What is an HVAC tune-up? It is a scheduled check of a heating and cooling system in which a technician inspects the equipment, takes measurements, cleans what needs cleaning and makes small adjustments, so the system goes into its busy season in good order. ENERGY STAR recommends one before each season: the cooling side in spring and the heating side in fall.
The word "tune-up" has no legal definition, so two companies can sell very different visits under the same name. The tables below are built from the ENERGY STAR maintenance checklist and the structure of ANSI/ACCA 4 QM, the industry standard for residential HVAC maintenance. Use them to compare offers and to know what to ask for at the end of the visit.
For when to book around the Houston seasons, see AC maintenance in Houston. For whether a yearly visit is worth paying for, see is an HVAC tune-up worth it.
The standard behind a real tune-up: ANSI/ACCA 4 QM
The Air Conditioning Contractors of America (ACCA) wrote the residential maintenance standard known as ANSI/ACCA 4 QM. ACCA lists the current version as the 2019 edition, reaffirmed in 2024. It sets the minimum inspection tasks for HVAC equipment in single-family and multifamily homes.
- Why it exists. ACCA has explained that there was no way to tell whether the many "seasonal tune-ups" and "clean and checks" on the market were equivalent. The standard gives a common minimum.
- What it covers. Checklist tasks for inspecting, testing and measuring the electrical, controls, mechanical, venting, air distribution and piping parts of a home system.
- Inspection versus repair. Each checklist separates the required inspection task from the recommended corrective action. Finding a problem is part of the visit; fixing it is a separate decision for you.
You do not need to read the standard yourself. It is enough to ask a company whether its tune-up follows ACCA 4 and to request its own task list in writing.
What an HVAC tune-up includes: the checklist
Every row is a technician task unless it says otherwise. The last column shows why the item matters, drawn from ENERGY STAR and Department of Energy guidance where they address it.
Cooling side
| Task | Why it matters |
|---|---|
| Inspect and clean the evaporator coil (indoor) as needed | Dirty coils reduce cooling and make the system run longer, raising energy costs and shortening equipment life (ENERGY STAR). DOE says to check this coil every year. |
| Inspect and clean the condenser coil (outdoor) | The outdoor coil sheds the heat taken from the house; dirt and debris slow that down. |
| Check refrigerant charge against the manufacturer's specification | Too much or too little refrigerant can damage the compressor (ENERGY STAR). |
| Measure the temperature drop across the indoor coil | A quick sign of whether the system is removing heat as it should. |
| Check the outdoor fan motor and blade | A weak fan lets heat build up at the outdoor coil. |
| Straighten bent coil fins where needed | Bent fins block airflow through the coil (DOE). |
Gas heating side
| Task | Why it matters |
|---|---|
| Check gas connections and gas pressure | On the ENERGY STAR heating checklist; wrong pressure affects safe, efficient burning. |
| Inspect and clean burners, check burner combustion | A dirty burner causes improper burner operation and can make the furnace run less safely (ENERGY STAR). |
| Inspect the heat exchanger | A cracked heat exchanger is a safety concern (ENERGY STAR). |
| Combustion analysis | Measures how cleanly the burners fire and checks for carbon monoxide in the flue gases. Ask whether the visit includes it. |
| Inspect the flue pipe for rust, gaps or signs of backdrafting | Venting carries combustion gases out of the house. |
| Test the igniter, flame sensor and safety controls | Confirms the furnace starts reliably and shuts down when something is wrong. |
Heat pump
| Task | Why it matters |
|---|---|
| Run it in both cooling and heating modes | A heat pump does both jobs, so both need checking. |
| Confirm the switch between heating and cooling works | The same valve that changes modes is used during winter defrost. |
| Test the backup electric heat | If the heat pump fails on a cold night, the backup heat is what keeps the house warm. |
| Clean the condensate drain pan and check for clogs | A heat pump makes condensate whenever it cools; a blocked pan or line can overflow. |
Electrical and controls
| Task | Why it matters |
|---|---|
| Tighten electrical connections; measure voltage and current on motors | Faulty connections can make the system unsafe and shorten the life of major parts (ENERGY STAR). |
| Check controls and the start-up cycle | ENERGY STAR lists confirming that the system starts, runs and shuts off properly. |
| Test capacitors and contactors | Starting parts wear with use, and testing them can catch one that is weakening. Technician only. |
| Check thermostat settings and operation | ENERGY STAR includes checking settings so the system keeps you comfortable at home and saves energy while you are away. |
| Lubricate moving parts where the motor design calls for it | Lack of lubrication causes friction, raises electricity use and wears parts faster (ENERGY STAR). |
Airflow and ducts
| Task | Why it matters |
|---|---|
| Clean and adjust blower components | Airflow problems can cut efficiency by up to 15 percent (ENERGY STAR). |
| Check or replace the air filter | A clogged filter makes the system work harder; replacing it can lower AC energy use by 5 to 15 percent (DOE). |
| Look over visible ducts, grilles and registers | Air distribution is one of the areas the ACCA 4 standard covers. NIST research ranked duct leakage among the installation faults with the largest effect on energy use. |
Condensate drain
| Task | Why it matters |
|---|---|
| Clear and flush the condensate drain line | A plugged drain can cause water damage, affect humidity and breed bacteria and mold (ENERGY STAR). |
| Inspect the drain pan under the indoor unit | Rust or standing water in the pan is an early warning of a leak into the ceiling. |
| Test the float or overflow safety switch | This switch shuts the system off before a full pan overflows. In a humid Houston summer the drain carries a lot of water. |
How a thorough visit usually unfolds
Companies order the work differently, but a complete tune-up tends to follow a logical path from questions to measurements to a report. Knowing the sequence helps you tell whether anything was skipped.
