The lost art of natural ventilation

Natural ventilation is healthy for you and for the building you occupy. In our quest to make old and new buildings thermally efficient and more comfortable could it be possible we are making them too air tight?

The United States Environmental Protection Agency recently produced information about indoor air quality and improving natural ventilation in relation to COVID-19. Guess what they recommend?

Yes, you guessed it… opening your windows and doors. 

What we have found from talking to thousands of customers over the years is that the art of using opening sashes properly to promote air flow is misunderstood or not known.

For double-hung windows, open the top sash 10cm and the bottom sash the same. The warmer air, which is higher in the room, will flow out the top and cause a tumbling effect to drag air in through the bottom sash. Better still, open a top sash on one side of the building and a bottom sash on the other side of the building and a cross flow of air will happen.

Simple eh! Many people are so used to having their top sashes stuck shut, they don’t realise how well this can work.

For other window types such as casements and awnings and doors – open them on opposite sides of the building to create a cross-flow effect.

Have you become reliant upon fans and air conditioners because your windows don’t open and close properly?

Sealasash provides a simple, environmentally sustainable and cost-effective solution. 

For windows that open properly when you want them open, and which are properly draught sealed when you want them shut, contact us for a quote.

If you would like to talk to a timber window expert who understands all your options, and who will listen to your priorities, then please don’t hesitate to contact us.

Looking for double glazing for your sash windows or wooden windows?

Sealasash can double glaze your old timber, wooden and sash windows with new high-performance glass.  We also upgrade windows to include draught and acoustic seals that further improve the comfort and energy efficiency of your windows. 

Learn more about Sealasash:


Vacuum Insulated Double Glazing

Our ultra-high performance double glazing fits perfectly within your existing timber work, eliminating any bulky or expensive modifications.


Fix Those Annoying Rattles

With our draught and acoustic seals you’ll achieve amazing new comfort levels by reducing infiltration of outside air, noise and dust without the annoying rattles.

Related posts

Using traditional craftsmanship and modern materials, we’ll restore your windows and make them better than new.  This includes high-performance double glazing and draught seals that will dramatically improve the comfort and energy efficiency of old timber, wooden and sash windows.