A Guide to Thermal Curtain Lining

As an accredited Guild member, Fabrics Galore brings trusted expertise to this guidance on thermal curtain lining, outlining how the right lining enhances insulation, comfort and fabric protection. Their knowledge provides a clear foundation for understanding the practical benefits explored throughout the article.

Thermal Curtain Lining is the unsung hero of the curtain world, but the difference it makes to the temperature of the room and to how the curtains hang is incredible. While you want your curtains to look good inside the room, lining curtains also serves a practical purpose making the lining as important as the carefully chosen room-facing curtain fabric.

The Origin of Curtains

Curtains are thought to have been used as early as 3000 BC by the Egyptians who used animal hides hung in doorways to divide rooms. In Medieval England, the earliest curtains were leather panels looped onto iron rods which were eventually replaced with woven wool hangings.  It was during the Elizabethan era when luxuriously patterned fabrics imported from Italy were used as curtains, while solid wooden shutters were still used during the winter.

Nowadays, with double glazing and central heating, curtains are used for privacy as much as for comfort; yet in older houses with single glazing and badly fitting windows and doors, where drafts and poor insulation rapidly cool the temperature, thermal curtain lining is a fantastic and cost-effective solution to improve the energy efficiency of your home. Even in modern homes with lots of glass, which often become overly warm, the thermal properties act as a blackout to keep the room cool.

Understanding How Thermal Curtain Lining Works

Our thermal blackout curtain lining is a special kind of curtain lining, which is much heavier than standard cotton curtain lining fabric, with a rubberised back to dampen noise and regulate room temperature. While most people associate thermal curtain lining with keeping rooms warm in winter, it is also highly effective at preventing the sun from heating rooms and acts as a blackout curtain lining during the summer months.

How thermal lining regulates temperature

Thermal curtain lining is made from multiple layers of fabric which improves thermal performance by creating a space for air to circulate between the warm room and the colder windows. If you think about it, a lined winter coat is always much warmer than an unlined coat, and the thermal curtain lining is made of a specific type of fabric to be even more energy efficient. In winter, the thermal lining blocks the cold from the outside of the building and in summer it reflects the heat of the sun back outside, keeping your rooms nice and cool.

Different types of thermal lining materials and their properties

Thermal curtain linings all have a protective coating applied to the reverse side of the fabric which prevents light seeping through the tiny holes in the weave of the fabric. There are several different types of thermal curtain lining including:

• Normal thermal lining has a single layer (1 pass) of coated acrylic compound which provides insulation and some light blocking.
• Blackout thermal lining has 3 layers (known as a 3 pass) of coated acrylic which offers the same thermal qualities but also eliminates all light penetration.
• Bonded Blackout Lining is a blackout fabric with interlining as above, which offers the most insulation. 

At Fabrics Galore we stock a Pass 3 blackout thermal curtain lining made of microfibre polyester with acrylic backing in white and cream.

In addition, we stock a superior energy reflecting thermal and blackout lining which uses patented energy reflecting technology to reflect heat energy back from the window into the room in cold climates and back out of the window in warm climates.

The Benefits of Thermal Curtain Lining

Improved Insulation

• • Heat retention in cold weather – keeping the warmth in. 
  • Heat reflection in hot weather – keeping the warmth out.

Energy Efficiency

• • Reducing heating and cooling costs: it is thought that closing curtains at dusk can reduce heat loss by up to 15% but that figure increases to 25% with thermal curtain lining.
  • By choosing to insulate our homes better with thermal lined curtains, lower use of energy has a positive environmental impact.

Enhanced Comfort

• • Maintaining a comfortable indoor temperature in winter and summer
  • Minimising drafts and cold spots
  • Keeps sunlight out in the summer months – making lie-ins far easier.

Noise reduction

• • Thermal curtain lining is also excellent at reducing noise from outside the windows, as the thick fibres dampen sounds helping you enjoy a better night’s sleep.

Protection for your curtains

• • Protects your face fabric from fading.
  • Prevents mildew forming as blocks the damp cold air.

Flexibility – Thermal lining can turn most fabrics into thermally insulated curtains and blinds. You can specify thermal lining for your made-to-measure curtains and blinds, or simply add it to your existing curtains or blinds with a new backing material.

Choosing the Right Thermal Curtain Lining

There are several factors to consider when choosing your thermal curtain lining:

Material types – what job do you primarily want the thermal lining to perform? Do you need it for warmth, cooling, light blocking or perhaps all three?

