Envelope Typical Values (Metric)

Glazing U-Factor (W/m2-k)

Description Lower Upper

Single Glazing

- including frame
and sash

3.7 6
Standard Double Glazing -
including frame and sash
3 3.7

Performance Double Glazing
(low-e)

- including frame and sash

2.1 3

Triple Glazing

- including frame
and sash

1 2.1

Triple Glazing (argon filled cavity)

- including frame and sash

0 1

 

Glazing SHGC

Description Lower Upper
Clear Single Glazing 0.7 1
Clear Double Glazing 0.4 0.7
Reflective Coated Glazing 0.2 0.4
Glazing with Internal Blinds 0 0.2

 

Surface Reflectance

Description Lower Upper

Mirror Finish

- highly reflective

0.9 1

Light coloured walls

- reflective

0.6 0.9
Medium coloured walls 0.4 0.6

Dark coloured walls

- low
reflectivity

0.1 0.4

Black

- very low reflectivity

0 0.1

 

Leakage (m3/m2-h)

Description Lower Upper
Leaky building 10 and above
Normal practice 5 10
Best practice 1 5
Extremely tight building 0 1

 

 

Roof Thermal Resistance U-value (W/m2-k)

Description Lower Upper

Uninsulated and single skin roofs

1.2 5

Poorly insulated

(approx. 50mm/2in insulation)

0.6 1.2

Insulated

(approx. 100mm/4in insulation)

0.25 0.6

Well insulated

(approx. 150mm/6in insulation)

 0.15  0.25

Extremely well insulated

0 0.15

 

Floor Thermal Resistance U-value (W/m2-k)

Description Lower Upper

Uninsulated and single skin roofs

4 5

Poorly insulated

(approx. 50mm/2in insulation)

1.4 4

Insulated

(approx. 100mm/4in insulation)

0.25 1.4

Well insulated

(approx. 150mm/6in insulation)

 0.15  0.25

Extremely well insulated

0 0.15

 

Walls Thermal Resistance U-value (W/m2-k)

Description Lower Upper

Uninsulated and single skin roofs

1.2 5

Poorly insulated

(approx. 50mm/2in insulation)

0.5 1.2

Insulated

(approx. 100mm/4in insulation)

0.35 0.5

Well insulated

(approx. 150mm/6in insulation)

 0.15 0.35

Extremely well insulated

0 0.15

 

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