How Do Curtains Reduce Heat Loss

Why Windows Are a Major Source of Heat Loss

Heat loss through glass

Glass is a poor insulator. Heat naturally moves from warm indoor air to colder outdoor air, and windows allow this transfer to happen quickly. Even modern double glazing still lets heat escape, especially at night.

The Energy Saving Trust estimates that around eighteen percent of heat loss in the average home happens through windows, making them one of the weakest points in thermal efficiency.

Draughts and air gaps

Small gaps around window frames allow cold air to enter and warm air to escape. These draughts create uneven temperatures and make rooms feel colder than they should.

Cold air circulation

When warm air touches cold glass, it cools and sinks. This creates constant air movement near windows, increasing the feeling of cold even in heated rooms

How Curtains Reduce Heat Loss in the Home

Curtains act as insulation

Curtains reduce heat loss by creating a physical barrier between warm indoor air and cold windows. When closed, they trap a layer of still air between the fabric and the glass. This air pocket slows heat transfer and keeps warmth inside the room.

Thermal curtains increase efficiency

Thermal curtains are designed specifically to reduce heat loss. They use thick fabrics and thermal linings that reflect warmth back into the room. Thermal velvet curtains are particularly effective because of their dense structure.

Products such as Hampton Thermal Velvet Eyelet Curtains combine heavy fabric with thermal backing to noticeably improve room warmth.

Reduced radiant heat loss

At night, heat escapes through windows by radiation. Curtains absorb and slow this process, reducing the amount of warmth lost while you sleep.

How to Use Curtains to Reduce Heat Loss Effectively

Close curtains at night

Heat loss through windows is highest after dark. Closing curtains in the evening traps warmth inside and prevents cold air from cooling the room.

Open curtains during the day

Opening curtains during daylight allows sunlight to naturally warm your home, reducing the need for heating.

Combine curtains with blinds

Using curtains alongside blinds creates multiple insulating layers. This combination is especially effective for bay windows and patio doors.

Avoid blocking radiators

Curtains should not cover radiators. Trapping heat behind fabric prevents warmth from circulating around the room.

What Type of Curtains Reduce Heat Loss Best?

Best curtain fabrics for warmth

Not all curtains reduce heat loss equally. Lightweight fabrics allow heat to pass through easily. For better insulation, choose curtains made from:

Velvet- such as our Velvet Blackout Eyelet Curtains
Chenille- such as our Chenille Blackout Eyelet Curtains
Wool blends
Thick tightly woven fabrics

Our Oxford Thermal Velvet Pencil Pleat Curtains are a strong option for combining insulation with traditional style.

Why thermal linings matter

Thermal linings add an extra insulating layer to curtains. They reflect heat back into the room and are especially useful in older homes, north facing rooms, and large windows. Shop our Curtain Linings here.

Our Amberley Thermal Lined Eyelet Curtains offer a balance between warmth, style, and everyday practicality.

Correct fit improves performance

Curtains should extend beyond the window frame and overlap fully when closed. Gaps around the edges allow heat to escape and reduce effectiveness.