A tech topped off your refrigerant last spring, the system ran fine through June, and now the house is warm again by mid-afternoon. That is not bad luck and it is not normal wear. A sealed refrigerant system does not use up refrigerant the way a car burns gas: if the charge is low, refrigerant is leaking out somewhere, and refilling it every season just means paying to top off the same hole again. Novus Mechanical tracks down the actual leak with instruments instead of a guess off the gauge, then gives you a repair price or an honest replacement conversation, whichever the leak actually calls for.
It shouldn't. An AC system is charged once at the factory or at install and stays sealed for the life of the equipment, refrigerant included. Nothing in a working system burns it, evaporates it, or uses it up in normal operation.
So if a technician is adding refrigerant on a return visit, that refrigerant left through a hole somewhere: a corroded coil, a bad flare fitting, a line rubbed through against a joist. Every top-off after the first one is paying for the same leak a second time, sometimes a fourth or fifth time over a few seasons, while the actual failure sits there untouched.
Running low on charge for months isn't harmless either. It starves the compressor of the oil that rides along with the refrigerant, and a compressor that runs dry long enough can fail outright.
Sometimes, and it depends entirely on how the leak behaves. A steady leak at a reachable fitting takes minutes to find. A slow one that only opens up when the line set vibrates or the attic hits 130 degrees in August can take more than one visit and a different method. That is why we do not commit to a single tool up front.
We use whichever method fits how the leak is behaving, not just one tool every time. An electronic leak detector sniffs along fittings, coil edges, and connections and reacts to refrigerant in the air, which is fast and precise when the leak is steady and reachable.
Intermittent leaks are a different problem. A leak that only shows up when the line vibrates or the attic gets hot in August won't always trip a sniffer on a calm morning. For those we add UV dye to the system, run it for a stretch, then come back with a UV light and find the stain at the source.
On a larger job, or where we suspect more than one leak point, we pressurize the sealed system with dry nitrogen and watch whether it holds. Rather than trust gauge pressure alone, which shifts with outdoor temperature, we weigh the refrigerant out of the system and back in, and check superheat and subcooling, the two readings that confirm the charge matches what that system was designed to run.
| Method | What it actually tells us |
|---|---|
| Electronic leak detector | Pinpoints a leak on contact, best for reachable fittings and coil edges |
| UV dye | Catches slow or intermittent leaks that only show up under vibration or heat |
| Nitrogen pressure test | Confirms whether the whole sealed system is holding pressure at all |
| Weighing the charge | Shows the true refrigerant amount in the system, not a pressure guess |
| Superheat and subcooling | Confirms the charge is correct for that system's specific design |
Evaporator coils fail from the inside more often than people expect. Formicary corrosion, tiny pinhole leaks that spread through the copper the way ants tunnel through wood, shows up on indoor coils that sat in a damp basement or a closed-up crawlspace for years. It is slow, it is common, and by the time it leaks enough to notice, the coil usually needs replacing rather than patching.
Schrader valve cores, the small spring-loaded valves under the service caps on the outdoor unit, are a cheap part that fails often and is a quick fix once found. Flare connections on mini splits are another frequent culprit: a line set flared slightly off during install holds for a year or two before it starts weeping.
Line sets themselves take a beating in the newer developments around Marlboro and Colts Neck, where long attic runs to far bedrooms get baked all summer and chafe against framing over time. And on the eastern side of the county, salt air off the coast attacks the thin aluminum fins and copper tubing on outdoor coils faster than it does further inland, so a ten-year-old condenser near the shore can already be leaking where the same unit further west would still be tight.
Yes, and it is worth understanding before you approve a recharge. R-410A, the refrigerant in most systems installed over the past fifteen years, is being phased down in favor of R-32 and R-454B. As of January 2025, manufacturers can no longer build new residential systems that use R-410A, and the refrigerant itself keeps getting more expensive to buy as production winds down under that same phasedown. A repair that used to mean a routine recharge is now a recharge at a rising price.
That matters most on an older R-410A system with a real leak, not a slow seep. If the leak is small and easy to reach, fixing it and recharging still makes sense. If the leak is in the evaporator coil of a system that is already twelve to fifteen years old, the math shifts: you are paying phase-down prices for R-410A to keep an aging system running a few more seasons, against a new system on R-32 or R-454B that will not carry that rising cost. We will price both and tell you plainly which side of that line your system sits on.
Refrigerant is a greenhouse gas, and it is not legal for just anyone to vent it into the air or hand it around loosely. The EPA requires certified technicians to recover refrigerant rather than release it, and governs how it is handled, stored, and disposed of. That is part of why a proper leak repair means more than adding refrigerant on top of a leak that is still open. It includes:
Depends entirely on where the leak is and how old the system is. A Schrader valve or a flare fitting on a system under ten years old is almost always worth repairing outright, since the part is cheap and the rest of the equipment is fine.
An evaporator coil leak on a system past twelve or fourteen years is a harder call, and we will not sugarcoat it. Coil replacement on an older unit sometimes costs close to what a full central AC replacement runs, especially once you factor in R-410A availability. When we find that, we price the coil repair and a full system swap side by side so you can see the real numbers instead of guessing.
The diagnostic visit is $150 and can reach $200 on a harder call, and that covers the actual leak search, not just a pressure reading. Most repairs, once the leak is found, start at $350, and you get that number before we touch the system. If the diagnostic turns into a full AC repair beyond the leak itself, that gets priced the same way: approved before work starts, never after.
Rolling a leak search into your fall or spring system check-up is often the cheaper path, since we are already in the unit measuring performance. Members of our Comfort Club get that check built into the plan rather than booked separately.
Not for a typical home system. The EPA's Section 608 rules set leak repair requirements and leak-rate thresholds for larger commercial and industrial refrigeration equipment, not for residential air conditioners and heat pumps, so nobody is legally requiring you to test yours. What Section 608 does apply to you is who handles the refrigerant: it has to be an EPA-certified technician, and venting refrigerant to the atmosphere is illegal regardless of system size. Confirm specifics with the EPA rather than taking any contractor's word for what is required.
In almost every case, yes. Residential leaks release small amounts into a large, ventilated space, and R-410A is not toxic at those concentrations. Two things change that. A large, fast release into a small enclosed space, a mechanical closet or a tight basement, can displace oxygen, so ventilate and step outside if that is your situation. And the R-32 and other A2L refrigerants now shipping are mildly flammable, which is why they come with leak sensors and why you should not run the system or use an open flame near a suspected leak. If you smell something sharp near the air handler, shut the system off and call rather than keep running it.
We work out of Freehold and cover the surrounding parts of Monmouth County: Marlboro, Manalapan, Colts Neck, Holmdel, Howell, and Millstone. Residential homes only, including the mini split systems we service and repair across the county.
Repairs and installs are scheduled Monday through Friday, 8 AM to 6 PM, and the phone is answered any time so you can get on the schedule as soon as you notice the house running warm. We do not advertise overnight emergency dispatch, because a leak search done right takes real instruments and daylight, not a rushed patch in the dark. Call and we will get you the earliest slot and find the leak instead of guessing at it again.
We measure your home, explain what we find, and hand you one clear price. Book a consultation in Freehold or Monmouth County.
Updated August 2026 by Novus Mechanical, Freehold, NJ
