13 Things Most People Forget to Check That Could Be Affecting Your Indoor Environment

When we think about keeping our homes healthy, most of us focus on the obvious things—vacuuming the floors, wiping down kitchen benches, cleaning the bathroom and taking out the rubbish. While these habits are all important, a home that looks clean isn't always the same as a home with a healthy indoor environment.

Many factors that influence the quality of the air we breathe are invisible or easy to overlook. Poor ventilation, excess moisture, hidden mould, dust, household allergens and even neglected air-conditioning filters can all affect your indoor environment without leaving obvious signs at first.

This matters because Australians spend around 90% of their time indoors, whether at home, work or school. As a result, the condition of our indoor environment can play an important role in our everyday comfort and wellbeing. Maintaining good indoor air quality is particularly important for people living with asthma, allergies or other respiratory conditions, although it can benefit everyone.

Here are the 13 commonly overlooked things around the home that could be affecting your indoor environment, along with practical tips to help you create a healthier space for you and your family.

1. Ventilation

One of the simplest ways to improve your indoor environment is to let fresh air circulate through your home. Opening windows and doors when weather permits, or using exhaust fans in bathrooms, kitchens and laundries, helps remove stale air, excess moisture and indoor pollutants while bringing in fresh outdoor air.

Homes that remain tightly sealed for long periods can allow moisture, odours and airborne particles to build up indoors. Even opening a few windows for a short time each day can help improve airflow and create a fresher indoor environment.

However, it's also worth considering outdoor air quality before opening your home to fresh air. During periods of high pollen counts, particularly in spring, opening windows and doors may allow more pollen to enter your home, which can be problematic for people living with hay fever or pollen allergies.

If you or someone in your household experiences seasonal allergies, consider checking local pollen forecasts before ventilating your home. The Australasian Society of Clinical Immunology and Allergy (ASCIA) Guide to Common Allergenic Pollen provides information on common pollen seasons across Australia and can help you identify times when pollen levels may be higher in your area.

2. Hidden moisture

Water doesn't have to be dripping from the ceiling to become a problem. Small amounts of trapped moisture can build up gradually over time, creating the ideal conditions for mould to grow before you even notice there's an issue.

While plumbing leaks and condensation on windows are common sources of moisture, it's also worth checking areas where air doesn't circulate well. These include:

• Behind wardrobes, bookcases and large furniture placed against external walls
• Inside cupboards under sinks
• Storage areas, garages and basements
• Closets packed tightly with clothing or linen
• Boxes stored directly on concrete floors
• Areas around washing machines, dishwashers and refrigerators
• Window sills and door frames where condensation may collect

Poor airflow in these spaces means moisture can remain trapped for longer, making it harder for surfaces to dry.

Don't overlook how you store things

Storage habits can also affect your indoor environment.

Packing cupboards full or pushing furniture tightly against walls restricts airflow, allowing moisture to accumulate unnoticed. Similarly, storing cardboard boxes, clothing or bedding in damp areas such as garages or sheds can encourage mould growth if humidity is high.

Read more about it: Why Your Stored Belongings Keep Going Mouldy (And How to Stop It)

Where possible, leave a small gap between large furniture and external walls, avoid overfilling cupboards and store items in clean, dry conditions with adequate ventilation.

3. Hidden mould

Mould often grows in places you don't see every day—and sometimes in items you use regularly without realising.

In addition to hidden areas such as behind cupboards, inside wardrobes against external walls, beneath sinks and around window frames, mould can also develop on everyday household items that stay damp for long periods.

These can include:

• Reusable water bottles that aren't thoroughly dried between uses, particularly around lids, straws and silicone seals.
• Wooden or bamboo chopping boards with deep knife grooves that trap moisture.
• Dish cloths, sponges and tea towels that remain damp between uses.
• Shower curtains, bath mats and bathroom accessories.
• Rubber seals around washing machines and dishwashers.
• Drip trays in coffee machines or refrigerators.
• Toothbrush holders and soap dishes where water regularly collects.

Mould doesn't always appear as obvious black spots. Depending on the surface and the species, it may look white, green, grey or even pink, or it may simply leave behind a persistent musty odour before any visible growth appears.

Regular cleaning, allowing items to dry thoroughly before storing them and replacing household items that have become difficult to clean can all help reduce the likelihood of mould developing in these overlooked places.

