In Melbourne, north facing windows cause the most cumulative fading because they receive the most total sun across the year. West facing windows cause the most intense damage in summer, delivering fierce low-angle afternoon sun straight into the room. East facing glass is a lesser concern and south facing glass rarely matters at all.

If you have a faded strip across your floorboards, a sofa arm two shades lighter than the other, or a rug that has gone patchy, the orientation of the window explains it, and it also determines which film you should be using.

Why north and west behave so differently

We are in the southern hemisphere, so the sun tracks across the northern sky. That single fact drives everything below.

North facing glass receives direct sun for the longest period each day, year round. In summer the sun is high, so it strikes the glass at a steep angle and penetrates less deeply into the room. In winter the sun sits low and drives deep into the space, which is exactly why good passive design puts living areas on the north side.

The result is the highest total annual dose of UV and light. Fading is cumulative, so north facing rooms are where you see the most damage over years, even though it rarely feels uncomfortable.

West facing glass is a different problem. In summer the afternoon sun is low, intense and shining almost horizontally through the glass. It penetrates deep into the room, hits furniture and flooring directly, and arrives at the hottest part of the day when the building is already warm.

West facing rooms deliver the highest peak intensity and the worst heat and glare, concentrated into a few hours. Damage tends to be sharper and more localised, often a distinct band across whatever the afternoon sun lands on.

East facing glass gets morning sun. Similar angle to west, but at the coolest part of the day, and typically for a shorter period before the sun moves north. It is a genuine but lesser concern.

South facing glass receives very little direct sun in Melbourne, mostly a small amount early and late in summer. Fading is rarely an issue.

What actually causes fading

It is not just UV, and this matters because it determines what a film can realistically achieve.

Fading is caused by a combination of:

•     Ultraviolet radiation, the single largest contributor

•     Visible light, a meaningful contributor in its own right

•     Heat, which accelerates the chemical breakdown of dyes

•     Humidity, artificial lighting and dye quality, which vary by material

A film that blocks up to 99 per cent of UV therefore removes the biggest factor but not all of them. It will substantially slow fading. It will not stop it entirely. Be sceptical of anyone promising your furnishings will never fade again.

What fades fastest

Not all materials degrade at the same rate. In rough order of vulnerability:

Most vulnerable

•     Silk and wool, particularly in rugs and upholstery

•     Natural dyes and vegetable-tanned leather

•     Watercolours, photographs and paper-based artwork

•     Timber flooring, especially darker stains and species like jarrah and blackbutt

Moderately vulnerable

•     Cotton and linen

•     Most modern synthetic upholstery

•     Painted surfaces and wallpaper

•     Stained and oiled timber furniture

More resistant

•     Solution-dyed synthetics

•     Stone, tile and concrete

•     Metal and glass

Timber floors are the ones people notice most, usually when a rug gets moved after a couple of years and there is a clear line. The rest of the room has aged and the covered section has not.

Which film for which orientation

This is the part generic advice gets wrong, because most articles recommend one product for everything.

Why clear UV film on north facing glass? Because you want to keep the winter sun. North facing rooms in Melbourne are passively heated by low winter sun, and that is worth having. A solar control film rejects that heat year round, which costs you comfort and heating through winter. Clear UV film blocks the fading agent while letting the warmth and light through. It also makes no visible change to the window.

Why solar control on west facing glass? Because the summer afternoon problem in a west facing room is heat and glare as much as fading, and there is little winter benefit to protect. West facing winter sun arrives late in the day when it does the least good. Rejecting solar energy on west glass is close to a pure win.

Full comparison of the film types is in our UV film vs solar film vs window tint guide.

Things you can do that cost nothing

Film is the most effective single intervention, but it is not the only one.

Rotate and rearrange. Turning rugs, moving cushions and occasionally shifting furniture spreads exposure so nothing develops a sharp line.

Move the valuable things. Original artwork, antique furniture and heirloom textiles do not belong in the direct path of a north or west facing window. This is the cheapest fix available.

Use external shading where you can. Eaves, awnings, pergolas and deciduous planting stop the energy before it reaches the glass, which is always more effective than treating it after it arrives. A deciduous tree on the north side is the classic answer, shading in summer and bare in winter.

Close blinds during peak hours in rooms you are not using. Not glamorous, but effective in west facing rooms during a heatwave.

Check your glass. Some modern double glazed units already include low-E coatings with meaningful UV performance. Worth knowing before you buy film.

How to work out which of your windows is the culprit

Walk around the house on a sunny afternoon in summer, ideally around 4pm to 5pm.

•     Which rooms are noticeably hot?

•     Where is sunlight actually landing on floors and furniture right now?

•     Where can you already see fading, and does it line up with where the light falls?

•     Which windows do you find yourself covering?

Then repeat mid-morning in winter and note where the low sun reaches. That combination tells you far more than any general rule.

Take photos with the sun on the glass. If you send them to us with the orientation of each window, we can specify the right film for each opening rather than treating the whole house the same way.

Frequently asked questions

Will UV film stop fading completely?

No. It removes the largest single cause and substantially slows the process. Visible light and heat also contribute.

Will UV film make my windows look different?

Clear UV film is essentially invisible once installed. Most people cannot pick which panes have it.

Does it reduce heat as well?

Only marginally. Clear UV film targets UV, not infrared. If heat is the problem you want solar control film.

Are curtains enough?

Curtains protect what is behind them, and only when closed. They do nothing for the floor in front of the window and nothing while they are open. Film works constantly without you doing anything.

Does double glazing already stop UV?

Standard double glazing reduces UV somewhat. Units with low-E coatings do better. Neither generally matches a dedicated UV film. Have the unit assessed before applying film to double glazing.

How long does UV film last?

Quality internal film on residential glass generally performs for many years. North and west facing glass works hardest, so those panes are the ones to check first over time.

Protect what you already own

Replacing a faded rug or resanding a floor costs considerably more than filming the window that caused the problem.

Send us photos of the affected rooms with a note on which way each window faces and we will tell you which film we would put on each one. In a lot of houses the answer is different room to room, and we would rather get it right than sell you the same product throughout.

We have been protecting Melbourne homes from sun damage since 2002. Request a free quote or call 1300 204 852.