/, Contextual, Cooling, Envelope, Heating, Long term, Owners, Physical environmental, Psychological, Social/2.1.14 Installation of efficient windows (low-E double glazing with PVC frames)

2.1.14 Installation of efficient windows (low-E double glazing with PVC frames)

2.1.14 Installation of efficient windows (low-E double glazing with PVC frames)


This measure consists in the replacement of inefficient windows (e.g. aluminium frame without thermal brake and single glazing) for an efficient one with Low-E double glazing and PVC frames. Low emissivity glasses are equipped with an invisible metallic coating that reflects inward part of the incident long-wave energy (heating), decreasing the absorption of the own glass and, therefore, the energy that emits to the outside. A typical transmittance of this type of windows is U=1.3  W/m2K


  • Airtightness improved

  • Energy costs reduced

  • It allows a perfect soundproofing and it reduces noise pollution

  • It does not need any special treatment for its conservation, just wash it with soap and water without risk of rot or damage to the material

  • There is a wide range of colors, although white is the most widely used color, there are imitation wood, without a too high price

  • Improve solar and thermal control

  • Reduce summer heat gain and winter heat loss

  • Decrease UV transmission such as furniture fading

  • Reduce condensation in double glazing


  • Double glazing cannot be repaired

  • During the summer months, trapping heat inside glass panes can lead to a stale and uncomfortable room

  • PVC frame is more expensive than the rest

  • PVC with high temperatures can be deformed

  • PVC is a polluting material

  • Valuable solar heat gain in colder climates can be reduced

Economic assessment

Energy costs are reduced.

Table 4. Cost savings of PVC frames. Source: Elaborated by CIRCE.

Type of frame

Total cost (10 m2 of windows and 6 months) % saving

Aluminium without thermal break

1.27 €/day



1.07 €/day



References and best practices

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Environment or playable world:

  • Residential

  • Academic

  • Offices

  • All

Carried out by:

  • Public building users

  • Owners

  • Operators

  • All

Reduce consumption of:

  • Heating

  • Cooling

  • DHW

  • Lighting

  • Electric devices

Type of driver:

  • Physical environmental

  • Contextual

  • Psychological

  • Physiological

  • Social

Time framework:

  • Short term
  • Long term

Type of measure:

  • Envelope
  • HVAC
  • DHW
  • Lighting
  • Electrical devices
  • Other
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