Heating & Cooling Solutions

5 Heating & Cooling Mistakes

September 24, 2025

5 Heating & Cooling Mistakes That Cost You Comfort & Money

Heating and cooling account for 40–50% of a typical Victorian household’s energy use. With electricity and gas prices climbing, small mistakes in how your system is chosen, installed, and operated can quietly drain hundreds of dollars every year. Worse, they often leave you less comfortable than you should be—rooms too cold in winter, or too hot in summer, despite paying high bills.

Here are the five most common heating and cooling mistakes Victorian households make—and how to fix them for good.

Mistake 1: Choosing an Oversized or Undersized Unit

Many homeowners think “bigger is better,” but oversizing an air conditioner is one of the most expensive mistakes you can make.

Oversized units: These cool or heat rooms too quickly, leading to constant “short cycling.” The system switches on and off more frequently, which wastes energy, creates uneven temperatures, and wears out components faster.
Undersized units: These struggle to keep up, running almost non-stop during extreme heat or cold. This leads to higher bills without ever reaching true comfort.

👉 Real example: A family in Melbourne’s eastern suburbs installed a 9kW system in a modest 3-bedroom home (when 6–7kW was sufficient). Their bills increased by 20% compared to neighbours with the right-sized units, and comfort was worse due to inconsistent cycling.

AC efficiency tip: Always request a heat load calculation before installing. Professionals consider home size, insulation levels, ceiling height, and orientation—not just square metres.

Mistake 2: Skipping Regular Maintenance

Like a car, your heating and cooling system needs servicing to stay efficient. Unfortunately, many households only call a technician when something breaks.

Dirty filters can reduce airflow, causing up to 15% higher energy use and poor air quality.
Clogged coils make compressors overwork, reducing lifespan.
Unserviced ducted systems often leak through cracks in ducting, wasting conditioned air into roof cavities.

👉 Reverse cycle efficiency in action: A study of reverse-cycle systems in Victorian homes found that well-maintained units used 25–30% less energy than neglected ones.

AC maintenance tips:

Clean/replace filters every 2–3 months.
Schedule professional maintenance annually before peak seasons.
Check ducts for leaks and insulation wear every few years.

This isn’t just about energy, it’s also about avoiding expensive breakdowns in the middle of a heatwave or cold snap.

Mistake 3: Poor or Inefficient Zoning

Ducted systems are fantastic when used properly. But without zoning, you may be paying to heat or cool your entire home when only two or three rooms are in use.

Without zoning: Families end up cooling empty spare bedrooms or heating unused studies.
With zoning: Only the living room in the evening, or just bedrooms at night, are conditioned, saving energy without reducing comfort.

👉 Energy saving tip: Modern smart controllers allow you to set zones via smartphone apps. You can pre-heat bedrooms before bedtime or pre-cool living rooms before arriving home, instead of running the system all day.

Takeaway: Zoning is not a luxury, it’s an essential for efficient ducted systems in Victoria’s variable climate.

Mistake 4: Ignoring Rebates and Incentives

The Victorian Energy Upgrades (VEU) rebate program exists to help households switch to more efficient heating and cooling systems—but many homeowners never take advantage.

Reverse cycle efficiency units often qualify for significant rebates.
Households replacing old gas heaters can access thousands of dollars in savings.
Some rebates also cover smart controllers and upgrades that improve system performance.

👉 Why it matters: Without rebates, a family might delay upgrading an old, inefficient system, sticking with high bills. With rebates factored in, the payback period can drop by years.

Action: Before replacing or upgrading, always check the latest rebates. Professional installers like GreenOz Solutions manage the paperwork for you—so you don’t miss out on savings.

🔗 Learn more: Smarter Winter Heating for Melbourne Homes

Mistake 5: Overlooking Insulation and Draught Sealing

Even the most efficient air conditioner can’t keep you comfortable if your home is leaking energy like a sieve.

Ceiling insulation prevents up to 35% of winter heat loss.
Wall insulation helps stabilise year-round temperatures.
Draught sealing stops conditioned air from escaping through cracks, gaps around doors, and poorly sealed windows.

👉 Real-world impact: A well-insulated home with a modest 5–6kW reverse-cycle unit may feel more comfortable and cost less to run than a poorly insulated home with a much larger 9kW unit.

Home insulation tip: Think of insulation as your first line of defence. Heating and cooling systems then act as the “second layer,” keeping your home at the comfort level you want.