Smart ventilation and the importance of good indoor air quality in self-build homes

The self-build boom

  • It is estimated there will be 20,000 custom and self-build homes completed in 2020
  • Research suggests that this number could grow even further with one in seven of the UK population currently researching building their own home
  • As part of a recent parliamentary enquiry held in 2017 into self-build it was calculated that the sector currently accounts for as many as 10 per cent of all completions

Self-build is big – and it’s getting bigger.

Self-build trends

The motivations behind building your own home are varied:

  • Saving up to 30 per cent on your house price
  • Designing things exactly as you want them
  • Selling for profit

Two dominant trends which span all these motivations have emerged in recent years:

  1. A focus on incorporating smart technology into the self-build project
  2. A desire to build an eco-home that is as energy-efficient as possible whist providing a healthy, comfortable internal environment

Let’s look at how these self-build trends coalesce around smart ventilation, energy efficiency and Indoor Air Quality (IAQ).


The clear links between poor ventilation and ill-health have, finally, made their way firmly into the mainstream. With modern airtight housing standards, it is now widely recognised that adequate ventilation is essential to prevent homes becoming toxic boxes of harmful chemicals and breeding grounds for damp, moisture and mould.

The need for ventilation for IAQ was recently highlighted in a study conducted by Zehnder. This found that everyday activities, such as applying nail varnish or cleaning, could result in dramatically poor IAQ. Cooking meals such as omelettes, stir-fries and grilled foods actually raised pollution levels in the kitchen to over three times that of a typical London road.

Part F of the Building Regulations, which provides guidance on building ventilation, is under continual review, with updates applied in 2006, 2010 and 2013. Research by government agencies on the issue of ventilation and IAQ in new homes continues to inform regulatory reform.

Self-build, energy efficiency and smart ventilation

The ideal self-build, modern home is a sealed home that keeps heat in to reduce carbon emissions and energy costs.

It offers automated and connected control over lights, heating, entertainment and security. It also has optimum ventilation. Without adequate ventilation sealed homes not only retain heat, they also retain moisture, VOCs and PM2.5 particles that are known to contribute to asthma and lung disease.

So, how can smart ventilation help?

The Air Infiltration and Ventilation Centre (AIVC), the international energy agency information centre on energy efficient ventilation of buildings, defines smart ventilation as:

“A process to continually adjust the ventilation system in time, and optionally by location, to provide the desired IAQ benefits while minimising energy consumption, utility bills and other non-IAQ costs (such as thermal discomfort or noise).”

A smart ventilation system adjusts ventilation rates by responding to one or more of the following:

  • Occupancy
  • Outdoor thermal and air quality conditions
  • Electricity demand (including signals from utilities)
  • Direct sensing of contaminants
  • Operation of other air moving and air cleaning systems

“In addition, smart ventilation systems can provide information on operational energy consumption and IAQ as well as signal when systems need maintenance or repair.”

In brief, it automatically responds to the environment to provide efficient and effective ventilation and monitoring.

Some examples of how smart ventilation works

For whole house ventilation, Mechanical Ventilation and Heat Recovery (MVHR) is a smart choice, especially when planned to be installed at the design stages of a self-build.

It offers year-round fresh ventilation and a welcome boost of low-cost warmth during the colder months, and is rapidly becoming a must-have for many self-build projects.

MVHR systems automatically remove stale air from a home and replace it with a fresh incoming provision. They also extract and recycle any warmth in the outgoing air by transferring it into the new supply, reducing the need for heating.

Units such as Zehnder ComfoAir Q can be simply and effectively controlled to ensure optimal performance around the clock. They will also react to the indoor environment, so you don’t have to.

The controllers can be linked with sensors to enhance comfort and offer total flexibility. For example, they will boost speed functionality when excessive levels of relative humidity or CO2 are detected.

Ultra-efficient counterflow heat exchangers that recover up to 96 per cent of the heat from extracted air add to their green credentials.

While MVHR is not a complicated install into new builds, it can be trickier to retrofit or add in late into the project. Continuous mechanical extract ventilation is another option, particularly for those who haven’t factored in ventilation from the get-go. Trickle ventilation is also known as continually running ventilation. The latest incarnation of continually running ventilation is decentralised Mechanical Extract Ventilation (dMEV). dMEV is a low-maintenance, ultra-quiet system of ventilation. Products with the option of SMART technology are proving revolutionary in responding to humidity levels and ensuring optimum ventilation.

dMEV is a low-energy ventilation system designed to replace noisy and inefficient conventional bathroom extractor fans (it can be installed in any room, however). The fans run continually at a low trickle rate, boosting automatically when moisture levels rise, for example when cooking, taking a shower or running a bath.

Smart ventilation at the crossroads

The self-build home is becoming a smart and energy efficient home. Standing at the crossroads between the two is the latest breed of smart ventilation. And that’s a real breath of fresh air.