Option 1: Curtains That Hang to the Top of the Sill

This is the shortest and neatest option. The curtains hang down to the top of the window sill and usually sit closer to the window.

With this setup, the curtain track is normally fitted within the bay, closer to the glass. Depending on the bay, it may be ceiling fixed, wall fixed, or sometimes frame fixed.

This can work well when you have a deeper sill, furniture below the bay, or a radiator that you do not want to cover.

It is also a good choice if you want the curtains to feel more understated rather than making the bay window the main feature of the room.

Option 2: Curtains That Hang Just Below the Sill

This is one of the most common setups in UK bay windows.

Instead of the curtains stopping on top of the sill, they hang in front of the sill and drop just a few centimetres below it.

This gives a softer, more finished look than curtains stopping at sill level, but still keeps the curtains short enough to avoid covering too much of a radiator below the window.

In this situation, the curtain track usually sits just in front of the sill rather than close to the window. In most cases, this means the track is ceiling fixed.

This option can be a very good middle ground if you want the curtains to look more generous without going all the way down to the floor.

Option 3: Floor-Length Curtains

Floor-length curtains usually give the biggest design impact. They can make a bay window feel softer, taller, and more of a feature in the room.

With floor-length curtains, the track normally sits in front of the sill rather than close to the window. This allows the curtains to hang down freely without catching on the sill.

This setup often works especially well when the curtain track returns out of the bay and onto the side walls. It gives the curtains more room to stack when open and helps frame the bay nicely.

Floor-length curtains are usually the best-looking option if the room allows for them, but they are not always the most practical choice if there is a radiator directly under the bay window.

What About Radiators and Heat Loss?

One of the most common concerns with bay window curtains is heat loss.

Many UK bay windows have a radiator below the window. If the curtains hang over the radiator, some of the heat can be trapped behind the fabric instead of flowing freely into the room.

This is why shorter curtains are often chosen for bay windows with radiators.

Curtains that stop at the top of the sill will usually leave the radiator fully clear. Curtains that hang just below the sill can also work well if they stop just above the radiator.

Floor-length curtains can still be used, but you need to be comfortable with the fact that they may cover the radiator when closed.

When the Radiator Has Been Moved

Increasingly, radiators are being moved away from underneath bay windows and placed elsewhere in the room.

This can make floor-length bay window curtains much easier, because the curtains no longer need to hang over the radiator below the window.

However, it can sometimes create a new issue if the radiator has been moved onto one of the return walls outside the bay.

If this happens, you may need to think carefully about how far the curtain track returns onto the side wall. You do not want the curtains stacking directly over the radiator when they are open.

So even when the radiator is no longer under the bay window, it can still affect the best curtain track layout.

How the Window Sill Affects Curtain Length

The window sill is often the detail that decides where the curtain track should sit.

If the curtains are hanging to the top of the sill, the track can usually sit closer to the window.

If the curtains are hanging in front of the sill, either just below it or all the way to the floor, the track normally needs to sit in front of the sill.

This is especially common with deeper bay window sills, where fitting the track too close to the window would cause the curtains to catch or push forward against the sill.

Which Option Looks Best?

There is no single best option for every bay window.

Curtains to the top of the sill look neat, simple, and practical. They are often best when you want the curtains to sit quietly within the bay.

Curtains just below the sill give a slightly softer look while still being practical for radiators and everyday use.

Floor-length curtains give the most generous and decorative finish. They usually make the bay window more of a feature, especially when the curtains return out of the bay.

Still Not Sure Which Curtain Length Is Best?

If you are unsure, start by looking at your sill depth, radiator position, and whether you want the curtains to stay inside the bay or return out onto the side walls.

Once you know those things, the best curtain length usually becomes much clearer.

Frequently asked questions