G7/AS1 and G7/AS2 Natural Light

Each habitable room checked against both of G7's Acceptable Solutions: G7/AS1's glazing, glass and window head for houses up to three storeys, and G7/AS2's deepest room for apartments and any other housing.

G7/AS12nd Edition29 Nov 2021
G7/AS21st Edition29 Nov 2021

Tools

Rooms Terminology Resources

The building

G7/AS1 is written for smaller buildings than G7/AS2. Say which this is, and each room is worked by every document that covers it.

Housing, an old people's home or an early childhood centre of up to 3 storeys, detached or side by side

Habitable rooms

One card a habitable room: a bedroom, a living or dining room, a study. Bathrooms, laundries, toilets, hallways and walk-in wardrobes are not habitable spaces and need no natural light under G7.

Remove Living?

Its figures go with it.

The room

Floor aream²Depth from the window wallmFrom the inside face of the wall with the windows to the far wall.Floor to ceilingm

The windows

Glazing on the window wallm²The glass alone, frames and mullions left out.Area of that wallm²The external wall holding the windows, windows included.Visible light transmittance%

Window head above the floormTransparent glazing in the bandm²Clear glass between 900 mm and 2000 mm (2 m) above the floor.

Other windows

NoneOn an adjacent wallOn the opposite wall

Outside

An overhang over the windowsBuildings or trees opposite

G7/AS1's own questions

Part of the floor is beyond the no-sky lineMore than 50% of the glazing is blocked by something permanent within 1 mThe windows face a porch or covered walkway, or are under a balcony

Key figures

Least glazing: 2m²; G7/AS1 2.1.2.1 a)
Least head height: 2000mm; G7/AS1 2.1.2.1 c)
Deepest room: 6m; G7/AS2 Table 2.1.4.1

Shown by

G7/AS1
Met: this room's natural light is shown by this document.
G7/AS1
G7/AS2
Met: this room's natural light is shown by this document.
G7/AS2

G7/AS1

Area of glazing
3.6 m² of glazing, against the 2 m² that 10% of the floor area asks.
G7/AS1 2.1.2.1 a)
Light through the glass
A transmittance of 72%, at least the 70% asked.
G7/AS1 2.1.2.1 b)
Window head height
A head at 2100 mm (2.1 m), at least the 2000 mm (2 m) asked: the room's width ÷ 2, windows on one side or adjacent sides.
G7/AS1 2.1.2.1 c) i)
Surface reflectance
Medium reflectance at least: ceiling 0.7, walls 0.4, floor 0.2.
G7/AS1 2.1.2.3, Table 2.1.2.4

G7/AS2

Read at
A ratio of 30%, read at 30%; a transmittance of 72%, read at 70%; an overhang angle of 0°, read at 0°; an exterior obstruction angle of 0°, minor obstruction.
G7/AS2 2.1.3.2, 2.1.3.4, 2.1.3.5, 2.1.3.7
Room depth
4 m deep, within the table's 6 m.
G7/AS2 2.1.4.1, Table 2.1.4.1

Awareness of the outside

Transparent glazing
3 m² of transparent glazing between 900 mm and 2000 mm (2 m), at least the 1.8 m² that 50% of the glazing asks.
G7/AS1 3.1.2.1, G7/AS2 3.1.2.1

Remove Bedroom?

Its figures go with it.

The room

Floor aream²Depth from the window wallmFrom the inside face of the wall with the windows to the far wall.Floor to ceilingm

The windows

Glazing on the window wallm²The glass alone, frames and mullions left out.Area of that wallm²The external wall holding the windows, windows included.Visible light transmittance%

Window head above the floormTransparent glazing in the bandm²Clear glass between 900 mm and 2000 mm (2 m) above the floor.

