Which way a thermal curtain faces, and which windows to do first

The two meanings of thermal curtain direction

People who search for thermal curtain direction are usually asking one of two things. The first is practical and immediate: I have a curtain with a white or silvery coated back, which side goes towards the window? The second is about planning: which way do my windows face, and does that change what curtains they need and when to close them? Both matter, and the second has a bigger effect on how warm the house feels. This guide answers the first quickly and spends most of its time on the second.

Which side faces the glass

The lining faces the window. The decorative face fabric faces the room. On a made-to-measure curtain this is built in: the workroom sews the thermal, blockout or standard lining to the back of the face fabric, fits the heading tape to the back, and turns the side and bottom hems towards the lining. When the curtain is hung on its hooks or carriers, the lining can only face the glass.

There are good reasons for the convention beyond looks. A coated or thermal lining protects the face fabric from sun, which is often the main thing that fades and weakens curtains on sunny windows. A pale lining also reflects some summer sun back through the glass before it reaches the face fabric and the room. And from the street, a house where every window shows the same pale lining looks tidy and consistent, whatever colour each room's curtains are on the inside.

Turning a curtain around so the coated side faces into the room does not make it warmer. The heat-saving effect comes from trapping still air between the curtain and the glass, which works whichever way the fabric faces, and relies far more on how well the curtain seals at the top, the sides and the floor. Reversing it exposes the heading tape and raw hem turns to the room and puts the face fabric in the sun.

Telling front from back on a ready-made thermal curtain

Ready-made thermal curtains sometimes look similar on both sides, especially when the backing is a light-coloured bonded layer rather than a separate lining. A few details give it away. The heading tape, the eyelet backing ring or the rod pocket seam sits on the back. The side hems and the bottom hem fold towards the back, so the neat side of each hem faces the room. The care label is usually sewn to the back near a side hem. If the curtain is sold as having a coated or blockout back, that surface normally faces the window, but read the packaging or the maker's instructions for the specific product.

Reversible curtains are the exception. Some ready-mades are designed with two usable faces. If the product says reversible, choose whichever colour suits the room, and keep in mind that the side facing the glass will take the sun and fade first.

Checking curtains already in the house

Curtains that came with a house, or were rehung after painting or cleaning, are sometimes back to front, swapped left for right, or hung with the lining showing on one side of a pair. A quick walk around the house at night with the lights on inside will show most problems. From the room, you should see only face fabric, including around the ends. From outside, you should see the lining on every panel, with no heading tape or face fabric showing. Hems should turn towards the glass, and the bottom edges of a pair should be level.

If a panel has been swapped from one side of the window to the other, the leading edge, which is often finished differently or carries a weight in the hem, ends up at the wall and the return end ends up in the middle. The pair will not overlap properly and may not reach the return arm. Swapping the panels back usually fixes it. If the curtains seem to be the right way round but still look uneven, the hook positions in the heading may have been moved, which changes the height each panel hangs at. The curtain cleaning and care guide covers how to record hook positions before taking curtains down, so they go back exactly as they were.

Direction at the edges: returns and overlaps

There is a second, smaller kind of direction on a curtain: how the ends and the middle are arranged. At each outer end, a return carries the curtain back towards the wall so warm room air cannot slip around the side. In the middle, an overlap arm lets one leading edge sit in front of the other so the pair crosses rather than meeting edge to edge. These details are covered in the thermal curtains for winter guide. For direction purposes, the point is that the lining side continues around the return towards the wall, so no face fabric is exposed to the glass and no gap opens at the ends.

Window aspect in a Pakenham house

The Australian Government's YourHome guide sets out how the sun moves around a house in southern Australia. North-facing walls and windows receive more sun in winter than in summer, because the winter sun sits lower in the sky. East and west windows receive more sun in summer, early in the morning and late in the afternoon when the sun is low and hard to shade with eaves. South-facing glass receives relatively little direct sun in either season at these latitudes. The same guide recommends snugly fitted curtains with pelmets that trap a layer of still air next to the window, and eliminating gaps around the curtain and pelmet. Links to both pages are in the sources below.

North windows are the ones to open. On a clear winter day, sun through north glass warms the floor and furniture, so keeping those curtains closed all day throws away heat the sun would otherwise add. Their job is to close before sunset and hold that warmth overnight. They benefit from a good seal and floor length, but they do not usually need the heaviest possible lining, because they are open for much of the day.

South windows give little back in winter. They lose heat all day and night with almost no sun to offset it, and they are often where the coldest glass in the house sits. These are strong candidates for the most insulating construction, such as a thermal lining with interlining, and for staying closed on grey days in rooms you are not using. South rooms are also where condensation often shows first behind a well-sealed curtain, so open them for a while on drier days to let the glass and reveal dry out. The mould on curtains guide explains why.

West windows are the summer problem. Afternoon sun hits the glass low and almost square-on, and it arrives when the house has already warmed up. Close west-facing curtains before the sun reaches them, not once the room is hot. A pale lining helps here, and a blind behind the curtain can handle the glare while leaving the curtain for warmth. The curtains and blinds together guide covers that combination. In winter, west windows behave more like ordinary heat-losing glass once the short afternoon sun has gone.

East windows bring early summer sun into bedrooms, which is as much a sleep problem as a heat one. Blockout lining suits east bedrooms, and closing the curtain properly at night means it is already doing its summer job when the sun arrives at dawn.

Opening and closing by aspect

A thermal curtain only works when it is closed, and it only helps in winter if it is closed at the right time. A simple routine by aspect makes more difference than most people expect. In winter, open north curtains in the morning once the sun is on the glass and close them in the late afternoon while the room is still warm. Open south and east curtains long enough to let light in and let the glass dry, then close them earlier than the north ones. In summer, close east curtains overnight so they block the dawn sun, and close west curtains around lunchtime, before the afternoon sun arrives. North glass in summer is often shaded by eaves, so those curtains can usually stay open unless the room gets direct sun.

In hills areas such as Emerald and Pakenham Upper, tall trees and slopes can block sun that a flat estate block in Pakenham or Officer would receive, so a north window in the hills may behave more like a south one in midwinter. Watch where the sun actually falls in your house for a week, and set the routine from that rather than a compass alone.

Which windows to do first

Most households cannot, or do not want to, replace every curtain at once. Ranking the windows helps put the budget where it changes the most. The strongest signal is use: rooms you heat in the evening, such as the living area and main bedroom, matter more than a spare room kept closed. Next is glass area. A three-panel sliding door loses more heat than a small bedroom window and deserves attention first. Then aspect: south glass and exposed west glass generally rank above north glass, because north windows earn some of their heat back in winter sun.

After that, record the problems separately. A curtain that stops at the sill or leaves a gap at the ceiling may allow air to circulate around it. A cold sensation near glass can come from air cooling at the pane or from a leaking window seal, which need different responses. Condensation means moisture has met a sufficiently cold surface; it does not prove the curtain is poorly sealed. Water can collect behind a close-fitting curtain too. Record where it appears and discuss ventilation, indoor moisture and window condition before treating a new curtain as the answer. Single glazing and exposed frames are useful details to include in that conversation.

Once you have a ranked list, the thermal curtains page covers what a full thermal fit involves, and the lining guide compares the backing options room by room. If the window you ranked highest is a wide door where the curtain will need to stack clear of the opening, read the stack-back and track layout guide before the measure.