Dome roof light vs roof lantern

Dome roof lights and roof lanterns both rise above a flat roof, but they answer different briefs. A dome is usually a moulded plastic skylight — practical and inexpensive. A roof lantern is a framed glazed structure — architectural, insulated and specified for living spaces. Confusing the two leads to mismatched expectations on appearance, thermal performance and cost.

Dome roof lights

A dome roof light is a raised moulded unit, most often polycarbonate, set onto a kerb or upstand. Single-skin and double-skin versions exist; the double-skin adds an air cavity for modest insulation.

Domes are lightweight, impact-resistant and common on commercial flat roofs, corridors and budget domestic refurbishments. The curved form sheds water and is self-supporting without a complex frame.

Roof lanterns

A roof lantern is a raised glazed assembly with a timber or aluminium frame supporting insulated glass panes on pitched faces. Traditional lanterns are hipped or pyramidal; contemporary designs may use slim aluminium sections with large glass facets.

Lanterns are specified for orangeries, period-style extensions and projects where the roof glazing is a deliberate architectural feature visible inside and out.

Form and appearance

• Dome — smooth curved plastic bubble; utilitarian externally; can yellow over time.
• Lantern — framed glass facets forming a recognisable roof feature; crisp lines; maintains clarity.
• Internal effect — dome: small raised plastic aperture; lantern: glazed well with visible frame members creating a room centrepiece.
• Scale — domes are typically modest in diameter; lanterns can span large extension widths.

Material and performance

• Glazing — dome: polycarbonate plastic; lantern: sealed insulated glass units with safety panes.
• Thermal performance — dome: poor to modest; lantern: comparable to good flat glass roof lights when correctly specified.
• Durability — dome: UV degradation and surface crazing over years; lantern: glass clarity maintained for decades.
• Rain noise — dome: thin plastic transmits impact sound; lantern: laminated glass dampens rain noise better.

Cost and specification level

• Dome — lowest upfront cost; suited to utility and commercial applications.
• Lantern — premium product; higher cost for framing, multiple glass panes and installation.
• Flat glass alternative — a flush frameless or framed roof light often delivers more daylight area per pound than a small dome or modest lantern, with a cleaner internal ceiling.

When to choose each

• Dome — unheated plant rooms, commercial back-of-house areas, temporary or budget refurbishments where building control accepts non-thermal plastic glazing.
• Lantern — orangeries, period extensions, design statements where a raised glazed feature is part of the architecture.
• Flat glass roof light — contemporary extensions prioritising ceiling height and maximum daylight without a raised structure. Non-standard lantern sizes or shapes may need a bespoke roof light enquiry.

Summary

Domes and lanterns are both raised roof glazing, but they occupy different specification tiers. Domes are plastic, economical and utilitarian. Lanterns are glass, architectural and suited to living spaces. For habitable extensions, choose a glass lantern or — for a lower profile and often better value — a flat insulated glass roof light instead of a polycarbonate dome.

Every Vant Glass roof light is made to order in Britain, backed by a 20-year guarantee and free UK mainland delivery. Configure frameless or framed sizes in the online calculators or call 03330 902 592.