The thickness and density of your thermal lining is critical. A thicker, denser lining will act as a complete blackout lining while also providing additional warmth in the cooler months. However, if your facing curtain fabric is lightweight, you may not want a very heavy lining which weighs the curtains down and affects the natural drape. It’s also important to think about where the curtain is hanging, if you don’t have a huge amount of space either side, as adding a thick lining may not be possible.

Colour options – contrary to popular belief blackout lining is not necessarily black but usually comes in a white or a cream/off-white colour. Different colour options are available to match the facing curtain fabric and navy blue is a popular choice for curtain lining.

Compatibility with Existing Curtains – if you are retro-fitting thermal lining to existing curtains, be sure to consider the weight and density of the decorative curtains so that you choose a compatible thermal lining.

Cost vs. Long-Term Savings – although thermal curtain lining is more expensive than regular lining, it can pay over the long -term as it will stop heat escaping from your windows and block drafts, resulting in lower energy bills.

Thermal Lining Measuring and Installation Tips

  – Measure your curtain pole rather than the window frame for the width of the curtain. To work out how much fabric you need for your curtains you then times the width of the curtain pole by anything from 1.5 or 3 depending on how full you want your curtains. You divide this by the width of fabric to work out how many drops you need. (The drop is the height of the window from the curtain pole to the floor).

  – Check whether your thermal lining is the same width as your curtain facing fabric; if it is, you will need the same number of drops. If the fabric is wider than the lining, you will need to allow extra drop(s) of lining to fully span the fabric width. If the fabric is a bit narrower than the lining, you can cut the excess lining when you make the curtains.

  – According to Jane Clayton, curtain linings should be cut to include 15cm (6”) for hems and enough turning at the top to finish behind the heading tape – 5cm (2”) for pencil pleat tape. Because the finished lining hem will sit 2.5cm (1”) higher than the curtain hem, the total cut length of the lining in this case will be curtain finished length less 2.5cm (1″) (set up from hem) plus 15cm (6″) (hem turning) plus 5cm (2″) (top turning).

  – Don’t forget that the coated side of the thermal lining must face the window to resist the sun, cold and damp.

  – You can improve the thermal and blackout qualities of the curtains by hanging them several inches above the top of the window and below the level of the windowsill. Full length curtains should always reach the floor to prevent drafts from escaping underneath. Some people even use Velcro on the lining to secure the curtains to the windows.

  – If you are installing thermal lining to existing curtains, remove your curtains from the pole or track, place them flat on a clean surface and place the thermal lining inside the fabric using weights, tape and pins to hold everything securely in place.

Tools and equipment needed

• Thermal lining fabric
• Tape measure
• Ruler
• Marker Pen
• Sharp scissors
• Pins
• Matching thread (to your room-facing curtain fabric)
• A large space – we would recommend either a large table or a clear floor.

Common mistakes to avoid during installation

• Don’t necessarily sew your fabric lining to the curtain fabric along the bottom of the drop, if you want to make sure you maintain the drape of the curtains.
• Don’t match your thread to the lining, match it to the curtain fabric.
• If measuring for blinds, make sure you have the correct measurements for a recessed blind versus a full window frame width blind. Please see our blog on  How to Make a Roman Blind Part 1: Measuring Windows

Maintenance and Care

• You should always professionally dry clean curtains fitted with thermal lining and most curtains and blinds tend to be dry clean only.
• You can gently brush away dust and cobwebs on both sides of the curtains and use the curtain and upholstery setting on your vacuum cleaner for gentle removal of surface dust or debris.
• To keep your curtains in good condition, don’t leave windows open for long periods of rain, as the lining next to the window may develop mildew or mould from being damp.
• Be careful that window arms protruding into the room don’t tear the lining fabric when opening or closing the curtains.

Thermal Curtain Lining is a Smart Choice

We hope that you will better understand the benefits of thermal curtain linings, not least the fact that they keep your rooms warm in winter and cool in summer. If you are replacing curtains, think very carefully about investing in thermal curtain lining.

They are a smart choice for their superior insulation properties, their contribution to an energy-efficient living space and enhanced comfort for the long term. Finally, they also protect your beautiful facing curtain fabric from degradation from heat, cold, damp and mould.

Explore Fabrics Galore’s range of thermal curtain linings to see which is right for you. If in doubt, please don’t hesitate to contact their team via www.findacraftsman.com or on 020 7738 9589