Answer first, context after
Why won't my brand new AC cool?
A new system that will not cool is almost never a defective machine. It is usually the installation: the refrigerant charge is off, the airflow is wrong, the system was sized from a guess instead of a load calculation, or the startup measurements were never taken. That is fixable, and if someone else installed it, their labor warranty should cover the fix rather than you paying twice.
Tell us what it is doing and roughly when it was installed. If the company that put it in should be fixing it under warranty, we will say so, even though that means we do not get the job.
Spending five figures and still being hot is a special kind of frustrating, and the reaction most people have is that they got a lemon. Equipment defects happen, but they are rare. The far more common story is that the box is fine and the installation is not.
The usual suspects, in order.
- Refrigerant charge is off. This is the big one. A system that is undercharged or overcharged will run constantly and cool poorly, and at the extremes it will ice up. Charge has to be set by measurement, not by feel, and on a hot day it has to be adjusted for the conditions.
- Airflow was never verified. New condenser, same undersized or leaky ducts. The equipment cannot deliver capacity it cannot move. If your ducts were not measured, nobody knows whether they can carry what the new system makes.
- It was sized by copying the old unit. Sizing from “it was a four ton before” instead of a Manual J load calculation is how houses end up with equipment too big, which short cycles, cools unevenly, and never pulls humidity down. Related: what size AC does my house need.
- Startup was skipped. Superheat, subcooling, temperature split, and static pressure should all be measured and recorded on the day of install. If nobody has numbers, nobody knows whether it was ever set up right.
- A thermostat or wiring mistake, such as a heat pump wired without the right staging, which shows up as lukewarm air rather than no air.
Freezing up on a new system means the same short list. Ice on a new unit is nearly always low charge or restricted airflow, and running it iced is hard on the compressor. Turn the cooling off and the fan on to thaw it, then get it diagnosed: ice on the refrigerant lines.
Who should pay for this. If another company installed it, the labor warranty on their work is usually where this belongs, and the parts are almost certainly still under manufacturer warranty. We will tell you that plainly, in writing, even when it means the repair is theirs to do for free rather than ours to bill. See how do I know if my HVAC is still under warranty.
What our visit looks like. We measure rather than guess: charge, airflow, temperature split, and static pressure, and you get the readings. If the install is correct and the equipment is genuinely faulty, that is a warranty claim and we will document it so you can make it. The $89 diagnostic is waived when you book the repair with us.
New system, still hot? Let's find out why.
A straight diagnosis in writing, including whether the original installer should be covering it. Our technicians earn no commission, so nobody here is paid to sell you a second system.
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