A new AC not cooling properly after installation is almost always caused by one of six fixable issues — incorrect refrigerant charge, wrong unit size, poor outdoor unit placement, drainage problems, loose connections, or simple settings errors. Most of these trace back to installation quality, not the AC brand. If you're in Pune, Coolex Air Conditioning offers professional post-installation checks to diagnose and fix the problem fast, so your space cools the way it should.
You just spent ₹35,000–₹60,000 on a brand new air conditioner. The technician packed up and left. You switch it on, excited for that first wave of cool air — and nothing. The room is still warm. The AC is running, the LED is on, the fan is blowing. But it just isn't cooling.
That sinking feeling is more common than you think.
If your new AC is not cooling properly after installation, take a breath. In most cases, the problem is not a defective unit. It is not bad luck. And it is not something that will cost you another fortune to fix. In the majority of cases, poor cooling after a fresh installation points directly to how the AC was set up — not what brand you bought or how much you paid for it.
This guide walks you through every likely cause, in plain language, so you know exactly what is happening and what to do next.
A new AC that does not cool after installation is usually caused by incorrect refrigerant charging, wrong unit sizing, a badly placed outdoor unit, or loose connections made during setup. These are installation-quality issues, not manufacturing defects. The good news is that every single one of them is fixable — usually without replacing any parts.
Understanding the root cause is the first step. Let's go through each one.
Refrigerant is the chemical that does the actual cooling. It flows through your AC, absorbs heat from your room's air, and releases that heat outside. Without the right amount of refrigerant, your AC is basically just blowing air. It runs, but it cannot cool.
There are two common reasons why your refrigerant may be low: the air conditioning system was undercharged during the installation process, or there is a leak somewhere in the system.
When a technician undercharges the refrigerant during installation — which happens more often than it should — your AC runs continuously but struggles to bring the room temperature down. You may notice the air coming out feels mildly cool rather than cold. You might also see ice forming on the copper pipe near the indoor unit, or hear a faint hissing sound.
Refrigerant issues require immediate professional attention. These chemicals are potent and can be harmful to your health if you are exposed to them. Only certified professionals have the proper equipment and training to safely locate leaks, repair them, and recharge the system.
This is not a DIY fix. Never attempt to top up refrigerant on your own. Call a certified technician.
At Coolex Air Conditioning, every installation includes a refrigerant level check using calibrated equipment. Our technicians do not leave your premises until the system is charged to the manufacturer's exact specification. If you suspect undercharging, call us at 9326168231 for a post-installation inspection.
This is one of the most overlooked reasons a new AC fails to cool — and it is almost always a planning mistake, not an equipment failure.
Air conditioners are sized in tonnes. A 1-ton unit is designed to cool roughly 100–120 square feet under normal conditions. If your room is larger, or if it has big west-facing windows, a high ceiling, or poor insulation, a 1-ton unit will run non-stop and still leave you sweating.
Undersized units have the opposite problem: they run nonstop trying to keep up but still cannot get your space comfortably cool. This often happens because a proper load calculation was not done before selecting the unit.
Oversized units cause a different problem. They tend to short cycle, meaning they turn on and off frequently. That cools the room quickly but does not remove enough humidity, so your space can still feel sticky and uncomfortable.
The fix for an undersized AC is either upgrading to a higher capacity unit or adding a second unit for the room. Neither is cheap — which is exactly why getting the sizing right before installation is so critical.
At Coolex, every installation starts with a site inspection. Our technicians assess your room's dimensions, sun exposure, floor level, and ventilation before recommending a unit. We have seen this save customers in Hinjewadi and Baner from buying the wrong-sized AC more times than we can count.
Your outdoor unit does a very important job: it takes the heat pulled out of your room and dumps it outside. If it cannot do that efficiently, the whole system suffers.
Sometimes the reason your new AC is not cooling is surprisingly simple. Before concluding it is an installation issue, run through these quick checks yourself.
If none of these solve the problem, the cause is almost certainly installation-related.
When the drainage line is not fitted correctly, your AC can stop cooling without any obvious reason.
Every problem listed in this guide comes down to one thing: the quality of installation.
A well-trained technician with the right tools, the right process, and enough time to do the job properly will prevent all of these issues before they start. A rushed technician who skips steps will leave you with a brand new AC that doesn't cool, and no accountability.
At Coolex Air Conditioning, our installation process is built to eliminate these problems at the source.
We start with a site inspection — our technicians assess your room size, sun exposure, wall strength, and electrical points before recommending any unit. This prevents wrong sizing and bad outdoor unit placement from day one.
Our professional setup covers correct refrigerant charging to manufacturer specifications, precise drainage slope installation, and verified electrical connections. We use branded tools, and our technicians are certified to work across all major brands including Daikin, Voltas, LG, Blue Star, and more.
After installation, we run a full system diagnostic — checking cooling temperature, drainage, airflow, and compressor function before we consider the job complete.
And when you have questions after we leave, our post-installation support means you are never left figuring things out alone.
We serve all areas across Pune including Wakad, Baner, Aundh, Kothrud, Hinjewadi, and Deccan. Whether it is a residential flat or a commercial office, we bring the same level of precision to every installation.
If your new AC is not cooling properly and you are in Pune, do not wait. Call Coolex Air Conditioning at 9326168231 orbook a service visit today. A perfectly cool room is only one call away.
A new AC failing to cool is frustrating — but it is almost always fixable. Incorrect refrigerant charge, wrong unit size, a poorly placed outdoor unit, drainage issues, and simple settings errors are the six most common culprits. Most of them trace back to installation quality.
The best way to avoid all of this is to start with a certified, accountable installer who inspects first, installs carefully, tests thoroughly, and supports you afterward.
That is exactly whatCoolex Air Conditioning delivers — professional AC installation in Pune with precision, transparency, and zero shortcuts.
If something is already wrong with your current installation, don't ignore it. The longer an underperforming AC runs, the more it strains the compressor and drives up your electricity bill. Contact Coolex today, and we will diagnose and fix it fast.
Why is my brand new AC running but not cooling the room? If your new AC is running but not blowing cold air, the most likely causes are incorrect refrigerant charging during installation, wrong unit size for your room, or a badly placed outdoor unit. Check your thermostat settings and mode first. If those are correct, call a certified technician to inspect the refrigerant levels and installation quality.
How do I know if my AC refrigerant gas is low after installation? Signs of low refrigerant include air that feels mildly cool but not cold, ice forming on the copper pipe near your indoor unit, a faint hissing or bubbling sound, and the AC running continuously without cooling the room to the set temperature. Low refrigerant must be diagnosed and refilled by a certified technician only.
Can the wrong AC tonnage cause poor cooling in my room? Yes. An undersized AC will run non-stop but still fail to cool a large room, especially in Pune's peak summer heat. An oversized AC will cool quickly but leave the room feeling humid and uncomfortable. The right tonnage depends on your room's size, sun exposure, floor level, and insulation — all of which Coolex assesses during a free site inspection before installation.
What should I check if my new AC is not cooling in the first week? Start with the basics: confirm the mode is set to COOL on the remote, set the temperature well below the current room temperature, check that no protective film is blocking the filter, and check whether the circuit breaker for the outdoor unit has tripped. If these checks don't help, the problem is likely an installation issue and you should call your installer immediately.
Does Coolex Air Conditioning provide post-installation support in Pune? Yes. Coolex provides complete post-installation support and service across Pune including Wakad, Baner, Aundh, Kothrud, Hinjewadi, and all nearby areas. If your AC is not cooling correctly after a Coolex installation — or any other installation — you can reach our team at 9326168231 or visitcoolexairconditioning.com to book a service visit.