In this post, we’ll be exploring how condensation causes mould.
Condensation is a common phenomenon that occurs when moist air comes into contact with a cold surface, leading to the formation of water droplets.
While condensation can affect various surfaces, metal roofs, particularly those with a low angle, present unique challenges. In this blog post, we will explore the impact of condensation on metal roofs, focusing on its potential to cause mould growth and its implications for health.
By understanding this relationship, homeowners and builders can take proactive measures to mitigate the risks associated with condensation.
The Nature of Metal Roofs
Metal roofs have gained popularity due to their durability, longevity, and aesthetic appeal – they’re also relatively low cost, and are quicker and easier to install than more traditional roofing materials, such as tiles.
However, they also possess certain characteristics that make them susceptible to condensation-related issues – namely that metal is a good thermal conductor – meaning it can cool and heat up relatively quickly. What happens then, is that metal roofs are often close to the outdoor temperature and thus can be very different to the temperature within a roof space or attic.
Metal roofs are typically installed with an angle of less than 22 degrees, which poses challenges when it comes to managing water runoff (Australian Building Codes Board, 2021), we’ll come back to this.
Condensation Drips and the Risk of Mould Growth
In traditional roofing systems with steeper angles, rainwater efficiently runs off the surface, minimising the chances of water accumulation and subsequent condensation-related problems.
However, when the angle of a metal roof is less than 22 degrees, condensation cannot run off it, which results in it dripping.
As I always say, mould is a moisture issue.
Mould spores are everywhere and are waiting for the right level of moisture to become active. Metal roofs with condensation issues can provide an ideal environment for mould.
The growth of mould on a roof's underside not only compromises its structural integrity but also poses serious health risks to occupants (National Construction Code, 2021).
I want to illustrate this for you with some photos I took of the underside of a metal roof that covered a deck.
These photos were taken mid morning after a cold night. You can see the condensation lined up along the valleys of the metal roof (left). As well, you can see the moisture on the table beneath (right).
Health Implications of Mould Growth
Mould growth can have significant implications for human health. Exposure to mould spores, particularly indoors, can cause a range of health problems, including allergies, respiratory issues, and even infections. Individuals with existing respiratory conditions, such as asthma, are particularly vulnerable to the adverse effects of mould exposure (Wang et al, 2023; ABCB, 2019).
There is a growing body of research that highlights the detrimental effects of mould on respiratory health, emphasising the importance of preventing mould growth in buildings to safeguard occupants' wellbeing.
Mould, including the strains commonly found in damp and poorly ventilated areas, thrives in the presence of moisture. Metal roofs are condensation risks, and without enough slope, this can drip onto insulation or the plasterboards of the ceiling, and result in “hidden mould”, and thus can be playing a role in health issues, even when there is no visible mould.
Understanding the Causes of Condensation
To effectively address condensation-related issues on metal roofs, it is crucial to understand the underlying causes.
While the slope of the roof is an incredibly important factor, there are other important considerations. These are high humidity levels within the building, inadequate ventilation, and temperature differentials between the interior and exterior environments. Identifying these causes allows homeowners and builders to implement appropriate measures to control condensation and mitigate its impact (ABCB, 2019).
Mitigating Condensation Issues on Metal Roofs
To combat condensation problems and prevent mould growth on metal roofs, several strategies can be employed:
Adequate ventilation is essential to expel excess moisture and maintain a balanced humidity level. Proper airflow helps in reducing the likelihood of condensation formation (Australian Building Codes Board, 2021; New Zealand Building Performance, n.d.). Some simple steps include venting extractor fans to the exterior of the building (not into the roof space), installing whirlybirds, depending on the climate, opening the roof space up to allow air circulation (e.g. having metal mesh soffits).
Insulating the Roof
Insulation acts as a thermal barrier, minimising temperature differentials between the interior and exterior surfaces of the roof. This helps reduce the occurrence of condensation by preventing warm, moist air from coming into contact with the cold metal surface (Australian Building Codes Board, 2021; New Zealand Building Performance, n.d.). Care also needs to be taken to ensure that the insulation does not block the condensation runoff, and also that it isn’t directly beneath the metal roof.
