It is a familiar winter experience across western Melbourne: you run the heater to warm the house up, and within a few hours your skin feels tight and dry, your eyes are gritty and irritated, and you are reaching for lip balm you did not need in summer. This is not a coincidence, and it is not simply a matter of cold weather. Your heating system in Melton is actively changing the air inside your home in ways that directly affect the moisture levels in your skin and eyes. Understanding what is happening — and what you can do about it — makes a real difference to how comfortable your home feels through the cooler months.
What Heating Does to the Air in Your Home
The core issue is relative humidity — the amount of water vapour in the air relative to the maximum it can hold at a given temperature. When you heat air, its capacity to hold moisture increases, but the actual amount of moisture in it does not. This means the relative humidity of the air in your home drops every time you heat it, even if no moisture is being removed.
- Cold winter air in Melbourne typically has low absolute moisture content to begin with — there is simply less water vapour present in winter air than summer air
- When that cold, already-dry air enters your home and gets heated from, say, 12 degrees to 22 degrees, its relative humidity drops significantly — often to below 30 percent
- The comfortable range for human health and skin hydration is generally accepted as 40 to 60 percent relative humidity
- At humidity levels below 30 percent, moisture evaporates from the skin’s surface and the mucous membranes of your eyes more quickly than normal, producing the dryness and irritation you notice
How Different Heating Systems Affect Your Comfort
Not all heating systems create the same degree of dryness. The type of heating you have in your Melton home has a direct influence on how low the humidity drops and how quickly the effects become noticeable.
Ducted Gas Heating
Ducted gas heating is the most common heating system in western Melbourne homes. It heats air in a central unit and distributes it through vents throughout the house.
- Ducted gas systems heat air rapidly and distribute it at relatively high temperatures, which accelerates the reduction in relative humidity throughout the home
- The system draws in and recirculates the same dry indoor air, creating a drying cycle that continues the entire time the heater is running
- Older ducted systems that pull fresh air from the roof space can introduce even drier outdoor air into the home during colder periods
Split System Heating
Reverse-cycle split systems are increasingly used for heating in Melton homes. They work by extracting heat from the outside air and transferring it indoors via the refrigeration cycle.
- Split systems do not introduce new air into the home — they recirculate existing indoor air, which means they tend to create moderate dryness rather than the rapid drop associated with gas systems
- However, they still lower relative humidity by heating the air, and in a well-sealed modern home the cumulative effect over a full day of use is noticeable
- At very low outdoor temperatures, the outdoor unit can develop ice on the coil, triggering a defrost cycle — during which the system briefly stops heating — but this does not meaningfully affect indoor humidity
Gas Space Heaters and Wall Furnaces
Unflued gas heaters — wall furnaces and portable gas space heaters that vent combustion products directly into the room — actually add some moisture to the air as a byproduct of combustion, since burning natural gas produces water vapour.
- This moisture addition partially offsets the drying effect of heating, which is why some people find unflued gas heaters less drying than ducted gas systems
- However, unflued heaters also produce carbon dioxide and nitrogen dioxide as combustion byproducts, and current health guidance in Australia recommends adequate ventilation when using them — which itself reduces indoor humidity
- Flued gas heaters vent combustion products outside, so they do not add moisture to the room and have a similar drying effect to ducted systems
How Low Humidity Affects Your Skin
The skin has its own moisture regulation mechanisms, but they are not unlimited. In low-humidity environments, the rate of transepidermal water loss — moisture evaporating from the skin surface — exceeds the skin’s ability to replenish it from within.
Tight, Flaky or Itchy Skin
The most common skin complaint associated with heated indoor air is a feeling of tightness, particularly on the face, hands, and lower legs — areas where the skin is thinner or more frequently exposed.
- Dry air draws moisture from the outermost layer of skin, causing it to lose elasticity and feel tight or papery
- In more severe cases, particularly for people with a pre-existing tendency to dry skin, eczema, or psoriasis, heated indoor air can trigger significant flares
- Fine lines on the face can become more prominent during winter simply because of moisture loss at the skin’s surface, even in people without inherently dry skin
Cracked Lips and Fingertips
The lips have no oil glands and rely entirely on environmental moisture and conscious application of lip products to stay hydrated. Heated indoor air strips this moisture rapidly.
- Cracked or chapped lips that persist through winter despite regular application of balm are often a sign that the indoor humidity is too low
- Fingertip cracking — where the skin at the tip of the finger splits — is similarly common in people spending long periods in heated, low-humidity environments
How Low Humidity Affects Your Eyes
The surface of the eye is covered by a tear film that keeps it lubricated, comfortable, and clear. In low-humidity environments, the tear film evaporates more quickly than the eye’s glands can replenish it.
Gritty, Burning or Irritated Eyes
A feeling of grittiness, a burning sensation, or general irritation in the eyes during winter heating months is typically a symptom of dry eye — where the tear film is not maintaining adequate lubrication.
- Low indoor humidity is one of the most common environmental triggers for dry eye symptoms, and the effect is amplified by screen use, which reduces blink rate and further disrupts the tear film
- People who wear contact lenses often find winter significantly more uncomfortable in heated environments, as lenses absorb moisture from the tear film
Watery Eyes as a Reflex Response
Paradoxically, dry eyes can produce excessive tearing as the eye attempts to compensate for the disrupted tear film. Reflex tearing produces watery, irritating tears rather than the stable, lubricating film the eye needs.
