How to Improve the Air Quality in Your Home
Want to ensure your home environment is clean and healthy? Start by assessing the quality of your air
Professional advice from: Cat Hoad of Absolute Project Management; Kit Knowles of Ecospheric; Kieran Hawkins of Cairn
“The topic of ventilation and air quality is possibly the most important aspect of any home renovation and is probably the most overlooked,” Kit Knowles says.
“It’s an increasingly important topic as we become more aware of the impact that poor air quality has on our health,” Kieran Hawkins agrees.
Cat Hoad says, “[This subject] is gaining importance as clients become more aware of the key role of wellbeing in their homes.”
Ironically, many of the things we do to make our homes efficient and reduce our energy consumption, such as making them airtight and improving insulation, can actually have a knock-on effect on air quality indoors.
“Our homes are … becoming more tightly sealed to the outside world, with higher-quality construction a necessity to reduce our use of fossil-fuelled space heating,” Kieran says. “So we can’t rely on a flow of naturally ventilating air, as we could in a draughty Victorian house.”
As such, pollutants can become trapped indoors, and condensation and damp levels can increase without a controlled flow of fresh air.
“There are various standalone monitors that track components of air quality (general urban pollution, pollen and other allergens, waste gases from household appliances and so on), many of which have app functionality, too,” Cat says.
“There are a number of electronic devices on sale that will report on indoor air quality, showing you the levels of pollutants ranging from pollen to carbon monoxide and mould,” Kieran agrees. “These are relatively low cost and can be a good investment. But of course, diagnosing a problem can be much simpler than determining how to solve it.”
Browse reviews of architects and building designers on Houzz to find the right expert to advise on ventilation for your home.
“The first step will be to identify what the specific issue is before determining how to tackle it,” Kieran says. “Air quality is closely tied to other concerns, such as insulation, airtightness and damp-proofing. You need to be careful not to cause an issue elsewhere when addressing one of these areas in isolation.
“A house is an environmental system more complex than many people realise and should be looked at holistically,” he continues. “If in doubt, I would always recommend contacting an expert.”
More: How to Deal With Penetrating and Rising Damp
Avoid products that can release harmful gasses
Firstly, assess what you’re bringing into your home. ‘Off-gassing’ is when indoor products, such as furniture or soft furnishings, release harmful chemicals into the air.
“It’s important to avoid bringing items into the home that off-gas,” Kit says. “A typical mattress or sofa consists of more than 70% oil-based products … so choose petrochemical-free items.”
Formaldehyde is another product that occurs in a surprising number of household products. “It’s a carcinogen, and one of the most prevalent household pollutants, found in furniture, flooring, carpets, paints, and so on,” Kit says.
“As much as possible, we recommend using natural materials, such as wood, clay plaster and natural paints, that won’t give off toxic fumes like many synthetic options,” Kieran says. “Natural materials often also absorb and filter pollutants from the air. Limiting carpets to bedrooms also helps in reducing airborn pollutants.”
Paints can also cause indoor pollution, so consider this when decorating. “We’d encourage the client to choose low VOC paints,” Cat says. “There are now a number to choose from, and even the big ‘trade’ brands are offering some alternatives.”
“For our Zetland Passive House project [pictured], we specified lime plasters and lime-based paints, which buffer moisture and even absorb volatile organic compounds (VOCs) and CO²,” Kit says. “We only used natural, breathable materials to construct the walls and roof, including insulants such as wood fibre and cellulose made from recycled newsprint, and avoided formulated products.”
More: Houzz Tour: Is This the UK’s Greenest Victorian House?
As well as optimising the use of natural materials, Kieran recommends ensuring any areas of damp or condensation are rectified. “This can often be helped by carefully increasing the levels of insulation,” he says. “Air purifiers and dehumidifiers can be added to the mix if necessary.”
“Pathogens, allergies and respiratory infections all decline when 40% to 60% relative humidity is maintained [and indoor humidity meters are fairly cheap to buy if you’re keen to check this],” Kit says. “As well as being good for the health of the occupants, [maintaining correct levels of humidity] also reduces the likelihood of a mould/rot infection in the building fabric.”
More: How to Deal With Condensation Damp
As well as reducing indoor pollutants, good ventilation is key to improving your home environment. If you have a super-insulated home, you’ll need to consider how to ventilate the space to ensure air flow, Cat says. For example, if she’s undertaking a renovation that includes improved insulation, her company will look at upgrading the ventilation “as a necessary counterpart to this”.
“The problem with [some] ventilating is that it increases energy [use] and costs, because the energy invested to heat the air within the property is lost to the external environment,” Kit says. “The key is to take control of ventilation. Ideally, a healthy and comfortable internal air quality is achieved by controlling air flow using mechanical ventilation.”
However, while this might be the right system for those looking to take a Passive House approach, others suggest using it only when other avenues have been explored. Kieran recommends looking at using natural materials and other methods before considering an MVHR system.
“Additional active measures such as dehumidifiers and air filtering mechanical ventilation should only be used if absolutely necessary in a private house,” he says. “We always try to optimise the conditions by reducing and simplifying, rather than adding more equipment that will inevitably need to be serviced and eventually replaced.”
If you’re considering an MVHR system, Kit suggests you do your research and speak to an MVHR supplier or ventilation specialist first. “Make sure your ventilation supplier and architect work together to design a system that’s optimised for your specific project,” he says.
More: How to Retrofit Healthy Ventilation into Your Home.
Recent research has started to link burning wood indoors with the release of small particulate matter – a pollutant that can be harmful to health.
“I think there’s ample evidence that both open fires and wood-burners can significantly increase certain pollutants in the home while they’re being used,” Cat says. “However, they are very popular, so I’d say if you’re going to use one, you should make sure your chimney is fitted with a flue/filter to the current applicable regulations and think carefully about internal ventilation (ie, don’t use one in a closed room for too long). [You should] also consider occupants of the house – small children or people with respiratory issues should probably avoid them.”
“The current evidence seems to be that they should be avoided if occupants are vulnerable to respiratory issues,” Kieran agrees. “For a lot of clients, though, the wood-burner is a real priority as a focal point in their home. Like many things, the pros and cons will need to be weighed up in each case.”
A quick, easy and visually pleasing way to reduce indoor pollutants is to invest in a few houseplants, many of which can absorb pollution from the air. “We love houseplants,” Cat says. “We use them wherever possible to add beauty and a connection to the natural world. Many species [also] actively reduce pollution in the home, just by being there.”
Nasa undertook a clean air study in the 1980s that’s still cited as the main piece of research into the benefits of houseplants in removing indoor pollutants. Take a look at its list of recommended plants here.
“Our number one piece of advice is that any renovation or low-energy retrofit requires ample planning,” Kit says. “While any retrofit can be staged, there are certain technologies and changes that should come first in order to optimise the health and thermal performance of a building.”
Have you taken steps to improve the air quality in your home? Share your thoughts and suggestions in the Comments.