The importance of considering the total window/glass combination
description
Transcript of The importance of considering the total window/glass combination
The importance of considering the total window/glass combination
Glass Terminology
SOLAR CONTROL
• SHGCSolar Heat Gain Coefficient
– How well a product blocks heat caused by the sun.– Expressed as a % of solar heat gain transmitted.
• SCShading coefficient
Similar to SHGC, not commonly used.
THERMAL INSULATION• U value
– The rate of heat loss– Smaller the number the better
VISIBLE LIGHT• VT
– Expressed as a % of visible light transmitted.
DOUBLE GLAZING• IGU
– Insulating glass unit. – The hermetically sealed glazing unit, normally comprising
of 2 sheets of glass and a spacer bar.
3mm Clear Glass
• Standard 3mm glass• Basis of all other glass
calculations and comparisons.
U value = 4.53
SHGC = 0.8787% of solar heat gain transmitted
SC = 1
3mm Bronze Glass (Toned)
• Traditional toned glassU value = 4.81
SHGC = 0.73
73% of solar heat gain transmitted
VT = 0.63
63% of visible light transmitted
5mm Spectrally Selective Glass (SST)
• Spectrally selective toned glass
• Lower solar heat gain
• High light transmission
U value = 4.8
SHGC = 0.66
66% of solar heat gain transmitted
VT = 0.63
63% of visible light transmitted
SC = .57
3/12/3 Clear Double Glazing (D3123)
• Cuts heat loss in ½ due to the insulating air space between the glass layers.
• Allows transmission of high % of visible light and high solar heat gain.
U value 2.43
VT = 0.81
81% of visible light transmitted
SHGC = .77
77% of solar heat gain transmitted
SC = .891
Low E Low Transmittance (DGET)
• Best used on position 2 of a IGU
• Spectrally selective
• Use to reject heat
• Not generally available, additional cost involved.
U value 2.2
SHGC = 0.39
39% of solar heat gain transmitted
SC = .45
VT = 0.70
70% of visible light transmitted
Low E Argon Filled (DLEA)
• Best used with Low e on position 2 of a IGU
• Spectrally selective
• Use to reject heat
• Not generally available, additional cost involved.
U value 1.5
SHGC = 0.39
39% of solar heat gain transmitted
SC = .45
VT = 0.80
80% of visible light transmitted
Low E ( High Transmittance)
• Used on position 3 of a IGU
• Enhances the insulating value of a IGU
• Ideal for a heating environment to retain internal heat.
U value 1.92
SHGC = 0.71
71% of solar heat gain transmitted
SC = .82
VT = 0.75
75% of visible light transmitted
Window Terminology
• Window frame
Generic Aluminium (ALSTD)
Aluminium Improved (ALIMP)
Thermally Broken (ALBRK)
Timber (TIM)
PVC
Steel
Generic aluminium windows
• Readily conducts heat.• Increases the overall U
factor of the window.• In cold climates
condensation can form on the inside surfaces.
Thermally Broken
• Thermally broken by splitting the frame into interior and exterior pieces.
• Frame U value = 3.8 compared to Generic Aluminium window of U = 12.7
Aluminium Improved Frame
• Slender frame, reducing the overall frame area.
• Built into a timber reveal breaking the heat loss path from inside to outside
Timber Windows
• Energy efficient frame
• Requires good sealing system to minimise air leakage
• Maintenance
• A&L Windows• Canterbury Windows• Efficient Windows Collaborative• Pilkington• SEAV
AGGA would like to thank the following:
For further information on energy efficient glass contact
AGGA on 03 9853 3464
03 9853 3464