What an inspector actually measures
A Texas inspection of a heating and cooling system is a performance check, not an engineering review, and the distinction is written into the rule. Under the Texas Standards of Practice the inspector operates the equipment with normal controls and reports as Deficient, among other things, deficiencies in the performance of the cooling system that fails to achieve a 15 degrees Fahrenheit to 22 degrees Fahrenheit temperature differential — the difference between the air entering the return and the air leaving a supply register while the system runs.
The same rule then states that the inspector is not required to determine sizing, efficiency, or adequacy of the system. Read those two provisions together and they define the job. An inspector measures how the equipment performs today; it does not decide whether it is the right equipment for the house.
The split is a screening test, not a diagnosis. It moves with outdoor temperature, humidity, filter condition, airflow and run time before the reading. A result outside the range means something warrants investigation — low charge, restricted airflow, a dirty coil, a failing compressor, return-side leakage pulling in attic air — but not which. The system is low on refrigerant is a conclusion no inspector can reach: only an EPA Section 608 certified technician may open the circuit.
Working out how old the equipment is
Determining equipment age is not a Standards of Practice requirement; most inspectors report it anyway, because it is the fact buyers care about most. Treat any age in a report as an estimate read off a data plate, not a certified fact.
Read the data plate first. Many manufacturers print a manufacture date or an MFG date field on the nameplate, and if it is there nothing else is needed. Decode the serial number second. There is no universal format; each manufacturer uses its own and has changed it over the years. Common patterns embed a week-and-year or month-and-year in the first four characters, or code the year as a letter — so a decoding chart is worth what its source and date are worth, and most online decoders carry neither. Cross-check third, against the AHRI reference number, the electrical inspection sticker in the air handler closet, and the municipal permit history.
Then be sceptical of any single data point. A house does not have one HVAC age; it has several. A condenser replaced under warranty may be a decade newer than the air handler, and both far newer than the ductwork, which in many DFW houses is original. One shortcut beats serial decoding for reliability: the refrigerant type on the outdoor data plate. R-22 predates the changeover to R-410A, which puts a floor under the age without decoding anything.
The service life figure this page will not give you
You have already seen the number: a tidy range of years, quoted on contractor sites, in listing remarks and in inspection reports, always without a citation. This site takes a deliberate position. There is no credible public source for the service life of residential heating and cooling equipment, so we are not going to publish a figure.
ASHRAE's public Service Life Database is real, and it is not about your house. As of August 2026 it holds data from 345 buildings and 38,946 equipment entries across eight system categories — but it is a commercial and institutional building dataset. Its cooling category holds fewer than a thousand entries, and its taxonomy does not break out residential split-system condensers, air handlers or gas furnaces at all. It cannot support a statement about a three-ton split system in a Plano house.
And the charts circulating under ASHRAE's name are not that database. The life expectancy PDFs shared across contractor and inspector websites are uncontrolled reproductions of a table from a paywalled handbook, of unclear edition and vintage, passed hand to hand until nobody can say what year the underlying data describes. A reproduction of a reproduction is not a source.
What actually predicts remaining life
- Accumulated run hours. The honest North Texas argument: a DFW condenser runs a long season at high ambient temperature and puts far more compressor hours on the clock per calendar year than the same unit in a mild climate. That is directional reasoning, not a statistic — but it is sound, and it means national rules of thumb understate wear here.
- Maintenance and installation quality — coils cleaned, filters changed, drain lines cleared, the charge verified rather than topped up repeatedly to chase a leak; and, from day one, line set routing, airflow across the coil and duct design.
- Whether it was oversized from the start, which shortens equipment life.
Age alone is not a defect. A system well past its first decade that holds a proper split and runs quietly has not failed. It is a foreseeable capital replacement — a far more useful thing to tell a buyer. Plan for it, price it into the deal if the timing is right, and stop treating a number nobody can source as a diagnosis.
Sizing, and why a bigger system is not a better one
Sizing is a code requirement on new work, not merely good practice. The International Residential Code requires that equipment be sized in accordance with ACCA Manual S or other approved sizing methodologies based on building loads calculated in accordance with ACCA Manual J or other approved methodologies.