- If your eyes water frequently indoors during winter but feel dry and gritty at other times, low humidity from heating is a likely contributor
- The situation typically improves when humidity is restored to the 40 to 60 percent range
What You Can Do to Reduce Dryness from Heating
There are practical steps you can take to reduce the impact of heating on your skin and eyes without sacrificing comfort during the colder months in western Melbourne.
Use a Humidifier
Adding a humidifier to your living space is the most direct solution to low indoor humidity. It replaces moisture in the air that heating removes.
- An evaporative humidifier is a low-energy option that works well in medium-sized rooms and requires no heat to operate
- Ultrasonic humidifiers are quiet and effective for bedrooms, where maintaining comfort overnight is particularly important
- Aim to maintain indoor humidity between 40 and 55 percent — a basic digital hygrometer (available cheaply online) allows you to monitor this accurately
Set Your Thermostat Lower
The higher the temperature your heating system maintains, the lower the relative humidity becomes. Dropping the set temperature by even 2 degrees reduces the drying effect while also lowering your energy bills.
- Most people are comfortable in winter at indoor temperatures of 19 to 21 degrees, and the Australian Government’s guidelines suggest 18 to 20 degrees as an efficient and healthy range
- Running the system at 24 or 25 degrees accelerates moisture loss from both the air and your skin significantly more than a moderate setting
Keep Your Heating System Serviced
A dirty or poorly maintained heating system does not just cost more to run — it can also distribute dust and particulates through your home that further irritate already-dry eyes and skin.
- Dirty ducted heating filters trap less dust over time as they become clogged, allowing more particulates to pass into the home’s air supply
- Annual servicing of your ducted gas or split system heating, including filter cleaning or replacement and duct inspection, reduces airborne irritants alongside improving efficiency
- A well-maintained system also reaches the set temperature more quickly, meaning it runs for less time overall and reduces the cumulative drying effect on indoor air
Hydrate More During Winter
Internal hydration is the foundation of skin and eye moisture. Many people drink less water in winter because they feel less thirsty than in summer, but the dry indoor air means your body is losing moisture at an elevated rate.
- Aim to drink at least 8 glasses of water per day through winter, and more if you are spending long periods in heated indoor environments
- Herbal teas and warm drinks count toward hydration and are more appealing in cold weather than cold water
Use Preservative-Free Eye Drops
If your eyes are consistently uncomfortable during the heating months, lubricating eye drops can help supplement the tear film during periods of low humidity.
- Look for preservative-free formulations, which are gentler for regular use and do not carry the risk of preservative-related irritation with frequent application
- If symptoms persist or worsen, discuss them with an optometrist or GP, as persistent dry eye can have causes beyond environmental humidity
Frequently Asked Questions
Is running a heater all night bad for your skin?
Running heating overnight in a closed bedroom will significantly reduce indoor humidity over several hours, and prolonged exposure to low-humidity air during sleep — when you cannot consciously compensate by drinking water or applying moisturiser — can leave skin feeling very dry by morning. If you need heating overnight, consider a lower thermostat setting, leaving a door ajar for air circulation, or using a bedroom humidifier to maintain comfort without the drying effect.
Can a poorly maintained heater make skin and eye dryness worse?
Yes. A dirty or poorly maintained ducted heating system circulates dust, allergens, and particulates along with the heated air. These airborne particles irritate the mucous membranes of the eyes and can contribute to skin irritation independently of the humidity effect. Servicing the system, cleaning or replacing filters, and having the ducts inspected reduces this additional source of irritation.
What indoor humidity level should I aim for in winter?
The ideal indoor relative humidity for human comfort and health is generally considered to be between 40 and 60 percent. Below 30 percent, symptoms of skin dryness, eye irritation, and dry throat become common. A basic digital hygrometer will show you your current indoor humidity level and help you assess whether a humidifier is needed and how well it is working.
Does the type of heater make a difference to how dry my skin gets?
Yes. Ducted gas heating tends to produce the greatest reduction in indoor humidity because it heats air rapidly and distributes it throughout the entire home. Split system heating in a single room tends to have a more localised effect. Unflued gas heaters produce some moisture as a combustion byproduct, which partially offsets the drying effect — though ventilation requirements limit this benefit. Regardless of heater type, the fundamental cause is the same: heating air lowers its relative humidity.
Conclusion
Dry skin and irritated eyes in winter are not just a matter of the season itself. Your heating system plays a significant role. By understanding how heated air loses relative humidity, you can take targeted steps to stay comfortable without sacrificing warmth. Simple measures like a humidifier, a slightly lower thermostat setting, and a well-serviced heating system make a real difference to how your home feels and how your skin and eyes hold up through the colder months.
If your ducted heating or split system is due for a service, or if it seems to be working harder than it should to maintain comfortable temperatures, the team at New Image Heating and Cooling Melton can help. We service and repair heating systems across western Melbourne, keeping them running cleanly, efficiently, and without sending unnecessary dust and dryness through your home. Call us on 0468 125 098 or reach us through our online form to book a service before winter gets underway.
