The 19:45 Curtain Trick: Save Energy This Spring

With the start of spring, many people turn their heating down slightly but keep it running. Yet a simple habit offers considerable savings potential: closing your curtains at the right time can keep warmth inside and noticeably reduce your energy bills – without any high-tech solution, simply through good timing and suitable fabrics.

How the curtain trick works

The principle is remarkably straightforward: during the day, sunlight heats your home for free. Windows in direct sun in particular act rather like a magnifying glass, allowing plenty of energy indoors. Once darkness falls, however, the process reverses, with heat escaping outside through the same surface.

Closing curtains at dusk creates an extra layer of warmth in front of the window – much like thin, flexible insulation.

In many regions, this point falls at around 19:45 in March. This is when outdoor temperatures become noticeably cooler, even though the warmth gathered during the day could still be useful indoors. If curtains and blinds stay open, much of that energy is lost and the heating has to compensate.

Why spring matters so much

March brings longer days, a higher sun and stronger solar warmth. Homes facing south or west benefit especially. The heating season is not over, though: nights remain cool and living spaces can quickly lose heat.

By deliberately “trapping” the day’s warmth, you can often reduce the heating by one or two settings. This makes more of a difference in poorly insulated older properties than in modern homes, but the effect is still worthwhile over weeks and months, even in well-insulated flats.

How much money curtains can really save

The precise amount depends on numerous factors, including window quality, insulation standards, heating system and energy prices. Nevertheless, energy advisers consistently report that purposefully closing curtains and blinds can significantly reduce heat loss through windows.

• Windows are often the weakest point in a building’s outer shell.
• Glass transfers cold and heat more quickly than an insulated wall.
• The larger the window area, the more energy is lost without protection.

If better heat retention means you can lower your heating by just one degree in the evening, heating energy demand falls by around six per cent on average. Over a year, a typical household can soon save sums ranging from the mid two-figure to the low three-figure euro range – solely by changing its evening routine.

Thermal curtains: what they can and cannot do

Ordinary decorative curtains already make a difference when they cover the window area as fully as possible. The approach is considerably more effective with specialist thermal curtains, however. These usually have a thick, multi-layered construction or an insulating backing.

Thermal curtains work as an additional, soft insulating layer in front of the glass – keeping warm air in the room and blocking cold draughts.

High-quality options can cost around 100 euros per pair. Although this may initially seem a significant investment, their lifespan puts the price into perspective: if they help you use less heating for several years, they will often pay for themselves.

What to look for when buying

• Fabric thickness: The thicker the material, the better its insulating effect.
• Backing: A thermal coating or lining made from fleece, felt or a similar material.
• Length: Curtains should reach almost to the floor, preventing cold air from flowing underneath.
• Width: At least twice the width of the window, so that no gaps remain.
• Fitting height: Install them as close above the window as possible, so heat cannot escape at the top either.

How to use the 19:45 curtain trick every day

At its heart, this is about creating a routine. Once you are used to closing your curtains at a fixed time each evening, it eventually becomes automatic. A few practical steps can help you get started:

• Check the time: When does it actually get dark in your area in March? Around 19:30 to 20:00 is a useful guide.
• Set a reminder: Use an alarm on your phone for the first two weeks.
• Establish an order: Air the room briefly first, then close the windows and draw the curtains.
• Adjust the heating: After a few days, test whether the room temperature remains steady when you turn the heating down slightly.

After just a few evenings, you will often notice that the room stays pleasantly warm for longer while temperatures outside fall markedly.

Summer bonus: a heat shield rather than a heat store

Thermal curtains are not solely for winter. In summer, their effect is reversed: air your home through briefly in the morning while the outside air is still cool, then shut the windows and close curtains or blinds during the day. This allows less heat into the home and keeps rooms tolerable for longer.

This can noticeably reduce peak temperatures, particularly in top-floor flats and rooms with large window areas. If you currently reach straight for a portable air conditioner on hot days, smart curtain management can often reduce its use – saving electricity in the process.

Curtains are only one part of the solution – these combinations achieve more

The curtain trick works best alongside other straightforward measures. Here are some examples:

Measure	Winter benefit	Summer benefit
Close shutters at night	Further reduces heat loss alongside curtains	Blocks direct sunlight
Sealing strips on window frames	Less draught and a more even indoor climate	Protects against warm air currents from outside
Rug on cold floors	Keeps feet warm, subjectively reducing heating needs	More comfortable barefoot feel, less awareness of temperature

Each of these measures delivers only part of the benefit on its own, but together they can create a clearly noticeable improvement in comfort while reducing energy costs.

Common mistakes that undermine the saving effect

Certain habits reduce the effectiveness of thermal curtains. These include:

• Hiding radiators behind fully closed curtains – the heat then barely circulates around the room.
• Arranging curtains decoratively at the sides only, leaving large areas of glass uncovered.
• Leaving windows on the latch while drawing the curtains – warm air flows straight outside.
• Choosing short curtains that reach only to the windowsill.

Ideally, the curtain should end just in front of the radiator or be fitted so that warm air can still flow into the room. In rented homes with poorly positioned heating, special poles or brackets can sometimes guide the fabric slightly away from the radiator.

Why this straightforward trick is especially appealing now

Many households still feel the impact of higher energy prices. Major upgrades, such as new windows or external wall insulation, are expensive and cannot be completed overnight. Using curtains consciously may seem almost trivial by comparison, yet it has an immediate effect, requires very little effort and can be done in any home, whether rented or owner-occupied.

Once you understand the principle, you often start viewing your windows differently: what do I do in the morning and in the evening? When do I let light and warmth in, and when do I block them out? Thermal curtains and fixed times such as 19:45 are only tools – the real difference lies in the daily routine.