The sequence runs in three steps: Manual J calculates the load, Manual S selects equipment to match it, Manual D designs ductwork to deliver it. Manual D is where most DFW replacement work falls apart, because contractors reuse ductwork designed — if at all — for a different system. Note the boundary: this governs new installations subject to permit, and no inspector can verify a Manual J was ever performed.
Square-footage rules of thumb are wrong because a load calculation accounts for orientation, glazing, insulation, infiltration, duct leakage, internal gains and occupancy. Two Plano houses of identical square footage — one with west-facing single-pane glass and R-19 attic insulation, the other with low-E glass and R-38 — have materially different loads.
What oversizing actually does
- Short cycling. The system satisfies the thermostat quickly and shuts off. Frequent starts wear the compressor and contactor, and each start-up runs at low efficiency before reaching steady state.
- Poor dehumidification, which is the real problem here. An air conditioner removes moisture only once the evaporator coil is cold and wet, and that takes several minutes of continuous running. A short-cycling system never reaches sustained moisture removal, so the house hits its setpoint while staying humid. The occupant feels a cold, clammy house, assumes it is not keeping up, and lowers the thermostat — shortening the cycles further. In a humid Texas summer, run time matters more than raw capacity. Homeowners routinely misdiagnose this as insufficient cooling.
Undersizing fails the other way, but oversizing is far more common in replacement work, because the new unit is usually sized by matching the old tonnage rather than by calculation — perpetuating the original error for another twenty years. Get a Manual J at replacement, not at inspection, when it costs little against the project and changes the outcome.
Two refrigerant transitions, and the same myth twice
R-22, the ozone phase-out
As of 1 January 2020, domestic manufacturers may no longer produce new HCFC-22 and importers may no longer import it. Only recycled, reclaimed or previously produced R-22 may be used to service existing equipment.
Now the correction. EPA states there is no EPA requirement to get a new system or convert an existing HCFC-22 unit to a substitute refrigerant. An R-22 system is not illegal and a homeowner is not required to replace it. Contractors sometimes say otherwise; they are wrong. The real constraint is the supply and price of reclaimed refrigerant, which makes a large leak repair a poor investment — a business decision, presented as one.
R-410A, the climate phase-down
Under the American Innovation and Manufacturing Act and EPA's Technology Transitions Rule, residential and light commercial air conditioning and heat pump systems carry a global warming potential limit of 700. The manufacture and import compliance date was 1 January 2025, as was the installation compliance date — with one carve-out that matters: there is no installation compliance date for systems where all specified components were manufactured or imported before that date, so equipment already in the supply chain could still be installed.
New systems therefore use lower-GWP refrigerants, principally R-454B and R-32, both classified A2L, meaning mildly flammable. The myth then repeats exactly: an existing R-410A system is not illegal and does not have to be replaced. Replacing only the outdoor condenser may become harder to match over time, and A2L equipment carries different installation and service requirements — which argues for replacing matched systems rather than halves.
Status note, current as of August 2026: EPA has proposed targeted relief from certain Technology Transitions Rule requirements. This is an actively moving rulemaking — check its status rather than rely on any dated page, including this one. See EPA on technology transitions.
What an inspector can and cannot determine
The Standards of Practice draw the line (22 TAC §535.230).
Must report: inoperative units; cooling performance failing the 15 to 22 degree differential; noticeable vibration; water standing in drain pans; deficient refrigerant line insulation; deficient thermostats; and, on gas equipment, gas leaks in the heating equipment itself, flame impingement, uplifting flame, improper flame colour, excessive scale, and burners less than 18 inches above a garage floor.
Not required to: determine sizing, efficiency, or adequacy of the system; inspect for refrigerant pressure or leaks; program digital thermostats; inspect winterized or shut-down equipment; operate equipment where doing so may damage it; or determine code compliance. Equipment age sits outside the required scope too, as does any judgement about whether a system will last another year.
