Ventilation - The Responsibility of the Landlord

Ventilation - The Responsibility of the Landlord

In this article, we will be looking at the responsibilities of landlords laid out in new government guidelines in response to the health risks attached to damp and mould as well as internal air quality, but if you are a homeowner, please do read on - the information here is just as relevant to you and your family. Links to products mentioned in this article can be found below and highlighted within the article text:

MVHR Systems
Single Room Heat Recovery Systems
MEV Systems
dMEV Fans
Alarms and Sensors

Amid mounting worries about indoor air quality, particularly following the tragic 2020 passing of toddler Awaab Ishak in Rochdale due to mould exposure, it's imperative to prioritise appropriate solutions for rental property to reduce the risks to residents.

As a landlord or property manager, it is your responsibility to ensure a safe and healthy living environment for your tenants. On September 7th 2023, the government published the guidance document “Understanding and addressing the health risks of damp and mould in the home” which amongst other things put the emphasis firmly on private landlords to take responsibility for issues of damp and mould in their rental properties.

“As this guidance also makes clear, tenants should not be blamed for damp and mould. Damp and mould in the home are not the result of ‘lifestyle choices’, and it is the responsibility of landlords to identify and address the underlying causes of the problem, such as structural issues or inadequate ventilation.”

The document takes into account a number of areas including the health effects of damp and mould, legal standards on damp and mould in rented homes, identifying & addressing damp and mould problems, and how to reduce the risk of damp and mould developing.

In this article we will focus on the areas that pertain to ventilation and the monitoring of Indoor Air Quality (IAQ) to help you find suitable solutions for your properties that not only help to reverse the effects of damp and mould, but can help you to prevent it happening in the first place. As well as mechanical ventilation systems, we will look at some universal environmental sensors that can be installed in homes to allow both you and your tenants access to real time data showing the IAQ and that can alert you and your tenant to problematic levels before they can cause either health or structural damage.

There are different causes for damp issues in the home:

Condensation damp

Condensation damp occurs when moisture produced indoors cools and condenses onto colder surfaces within buildings, such as window frames, corners & low points on walls, and behind furniture like sofas or wardrobes. This type of damp is the most prevalent.

Penetrating damp

Penetrating damp refers to water infiltrating the building from external sources due to faults in the walls, roof, windows, or floors.

Rising Damp

Rising damp is moisture originating from the ground that ascends through sections of buildings in contact with the ground, such as walls and floors. Typically prevalent in older properties, rising damp is frequently misdiagnosed. Visual inspection can reveal its presence, yet chemical testing offers the most accurate confirmation. Often, defective damp proof courses and membranes will be the cause.

Traumatic damp

Traumatic damp can stem from various sources, including leaking water from supply, waste and heating pipes, overflowing baths or sinks, burst pipes, or faulty water tanks within the building. It can also result from external factors, such as water intrusion from neighbouring buildings or environmental flooding.

Penetrating, rising and traumatic damp are usually caused by a structural defect or an “act of God”, and where suitable mechanical ventilation can certainly help with the internal recovery, remedial structural work will likely be needed to prevent these damp issues from recurring. However, condensation damp is a different matter.

To understand this issue we need to establish where the moisture is coming from and what factors can be attributed to the accumulation of the moisture causing damp. In modern homes, usually referring to post-1970s builds and most certainly to those built within the last decade or so, a huge amount of effort has been put into improving the retention of heat. This has made houses more airtight than ever to stop heat from leaching out through air gaps in the fabric of the building. The unintended knock-on effect of this is the retention of stale air, internal pollutants and humidity.

Humidity in the home comes from various sources, such as the obvious contributors of hot water appliances (showers and baths etc.), cooking and drying clothes, to the less obvious such as human respiration and perspiration. The danger is the moisture in the air will condense onto surfaces and materials within the home, soak into these surfaces and materials and cause damp areas. Damp on its own can be damaging but it also provides the perfect environment for mould to thrive.

Temperature contributes to the issue in two ways. Firstly, colder temperatures in a property will lead to colder surfaces. This speeds up the condensation of the moisture in the air when they come into contact with these surfaces. A good example here that is most noticeable is a cold external wall in a bathroom which will end up streaming with condensation when a hot shower is running. It is therefore imperative to ensure that properties are well heated & insulated, therefore raising the temperature of these surfaces - especially in colder months - to slow the process of condensation from happening. The warmer the air inside your home will also benefit the removal of moisture suspended in the air. As steam cools, the water molecules in the air start to bind together, forming larger water droplets. This is easily recognisable in the bathroom analogy above when steam becomes very visible clouds in the room. The larger the water droplets become, the heavier they are. This larger mass makes the droplets slower to move and in turn slows the air movement in the home, contributing to the retention of not just the water but also other air-borne pollutants present. Keeping a higher air temperature - especially in high moisture areas such as bathrooms, helps to slow the binding of the water molecules and therefore keeping the air-borne moisture lighter and easier to remove through suitable ventilation.

