What to check after AC installation

Why the first days matter

ENERGY STAR material states that nearly half of heating and cooling equipment in US homes never performs to its advertised capacity and efficiency because of installation problems. Many installation problems, such as a wrong charge, poor airflow, a sagging drain line or a mismatched coil, are easiest to spot and cheapest to fix in the first days, while the installer's labor warranty is fresh and the crew still remembers the job.

You do not need tools or HVAC training for most of this checklist. It is about what you can see, hear and feel, and about the paperwork you should hold before the final payment. Anything technical, such as refrigerant pressures, is a question for the installer, not a job for you.

Before the installer leaves: the walkthrough

Ask for a walkthrough at the end of the job and go through these items with the lead installer. It usually takes a few minutes and settles most questions on the spot.

1. Run it. Ask them to start the system in cooling with you present and let it run while you walk the house.
2. Feel the supply air. Air from the vents should feel noticeably cooler than the room within a few minutes.
3. Check the outdoor unit. The fan spins, the unit sits level on its pad, and there is clear space around it.
4. Look at the indoor unit. In the attic, closet or garage: panels on, no loose wiring, drain line connected and sloped away.
5. Confirm the thermostat. Ask them to show cooling, fan and, for a heat pump, heating and emergency heat settings.
6. Find the filter. Know where it goes, which size, and how often they suggest changing it.
7. Ask for the readings. Many installers record start-up measurements. Ask for a copy for your file.

If the delivered equipment differs from the quote, raise it now. Ask in writing why, and whether it is an equivalent matched system with the same ratings. The questions to ask an HVAC installer guide lists what the quote should have named.

Does the equipment match the quote?

Model numbers are printed on a rating plate on each unit: on the side or back of the outdoor condenser, and on the indoor coil and furnace or air handler. Photograph each plate and compare it with the quote and invoice.

A central split system's efficiency rating applies to the matched combination of outdoor unit and indoor coil, which is why a swapped coil matters even when the outdoor unit is right. Texas is in the DOE Southeast region. Since 1 January 2023 a split-system central AC under 45,000 BTU (about 3.75 tons) must be at least 14.3 SEER2 on the date it is installed; larger systems need 13.8. Split heat pumps need 14.3 SEER2 and 7.5 HSPF2 nationwide.

On refrigerant: Equipment made or imported since 1 January 2025 uses lower-GWP A2L refrigerants (R-454B or R-32) instead of R-410A. An EPA rule finalized in May 2026, effective 27 July 2026, removed the 1 January 2026 cutoff, so contractors may install pre-2025 R-410A systems until that stock runs out. Either can be legitimate, but it should be what the quote said. See R-410A versus the new refrigerants.

The paperwork to collect

Paperwork is your proof of what was installed, by whom, and under which warranty. The licensee’s number must appear on all advertising, proposals and invoices, an invoice is required for all ACR work, and proposals, invoices and written contracts must carry the notice “Regulated by The Texas Department of Licensing and Regulation, P.O. Box 12157, Austin, Texas 78711, 1-800-803-9202, 512-463-6599; www.tdlr.texas.gov”.

1. An itemized invoice showing the company name, the TDLR license number and the TDLR consumer notice.
2. Model and serial numbers for every piece of equipment.
3. The AHRI reference number for the matched system, if the quote gave one.
4. The permit number and which office issued it.
5. The labor warranty terms in writing.
6. Who is registering the equipment warranty, and the confirmation once done.
7. Any start-up or test readings the installer recorded.
8. The manufacturer's homeowner manual and warranty booklet.

In Texas, labor to repair or remodel residential property is not taxable; the materials are. Your invoice can be lump-sum (tax built into the contractor's material cost) or separated (tax shown on the materials line). Both are normal.

Check the license number on the invoice against the TDLR license lookup, and keep everything in one folder or one email thread. You will need it for a warranty claim or when you sell the house.

The permit inspection

In most DFW cities the contractor who pulled the permit also arranges the inspection. The inspector checks the installation against the city's adopted code. The permit record ties the work to your address, which can matter at resale.

The City of Dallas issues mechanical permits through its DallasNow portal so that work complies with the Dallas Mechanical Code and is performed by a licensed air-conditioning contractor. Installing or replacing a central system is mechanical work; no City page we found states the replacement rule in one sentence, so confirm with Development Services for your job. In the City of Dallas, from 1 June 2026 plumbing and mechanical rough inspections are scheduled together on the same day. TDLR adopted amended ACR rules effective 1 September 2026, moving the state’s adopted model codes from the 2021 to the 2024 editions. Cities enforce their own adopted codes; Dallas’s current set is the 2021 codes with local amendments.

1. Ask for the permit number on the day of installation.
2. Ask who schedules the final inspection and whether you need to give access.
3. Ask for the result once it has passed, or look it up on the city portal if it offers one.
4. If it fails, ask what failed, who fixes it, and when the re-inspection is.

Warranty registration: the 60-day clock

Registration is the item most often forgotten, and for some brands it decides how long the parts warranty lasts.

