How To Clean Sash Windows

How to Clean Sash Windows

Anyone who has some experience with sash windows knows that cleaning them takes more time than washing regular windows. The main reason is that there are a few types of sash windows and each has its own specifics in terms of mechanism. 

In this guide, London Sash Windows explores the best way to clean your sash windows depending on their type.

Open your Sash Windows for Cleaning

Fortunately, almost all the different types of sash windows can be cleaned from the inside as the window mechanisms are made to allow the sashes to move in different directions. 

Hence, there are ways you can reach around and clean every nook and cranny without having to go outside and potentially endanger your life

Double-hung Windows

Whether your windows are Georgian, Victorian or Edwardian in style, traditionally they are double-hung sash windows. 

What does this mean? 

It means that both of the sashes are regulated by hung weights and can be moved vertically. This mechanism comes in handy when you want to clean both sides of the window because you can securely adjust its position during the cleaning process. 

Just alternate moving the upper and the lower sash until every part has been thoroughly washed, including between the two sashes. 

Sliding Sash Windows

Another variation is the Yorkshire sash window, where only one of the sashes slides horizontally.

That’s why they are also sometimes referred to as sliding windows. Having one of the sashes fixed in one place, however, significantly limits the ability to reach all sides of the window.

Unless your window is positioned on the ground floor or it has a hinge mechanism which allows the sashes to open inwardly, it’s better to refer to a reputable window cleaning company, like Fantastic. 

Don’t forget – safety comes first!

How to Clean the Outside of Sash Windows from Inside

It is recommended to wash your windows at least twice a year, preferably during spring and autumn. This way you can avoid the freezing temperatures in winter or the scalding sun in summer during the washing process, and inspect if your sash windows are in need of repair

As mentioned above, the safest way to wash your sash windows is to do it from the inside. With that in mind, here are all the materials and tools you’ll need:

  • Glass cleaner
  • Dishwashing liquid
  • Hot water
  • Empty spray bottle
  • Microfibre cloths or a lint-free cotton rag
  • Non-abrasive sponge or a squeegee
  • Hoover/feather duster
  • Oilcloth

Internal Windows

Since the inner part of the sash window is not often exposed to the outside world, it usually does not accumulate as much dirt as the external side. Thus, you will only need the help of a regular glass cleaner and a clean microfibre cloth to return the shine of the inner glass panes. 

  1. Vacuum the window treatments to remove the larger dust particles, as well as any cobwebs. If you don’t have a hoover, use a feather duster;
  2. Spray the frames and the panes with the glass cleaner;
  3. Scrub with a non-abrasive sponge or a squeegee;
  4. Wipe with a clean microfibre cloth or an old lint-free cotton rag.

Avoid using newspapers because they may leave ink on the wooden frames and the glass.

External Windows

Due to their exposure to the outside world, external windows accumulate layers of exhaust-gas particles and pollen, which can get etched if neglected for too long. 

As a result, you will need a stronger cleaning solution in order to remove the dirt build-up. 

Here is how it’s done:

  1. If your windows have hinges and you are able to open the sashes inwardly, lay down the oilcloth to gather the excess cleaning liquid and open the sashes. Vacuum any big dust particles with the hoover. Alternatively, use the feather duster to gently brush the outside windows.
  2. Mix hot water and a few drops of dishwashing liquid in an empty spray bottle and shake well;
  3. Spritz the outer glass panes;
  4. Scrub with a squeegee or a non-abrasive sponge;
  5. Wipe the grime with a microfibre cloth. Avoid washing the external windows on a sunny day, because the detergent can quickly dry up and leave streaks on the glass panes;
  6. Use a lint-free cloth to dry the frames and prevent damage to the wooden frames.

That’s it! 

Now you can relax and enjoy your sparkling clean windows!


I'm Simon and I work on sash windows and have done so for twenty years. I enjoy running and living in London.