General information about how these parts fail and how a diagnosis is confirmed. Your system may differ, and nothing here replaces someone measuring your equipment. We are an independent contractor and not affiliated with any manufacturer.
What the part actually does
It is the indoor half of your air conditioning, and it is expensive to replace, which is why the diagnosis deserves scrutiny.
It is where the cold actually happens
Refrigerant expands inside it and absorbs heat from the air passing over it. It sits above or beside your furnace, inside a sheet metal cabinet.
It is also where the water comes from
Pulling heat out of the air condenses moisture, which drains away. That is why there is a drain line and a pan under it.
Replacing one is a big job
Recovery, a new coil, a new filter drier, a deep vacuum and a full recharge. On many systems the total lands at a substantial fraction of a new matched system.
It is usually under a ten year parts warranty
To the original registered owner. A coil under warranty turns this into a labour job and changes the decision entirely, so ask before anything else.
What is actually going on
Two claims to push back on
Both get used to move people toward a replacement they may not need.
“The EPA requires us to replace this coil”
That is not true for a home system
The leak repair rule people are referring to applies to appliances holding fifty pounds of refrigerant or more. A residential system is nowhere near that and is not covered by those repair deadlines. Venting refrigerant deliberately is illegal, and always has been. Being required to replace your coil is not a thing that exists.
“We just need to top it up again”, for the third time
Topping up a leaking system is legal and it is money into thin air
There is nothing improper about adding refrigerant to a residential system. But if it has been added more than once, the honest next step is finding where it is going. Before you authorise a third recharge, ask where the leak is.
What you can establish yourself
Two of these genuinely change what a technician can measure when they arrive.
Keep the invoices
The single most useful record a homeowner can keep
How many times refrigerant has been added, and when. That history tells a technician more about the size and location of a leak than almost anything they can measure in one visit.
If the coil is frozen, switch to FAN ONLY and let it thaw
Not COOL. FAN.
A frozen coil makes real measurement impossible, so a technician arriving to a block of ice cannot do much except tell you to thaw it. Doing it before they arrive means the visit is actually useful.
Check the filter and every register
Ice is more often airflow than refrigerant
Federal research found half to nine tenths of systems running below the airflow they need. A dirty filter, a crushed flex duct, a dirty blower wheel or closed registers freeze a coil in exactly the way a leak does.
Look at the drain pan
Standing water tells you something
A blocked drain will shut some systems down entirely through a safety switch, which presents as a dead system rather than a coil problem.
What a real leak diagnosis involves
The difference between finding a leak and assuming one is several thousand dollars.
Was it ever charged correctly?
A worrying share of systems never were
Federal review of field studies found systems undercharged in anywhere from a third to three quarters of cases, and overcharged in a good number too. A system reading low may simply never have been right from the day it went in.
The leak has to be located, not inferred
And it is often somewhere far cheaper than the coil
Schrader valve cores, service valve caps and stems, the brazed joints, the line set between indoors and out, the condenser coil, the filter drier. Line set leaks in particular get missed and the coil gets blamed.
The airflow has to be measured
Before any refrigerant conclusion is possible
A system starved of air reads like a system short of refrigerant. Thawing the coil and measuring airflow comes first, and skipping it is how coils get condemned for a dirty filter.
A dirty coil is not a failed coil
It cleans
A coil packed with dirt on the entering air side loses capacity and freezes up. That is a cleaning job, not a replacement.
Four things worth knowing before you authorise this
- Low refrigerant is a symptom. It is not a diagnosis. Refrigerant is not consumed. If a system is low, it left somewhere. The useful question is not “how much does it need” but “where did it go”, and a quote that cannot answer the second one is incomplete.
- A coil swap on an old system creates a mismatched system. Putting a new coil onto an old outdoor unit gives you a pairing that was never rated together. You get lower efficiency than either component claims and no matched performance figure. Sometimes it is still the right call — but it should be said out loud rather than discovered later.
- The duct system is a suspect and rarely gets named. The same federal review found leakage in the duct system on two thirds to essentially all of the homes studied, and at least one performance-compromising fault on seventy to ninety percent of systems. Poor cooling is not automatically a refrigerant story.
- R-410A is not banned and coils are still available. The Environmental Protection Agency states that components used to repair existing systems are not restricted, and that you may continue repairing what you own. What changed applies to newly manufactured equipment. Anyone telling you the law now forces a replacement is mistaken.
When replacing the coil genuinely does stop making sense
We would rather give you the honest boundary than pretend every repair is worth doing. If the coil is under warranty, repair almost always wins, because you are paying labour rather than the part. If the system is under about ten years, repair usually wins too — but only once the leak has actually been located, because otherwise you are buying the same problem again. Out of warranty, on a system past twelve years, a coil plus a full recharge frequently approaches what a new matched system costs while doing nothing about the age of the compressor, the fan motor or the metering device. On an older R-22 system it rarely makes sense at all — and that is a cost argument, not a legal one. Ask for both numbers written down and compare them side by side.
Been quoted a coil?
Book a visit. We will find the leak before anyone talks about replacing anything.
Book a Diagnostic Visit60 seconds online · or call (206) 486-6373
How it works when you book
- 1
Tell us what you were quoted, or do not — both work Some people would rather we came in cold. We diagnose it ourselves either way.
- 2
We measure it and show you the reading The number off the meter and the number printed on the part. If those two do not disagree, the part is not the problem.
- 3
You get the price in writing before anything starts Itemised, and you approve it. If the honest answer is that nothing needs replacing, that is what you get.
Our service areas
We run out of Covington and cover the greater Puget Sound area.
King County
Covington, Kent, Renton, Maple Valley, Auburn, Federal Way, Des Moines, Enumclaw, Bellevue, Issaquah, Sammamish, Bothell
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Tacoma, Puyallup, Lakewood, Sumner, Bonney Lake
Snohomish County
Lynnwood, Everett
Not on the list? We cover the greater Puget Sound area around our Covington base. Book it and a technician confirms within 1 business hour.
Why homeowners hand it to us
- You approve the price first. Upfront quote before a single screw turns.
- We answer 24/7. Book in a minute, hear from a technician within 1 business hour.
- 500+ jobs done by 4.9★ rated, professional technicians.
- Fixed right, guaranteed. If it’s not right, we make it right.
Quick answers
How do I know the leak is really in the coil?
Because someone found it, and can tell you where. Leak detection is a real procedure with real tools, and the answer should be a location rather than a deduction. If the reasoning is only that the system is low and the coil is the usual suspect, that is not the same thing.
Can a leaking coil be repaired rather than replaced?
Sometimes, depending on where the leak is and what the coil is made of. It is worth asking. It is not always possible and it is not always wise, but it should be a conversation rather than an assumption.
The system is icing up. Is that the coil?
It might be, and it is more often airflow. Switch the system to fan only and let it thaw completely, then check the filter and open every register. If it ices again with clean airflow, that points harder at refrigerant.
Is it worth adding refrigerant while I think about it?
For a season, sometimes, and it is legal. Just go in knowing it is a holding action rather than a repair, and that the cost adds up faster than people expect across two or three visits.
My coil is under warranty. What does that actually cover?
Typically the part itself, to the original registered owner. Labour, refrigerant, the drier and the evacuation are usually yours. That still changes the number substantially, which is why it is the first thing to establish.
Find the leak first.
Book online in about a minute. We will tell you where it is going before anyone quotes a coil.
Book a Diagnostic Visit60 seconds online · or call (206) 486-6373
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