Choose a roof lantern when you want extra height and light from every angle in a single-storey room; choose a flat rooflight when you want a cleaner, lower roofline, a simpler install and a lower price. Both bring in far more light than a wall window of the same size.
How do they differ?
A flat rooflight is a single glazed unit lying close to the roof surface on an upstand. A roof lantern is a raised, hipped glass structure with glazing on every face, meeting at a ridge. The lantern sits higher, catches low sun from the sides, and makes the ceiling feel taller.
Which lets in more light?
For the same footprint, a lantern usually gathers more light across the day because its sloped sides face the sky at several angles. A flat rooflight delivers strong overhead light, especially around midday, and is often specified larger for the same budget.
Which looks better from outside?
Flat rooflights almost disappear from ground level, which suits modern extensions and sensitive locations. Lanterns are a visible architectural feature — attractive on orangeries, less so where neighbours or planners want a quiet roofline.
Which costs less?
A flat rooflight of the same footprint usually costs less to buy and fit. Lanterns need a stronger kerb and more glass, and larger ones may need a ring beam.
What about overheating?
Both can overheat on a south-facing roof with clear glass. Solar-control glass, an opening vent or unit, and a blind under a flat rooflight solve most problems.
Quick comparison
- Height and drama: lantern
- Low-profile roofline: flat rooflight
- Cost per square metre of glass: flat rooflight
- Light across the whole day: lantern
- Simplest install into an existing roof: flat rooflight
- Walk-on option: flat rooflight only
This guide gives general information, not legal or structural advice. Rules change and every property is different — check with your council or building control for your address. We review our guides regularly; the date above shows the last review.
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