Heat and sound insulation in frames and panes has several benefits for your home:

• better temperature regulation, and better insulation against outside noise;
• energy savings, which are good both for your wallet and for the environment.

If your frames and/or panes do not provide sufficient insulation, replacing them could prove a sound investment. However, you can't just wing it with this kind of work.

Do I need to replace the windows in my home?

If your windows are not efficient enough, they let heat escape from your house.

There are 2 key elements:

• the panes: they let 4 to 5 times more heat escape than a brick wall. To limit heat loss, highly insulating double glazing is recommended, which should not be confused with the old style of double glazing (dating from before 2000), which is much less efficient.
• the frames: if they are poorly insulated or do not close properly, frames can cause drafts, let rainwater in or lead to heat loss through radiation. To be efficient, they must have thermal insulation and air-tight seals. They must close properly too.

If your frames are in a good condition, but your panes leave much to be desired, you may be able to replace only the panes. The frame will just need to be adapted, which is much cheaper!

However, if you have older frames with antique value, it may be possible to place a second glazed frame inside, or double glazing over the top.

Do you need some help choosing your new panes and frames? Let's have a look at all the different options available and criteria to consider.

How much can I hope to save?

In an urban area, windows make up around 5% of the surface area of outside walls. In Brussels, if you have a new frame with double glazing installed, you can hope to save around 220 kWh per m2 per year.

In concrete terms, if you have gas-powered heating (around €0.06/kWh), this amounts to around €13.3/m2 per year. The return on your investment is therefore around 22 years.

You can also get grants for this work.

If you want to replace your windows in spring, it's best to think about it in autumn!

If you decide to replace your frames, it may be around 2 months before they can be fitted. They are always made to measure.

You would probably prefer to book this work in for the better weather, so why not think about it several months in advance and contact a few companies so they can take the necessary measurements and provide a quote? Then you can compare the different quotes and place an order.

Replacing your windows or insulating your loft: where to start?

It is always better to insulate your loft first before moving onto the windows. The former is cheaper and provides greater benefits more quickly.

Once that is sorted, you can get started on your frames and panes! For more information, see the section What you need to know about insulation.