Making room for photovoltaic panels and daylight

It’s clear that a commercial roof can put sunlight to work in two ways. Photovoltaic (PV) panels generate electricity, while rooflights bring natural light into the building, reducing the need for electric lighting. Planning for both helps a roof deliver more value, through the energy it generates and the environment it creates inside.

For large-span industrial and commercial buildings, the benefits of rooflights go beyond lower lighting energy consumption. Daylight also supports the people working below, giving building owners and occupiers good reason to look beyond how much electricity a roof can produce.

The changing light throughout the day connects occupants with the outside world and supports a healthy 24-hour body clock. Daylight has also been shown to improve alertness and concentration, both welcome additions to the working day.

Spaces well-lit with daylight are associated with better staff retention and reduced absenteeism. Sufficient exposure to daylight is also believed to support long-term health and wellbeing. There are property benefits too: good daylighting has been shown to increase asset value and space utilisation.

Some of these benefits are easier to measure than others, but all deserve consideration when deciding how to use the roof.

For non-residential industrial and commercial buildings, effective daylight provision typically requires rooflights across 10–20% of the roof area. This is a useful starting point when planning rooflights alongside PV panels. The right balance will depend on how the space below is used, the positioning of rooflights and the other equipment the roof needs to accommodate.

There is plenty to fit in, which makes early planning essential. In large-span buildings, daylighting performance is directly related to the proportion of roof allocated to rooflights. Their position matters too. Leaving daylight provision until other rooftop requirements have been settled limits the options available.

For architects, specifiers and roofing contractors, planning rooflights and PV together helps make the most of the available space. It allows the needs of the building and its occupants to shape the roof design from the start.

A successful roof earns its keep in several ways: generating electricity, reducing lighting demand and creating a better working environment. Giving PV panels and rooflights their place in the design helps deliver all three.

At Filon, our specialist rooflighting expertise can help you make daylight part of a balanced, high-performance roof design. Reach out to our team at sales(Replace this parenthesis with the @ sign)filon.co.uk, or explore our range on NBS Source.