Installing Vapour Barriers
Vapour barriers are effective in preventing moisture from permeating into the roof structure. By creating a barrier, they minimise the chances of condensation formation (Australian Building Codes Board, 2021; New Zealand Building Performance, n.d.). What they do is allow water vapour to escape from within the building envelope.
Compliance with Building Codes and Standards
To ensure the safety and quality of construction, it is crucial to adhere to relevant building codes and standards. In the case of metal roofs and condensation management, the Australian Building Codes Board and National Construction Code provide guidelines and regulations to mitigate the risks associated with condensation and mould growth (Australian Building Codes Board, 2021; National Construction Code, 2021).
In New Zealand, where “leaky buildings” have been a significant issue, the New Zealand Building Performance provides valuable resources and information on weathertightness and managing condensation to address these concerns (New Zealand Building Performance, n.d.).
While Condensation Causes Mould it Can Be Mitigated
Condensation on metal roofs, especially those with angles less than 22 degrees, can lead to the formation of condensation drips, increasing the risk of mould growth. This can have detrimental effects on both the structural integrity of the roof and the health of the occupants. Mould exposure can result in allergies, respiratory issues, and infections, particularly for individuals with pre-existing respiratory conditions.
Understanding the causes of condensation, such as high humidity levels and inadequate ventilation, is crucial in developing effective strategies for mitigating condensation-related problems. Improving ventilation, insulating the roof, and installing vapour barriers are practical measures to control condensation and prevent mould growth.
Compliance with building codes and standards ensures that construction practices align with recommended guidelines for condensation management. By implementing these strategies and following regulatory requirements, homeowners and builders can create healthier living environments and prolong the lifespan of metal roofs.
Taking proactive steps to address condensation issues on metal roofs is essential for safeguarding the integrity of the structure and the well-being of those who reside within. By prioritising proper ventilation, insulation, and moisture control, homeowners and builders can minimise the risks associated with condensation and create a safer, mould-free living environment.
Wang, J. et al (2023). Effects of mold, water damage and window pane condensation on adult rhinitis and asthma partly mediated by different odors. Building and Environment, 2023. Retrieved from https://doi.org/10.1016/j.buildenv.2022.109814
Consider natural deodorants – some of my clients have used bicarbonate of soda, other swear by cider vinegar, personally, I prefer to mix up essential oils in a bottle of rose water and spray that on every few hours (essential oils evaporate quickly)
Reduced Indoor Air Quality
Closing the windows to keep the heat out and the cool in can cause indoor air pollutants to build up, which is never ideal.
This is made worse when bringing new items into the home – which are often still off-gassing volatile organic compounds (VOCs) and potentially also formaldehyde.
Adding another layer to this is the increased temperatures speeding up the release of VOCs, which can readily form by-products in the air.
The great thing about this problem is that the solutions are simple!
Ventilate your home. Open doors and windows at least 3 times a day (the ideal would be every hour) to exchange the air in your home.
When you’ve got the windows closed, ensure your airpurifier is going.
Avoid using “air fresheners” and other scented products.
Moisture in the Interstitial Spaces
Condensation forms where there are variations in temperatures. What we see with the use of air conditioning, is condensation forming on the other side of plasterboards, outside of windows and also on the other side of the ceiling.
These areas are referred to as “interstitial spaces” and can be the site of many cases of “hidden mould.”
In 2018, I was in far north Queensland to present training on mould and was amazed to see the windows literally streaming with condensation – to the point that it looked like it was raining heavily.
This is a complex problem, but ultimately it rests heavily on the use of air conditioning – as this is what causes massive temperature variations.
Explore alternative ways to cool – installing plants along the paths and in front of your windows to naturally cool the air, hanging a wet sheet across the open window or door, wetting your hair, clothes or skin.
Aim to keep the inside temperature closer to the outside temperature – don’t set the cooling for 15oC, instead, set it for 25-30oC.
If you can, keep the windows open a little to help even out the temperature a bit.
