How to choose a dome rooflight
In this guide — jump to a section
1. What should the rooflight do?
Distinguish four functions: daylight, day-to-day ventilation, roof access, and natural smoke and heat exhaust ventilation. A fixed dome provides light; an opening version needs a mechanism suited to its intended use. A normal ventilation opening is not, by itself, a smoke vent.
2. What is the room below used for?
Tell us whether the space is heated, how it is used, and whether summer heat or glare is a concern. The number of layers affects thermal performance and daylight transmission. Compare both properties together, not just one figure.
3. Acrylic, polycarbonate or TOPtermo?
- Acrylic: catalogue options in clear or opal finishes, with one to four layers.
- Polycarbonate: an option where greater impact resistance than acrylic is important. This does not mean it is indestructible in every storm.
- TOPtermo: a build-up with an intermediate 10 or 16 mm multiwall polycarbonate sheet for improved thermal performance.
4. Compare the specific build-up
The catalogue lists Ug = 1.9 W/m²K for a standard three-layer dome and 1.5 W/m²K for a four-layer dome. Listed TOPtermo values range from 1.4 to 1.0 W/m²K. Do not treat these figures as the thermal performance of the complete installed assembly, including the upstand and roof junction.
5. Confirm dimensions and opening
Nominal size, structural opening and clear opening are not the same. For replacement, also provide screw-centre dimensions and photographs of the existing upstand. Choose the opening mechanism according to accessibility, power supply and purpose. Ventilation can also be complemented with a wind and rain sensor.
Next step
For an initial quotation, send the building location, number of domes, labelled measurements, photographs and intended function. Mention any information you do not yet have; manufacturing dimensions are confirmed before ordering.
Dome configurations and technical tables · Send details for a quotation
Technical source: POS plastika catalogue “Svetlobne kupole in trakovi”, 2026 edition. The figures describe the specified catalogue configurations; confirm the exact build-up, dimensions and documentation before ordering.