It’s summertime, and the living is easy – unless you’re one of the many people who suffer from overheating in their living spaces. Since no one enjoys suffering through summer as a hot and sweaty mess in their own home, we will show you how we overcome the problem of overheating in living spaces.

In this Cool Runnings case study, we’ll look at how we offset the potential of overheating in the recently completed Lewisham Exchange building.

The Lewisham Exchange building is a 19-storey student and residential accommodation block in east London. The tall, slim building is situated just yards away from a busy train line, which brings with it the challenges of both external noise and vibration.

Not to mention the potential for severe overheating.


The building has non-openable windows – a design feature that’s becoming increasingly common in new multi-occupancy buildings. In addition, building restrictions are increasingly becoming a cause of overheating, and building occupants are prevented from opening windows due to planning restrictions. This problem also persists when people cannot open their windows due to external noise, odour, pollution, and even security concerns. The result is overheating issues on warm days.

Here are the other factors that contribute to overheating in buildings:

New buildings that utilise increased insulation levels, airtightness, and large areas of glazing all increase the problem of overheating.

Solar gain
Homes with unshaded, double-glazed windows will amplify the heat on hot days. This issue becomes even more prominent if the house happens to have west-facing glass.

External temperature
Even opening the windows has little effect on overheating when there is no wind on a hot day.

Internal heat gain
Internal heat gain is increased by the number of people, mechanical services, and electrical appliances working in a home.

How we overcame the challenge of overheating in the Lewisham Exchange building:

The first step was to identify the cause of the overheating. In most cases, it is due to a build-up of hot air in the room. However, this can be caused by many factors, such as sun exposure and poor ventilation.

Once we had identified the cause of the overheating, we could devise a solution that would work for the specific situation. In this case, we installed a system that would supply and extract air simultaneously at a rate of four times the standard rate, helping to replace the stale air with fresh, filtered air without causing a noise disturbance.

To combat overheating, we installed two Vectaire Midi MVHR (mechanical ventilation with heat recovery) systems per studio. In addition, we fitted both systems with complete sound attenuation and acoustic air valves to reduce background noise.

We also collaborated daily with an acoustician, designer, and consultant to ensure that the system met all the requirements. We also carried out sound checks after hours to avoid any interference from traffic noise.

Here are the technical specs of our MVHR installation at the Lewisham Exchange building:

  • Studio floor total floor size: 15.1 sqm
  • Air flow rate requirement per MVHR System (2 per studio)

– Trickle: 13l/s (continuous)

– Boost: 21l/s (10min overrun)

– Purge: 60l/s

*Each system was terminated externally via double air bricks to allow a smoother pass of air in and out of the property.

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Our Range of Economical Ventilation Systems

We supply and install Heat Recovery Systems (MVHR), PIV units, Bathroom or Kitchen Extractor Fans (MEV), and Single Room MVHR Units (DMVHR)

There is no one-size-fits-all approach when it comes to choosing a ventilation system. The layout of your property, the specific issue and your budget are all important factors to consider before taking steps to address needs.