Higher levels of relative humidity in tropical and subtropical regions is the number one problem here.
It’s important to remember that there are mould spores everywhere, waiting for the right conditions.
Often all they are waiting for is enough moisture.
And high levels of relative humidity can provide this.
(This is why “mould is a moisture issue” – as I’m sure you’ve heard me say time and again).
Keep an eye on the levels of relative humidity with a hygrometer, remembering the ideal range is 40-60% RH, with 50% RH being the magic number.
If the relative humidity levels go above this, use a dehumidifier to bring them down to below 60% RH.
Pull furniture from against the walls, so that air can circulate around it, as well as giving you the opportunity to check the walls for mould.
The combination of higher temperatures and higher levels of rainfall (as we’ve been seeing in Australia) results in more active breeding of mosquitoes, termites, cockroaches and rodents.
Each of them bring their own risks to either human health and/or the health of our homes.
While we consider them pests, we need to be considered in how we deal with them.
My preference is always to deter them, rather than kill them.
If you prefer to kill them, then take great care with poisons – especially rodenticides (poison for rodents – rats and mice). Poison can be slow acting, and other animals further up the food chain can also be killed as a result. I’ll be putting a post together on this soon. In the meantime please read more here – as they also include a post about safer poisons.
Install fly screens over doors and windows; and repair any old ones that are damaged.
Flooding is something we’ve recently experienced on a scale that really hasn’t been seen before.
I’m not a scientist or meteorologist, but experts say this is due to either or both La Niña and climate change.
Flooding – the Primary Effects
Primarily, flooding is going to result in mould issues. Mould is a moisture issue and with the abundance of moisture (rain, on the ground and the high levels of relative humidity), we’re seeing a perfect storm brewing for mould and microbial activity.
The focus of today’s post is the secondary effects.
So, I’ll leave the topic of mould here, with the following pointers:
Anything that’s been wet for more than 48 hours can create the opportunity for mould and microbial activity
Porous materials that have been wet, need to be replaced
Semi- and non-porous materials can be saved, but need to be addressed by the appropriate professionals (those who’ve trained with IICRC and have achieved the Mould Remediation accreditation)
If you want to learn more about dealing with mould, I have a course by that very name – you can check it out here.
www.EWG.org will also list options, however, I’ve found that these are often not available in Australia (and I don't recommend purchasing these types of items online from overseas as they may not meet our safety standards)
I’m going to bring back my essential oil based Bug Repellent (contact me if you're interested)
If you opt for a non-natural option, apply an oil-based moisturiser on your skin first, so the repellent sits on the surface of your skin (and is also easier to wash of)
Another way to use the non-natural option is to spray it onto clothing, instead of your skin
DIY – make your own with essential oils, such as tea tree, rosemary, eucalyptus blue mallee, and lavender. You can mix them up in water and spray them on your clothes/skin and reapply every 2-3 hours
We can expect some pretty big issues with termites with the high levels of moisture.
According to Professor Dieter Hochuli, Integrative Ecology Group at the University of Sydney,
“It’s going to be a massive year for termites as the high levels of soil moisture are ideal for them to burrow and flourish” (ABC News, 31 Oct 22).
A bit like house dust mites, termites thrive in moist conditions.
Termites are attracted by the moisture then go in search of food – wood.
Here are some things to do.
Clear away wood (fallen branches, sleepers, wood piles) from around your home and property
Keep things as dry as you can
Be vigilant – keep an eye on your building, including the subfloor. If you’ve got termite caps at the top of your stumps, then you should be able to spot their activity easily.
Have your home inspected
Termite traps can be useful around your property, too
Cockroaches and Rodents
Cockroaches and rodents (rats and mice), as well as other pests are likely to increase, particularly as the weather warms up.
Some actions that you can take are:
Installing fly screens on windows and doors
Keep your home clean
Clean up food scraps and mess
Ensure your bins close properly
If you’ve got a compost bin, keep it away from the home
If you’ve got chooks, look into getting a feeder that doesn’t spill their food around
Keep pet food (and your own) in sealed containers
Other Steps You Can Take To Reduce the Secondary (and Tertiary) Effects of Flooding
Keep an eye on the relative humidity levels – these should be between 40-60%. A hygrometer is handy for this.