What to do about it
- Operating normally, within the split, well into its life — budget for it. A planned capital item, like the roof. Not a defect, and not a reason to walk.
- Split outside the range, vibration, water in the drain pan, or missing line insulation — get it evaluated. Water in the pan is a live condensate problem that may be causing damage now.
- Any gas-fired finding — get it evaluated before closing, urgently. Flame impingement, an uplifting flame, improper flame colour or heavy scale are carbon monoxide pathways.
- Inoperative unit — get it evaluated before closing. An R-22 system, by contrast, is simply a budget item: neither illegal nor required to be replaced.
- Sizing concerns — do nothing now. Get a Manual J at replacement, and never read a report as saying the system is undersized.
Who does the work. Air conditioning and refrigeration contracting in Texas is licensed by the Texas Department of Licensing and Regulation, and anyone opening the refrigerant circuit must also hold EPA Section 608 certification. A contractor can run the load calculation and verify the charge; an inspection does neither.
Common questions
How long does an air conditioner last in Texas?
Nobody can tell you honestly, and this site will not pretend otherwise. There is no credible public dataset for the service life of residential cooling equipment. ASHRAE's public Service Life Database is commercial and institutional building data and does not break out residential split systems at all, and the life expectancy charts circulating on contractor sites are uncontrolled reproductions of a paywalled table of unclear vintage. What can be said is that a DFW condenser accumulates far more compressor run hours per calendar year than the same unit in a mild climate, and that run hours, maintenance, installation quality and original sizing predict remaining life far better than the calendar does.
How do I find out how old my air conditioner is?
Start with the data plate on the outdoor unit and the air handler, because many manufacturers print a manufacture date outright. If there is no date field, the serial number usually encodes one, but formats are manufacturer-specific and have changed over time, so use the brand's own literature rather than a generic decoder. Cross-check against the AHRI reference number, the electrical inspection sticker in the air handler closet, and the municipal permit record. Check the outdoor unit, the indoor unit and the ductwork separately — they are frequently three different ages.
Does an R-22 air conditioner have to be replaced?
No. EPA states there is no requirement to replace an existing R-22 system or convert it to another refrigerant. What changed on 1 January 2020 is that R-22 can no longer be produced in or imported into the United States, so only recycled, reclaimed or previously produced refrigerant is available to service existing equipment. That makes a large leak repair expensive enough that replacement often wins on economics — but that is a financial judgement, not a legal requirement, and a contractor who tells you the system is illegal is misinformed. The same applies to R-410A systems under the newer phase-down.
Can an air conditioner be too big for a house?
Yes, and in North Texas an oversized system is the more damaging error. Air conditioners remove humidity only after the evaporator coil has run long enough to get cold and wet. An oversized system reaches the setpoint and shuts off before that happens, so the house ends up cool and clammy, the occupant lowers the thermostat, and the cycles get shorter still. Oversizing also causes short cycling that wears the compressor and contactor. It is common in replacement work because the new unit is usually sized by matching the tonnage of the old one instead of by calculation.
Does a home inspector check whether my AC is the right size?
No. The Texas Standards of Practice state that an inspector is not required to determine sizing, efficiency, or adequacy of the system. An inspector measures performance — principally whether the cooling system achieves a 15 to 22 degree Fahrenheit temperature differential — and reports what is deficient. Determining correct size requires an ACCA Manual J load calculation accounting for orientation, glazing, insulation, infiltration and duct losses. Have that done at replacement, by a licensed contractor.
What does the 15 to 22 degree temperature split mean on my report?
It is the difference between the temperature of the air entering the return and the air leaving a supply register, and Texas rules require an inspector to report a cooling system that fails to achieve it. Treat it as a screening result rather than a diagnosis. The reading moves with outdoor temperature, indoor humidity, filter condition, airflow and how long the system ran beforehand. A split outside the range means something warrants investigation — low charge, restricted airflow, a dirty coil, a failing compressor, or return ducts pulling in attic air — but it does not say which, and only an EPA Section 608 certified technician can open the refrigerant circuit to find out.