Ventilation and air quality

Achieve efficient ventilation with VELFAC windows

Given the amount of time people spend indoors, creating a comfortable environment and maintaining a good indoor climate is particularly important. Essential in the creation of a comfortable building is the ventilation and management of air flow. Ventilation helps removing irritants such as pollen and dust from the environment, and can reduce problems such as condensation or mould caused by too much moisture in the atmosphere.

How to improve ventilation and air quality



Consider the project as a whole

A successful ventilation strategy must be aligned with the project's context, which includes geographical location, building materials, architectural style and the habits of users occupying the space. Buildings in hot and humid environments require a very different design from those in cold and dry locations; so every building needs to be evaluated according to different parameters. Other important factors to take into account are the size of each room and number of people who are going to use it. Recent changes in Building Regulations also stressed the importance of ensuring the right level of ventilation in each area of a building.




Natural ventilation

The key advantage of natural ventilation is its ability to provide a very high air-change rate at a low cost, with a simple system. Buildings with modern natural ventilation can achieve very high air-change rates by natural forces, which can greatly exceed minimum ventilation requirements. Window sizing and placing is an important aspect of a natural ventilation system.


Windows should be placed across from each other but not directly opposite to allow the air in the room to mix more effectively resulting in a better distribution of cool and fresh air.




Mechanical ventilation

Make sure that mechanical systems which recirculate air, including air-conditioning systems, have been designed with fresh air inlets and that they are kept open to avoid the air becoming unhealthy. This is particularly important for rooms where a printer is installed for example, as chemicals particles can be dangerous to breathe.




Triple glazing for better insulation

Thermal bridges, cold drafts and overheating are all factors that can affect both the indoor climate of a room and its users health and comfort. For improved air quality choose triple glazed windows to significantly reduce the risk of thermal bridges - and therefore internal condensation 









The right temperature all year round

Ventilation essential for an healthy indoor climate, and so is the room temperature. Here's some advice on how to control internal temperatures by installing specific windows and doors.

Avoid draughts and excessive temperature fluctuations. Triple glazing can improve thermal comfort by reducing cold spots and eliminating cold downdraughts.

Avoid excessively high temperatures during the summer. External shading is the most effective way to reduce the impact of direct sunlight. Install tinted glass in large windows in south or southwest facing facades.

Temperature regulation

The impact of daylight and solar gain can be mitigated by strategic windows and glass specification. The number, size and distribution of windows across a building can be used to control the impact of daylight, while glass can be specified in a wide range of functions and coatings.


What type of glass can meet all the requirements of an ideal indoor climate? Download our flyer “More daylight, less heat” to find out more about pros’ and cons’ of different glass types.







Effective solutions for natural ventilation

In recent years, people have become increasingly environmentally-aware, opting for more passive ventilation solutions to reduce energy consumption and carbon footprint. This awareness means that automated HVAC systems have been replaced by wind, a natural, free and renewable resource that can easily improve internal air quality. Today leading architects incorporate climate-mediating strategies into their designs setting new standards for modern enviormentally friendlyarchitecture.


In terms of Building Regulations, ventilation levels are regulated by Approved Document Part F, which looks at three different ventilation types: 

  • Intermittent - usually mechanical (an extractor fan, for example) 
  • Background - usually provided by trickle vents installed within a window frame 
  • Purge - either natural (by opening a door or window) or mechanical 


Windows and doors are vital for effective background and purge ventilation, but performance has to meet the specific demands of Part F. Here’s some useful advice on how to achieve compliance. 

Motorised windows

Click vents

VELFAC click vents are built into the window frame, to ensure even air flow into to the room. The vents can be activated and deactivated just by clicking on the button. VELFAC windows are marked with the equivalent area (EA) of one click vent which can be found on the window ID-label.


VELFAC windows can be specified with specific restrictors that limit the opening to maximum of 10cm for ventilation. In side-hinged and side-guided opening functions the restrictor is installed in the jamb while for fully reversible windows it is installed at the cill.

Motorised windows

Effective natural ventilation can also be achieved by installing Window Master motors, a system which automatically opens the windows to let fresh air in. The Window Master motor is integrated within the window frame and is invisible when the window is closed, making it the ideal solution for natural ventilation projects or for windows that are difficult to reach.



Achieve optimal indoor climate and meet your energy targets

We provide a range of services designed to ensure impressive performance levels, backed by advice and guidance on technical issues and regulatory compliance.


More inspiration and knowledge


Fact sheet More daylight, less heat

Download our fact sheet and learn how to avoid overheating, regardless of fenestration.



"We wanted to make sure the building could stay comfortable without the need for mechanical cooling, even through the hottest summer. ‘This meant the placement of smaller windows on south facing facades, to manage solar gain, and the specification of multiple opening units across the building, including high level teleflex-operated lights."


- Corrie Rounding, Architect, Innes Associates


Contact our team to receive
Consultancy and advice for your project

Our team of experts can help you achieve your performance targets by providing tailored advice based on windows position, room orientation and specific requirements for your project