Mould sensitivities are more common than most people realise.
If you're a regular here at Eco Health Solutions, it is highly likely that you have mould sensitivities or other environmental sensitivities, know someone who does, or know enough about them to want to prevent them… If you're new, then feel free to peruse this and other posts on environmental sensitivities.
I wanted to bring you a different, and more technical, perspective on mould and health – so invited my friend Tim Law, an architectural scientist with a strong interest in this topic to share his insights with you.
Grab a cuppa and pen and paper and settle in for this great read.
I am an architectural scientist, one who uses the principles of physics, biology and chemistry to understand buildings.
On the positive side I try to make buildings perform optimally, and on the flip side I explain why they fail.
If you are reading Lucinda's website, you are most likely aware that conventional medicine has a very limited understanding around the health implications of mould in water-damaged buildings.
This article is written to help you understand that even though your physician may not be familiar with mould sensitivities you should not feel alone. There are many others like you.
Fungi, the fifth kingdom. Ubiquitous, prolific, little understood. They are the great recyclers, decomposing trees, recovering its nutrients, nourishing the soil. They are selectively symbiotic, and at times territorial.
But once they sporulate in water-damaged buildings, they become unequivocally unhealthy to humans.
You are not alone in your home.
There is an entire ecosystem of microorganisms waging biological warfare. Quite different from human warfare, there is no morality in this war, no good vs evil, no heroes or villains, it is simply what fungi do.
It turns out that mould does not live a solitary existence. They form colonies. The word ‘colony’ has been well chosen.
Mould can team up with other organisms such as bacteria to form biofilms — a kind of fortified city wall to protect the organisms within its confines.
More significantly, mould colonises. It is opportunistic, dormant until the conditions are right, then invades and proliferates. Like any colonist, mould does not like to share. It is hypothesised that mould sends out mycotoxins (mould toxins) to eliminate its competition.
The strategies largely fall in two methods: arrive early and multiply quickly, or arrive late and carry some big guns.
Microbiologists divide the continuum as primary, secondary and tertiary colonisers.
They also follow the same neat order of water activity (or wetness of a porous material): primary colonisers germinate when the material is moderately damp for a few days, and tertiary colonisers when it is very damp for a long period of months.
The Might of Mould
Human ingenuity has turned these mould metabolites into medicines — a vast range of fungal antibiotics are derived from mould.
Humans also figured that we could isolate and weaponise mycotoxins. In the stuff of nightmares, trichothecenes can be derived from the common tertiary coloniser found in water-damaged buildings, Stachybotrys chartarum, that gram for gram, exceeds mustard gas in toxicity.
Stachybotrys chartarum has received superstar status in the media and is commonly referred to as “toxic black mould”. This turns out to be a rather unhelpful description since mould has different colours depending on the substrate it feeds on, and changes colours across its life cycle, just like trees do across seasons.
Yet not all moulds are hazardous. Some moulds are brilliantly delicious. Koji (Aspergillus oryzae) creates umami-charged cuisine.
Impressively, one could marinate raw meat with shio-koji and let the process continue for days unrefrigerated without bacterial overgrowth, according to Jeremy Umansky, author of Koji Alchemy.
One wonders if this can be applied to buildings. And indeed this idea is not far-fetched. Japanese Koji houses are dedicated fermenteries — no other ferments are permitted in the facility so as to minimise cross contamination.
Before fermenting is commenced, the Koji master goes through the ritual of scattering Koji spores all around the timber building structure to essentially stave off any other moulds from colonising.
Mould in Buildings
We should attend to our buildings with a similar care, seeing how most of Australian domestic construction is dominated by cellulose material.
From timber frames to engineered timber products like LVLs (laminated veneer lumbers) and plywood, to particle board flooring, MDF (medium density fibre) boards, to paper-faced plasterboard wall and ceiling linings — virtually everything we build with in a typical Australian house is mould food, you just have to add water.
It should be pointed out that mould is not the only problem with dampness.
