tightness have been maintained. Larger commercial BIPV falls outside that scheme, so the evidence comes from the designer and maker. As examples of maker evidence, GB-Sol says its Infinity and Integrated roofs achieved EXT.S.AA under BS 476-3:2004 in independent fire tests. Ask for the report for the exact build-up, not a family claim. Reflection from glass roofs is a separate planning question, covered in the glint and glare guide.
What drives cost and payback compared with rooftop PV?
This page gives no prices, because no official source publishes them. The drivers are visible without them:
- The element replaced. Makers argue the module displaces conventional material: GB-Sol says its system "offsets the cost of the standard roof covering", and Onyx Solar says its glass "offsets conventional building material costs". A fair comparison nets off the avoided element, and asks whether it was due for replacement anyway.
- Output per square metre. GB-Sol says slates give about 80% of the output per m² of larger panels, and spaced-cell glass trades power for daylight.
- Orientation. Facade surfaces face away from the best angle, as the wall-mounted guide shows.
- Replacement. If the module is the weather skin, changing one is a roofing or cladding job. Ask about spares and lead times: GB-Sol says its lead times can vary greatly with its order book.
- Warranty split. Ask who covers weather-tightness and who covers power output.
Listed and conservation-area buildings have their own tests, set out in the listed buildings guide. The standard module route is compared in the commercial PV panels guide, and a designer can price both routes for the same facade or roof if you send site details through the site's enquiry form.
Sources
- BSI, BS EN 50583-1:2016 Photovoltaics in buildings, BIPV modules and BS EN 50583-2:2016 BIPV systems, BSI Knowledge pages, checked 22 October 2026.
- legislation.gov.uk, The Building Regulations 2010, regulation 7 and Schedule 1, checked 22 October 2026.
- Ministry of Housing, Communities and Local Government, Fire safety: Approved Document B (last updated 16 September 2026) and frequently asked questions (last updated 21 February 2025), checked 22 October 2026.
- MCS, MCS publishes update to MIS 3002 (18 March 2026) and Becoming certified, checked 22 October 2026.
- European Commission Joint Research Centre, PVGIS user manual and PVGIS 5.3 (PVcalc runs for Plymouth, Birmingham and Glasgow, 1 kWp, 14% losses), checked 22 October 2026.
- Onyx Solar, crystalline silicon photovoltaic glass, amorphous silicon photovoltaic glass, photovoltaic facades and home page, checked 22 October 2026. Supplier statements about its own products only.
- Megasol, Glare control in integrated photovoltaics (19 August 2026), checked 22 October 2026. Supplier statements about its own products only.
- GB-Sol, integrated solar panels, Infinity and FAQs, checked 22 October 2026. Supplier statements about its own products only.
Common questions
Is a BIPV facade covered by MCS?
Only up to MCS's scope, which MCS states as 50kW for electrical technologies, and only if installed by a certified installer. Larger commercial facades sit outside the scheme, so the maker and designer have to supply the fire, weather-tightness and structural evidence.
Does regulation 7(2) apply to a commercial office with solar cladding?
It applies only to a relevant building, meaning one with a storey at least 18 metres up that contains dwellings, an institution or a room for residential purposes. An office with none of those uses is outside it, but the B4 requirement on external wall fire spread still applies. Building control confirms the position for a given project.
Why does PVGIS show lower yield for a building-integrated array?
PVGIS assumes there is no air movement behind a module built into a wall or roof, so it runs hotter and converts less sunlight. In the runs above the loss is about 2% to 3% a year. Real products differ, so use the maker's data where it exists.
Can semi-transparent solar glass replace normal glazing?
It can sit in the same place as glazing, but it trades daylight for power. Onyx Solar says its crystalline silicon glass ranges from almost 0% to 75% light transmittance, and its amorphous glass reaches up to 30%. The glazing specification, not the PV rating, usually decides the choice.