Kromme Nieuwe Gracht, Utrecht: lighting a listed canal house

A canal house in the old city centre

The Kromme Nieuwe Gracht runs through the eastern part of Utrecht's historic centre, a conservation area of quays, wharves and centuries-old facades. On this canal stands a listed building whose entrance and quay were lit for years by a lantern with a conventional light source: high consumption, uneven light and a lamp that needed replacing regularly.

The brief was clear. The light point had to remain part of the historic streetscape, but with today's technology: less energy, less maintenance and a light distribution that illuminates facade and quay evenly without disturbing the residents across the water.

Classic form, modern LED

The choice fell on a luminaire with a classic lantern silhouette housing a modern LED module. From the outside the difference from the old lantern is barely visible; inside everything has changed: a sealed LED module, a driver and a gasketed housing.

In the Lichtplein range, the classic post-top luminaire from POLARIS matches this approach: 40 W, 4,000 lm, 140 lm/W, IP66, 120° light distribution and mounting on an 80 mm column top, with a 5 year warranty. The modern POLARIS is available with adjustable output from 30 to 60 W and a colour temperature of 2200, 3000 or 4000 K.

Light level and colour in heritage settings

Pedestrian areas and residential streets in a historic centre usually fall under the P classes of EN 13201: P3 or P4, which means 7.5 or 5 lux on average. More light is rarely better here. A lantern at a 4 metre mounting height with 4,000 lm generally covers that class, provided the columns are spaced no more than 3 to 4 times the mounting height apart, so 12 to 16 metres. A lighting calculation gives certainty on this.

With brick and natural stone, choose warm white, 2200 to 3000 K. It keeps the facade looking natural and produces less spill light into bedroom windows than cool white. A flat cover over the LED module prevents glare and upward light.

Permits and consultation

For a listed building or a conservation area, a new light point on the facade often requires a permit from the municipality. A free-standing column on the quay is often easier to agree than a wall bracket. Present the proposal early to the municipality's heritage department and bring a photo impression and a colour proposal.

A 4 metre steel column from TURRIS, powder coated in RAL 9005, is the least conspicuous choice in a historic street. The column connection box from NEXUS fits in the door hatch and keeps the fuse accessible.

How to approach a similar project

• Photograph the existing situation and measure the top diameter of the existing column.
• Measure the current light level in lux, so you know what you are improving.
• Have a lighting calculation made for the correct P class.
• Fit one trial luminaire on the column before ordering for the whole street.
• Allow 3 to 6 weeks lead time for columns; luminaires ship within 5 working days.

Frequently asked questions