Double-walled plastic skylights are unsuitable for heated spaces and provide little to no insulation. These cannot be compared to double glazing! Only use them for unheated spaces such as carports, garages or factory halls. Triple-walled skylights are suitable for hallways and storage rooms, but not for living areas such as living rooms, kitchens or bathrooms. Choose four- or five-walled skylights in heated homes. A four-walled skylight meets the Belgian EPB standards. With a five-walled skyligh, you can request insulation premiums . Combine the skylight with a well-insulating curb.

Type	Product	EPB compliant	Suited for passive houses	Insulation premium	Suited for which space
Flat roof window (glass)	iWindow2	✓		✓	Heated spaces
Flat roof window (glass)	iWindow3	✓	✓	✓	Heated spaces, passive houses
Hybrid	iDome	✓		✓ (with 5-walled skylight dome)	Heated spaces
Plastic skylight	Single- and double-walled				Unheated spaces (carports, garages, factory halls)
Plastic skylight	Triple-walled				Corridors, storage rooms (not living areas)
Plastic skylight	Four-walled	✓			Heated spaces
Plastic skylight	Five-walled	✓		✓	Heated spaces