Trane extends its warranty term only if the product is registered within 60 days of installation; registered late, it keeps the base warranty. Lennox requires registration within 60 days of installation (or closing, for new construction) for its extended limited warranty. Other manufacturers set their own terms, so read the booklet for your brand.

See the AC installation warranty guide for how parts and labor warranties differ.

The first week of hot weather

DFW summers test a new system quickly. DFW averages about 20 days a year at or above 100 °F (1991–2020 normal, computed from the NWS Fort Worth 100-degree-day table). Average first 100 °F day: July 1. Average last: August 27. If your system was installed in spring or fall, the first real test may come weeks later, so keep the checklist until then.

On the first hot afternoons, pay attention to how the house feels and how the system behaves. You are looking for patterns, not single moments.

For background, see problems with an oversized AC and hot and cold rooms.

The condensate drain

An AC removes moisture from the air, and that water has to go somewhere. In many DFW homes the indoor unit sits in the attic, so a drain problem can show up as a ceiling stain rather than a puddle.

Find where the drain line ends, usually outside near the foundation or into a plumbing drain. On a hot day it should drip steadily. Ask whether a secondary pan and a float switch were installed under an attic unit; the switch shuts the system off if the pan fills.

1. Primary drain line ends where you can see it, and drips on hot days.
2. Secondary pan under an attic unit is dry.
3. Float switch is fitted, if the quote included one.
4. No water marks on the ceiling below the unit.

Worked example: a Garland ranch house

Say a 1978 ranch house in Garland gets a new 3-ton AC in May. The walkthrough goes fine and the house cools. In the first week of June, the owner notices the system turning on and off every few minutes in the afternoon and the house feeling damp.

Using this checklist, the owner compares the rating plate with the quote and finds the outdoor unit is larger than quoted. They email the installer the same day with photos, ask why, and ask for the load calculation. The final payment is still held because the city inspection has not been completed.

This is a hypothetical case, but it shows why the order matters: photos and the quote in hand, a written question while the labor warranty is fresh, and payment tied to a finished job.

First upkeep

• Change or clean the filter on the schedule the installer or manufacturer recommends. A clogged filter cuts airflow.
• Keep plants, fencing and debris clear of the outdoor unit so it can move air.
• Do not stack storage against the indoor unit or block return grilles.
• Keep maintenance receipts with the invoice; manufacturer terms may refer to proper maintenance.
• Ask whether a maintenance plan is optional, and what it includes, before buying one.

ENERGY STAR estimates that about 20 to 30 percent of the air moving through a typical duct system is lost to leaks, holes and poorly connected ducts. If rooms stay uneven after the install, ask about the ducts; ductwork sealing and replacement explains the options.

If something is wrong

1. Write it down. Date, time, what you saw, photos or a short video.
2. Contact the installer in writing. Email keeps a record. Reference the invoice and the labor warranty.
3. Ask for a date. When will they come back, and what will they check?
4. Keep the final payment tied to resolution, if your contract allows.
5. Escalate if needed. Complaints against a licensee are filed with TDLR online or by mail.

The full checklist

1. Every room cools; supply air feels noticeably cool.
2. Outdoor unit level, clear, running quietly.
3. Indoor unit closed up; drain connected; secondary pan dry.
4. Thermostat works in every mode you need.
5. Model numbers and refrigerant match the quote.
6. Invoice with TDLR license number and consumer notice.
7. Permit number and passed final inspection.
8. Warranty registered, with confirmation, inside the manufacturer's window.
9. Labor warranty terms in writing.
10. No short cycling, clamminess, leaks or new noises in the first hot week.

Sources

• ENERGY STAR HVAC fact sheet (retrieved 2026-10-20) — verify before relying on it
• AHRI, "2023 Energy Efficiency Standards"; DOE regional standards (retrieved 2026-09-23)
• NAHB summary of the EPA final rule (May 2026); EPA AIM Act Technology Transitions program (retrieved 2026-09-23)
• Texas Comptroller, Publication 94-116, "Real Property Repair and Remodeling" (retrieved 2026-09-23)
• City of Dallas Development Services, mechanical permits (Dallas Mechanical Code, Chapter 55 amendments); process and fee: verify with the City before relying on it (retrieved 2026-09-23) — verify before relying on it
• Trane, Warranty and Registration (retrieved 2026-10-20)
• Lennox, Extended Limited Warranty FAQ (retrieved 2026-10-20) — verify before relying on it
• National Weather Service Fort Worth, "DFW 100° Day Data" (retrieved 2026-09-23)
• NWS Fort Worth, "DFW 100° Info" (retrieved 2026-09-23)
• ENERGY STAR, "Duct Sealing" (retrieved 2026-10-20)
• US EPA, Section 608 refrigerant sales restriction (retrieved 2026-10-20) — verify before relying on it
• 16 Tex. Admin. Code §75.71 (Cornell LII mirror) (retrieved 2026-10-20)
• TDLR, ACR rules effective 1 September 2026 (retrieved 2026-10-20)
• TDLR, complaints (retrieved 2026-10-20)
• City of Dallas, Development Services, Building Inspection (retrieved 2026-10-20)

Questions

Next step