Energy Saving

As the world faces the global warming crisis due to climate changes over the decades, one should think about possible way to reduce energy consumption as a global citizen. VEKA being a global company in window technology building in its uPVC window systems for over 50 years (since 1969), ours windows design and systems evolve and had achieved the energy saving concept used on uPVC window applications in this current modern world and its different regions of window culture for every window possible.

R&D Milestones


One chamber
without reinforcement
basic width 50mm


Two chambers
with reinforcement
basic width 50mm


Three chambers
with reinforcement
basic width 60mm


Multi chamber
with reinforcement
basic width 70mm

Product Types

Design Characteristic:

  • Basic width 58mm
  • Three-chamber system
  • Uf-value= 1,7 W/m²K

Design Characteristic:

  • Basic width 70mm
  • Five-chamber system
  • Uf-value= 1,3 W/m²K

Design Characteristic:

  • Basic width 82mm
  • Five-chamber system
  • Uf-value= 1,0 W/m²K

Maximum U Values for Building components

DescriptionEnEV old (2007)
EnEV new (2020)
Windows and DoorsUw ≤ 1,7Uw ≤ 1,30
GlazingUg ≤ 1,5Ug ≤ 1,10
Windows, French doors, skylights with special glazingUw ≤ 2,0Uw ≤ 2,00
Special glazing (e.g. for surrounding glazing)Ug ≤ 1,6Ug ≤ 1,60
Exterior doorsUd ≤ 2,9Ud ≤ 1,8

Asia Window Material

Asia windows are dominated in using aluminium windows as the basic windows consideration in terms availability of its design and its cost factors. However, it lacks the consideration on issues that aluminium has in nature to the product characteristics which is thermal conductivity. As can be seen on the chart below, it shows that aluminium materials has more than 100 times the thermal conductivity than uPVC, which means it could be heated up easily in a short period of time, causing energy lose in cooling a office or home during a sunny day. Before the comfort temperature is reach in the rooms, the aluminium frames started to get cold or at times still hot in the mid-day sun, thus loosing more energy in cooling down the room via the air-conditions units.

Thermal Conductivity U-Value in Accordance to DIN 4108

Aluminium (1,428.0)
Steel (414.0)
Glass (5.8)
uPVC (1.2)
Wood (1.0)

NOTE: Aluminium has the highest thermal conductivity


The other key component in a window is the glass used, Asia windows are still using single glazed glass which also contribute to the energy lose in a window. Comparing a single glaze glass and normal double glazed glass, energy lose is two times of a double glazing glass (without consideration of special glass of any kind).

Energy Loss with Glass


Single Glazing


Insulated Double Glazing


Specially Coated Glazing

Cost Saving

Calculation of energy usage

Total window area (3,000×2,200mm)6.6 sqm
Glass area5.4 sqm
Frame area1.2 sqm
U-value single glazing5.8 W / sqm×K
U-value double glazing3.0 W / sqm×K
Difference (Glazing):5.8 – 3.0  = 2.8 W / sqm×K
U-value aluminum profile7.5 W / sqm×K
U-value uPVC profile1.7 W / sqm×K
Difference (profile):7.5 – 1.7  = 5.8 W / sqm×K

Temperature difference between inside and outside = 20°K

Average Air-conditioner running time  apartments = 10 hours/ day

Energy savings for double-glazed uPVC window compared to single-glazed Aluminum window:

( 2.8 W × 5.4 sqm + 5.8 W × 1.2 sqm ) × 20°K × 10 hours = 4.416 KW / day

Therefore Energy savings (uPVC profiles):

( 5.8 W × 1.2 sqm ) × 20°K × 10 hours = 1.392 KW / day

Energy savings per day per window (as per example shown)4.416 KW / day / window
An average apartment has approx. 5 such windows5×4.416
Total possible energy saved per day in this apartment22.08 KW / day
Current approx. electricity cost in SingaporeUSD 0.171 / KWh
Total approx. energy cost saved per day in this apartment based on the window shown
22.08 KW × 0.171 USD

USD 3.7756

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