If you notice a persistent musty smell but can't identify the source, a mould test kit can help determine whether elevated mould levels may be present in your home, allowing you to investigate further before the problem becomes more widespread.

Read related article: Could Mould Be Making You Sick? Signs, Symptoms & Home Testing Guide

4. Indoor humidity

Humidity itself isn't a bad thing—in fact, some moisture in the air is important for both your comfort and the health of your home.

Humidity refers to the amount of water vapour in the air. If humidity is too high, it can encourage mould growth, create favourable conditions for dust mites and make indoor spaces feel stuffy. On the other hand, very low humidity can dry out the eyes, skin and airways, and may even contribute to static electricity and damage to some wooden furniture and flooring.

For most homes, an indoor relative humidity of around 30% to 60% is generally considered a comfortable and healthy range, although the ideal level may vary depending on your location, the season and your household's needs. 

Humidity changes throughout the year

Australia's climate is incredibly diverse, so humidity levels can vary widely depending on where you live. Coastal and tropical regions generally experience higher humidity, while inland areas are often much drier. The Bureau of Meteorology's long-term climate maps show that relative humidity is typically higher in northern Australia and along many coastal regions, with seasonal changes occurring throughout the year.

Managing indoor humidity

If you find that your home is consistently humid—particularly during warmer months or in naturally damp areas—a dehumidifier can help remove excess moisture from the air and maintain a more comfortable indoor environment.

The key is balance. While reducing excessive humidity can be beneficial, indoor air shouldn't become overly dry either. If you're unsure, a simple digital hygrometer can help you monitor your home's relative humidity and determine whether adjustments may be needed.

5. Air conditioner and heater filters

Heating and cooling systems circulate the air you breathe every day, making them an important part of your indoor environment. Over time, air conditioner and heater filters can collect dust, pollen and other airborne particles. 

You may also notice a musty or damp smell when you first switch on your air conditioner, particularly if it hasn't been used for some time. While a temporary odour can sometimes occur after a period of inactivity, a persistent musty smell may indicate moisture or mould has developed within the unit, particularly around the filters, evaporator coils or drip tray. Besides affecting indoor air quality, mould inside an air conditioner can continue to spread spores each time the system is running.

Regular servicing and routine filter cleaning can help keep your system operating efficiently and reduce the build-up of dust, moisture and other contaminants. 

Concerned about mould in your air conditioner? Read our guide on how to identify it, clean it safely and help prevent it from returning here.

6. Soft furnishings

Soft furnishings can make a home feel warm and comfortable, but they're also some of the easiest places for dust, pollen, pet dander and other airborne particles to settle over time.

Items with thicker fabrics, deep pile or textured surfaces tend to trap more dust than smooth, hard surfaces. Common examples include:

• Carpets and large rugs, particularly those with a deep pile
• Heavy curtains and drapes
• Upholstered sofas and armchairs
• Decorative cushions and fabric throws
• Fabric-covered bedheads and ottomans
• Plush toys

Because these items aren't always cleaned as frequently as floors or benchtops, particles can gradually build up over time. This may be particularly relevant for households with pets or people living with asthma, allergies or hay fever.

Regular vacuuming (using a vacuum with a HEPA filter, where appropriate), laundering removable fabric covers, and occasionally airing soft furnishings outdoors when practical can all help reduce dust build-up and support a healthier indoor environment.

7. Bedding and mattresses

We spend around a third of our lives in bed, making the sleeping environment an important part of a healthy home.

Over time, bedding and mattresses can accumulate dead skin cells, sweat, dust and other particles, creating an environment where dust mites may thrive. While dust mites are harmless to most people, they're a common trigger for asthma and allergies. Although bed bugs are far less common, regularly inspecting mattresses, bed frames and seams—particularly after travelling or purchasing second-hand furniture—can help identify any signs of an infestation early.

Regularly washing sheets and pillowcases, airing out bedding and replacing old pillows when needed can help maintain a cleaner sleeping environment. Mattress protectors can also make cleaning easier while helping protect the mattress from moisture, spills and everyday wear.

Another good habit is to change into clean sleepwear before getting into bed, rather than sleeping in clothes you've worn throughout the day. Clothing worn outside can collect dust, pollen, pet dander and other particles, which may then be transferred to your bedding.

