How To Improve Indoor Air Quality
The subject of indoor air quality is about more than just stuffy air; it is about air pollution inside your home. This article discusses what contributes to indoor air quality and the best solutions to ensure your home creates a healthy indoor environment.
What is indoor air quality?
Air pollution is a concern for most city dwellers. We know that cars, industry, dust and pollen cause poor urban air quality outside our homes. Exposure to poor air quality increases the risk of developing or exacerbating lung and breathing problems, skin conditions, cancer and organ damage.
We may feel isolated from this indoors, but it isn't the case. And since we spend 90% of our time indoors, indoor air quality is critical.
What creates poor indoor air quality, and what are the risks to us?
The air inside our home can deteriorate for several reasons.
The simple act of breathing exchanges oxygen for carbon monoxide, and replenishing fresh air is necessary for human survival. But breathing also introduces moisture into the air, as does boiling kettles, running baths and drying laundry indoors. It is essential to expel this air to keep your home and dry. High moisture content creates a more significant potential for mould growth; this is bad for your health and the health of your building.
Many household objects also contribute to the degradation of indoor air quality. There are the products we use such as cleaning products, the products we own like furniture made with MDF, and products used to make the building. All can contain volatile organic compounds (VOCs) that are bad for your health.
To expel this air and adequately ventilate a home, the obvious solution is to open the windows. But this is not always practical due to increased noise, reduced privacy and home security concerns, especially in urban areas. It also rains a lot in the UK. By expelling pollutants in this way, heat can escape, and poor-quality outdoor air can enter, the same air that causes many deaths in London every year.
The solution
There is a better way to solve all these problems. It's called mechanical ventilation heat recovery (MVHR).
MVHR is a whole-house ventilation system that exchanges indoor air with preheated and filtered fresh air. Outgoing air is extracted from wet rooms and spaces deep within the building and filtered before being expelled. A heat exchanger in the unit transfers outgoing heat to fresh, filtered air before being delivered to main rooms around the house.
What needs to be considered, and how is it done?
The size of an MVHR unit will depend on the size of the property it serves. A unit for a 3-to-4-bedroom home will typically fit within a cupboard or in the loft. MVHR is low maintenance, but filters should be changed at least twice a year, so maintenance access should be considered. The unit should be located internally close to an external wall or roof. It can be in a heat or unheated space, such as an uninsulated loft. The north side of the building, is the optimum location for the unit to benefit from cooler incoming air in the summer.
The supply and return ductwork layout for an MVHR system is radial, like a spider. When designing a home, it is essential to consider and coordinate duct runs with all structures. If you want to ensure beautiful, well-proportioned rooms that are visually pleasing and practical, the ductwork should be concealed in walls, floors and suspended ceilings. To a discerning eye, nothing is more disappointing than corner protrusions that cover oversights resulting from poorly planned pipework.
Due to spatial constraints, a whole-house mechanical ventilation system can be more challenging to integrate into older homes. Individual through-wall MVHR extractors are less efficient but, due to their size and lack of ductwork, easier to implement in this case. Multi-room extraction systems can also alleviate damp and indoor air problems from interior rooms but do not recover heat and are less efficient. But if you are planning a whole-house refurbishment, you have a unique opportunity to transform your home's air quality by including a whole-house MVHR system.
Why is it good for you?
OPTIMAL AIR QUALITY - The main advantage of MVHR is improved indoor air quality. It ensures home health by filtering both outgoing and incoming air, removing dust and pollutants. Air is exchanged a few times every hour, alleviating allergies and asthma, increasing alertness and improving sleep. Owners of homes with MVHR systems are often shocked by how dirty filters are when they are first changed. (Insert photo)
PRACTICAL, WARM AND DRY - It is a practical solution because it is independent of weather, ensures acoustic privacy and eliminates the security risk. Continuous low-volume background ventilation ensures that air moves around the house, equalising temperatures, humidity and air quality throughout the home. People with MVHR can dry laundry indoors and often don't use heated towel rails to keep towels dry.
QUIET - An MVHR system helps create a peaceful calm indoor environment due to the low-volume air change delivered without opening windows.
ENERGY-EFFICIENT - MVHR is extremely energy-efficient because it recovers up to 91% of the heat from the outgoing air.
Why is it good for your home?
CONDITION OF YOUR HOME - A warm and dry home is easier to maintain and helps it keep a good condition. This is good for the long term value of your home.
FUTURE PROOFING - The climate crisis will make high performing, energy-efficient homes the luxury of the future. An MVHR system will be a fundamental feature of these high-value properties.
Why is is good for the environment?
FACILITATES FABRIC FIRST - MVHR is one of the essential components of a fabric-first low-energy home and permits exceptionally airtight and heavily insulated buildings that use less energy to heat and are good for the environment.
What is next?
The improved comfort of a quiet, dry and warm home created by having an MVHR system may be hard to measure, but the benefits of an MVHR system are numerous and hard to dismiss. It is good for you, good for your home and good for the environment.
Good indoor air quality has always been a feature in our designs. When undertaking a complete refurbishment, we have always worked out ways to integrate a whole-house extraction system within the building, to extract from wet areas, ensuring continuous low volume airflow. Researching the best construction and environmental practices has brought us to Passivhaus. We now incorporate whole-house ventilation systems with heat recovery wherever possible.
If you have a project in mind, please get in touch.