Water supports life of a host of micro-organisms besides mould, it is just mould that is the most visible due to its mycelial structure.
To keep mould and other microorganisms away from houses, it is as simple as keeping moisture out.
Simple, but not easy.
If it were easy moisture-related defects would not be repeatedly the highest reported source of problems for apartments by the NSW Office of the Building Commissioner occurring in 53% of reviewed apartment buildings.
In Victoria, surveys conducted by the Australian Apartment Advocacy show water-related defects as a group of defects are well ahead of any other classification.
Regardless of state/territory and climate zone, there was a fairly consistent average that a third of these new buildings were estimated to have condensation problems.
If we add to this the water-related defects such as failures in plumbing, roofing, cladding, water-proofing and damp-proofing, then a building free from water damage is in the minority.
Condensation provisions were only introduced into the National Construction Code in 2019, meaning to say that houses and apartments built prior to this could be deemed to be code-compliant, and yet have unmitigated condensation, together with the mould and bacteria that invariably follows prolonged dampness of building materials.
When the micro-organisms proliferate, not only do they produce toxins to gain a competitive advantage, even their cell walls become a source of toxins.
These toxins are collectively referred to as biotoxins and create a range of maladies, broadly categorised as allergenic, pathogenic, toxicological and inflammatory.
In essence, it can be very broad, systemic, affecting multiple organs and expressed through multiple symptoms.
Early symptoms often include brain fog and chronic fatigue.
On prolonged exposure to water-damaged buildings, mould-sensitive patients eventually also develop chemical, light and electromagnetic hypersensitivities.
New Research into Mould Sensitivities and Biotoxin Illnesses
On top of that, in an Australian first, the NHMRC (National Health and Medical Research Council) is funding research into biotoxin illness. I am one of the investigators and am optimistic that recent advancements in data mining, next-generation sequencing, transcriptomics and metagenomics will enable us to tackle this complex problem which has hitherto been too complex to analyse.
There is almost a poetic irony that interconnected disciplines are required to unravel the interconnected symptoms of a patient suffering from interconnecting micro-organisms.
Thus, if you find yourself in a water-damaged building, remember you are not alone. There are many Australians in a similar predicament that you will be able to connect with.
Keep seeking for answers and keep applying pressure on the government (local, state and federal) to improve the quality of buildings we live, work and school in.
Keep connecting with like-minded people and build your support network.
There is a lot of information and misinformation about mould as science is working to understand it and its effects on health and wellbeing. Here are my Mould Dos and Don’ts to help clear things up. Before we dive in, let’s acknowledge some facts about mould.
Mould is Majestic
If you haven’t seen this video, please take a moment to watch fungi (mould is fungi) before continuing… It’ll make it clear why I say mould is majestic.
Mould plays an important role within our planet. However, we don’t want it in our homes.
Just like a caterpillar is amazing, but not in our salad!
Mould is Mighty
Mould is mighty in that it has well-developed strategies to survive multiple forms of attack and to keep its species going.
The main strategy is to release spores any time it feels threatened.
You could say that it’s a bit highly strung, because it feels threatened any time any of the following are changed.
If you’re a note-taker – then jot that down. 😉
Mould is Monstrous
Mould can cause incredible damage to our buildings – as by nature, its role is to break down materials.
Mould needs something to grow on, food (simplest for them are cellulose-based materials such as wood, paper, fabrics) and moisture.
Moisture can come in the form of rain, a burst pipe, condensation, increased humidity levels, a spill, and so on.
Mould Dos and Don’ts #1 – Don’t fall for the quick-fix of just cleaning mould off a surface
I get it – cleaning mould off a surface is much easier (emotionally and financially) than replacing plasterboard and more.
However, unless it’s only superficial mould, this isn’t going to address the problem.
What do I mean by “superficial mould”?
What I mean here is that the mould is literally only on the surface – it hasn’t gone deep and is not growing IN a substrate or material.
An example of this would be mould on a window pane, having formed because of condensation. Or mould on the ceiling of the bathroom that’s caused by poor ventilation – this would be in the early stages only.
