How to Lower Humidity in the House

It's fair to say that certain regions of Australia experience relative humidity in more extreme ways than others, especially as you get closer to the tropics. It comes as no surprise, then, that many of us are keen to know how to lower humidity in the house.

But apart from comfort, why would you want to do that?

The short answer is that lower humidity helps you keep rooms comfortable, healthy, and cheaper to run. High humidity inside your home negatively affects your indoor air quality. It also allows mould to grow and dust mites to thrive, both of which can trigger respiratory infections and other health issues.

It’s important to take a leaf out of Goldilocks’ book and aim for a humidity level that isn’t too high nor too low. You want it just right. So let’s take a look at how to go about it.

Know Your Numbers: Measuring Indoor Humidity Levels

Knowing how to lower humidity in the house starts with understanding exactly what your home’s humidity levels are. This involves taking a reading of relative humidity (RH) levels with a digital hygrometer, which you can pick up at your local hardware store.

Let’s backtrack a step first and explain what RH is. Relative humidity refers to the volume of moisture in the air compared with what the air can hold at that temperature.

For optimal comfort in most indoor environments, the National Asthma Council recommends aiming for around 30–60% RH. Keeping relative humidity in your home under that magic 60% figure will also give you better control over mould growth and dust mites.

Sometimes You’ll Just Feel the Excess Moisture

Aside from using tools to measure RH levels, excess humidity in your home just feels clammy, so you’ll notice it. It also fogs up windows and feeds any mould in the house. At the other end of the spectrum, low humidity creates dry air, itchy skin and static electricity.

Check several rooms, including wardrobes and wall corners, and log readings morning and night to spot patterns. If humidity indoors stays high, increase air circulation and ventilation to reduce humidity. If it dips too low, gently add to the moisture levels during cold weather.

Use Air Conditioning and Dehumidifiers Smartly

Installing air conditioners can quietly lower indoor humidity by cooling warm, moist air and condensing water vapour on the coil.

Many modern air conditioners, both split and ducted systems, come with a dry or dehumidifying mode. Use this on particularly sticky days to lower high humidity without over-cooling. Make sure you keep your air conditioner filters clean, and book regular servicing with a licensed technician so it maintains airflow and efficiently removes moisture.

In any rooms of the house that are particularly susceptible to high humidity (most of us have at least one), portable dehumidifiers can be a godsend. They absorb moisture from indoor air and help stabilise levels for better indoor air quality. Shut windows while running either appliance, then bring in fresh air later to purge humid air.

Finally, size equipment correctly to avoid short cycling and needless energy bills. That will go a long way towards lowering humidity levels.

Ventilation That Actually Works: Exhaust to Outdoor Air

Ventilation steps up its game when moist air leaves the building, not when it circulates throughout the room. To help your ventilation really work at its best:

• Switch on the bathroom exhaust fan during a hot shower. Do the same with your kitchen rangehoods when boiling water. Keep them running for a few minutes after to release moisture outdoors.
• Make sure your vented clothes dryer discharges to the air outside, not into the roof space.
• Where possible, open windows on opposite sides to increase air circulation and draw in fresh air.
• Seal any gaps in the house that recirculate humid air indoors.

If your house is susceptible to persistent indoor humidity, consider a run-on timer or humidity sensor so fans automatically remove moisture in the air.

Fix the Sources: Stop Water Getting In or Hanging Around

Next on our exploration of how to lower humidity in the house is eliminating sources of excess moisture. Got any leaks in the house? We’re talking dripping taps, weeping pipes, roof leaks, cracked grout, and failed silicone around showers. Fix them ASAP; they all contribute to high humidity in your home.

Improve water flow away from the house by clearing gutters and downpipes, grading soil, and extending stormwater drains. In subfloors, lay a suitable plastic cover over exposed soil to reduce ground moisture, and maintain vents for fresh air. Insulate cold water pipes and thermal bridges to limit condensation in cold weather, especially on window frames and wall corners.

If you’re renovating the house, make sure you use vapour-permeable membranes or a compliant vapour barrier to prevent moisture build-up and structural damage. This will also help to reduce high indoor humidity levels.

Quick Wins to Reduce Humidity

Small habits reduce humidity fast without costly upgrades. Here are some basic tips and habit changes you can adopt that can make a difference:

• Dry clothes outdoors; if not possible, use a vented dryer ducted outside.
• Improve air circulation with ceiling or portable fans; keep doors open.
• Open windows when outdoor air is drier to bring in fresh air; wipe condensation on windows and wall corners.
• Space furniture slightly off cold walls to deter mildew growth.

These are some truly doable quick wins that lower indoor humidity, protect finishes and improve indoor air quality.

When to Use a Licensed Technician

When considering how to lower humidity in the house, here’s an essential safety tip. If the job involves regulated electrical or refrigerant work, bring in a licensed technician. In fact, it’s not just a safety tip; it’s a legal requirement.

By law, you must have a licensed electrician to install any hard-wired exhaust fans, ceiling fans, and new circuits. For air conditioning installation, repairs or refrigerant leaks, use an ARCtick-licensed technician to protect indoor air quality. A licensed plumber should locate and repair water leaks and improve drainage.

Follow National Construction Code condensation management and AS 1668.2 for mechanical ventilation to outside air. Designed correctly, systems increase air circulation and keep humidity in the healthy range.

Breathe Easier: Keep Humidity in the Healthy Zone

Managing indoor humidity levels isn’t about making it complicated; it’s about being consistent.

Measure RH, vent moist air outside, fix leaks fast, and use air conditioning or a dehumidifier when humid air lingers. Choose fresh air and proper ventilation in kitchens, bathrooms and laundries, and dry clothes outdoors where possible.

Small habits reduce moisture, protect finishes and improve indoor air quality. For bigger jobs, use licensed technicians so systems remove excess moisture safely and efficiently.

When you follow these steps, you’ll control humidity, cut mould risk and keep energy bills sensible. That’s how to lower humidity in the house and keep your home comfortable all year.

Please note: Thanks for reading our blog “How to Lower Humidity in the House.” This information is provided for advice purposes only. Regulations differ from state to state, so please consult your local authorities or an industry professional before proceeding with any work. See our Terms & Conditions here.