Other windows

NoneOn an adjacent wallOn the opposite wall

Outside

An overhang over the windowsBuildings or trees opposite

G7/AS1's own questions

Part of the floor is beyond the no-sky lineMore than 50% of the glazing is blocked by something permanent within 1 mThe windows face a porch or covered walkway, or are under a balcony

Key figures

Least glazing: 1.2m²; G7/AS1 2.1.2.1 a)
Least head height: 1750mm; G7/AS1 2.1.2.1 c)
Deepest room: 5.2m; G7/AS2 Table 2.1.4.1

Shown by

G7/AS1
Met: this room's natural light is shown by this document.
G7/AS1
G7/AS2
Met: this room's natural light is shown by this document.
G7/AS2

G7/AS1

Area of glazing
1.8 m² of glazing, against the 1.2 m² that 10% of the floor area asks.
G7/AS1 2.1.2.1 a)
Light through the glass
A transmittance of 72%, at least the 70% asked.
G7/AS1 2.1.2.1 b)
Window head height
A head at 2100 mm (2.1 m), at least the 1750 mm (1.75 m) asked: the room's width ÷ 2, windows on one side or adjacent sides.
G7/AS1 2.1.2.1 c) i)
Surface reflectance
Medium reflectance at least: ceiling 0.7, walls 0.4, floor 0.2.
G7/AS1 2.1.2.3, Table 2.1.2.4

G7/AS2

Read at
A ratio of 22%, read at 20%; a transmittance of 72%, read at 70%; an overhang angle of 0°, read at 0°; an exterior obstruction angle of 0°, minor obstruction.
G7/AS2 2.1.3.2, 2.1.3.4, 2.1.3.5, 2.1.3.7
Room depth
3.5 m deep, within the table's 5.2 m.
G7/AS2 2.1.4.1, Table 2.1.4.1

Awareness of the outside

Transparent glazing
1.5 m² of transparent glazing between 900 mm and 2000 mm (2 m), at least the 0.9 m² that 50% of the glazing asks.
G7/AS1 3.1.2.1, G7/AS2 3.1.2.1

Reset the rooms?

The rooms go back to the two the page started with. The answers on Requirements and the ticks on Show on drawings are kept.

Terminology

The words the requirements lean on, as G7/AS1 and G7/AS2 define them.

Average exterior obstruction angle (AEOA)G7/AS2 Appendix B: The average angle from the horizon up to where the visible sky begins, measured at the floor level of the space being assessed.
External wallAppendix B: Any vertical outside face of a building, of primary or secondary elements, there to protect against the weather.
Glazing-to-wall ratio (GWR)Appendix B: The glazing, framing and mullions left out, as a percentage of the area of the external wall that holds the window.
Habitable space1.2.2.1, Appendix B: A space used for ordinary domestic living. Not a bathroom, laundry, toilet, pantry, walk-in wardrobe, corridor, hallway, lobby, drying room, or any other specialised space used neither often nor for long.
IlluminanceAppendix B: The light falling on a unit area of a surface, in lumens per square metre.
Overhang obstruction angle (OOA)G7/AS2 Appendix B: The average angle, measured from the zenith at the inside face of the external wall, to the furthest edge of whatever overhangs and blocks the sky.
ReflectanceAppendix B: The light a surface reflects as a share of the light falling on it.
Standard yearAppendix B: For natural lighting, the hours from 8 am to 5 pm each day, allowing for daylight saving.
Visible light transmittance (VLT)Appendix B: The light that passes through glazing or another translucent surface, as a percentage of the light falling on it. The higher it is, the more light gets through.

Resources

Where the rest of it is.

G7 Natural Light: the Acceptable Solutions, and G7/VM1, the daylight simulation for rooms neither covers.

building.govt.nz

The same rooms' openable area, worked room by room.

G4/AS1 Ventilation

Glazing a room needs for light is glazing the building's heat loss has to carry.

H1/AS1 Energy Efficiency

The building's facts, read by every clause.

The project

Educational. Confirm with your building consent authority and the current documents. G7/AS1 1.1.1.1, 1.1.2.1, 2.1.1.1, 2.1.2.1 and 3.1.2.1: values stated in the paragraphs listed. G7/AS2 2.1.1.1, 2.1.2.1, 2.1.3.7 and 3.1.2.1: values stated in the paragraphs listed.

building.govt.nz