A running AC that isn’t cooling almost always traces back to one of five culprits which are, airflow, refrigerant, ice, electrical, or ductwork.
Your thermostat says 68. Your living room says otherwise. There’s quite clearly a problem. Cool setting, warm result, is a very common call for our Missoula HVAC techs every June, July and August.
What’s Choking Your Cool Air
Before you assume the whole unit’s shot, walk through the short list first.
- Clogged air filter starving the system of airflow
- Low refrigerant from a slow leak, the actual coolant that pulls heat out of your home
- Frozen evaporator coil, often caused by the first two problems stacking on top of each other
- Dirty condenser coil outside, caked in airborne debris and road dust
- A failing capacitor or contactor, the small electrical parts that keep the compressor firing
- Leaky or crushed ductwork bleeding cold air into your attic instead of your hallway
The One Repair Getting More Expensive by the Season
As of January 1, 2025, the EPA’s Technology Transitions Rule capped new residential AC and heat pump refrigerants at a global warming potential of 700 or less.
That pushed the industry off R-410A and onto lower impact refrigerants like R-454B, sold under names such as Puron Advance.
Translation for your wallet. R-410A (refrigerant) is getting harder to source, and topping off a leaking older system costs more this year than it did two summers ago. If your unit is low on refrigerant, fixing the leak beats “recharging” it.
Key takeaway: Recharging without finding the leak is like bailing a boat without patching the hole.
When Western Montana Summers Make It Worse
Missoula Valley’s dry heat sneaks up fast.
A struggling A/C in Lolo, the South Hills, Miller Creek, Frenchtown, Linda Vista, or Stevensville turns a stuffy afternoon into a dreadful night. Older homes around Rattlesnake and the University District feel it hardest, since original ductwork wasn’t sized for today’s heat.
What Montanas Are Saying
One recent Google reviewer said
“I absolutely can’t say enough good things about the company, and to an even bigger degree, the crew!
It was a multiple day, large job.
Three split unit AC’s inside, with the outside main unit.
These guys were on time every single morning, despite having to drive 50 miles to get to Hamilton, to even start the job.”
Why Montanans Call Right Now Plumbing and Heating First
Licensed, insured, and based in Missoula, our techs carry parts for capacitors, contactors, and common coil fixes on the truck, so most calls get solved on the same visit.
We also provide free estimates and over the phone pricing for service calls so you know the price from the get go.
Common AC Questions
Why is my AC blowing warm air but the outside unit is running?
Usually a dirty air filter, low refrigerant, or a frozen evaporator coil. Shut the system off for an hour and check the filter first.
Can a dirty air filter really stop cold air completely?
Yes. A clogged filter starves airflow across the coil, which can freeze it solid and cut cooling to zero.
Is low refrigerant dangerous?
Refrigerant doesn’t wear out on its own, so low levels mean a leak somewhere in the system that needs locating and fixing.
How much does an AC repair cost in Missoula?
Most airflow and electrical fixes run far less than a full replacement. Depends on what you’re dealing with, call us and we’ll give you a price.
Should I keep running my AC if it’s only blowing warm air?
No. Running it while frozen or low on refrigerant can damage the compressor, the most expensive part to replace.
Written by the owner of Right Now Plumbing and Heating.
Sources:
U.S. EPA Technology Transitions Rule (effective January 1, 2025); Right Now Plumbing and Heating verified Google reviews.