8. Kitchen and bathroom exhaust fans

Most people clean their bathroom and kitchen—but forget about the exhaust fan.

Dust and grime can accumulate on fan covers and reduce airflow over time, making it less effective at removing steam, humidity and cooking fumes.

Cleaning the fan every three to six months, or more often if you notice visible dust build-up, can help maintain good ventilation and improve its ability to remove excess moisture from your home.

9. Indoor air quality

Everyday activities such as cooking, burning candles, using cleaning products or spraying air fresheners can release fine particles and volatile organic compounds (VOCs) into the air. While many of these products are safe when used as directed, using them frequently or in poorly ventilated spaces may contribute to indoor air pollution over time.

Simple ways to support better indoor air quality

You don't necessarily need to stop using these products altogether. Instead, a few simple habits can help reduce unnecessary build-up of indoor pollutants:

• Open a window or use an exhaust fan when cooking, cleaning or burning candles, where weather and outdoor air quality permit.
• Avoid burning candles for long periods in small or poorly ventilated rooms.
• Trim candle wicks to around 5 mm before lighting them, as this can help reduce soot production and encourage a cleaner burn.
• Choose fragrance products thoughtfully. If someone in your household has asthma, allergies or fragrance sensitivities, consider using unscented products or limiting the use of heavily fragranced sprays.
• Follow the instructions on cleaning products and avoid mixing different household cleaners unless specifically directed by the manufacturer.

Read related article: How Poor Air Quality in Your Bedroom is Ruining Your Sleep

10. High-touch surfaces

Light switches, remote controls, mobile phones, keyboards, cupboard handles and door knobs are touched countless times throughout the day—but they're often overlooked during routine cleaning.

Because these surfaces come into frequent contact with our hands, they can become places where germs, including bacteria and viruses, are transferred between people and surfaces. If someone has a cold, flu or another contagious illness, touching shared objects after coughing, sneezing or blowing their nose may contribute to the spread of germs within the household, particularly if hands aren't washed regularly.

Regular cleaning of frequently touched surfaces can help support good household hygiene, especially during cold and flu season or when someone at home is unwell. As a general guide, high-touch surfaces should be cleaned at least once a week as part of your regular household routine, and more frequently when someone in the household is sick or when surfaces are used by multiple people throughout the day.

11. Houseplants and indoor plants 

Indoor plants can brighten up a home, but they also need regular maintenance to ensure they don't unintentionally affect your indoor environment.

Overwatered potting soil, standing water in plant trays and decaying leaves can encourage mould growth or attract pests such as fungus gnats. While healthy indoor plants are unlikely to cause problems on their own, poor plant care can create unnecessary moisture around the home.

Check your indoor plants regularly by:

• Removing dead or decaying leaves.
• Emptying excess water from drip trays.
• Avoiding overwatering.
• Looking for visible mould growing on the surface of the potting mix.

Keeping plants healthy also helps keep the surrounding indoor environment healthier.

12. Your vacuum cleaner

It might seem ironic, but the appliance you rely on to remove dust can become a source of dust if it's not properly maintained.

Vacuum cleaner bags, dust containers, brushes and filters gradually fill with dirt, pet hair and fine particles. If they're not emptied or cleaned regularly, airflow can decrease and some vacuums may even release fine dust back into the room.

13. Ceiling fans

Ceiling fans often collect a surprising amount of dust on the tops of their blades, even when the rest of the room appears clean.

Every time the fan is switched on, accumulated dust can be disturbed and redistributed around the room. Including ceiling fan blades in your regular cleaning routine can help reduce dust build-up and keep your indoor environment cleaner.

Looking after your home, one check at a time

Creating a healthier indoor environment doesn't necessarily mean making major changes to your home. More often than not, it's the small, everyday habits—and the places we tend to overlook—that can make the biggest difference over time. 

It's also worth remembering that no single factor determines the quality of your indoor environment. Good ventilation, effective moisture control, regular cleaning and sensible maintenance all work together to support a healthier living space.

Making these checks part of your regular household routine can help you identify potential issues early—before they develop into larger problems such as mould growth, poor indoor air quality or unnecessary exposure to dust and allergens.

Create a Healthier Home with the Right Essentials