Summer in New Zealand can bring soaring temperatures, and a reliable air conditioning system is essential for keeping your home cool and comfortable. However, many homeowners make common mistakes that can lead to inefficiencies, higher energy bills, and even premature system failure. Whether you’re considering purchasing your first air conditioning unit or optimising the one you already have, these tips are designed to help you get the most out of your system.
In this article, we draw upon the thousands of customer interactions over the years to highlight some of the most common air conditioning mistakes homeowners make, why they happen, and practical tips to prevent them.
Learning these common air conditioning mistakes and avoiding committing them will help you make an informed decision for your home comfort and will help you save money in the long term.
Top 10 Common Air Conditioning Mistakes
Common Mistake #1: Installing the Wrong Size Air Conditioner
One of the most common errors homeowners make is seeing a special promotion at a hardware or consumer electronics store and getting influenced by the price in selecting an air conditioner that’s either too large or too small for their space.
Why it Happens: Many assume bigger is better, believing a larger unit will cool their home faster. On the other hand, some try to save money by opting for a unit that is too small for their room requirements.
The Problem: An oversized unit will cool the room too quickly without removing humidity, leaving the air feeling sticky and clammy. An undersized unit on the other hand will struggle to keep up with the cooling demands in particular (cooling output is usually weaker than heating performance) leading to a system that is constantly overworking and running up high power bills.
Solution: Always consult a professional to calculate the proper cooling capacity based on your home’s size, insulation, and orientation in relation to the sun. If your unit is too small for the hottest days, close the curtains to block out direct sunlight and run the system earlier to allow it time to get the room down to the desired temperature,
Common Mistake #2: Ignoring Regular Maintenance
Skipping maintenance is a frequent oversight that can lead to costly repairs or a complete system breakdown.
Why it Happens: Many homeowners overlook maintenance, thinking their system will continue working fine without it.
The Problem: Dust and debris build-up can restrict airflow, reduce efficiency, and cause parts to wear out faster.
Solution: Schedule annual servicing before summer begins. Clean filters regularly during high-usage periods, especially if your home has a plush carpet or long-haired pets. Regular maintenance ensures optimal performance and prolongs the lifespan of your unit.
Common Mistake #3: Poor Installation
Improper installation is a hidden culprit behind many air conditioning issues.
Why it Happens: Homeowners may choose unqualified installers to save money or attempt DIY installation.
The Problem: Poor installation can lead to poor condensate design, incorrect refrigerant levels, weak airflow in key areas, or even safety hazards.
Solution: Hire a licensed HVAC professional for installation. A certified expert will ensure the system is appropriately installed in the best location, optimising performance and safety.
Common Mistake #4: Setting the Thermostat Too Low
A common mistake is setting your thermostat down to the lowest level and then forgetting to reset it back to the actual correct temperature.
Why it Happens: Many believe that setting the remote to the lowest temperature possible will cool the house faster.
The Problem: Setting the thermostat too low forces your system to remain at maximum output as it is almost impossible to reach the low temperatures being set. This increases energy consumption and the risk of premature wear and tear.
Solution: Set your thermostat to a comfortable but efficient temperature, typically between 22–24°C. Consider installing a programmable or smart thermostat to maintain consistent cooling while saving energy.
Common Mistake #5: Not Addressing Air Leaks
Air leaks around doors, windows, or poorly insulated spaces can make your air conditioner work harder than necessary.
Why it Happens: Homeowners may not realise the impact of air leaks on cooling efficiency.
The Problem: Cool air escapes, and warm air enters, causing your unit to run longer to maintain the desired temperature.
Solution: Seal gaps and cracks with weather stripping or caulk. Ensure proper insulation in your home to prevent energy loss.
Common Mistake #6: Using Ceiling Fans Incorrectly
While ceiling fans complement air conditioning, they’re often used in a way that doesn’t support air conditioning.
Why it Happens: Some homeowners don’t adjust their fan direction seasonally.
The Problem: Fans can usually rotate in different directions : one way to push air down, the other to pull air up.
