A guide to sunpipes

Experienced renovator Michael Holmes explains how to bring extra light into a room with no exterior walls using sunpipes, a reflective tube that can duct sunlight into a space where a window or conventional rooflight is not feasible

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A sunpipe, or a sun tunnel, is the ideal solution for any room in your home that has no windows – or is light-starved – and would benefit from a good dose of natural daylight. This might be an en-suite bathroom, a utility room or a hallway with no exterior walls. Experienced renovator Michael Holmes explains how a sunpipe can be used to bring extra light into your rooms.

Find out more about maximising light in your home in our guide.

Sunpipes in a hallway by Velux

Sun tunnel by Velux

(Image: © Velux)

What is a sunpipe or sun tunnel?

A sunpipe is a reflective tube that can duct sunlight into a space where a window or conventional rooflight is not feasible. For example, it can make it possible to duct light through a loft, an upper storey, or even around a corner to get light into spaces where it would otherwise be impossible to introduce borrowed light.

How does a sunpipe work?

Natural light enters the tube through a clear dome (collector) set in a pitched or flat roof, and is channelled to where it is needed via a mirrored tube. This ends in a translucent dome (diffuser) resembling a conventional light fitting.

Sunpipe by Monodraught

Sunpipe by Monodraught

(Image: © Monodraught)

What kind of light does a sunpipe deliver?

Tests by Durham University have found that up to 12 times the equivalent light of a 100-watt light bulb can be achieved with a sunpipe using 3m of flexible reflective tubing. The sunpipe will perform best if facing due south and if the diffuser is directly below the collector. The amount of light reflected diminishes with each bend and as the pipe gets longer. The larger the pipe diameter, the greater the volume of light that is transmitted.

Which sunpipe to install?

As well as a choice of flexible or rigid pipe (rigid pipes are more effective but harder to install), there are models and fittings to suit various roof coverings (such as pantiles or slate). Most designs have an external dome, but some are converted to fit into a conventional or conservation rooflight, ideal where a polycarbonate dome is considered unsuitable due to planning regulations. There are diffusers in white, chrome and brass styles to suit your décor.

How much does a sunpipe cost?

A flexible sunpipe costs from £200 upwards. Installation can be done on a DIY basis, but may involve altering the rafters, as well as lifting and re-laying roofing, so most homeowners choose to use an installer at a cost of £500 to £750 (plus VAT), including scaffolding. A conservation sunpipe will be suitable for homes in Conservation Areas, and will cost upwards of £700.

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