In these cases, cleaning mould off a surface is acceptable.
And from there, you need to prevent the area being wet – so drying off the windows each day, or installing an extractor fan that dumps the hot moist air from your shower outside your building.
Yet in many cases, mould isn’t superficial.
And therefore, the cause needs to be addressed, and the mouldy material needs to be properly cleaned or replaced.
Mould Dos and Don’ts #2 – Don’t Use Vinegar OR Bleach to “Clean” Mould
I’m often asked, especially by journalists, to comment on vinegar (or bleach) as the go to clean mould off a surface…
And as I tell them, it’s not about the product, it’s the technique.
“However, it is the use of microfibre cloths and vacuum cleaners with true HEPA filters that can remove the mould.”
~ Lucinda Curran, quoted by Livia Gamble in Better Homes and Gardens
What’s wrong with vinegar?
The vinegar we can buy is very dilute, and then people often suggest a further 70:30 dilution. Basically, you end up adding more moisture to the mouldy area – which makes no sense when you know that mould is a moisture issue.
What’s wrong with bleach?
Bleach is to be avoided at all times.
All bleach does is whitens mould – so you can’t see it for a while, usually a few weeks.
It also is carbohydrate-based, so provides a food source for mould.
So what do you do?
Mould Dos and Don’ts #3 – Do Use a Detergent Solution to Clean Mould
Dip into the soapy solution using microfibre cloths square* and wipe down the surface. After you have used each square on both sides to remove mould, Lucinda says to throw it out. This is to avoid cross-contamination and causing the mould to spread.
*To clarify –
I recommend buying some cheap microfibre cloths from the hardware store – as they are going to be treated as “single use items.”
Cut each one up into smaller piece to minimise waste.
Use both sides of one smaller piece (or square) – without double-dipping, and then discard it.
A key point is not to cross contaminate.
“Always keep cross-contamination in mind – as it is easy to spread mould from one area to another, and cause it to release spores which will help it to spread.” (Gotta love it when the really important messages make it into an article!)
This is also why we’re not double-dipping and we’re disposing of each square of cloth that is used.
Mould Dos and Don’ts #4 – Don’t Put Additive in Your Paint
I’ve seen fungicides and “mildewcides” recommended to deal with mouldy ceilings.
This is a massive no-no.
Please don’t do it.
Anything that ends with “-cide” means it is designed to kill.
Fungicides are designed to kill fungi – mould is a fungi.
“Mildewcide” would be designed to kill mildew – which is mould, which is fungi. So another word for the same thing.
What’s wrong with these?
Simply put, these are like antibiotics… and can result in the mould equivalent of “superbugs.”
Mould is tough enough on our health, our buildings and to get rid of without having it mutate further into resistant strains…
So, address the issue, don't just paint over it.
Where’s the moisture coming from?
What’s been wet?
Is everything dry?
This is a complex area, and that’s why there are IICRC-trained mould remediation professionals.
Mould Dos and Don’ts #5 – Do Ventilate Your Home, Daily!
Ventilation dilutes indoor air contaminants, exchanging the air, and bringing fresh clean air into your home.
You may have seen statistics saying that indoor air can be 5-10 times more polluted than outdoor air. This is often due to a lack of ventilation.
(On that note, having an air purifier running 24/7 is NOT a substitute for ventilation.)
While it is an amazing thing to do, it won’t solve mould issues, instead it will help you to manage them.
What’s the best way to ventilate your home?
Go around your home opening every single door and window (internal and external). Wait 2 minutes, then close them again (if you choose).
Do this as often as possible.
Mould – Just the Facts
So there you have 5 Mould Dos and Don’ts.
Whilst I know there’s a lot to digest here, there’s so much more to it…
And if you’re keen to go deeper and learn about how to clean up your belongings (YES you can clean many things, not everything has to be turfed out), then enrol in my Dealing With Mould course for just $147 AUD – this is a game-changer, and is full of practical tips for you based on my training and experience in the field.
Winter with its cold and often wetter weather presents unique healthy home threats that differ from other seasons throughout the year.
What is a healthy home threat?
