How does double glazing reduce heat gain?
David Craig
Updated on April 06, 2026
How does double glazing reduce heat gain?
Hence, the thin layer of air of double glazed windows acts as a heat insulator. In other words, making an extremely thin gap for air to prevent it from circulating properly results in lower heat conduction. So, it reduces the overall heat loss.
Why is double glazing a good insulator?
Double glazing is effective because whilst glass is a good conductor of heat, air is not. The air pocket between the two panes of glass, therefore, creates a seal against the outdoors. This reduces the transfer of heat.
What is the R value of double glazing?
0.43
So an aluminium single-glazed window has an R-value of 0.15 while an insulated wall’s R-value is 1.99 – more than 10 times greater. Well-fitting heavy or thermal drapes will add an R-value of 0.26 to a window….R-values.
| GLAZING TYPE | DESCRIPTION | R-VALUE |
|---|---|---|
| Double | Low-e glass (argon-filled IGU) | 0.43 |
What is the U value of double glazed windows?
What is the minimum U-Value and Window Energy Rating for Windows?
| Property Material | Insulation | Approximate U-Value |
|---|---|---|
| Old Double Glazed windows with air space between glass. | None | 2.8-3.0 |
| Current double glazed units, argon gas, low-E coating. | 1.2-1.2 | |
| Latest triple glazed units, argon gas, low-E coating. | 0.9-1.0 |
How do you not lose heat through windows?
Don’t Lose Heat through Your Windows
- Hang insulating drapes. Heavy drapes can help you prevent heat loss through single-glazed windows.
- Look for cracks. If your windows seem drafty, look around the edge of the window for small cracks that could be letting cold air in.
- Insulate your windows.
- Fake your own double-glazing.
How do I stop my window from going into heat?
Tips & Tricks
- Curtains. One of the cheapest, most effective ways to prevent your home from losing heat is to cover the openings with curtains.
- Sunlight. Remember that big yellow disk in the sky that kept you sweating all summer?
- Close Off Unused Rooms.
- Set timers.
- Replace drafty windows.
- Invest in double glazing.
How does double glazing reduce heat loss through windows?
Heat loss through windows can be reduced by using double glazing. These special windows have air or a vacuum between two panes of glass. If the double glazing has a vacuum there will be no conduction or convection. If the double glazing is made with air between the glass then convection is minimised because there is little room for the air to move.
Why is there no convection in double glazing?
If the double glazing has a vacuum there will be no conduction or convection. If the double glazing is made with air between the glass then convection is minimised because there is little room for the air to move. Air is a poor conductor so there will be very little heat loss by conduction.
What does it mean to double glaze a window?
Double glazing involves putting an extra layer of glass in front of a window pane. This can be either installing a sealed glass unit or adding an extra pane that has not been sealed in a factory (secondary glazing). The two layers of glass have a small air gap between them.
What does the air gap in a double glazing do?
The trapped air in the gap is an insulator – it does not stop heat being conducted from the inner pane to the outer pane – but it does slow heat transfer by conduction down a lot! The air gap is too narrow to allow the air to circulate easily.
Heat loss through windows can be reduced by using double glazing. These special windows have air or a vacuum between two panes of glass. If the double glazing has a vacuum there will be no conduction or convection. If the double glazing is made with air between the glass then convection is minimised because there is little room for the air to move.
Can a double glazed window have condensation in it?
Your double glazed windows should not have any condensation on the glass surfaces that face inwards – the two surfaces that come into contact with the air space in between the two panes of glass of the insulated glass unit, or IGU. If you notice any moisture here, you have a problem with your double glazing. Will double glazing stop condensation?
If the double glazing has a vacuum there will be no conduction or convection. If the double glazing is made with air between the glass then convection is minimised because there is little room for the air to move. Air is a poor conductor so there will be very little heat loss by conduction.
Which is better double glazing or single glass?
Depends on the climate, and it depends on what you are comparing it to. In a cold climate double glazing will let heat out of the house. In a hot climate double glazing will let heat into the house. Double glazing is better insulated than single glazing, so it will reduce heat transfer better than single glazing.