Solution: Use ceiling fans at slow speed to assist the air conditioning to circulate cool air throughout the room (when a room is occupied). Remember that cool air drops, so if you want to speed up the cooling in a room, run the fan clockwise to push the cool air down faster. Once done, you may find all the cold air at ground level and noticeably warmer air higher up. If this is the cae, experiment with running the fan in the other direction to see if you can get the cold air lifted up and circulated around the room to even out the air temperature and improve occupant comfort.
Common Mistake #7: Overlooking Energy Efficiency
Failing to consider energy efficiency when purchasing or using an air conditioner can result in higher operating costs.
Why it Happens: Price-conscious buyers may prioritise upfront costs over long-term savings.
The Problem: Inefficient systems consume more energy, leading to higher bills and a larger carbon footprint.
Solution: Look inside technical specification charts for units with a high Energy Efficiency Ratio (EER) or Seasonal Energy Efficiency Ratio (SEER). Although these units (usually from top brands like Daikin, MHI and Mitsubishi Electric) cost more to buy up front, they save money in the long run by being more energy efficient and typically having longer lifespans as well.
Common Mistake #8: Running the AC Constantly
Leaving your air conditioner on all day might seem like the easiest way to stay cool, but it’s inefficient.
Why it Happens: Some believe it’s more energy-efficient to maintain a constant temperature rather than turning the system on and off.
The Problem: Running the AC continuously increases energy costs and wear on the system.
Solution: Studies have shown that turning air conditioning on when you need it and off when you don’t is more efficient than leaving it running 24/7. If you are less worried about your power bill and just want the convenience of a set-and-forget system, use the timer or programmable thermostats to cool your home during peak hours and turn it off when you’re away. It’s a good idea also to choose a heat pump with built-in WiFi (also available as an add-on) that allows you to turn it off remotely when you leave home in a hurry and forget to shut it down.
Common Mistake #9: Neglecting the Outdoor Unit
The outdoor unit plays a crucial role in the air conditioning process, but it’s often ignored.
Why it Happens: Outdoor units are typically located at the rear of a home or a wall where people don’t often go. That means they often accumulate dirt without people realising it, while insects love to create nests in areas where humans seldom disturb them..
The Problem: Dirt, leaves, and debris can block airflow, reducing efficiency. Insects can form nests in critical parts of the outdoor unit, potentially damaging the unit.
Solution: Regularly inspect and clean the area around the outdoor unit. Ensure it has at least two feet of clearance on all sides. Get a licensed gas handling technician to check the gas pressure levels to make sure they are at optimum levels.
Common Mistake #10: Choosing the Wrong Type of Air Conditioner
Selecting the wrong type of system for your home can lead to long-term dissatisfaction.
Why it Happens: Homeowners may not have had the full range of options explained to them and not fully appreciate the differences between ducted, split systems, and portable units.
The Problem: An unsuitable system may not meet your cooling needs or may not look as nice as it could, leading to dissatisfaction and buyer’s remorse, especially in the long run..
Solution: Consult an HVAC professional to discuss the best system for your home. Ask for all the different possible options to be presented and have their pros and cons carefully explained so you can make an informed decision. Air conditioner systems are not like paintings or furniture items : once installed, they are neither cheap nor easy to replace, so it makes sense to make sure you have chosen the correct system for your needs.!.
Ready to Purchase Your New Air Conditioner?
Avoiding common air conditioning mistakes can save you money, improve efficiency and ensure your system keeps you cool all summer long. Whether it’s sizing your unit correctly, keeping up with maintenance, or sealing air leaks, these small actions can make a big difference.
For Kiwi homeowners , choosing the right air conditioning system and maintaining it properly is key to a comfortable and energy-efficient summer. If you’re considering a new air conditioner or need help optimising your current system, contact a professional HVAC contractor like OneAir at 0800 663247. They can guide you in selecting, installing, and maintaining the perfect system for your home, ensuring your home remains comfortable inside, no matter what the weather is like outside