However, the second contributing factor relating to temperature that must be considered relates to mould and provides us with a dilemma. We know that damp creates a perfect environment for mould, but mould will thrive even quicker if that damp environment is also hot! This therefore creates a fine operating window for the ideal level to set your household heating. Ideally 18°c is optimal, any higher than 20°c creates the perfect conditions for mould to flourish.

So, having addressed the temperature variable, we now need to remove the humidity from the indoor air. The most effective way to achieve this is by using mechanical ventilation. The key to effective ventilation is to understand that for any air removed from a system, an equal volume of air must replace it. In household ventilation, the building is the system. Removing air from say a bathroom means that the equivalent volume must re-enter the bathroom, otherwise a vacuum will be created. Fan units are not designed to create vacuums and therefore if return air is obstructed from entering the bathroom at the same rate as the extracted air is being removed, the fan unit will be put under undue strain, slowing the rate of extraction which not only makes the ventilation less effective but will shorten the life of your extractor fan. This means that an equal airflow back into the bathroom needs to be possible from the rest of the house (not directly from outside) and that in turn, external air will replace the air into the house to balance the system.

This is not usually an issue in older builds where passive air movement through the fabric of the building allows for fresh air to enter the building, but can become problematic in new builds, where the design minimises the potential for heat loss through airflow to and from the outside. In these situations, the introduction of a fan system that both extracts and supplies air should be considered. With social housing needing to be as carbon neutral as possible whilst also being as economical to run and privately rented homes needing to meet minimum energy efficiency standards of a band E certificate (unless exempt), minimising heat loss while extracting stale and humid air can be a difficult task to complete. In these situations, MVHR systems are definitely worth looking into, especially if you are in the planning stages of a new build project. If you are looking to retrofit units into an existing build, then you can look at single room heat recovery systems as an alternative and less intrusive installation. Heat recovery essentially means that as warm air is extracted from the property, the heat is gleaned from the air as it passes heat sinks within the unit. This warmth is then transferred to incoming fresh air that the unit supplies back into the building. This not only balances the air movement in and out of the building but helps to retain the heat lost through extraction to minimise heating bills. For older properties, MEV systems which extract only can be beneficial or if a simpler option is needed for controlling damp and mould in problem areas, dMEV fans can be used to replace existing intermittent fans or as a new installation.

The key to all of these systems is constant flow. As opposed to the traditional intermittent fan systems which only extract when triggered, constant flow systems maintain continuous air movement through the home. This movement helps to improve the indoor air quality by removing stale pockets of air and keeps freshness levels raised.

This brings us to another consideration for landlords. Let’s say you rent six properties. At present all six properties show no signs of damp or mould. You have made sure that all six properties have suitable mechanical ventilation in bathrooms, utility rooms and kitchens. Your six properties are dotted around the country and not all are within a reasonable mileage of your home. The new guidance states:

“Landlords should periodically check properties for damp and mould, and for any risk factors such as inadequate ventilation and condensation.”

Considering that there is mileage to be travelled between these properties and that ample notice must be given to tenants before a visit, this can become a time-costly logistical nightmare for you to complete periodically.

The new guidance also states:

“Good data management is a crucial part of an effective response to reports of damp and mould, understanding damp and mould prevalence, identifying at-risk properties, and prioritising work. Landlords should collect and store information on damp and mould in their housing stock…”

The use of smart environmental sensors that can track the IAQ of your properties in real time and collate the data on cloud-based portals that both your tenants and you can access suddenly puts you in a far more efficient position to keep on top of your properties. Using this technology you can say goodbye to manual site checks, creating and updating spreadsheets manually and site-access issues - the technology does all of this for you. And to top it off, the majority of the new wave of smart sensor technology can even alert you to problematic properties before the issue has a chance to get a foothold.

Let's look at Aico’s system that we think should be on your radar:

Aico is the UK’s market leader in home safety. Their fire and smoke alarms are well known throughout the housing industry but they cover more than just optical smoke alarms, heat and carbon monoxide detection. Aico have a wide range of environmental sensors as well, including the Ei1025 sensor that monitors temperature, humidity and carbon dioxide, and provides insights into the levels of condensation, damp, mould and indoor air quality of a home. The sensor works in tandem with the Ei1000G SmartLINK Gateway which allows for remote management of not just the Ei1025 sensor but also any other radio frequency enabled Aico alarms or sensors. This means that you can manage not only the IAQ but also test and manage installed Aico smoke and heat alarms remotely as well. The SmartLINK Gateway receives information from the sensors via radio frequencies which then transits this data to a cloud based portal via the GSM network. The system is not GSM provider dependent so there is no SIM or contract needed for connectivity. The information sent is bidirectional data encrypted and has unique house coding allowing you to manage more than one household on the cloud-based portal by logging in to the respective account per house address. The portal is accessible via app or desktop and allows you to not only track alarm and sensor performance in real time and forecast replacement or maintenance but will also store all of the IAQ data from the sensor, giving you the data management you need to be in line with the new government guidance.

You can check out the full range of Aico products here.