A healthy home threat is something that challenges our efforts in creating a healthy home. It might be something that undermines what we’ve done, or perhaps something that needs to be considered to prevent issues.
Which Challenges Does Winter Bring?
I like to start with looking at the way that our behaviours change with the seasons, as well as the climatic conditions.
The drop in temperatures, the increase in rain in many parts of the country, the advent of snow in the ranges, and the shorter daylight hours tend to see us:
Be indoors more of the time
Perhaps light the fire, especially for date night
Close windows and doors to keep the cold out and heat in
Draw curtains and blinds for more hours due to the earlier sunset
We wear more layers of clothing
Our clothes are thicker
We may need to dry our clothes inside due to inclement weather
We often eat soups, stews and roasts – making the most of our ovens
Some people bathe more often or take longer and hotter showers to warm up
You may be surprised to discover that all of these behaviours can create healthy home threats.
Let’s take a look at the threats and what can be done to reduce any issues.
Reduced Indoor Air Quality
When we “close up” our homes (closing windows and keeping doors shut) to keep the heat in, we’re reducing the number of times that the air is exchanged. This means that the air doesn’t get diluted often, if at all, which can result in reduced indoor air quality.
What happens is that VOCs, gases and other contaminants build up in the air. Oxygen levels often are reduced and carbon dioxide can increase – leading to feelings of sleepiness.
Carbon dioxide (CO2) is one of the gases that we exhale.
Carbon monoxide (CO) is a deadly gas that comes from combustion – gas appliances are one of the biggest contributors to CO levels within our homes. Cars are another big source, which is why I don’t like people idling their cars in their garages or driveways.
Since we’re using gas appliances more during winter – heating, cooking, hot showers – there’s an increased risk.
Have your gas appliances checked by a licensed gas fitter every autumn so that they are ready for use in winter.
Ventilate your home often – as discussed above.
Avoid idling your car in the garage or driveway.
Poor Outdoor Air
The levels of outdoor air pollution can become very high in areas where people rely on wood fires for heating.
The smoke produced by wood fires can contain formaldehyde, carbon monoxide, chemicals (some of which are known carcinogens) and fine particulate matter.
According to the Environment & Human Health Inc. (n.d.) wood smoke “interferes with normal lung development in infants and children… can depress the immune system… [and, according to the WHO] can cause coughs, headaches, eye and throat irritation in otherwise healthy people.”
Whilst enclosed wood fires, such as Coonaras, don’t release the pollutants indoors, they are still released outdoors, and can readily affect your neighbours, particularly who are sensitive and/or have asthma or other respiratory complaints.
Avoid using wood fires.
Rug up and/or be physically active – this is a great time of year to get big gardening jobs done.
Invest in an air purifier to help clean your indoor air.
The obvious ones are bathing, drying clothes, and stovetop cooking. However, occupant activities that increase moisture also include using gas appliances, breathing and sweating (or perspiring).
Given we tend to not only wear more layers in winter, but also the layers are thicker, they take longer to dry. As a result, many people dry them inside near a source of heat, or pop them in the clothes dryer.
Combine our tendency to be indoors in winter with these activities, then add to it the closed windows and doors, you can see how quickly moisture levels can increase.
Monitor the levels of relative humidity with a hygrometer – we’re aiming for 45-55% RH; 50% RH is ideal.
Use extractor fans when cooking, bathing or laundering.
If your extractor fans don’t vent to the outside, or you don’t have efficient ones, then a dehumidifier can be useful.
Mould on Windows & Curtains
In the cooler months, many people report condensation on windows and glass doors especially in the mornings.
This happens because glass changes temperature quickly, and moisture in the air condenses out of it, forming condensation on this, and other, cold surfaces.
It is due to the presence of this moisture that mould can readily form on blinds or curtains that touch the glass, and even on the glass itself.
A. Green, M. Cohen-Zion, A. Haim & Y. Dagan (2017): Evening light exposure to computer screens disrupts human sleep, biological rhythms, and attention abilities, Chronobiology International, DOI: 10.1080/07420528.2017.1324878