The Three Fundamentals of Effective Natural Ventilation

An empty, open office with full windows By Tom Lymn, Director of Sales, WindowMaster.

One of the biggest challenges for businesses hoping for a seamless return to bricks-and-mortar will be that of employee attitudes towards office working.

Having become used to WFH arrangements, many workers will need some convincing to entice them back. For the first time, traditional working environments are playing second fiddle, and managers would be wise to reach out to building occupants about their concerns.

Taking one example, employees want good ventilation and limited capacities in addition to, rightly, high-standards of cleanliness 1. It’s criteria facilities managers will need to address to ensure a positive return-to-office.

Throughout the past year and a half, there’s been a growing emphasis on natural ventilation in particular, or opening windows, for the role it plays in helping ensure acceptable levels of fresh air and, in turn, minimising aerosol transmission of pathogens.

However, the efficacy of natural ventilation depends on the overall building design and how effectively the windows can be operated in conjunction with other components.

To help define those first steps towards designing in optimum natural airflow, I outline some crucial points for consideration to help you make the most of your windows in your ventilation strategy.

It’s Elementary

The first fundamental of effective natural ventilation is understanding how it works and the design processes behind it.

Both manual and automatic windows have benefits and disadvantages, and one may be more appropriate depending on the building, its spaces, usage and occupants.

The physical layout of your building presents a different range of approaches to consider: single-sided or cross ventilation for smaller buildings, and single zone stack, multizone atrium drive ventilation or multizone solar chimney for larger.

We recommend consulting built-environment and ventilation specialists to help optimise your building’s ability to accommodate as much natural airflow as possible, based on its size and layout.

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In Control

With a sound understanding of design processes, assisted by an experienced professional, the next pillar is good control strategies. These will help achieve optimum performance and air quality, which are the real benefits of automating your windows, virtually unachievable with only manual operation.

There are three essential ventilation strategies to be considered:

  • Purge ventilation: Opening windows before occupants arrive allows you to flush out stale air and prepare spaces without the risk of discomfort.
  • Preemptive ventilation: Carefully controlling ventilation in response to sensor readings before room conditions begin to fail, taking prevailing weather conditions and ventilation requirements into consideration.
  • Night cooling: Optimising comfort in the summer by releasing excess heat through windows.

Tech Talk

Even a great design with a well-thought-out strategy can fall flat without supporting technology. This last piece of the puzzle will ensure the quiet, intuitive and cost-effective delivery of your natural ventilation.

So don’t stumble on this last hurdle by using restrictive low-tech systems when there are ample sophisticated smart options available, and not necessarily at much greater cost.

A system comprising lower quality actuators is likely to function at a fixed speed and operate noisily. The windows open once room conditions have failed, opening quickly to bring in lots of fresh air at once before closing again. This can cause unstable and uncomfortable conditions as well as reducing actuator life. The optimum solution is to seek to achieve the ideal balance between ventilation supply and demand, opening in smaller increments to adjust and hit the right air quality-comfort-energy mix for as much time as possible.

An identical design, using the best technology, enables your windows and BMS to communicate with one another. In this situation, the BMS can tell the windows to open quietly to specific positions for background automation while minimising disruption, and more quickly if it’s raining or as an emergency function.

Using appropriate technology, you can use feedback from sensors and the BMS to help optimise set points for temperature and air quality based on what occupants find most comfortable. This is key: if you can’t monitor it, you can’t manage it.

With a good understanding of the fundamentals of natural ventilation, you can now breathe a little easier as you prepare for the return to the office.

For more information on how window automation can provide safer, healthier and more energy efficient environments for your buildings, visit: www.windowmaster.com

1 Office for National Statistics. Business and individual attitudes towards the future of homeworking, UK: April to May 2021.

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The Three Fundamentals of Effective Natural Ventilation