- A short conversation. The technician asks how the system has behaved: rooms that lag, noises, water, odd smells, recent bills. Your notes save diagnostic time.
- A look at the system as it runs. Before anything is cleaned or adjusted, the system is run so that starting, running and stopping can be watched and first readings taken. Readings taken before cleaning show the condition you were living with.
- Power off for hands-on work. Electrical connections, coils, the blower and the drain are worked on with the power safely shut off at the disconnect.
- The heating side. On gas heat, burners, flame, venting and the heat exchanger are inspected and combustion is checked. On a heat pump, heating mode and the backup heat are tested.
- A second run with final readings. The system is started again and measured, so you can see whether cleaning or adjustment changed anything.
- The report and any recommendations. Findings are explained, with any repair listed separately and priced in writing. You decide later; nothing beyond the agreed tune-up should start without your approval.
If the visit skips straight from arrival to a list of recommended repairs, with no readings in between, ask the technician to walk you through what was measured.
Readings a technician should write down for you
A tune-up that ends with "everything looks fine" and nothing on paper gives you no way to compare next year. Ask in advance for a written report with the readings below. Not every company records every item, but a careful technician should be able to give you most of them and explain what they mean.
- Equipment details: make, model and serial numbers, which give the age, and the date of the visit.
- Temperature drop: the air temperature entering and leaving the indoor coil.
- Refrigerant readings: the readings taken and the method used to judge whether the charge matches the manufacturer's specification.
- Electrical readings: voltage, and amp draw on the compressor and fan motors compared with the nameplate.
- Gas furnace results: gas pressure, combustion analysis results, and any carbon monoxide readings.
- Condition notes: filter, coils, drain and anything to watch, with photos where something needs repair.
- Recommendations: listed separately from the work done, each with a written price.
How long does a tune-up take?
The answer turns on the number of systems in the house, whether there is gas heat to check, how easy the attic or closet unit is to reach and how much cleaning the coils need. Rather than guess, ask the company how long it plans to spend at your home. A visit that covers the checklist above with real measurements cannot be rushed through in a few minutes; if the technician is gone almost as soon as the truck parks, ask what was checked.
What you can do on the day
Clear a path to the indoor unit and the attic access, put pets away, have the thermostat reachable and keep a list of anything odd you have noticed. If you change your own filters, mention the size you use.
What a tune-up does not include
The bill is easier to predict when you know where a tune-up stops. Ask the company to confirm which of these, if any, its price covers.
Usually priced separately
- Repairs and replacement parts, such as a capacitor or motor
- Adding refrigerant, which should come with a leak search
- Duct cleaning and duct sealing
- Add-on equipment such as air cleaners or new thermostats
Ask about these
- A deep chemical cleaning of the indoor coil
- Pulling the outdoor coil apart for a full cleaning
- A second system, such as an upstairs unit
- The heating check, if the visit is sold as an AC tune-up
Homeowner items you can safely handle
Between visits, check the filter monthly, keep the outdoor unit clear of leaves and clippings, look for water at the indoor unit, and test carbon monoxide alarms if you have gas heat. Leave refrigerant, wiring, capacitors and anything inside a gas furnace to a technician. Any gas smell means the whole household heads outside first, and the call to 911 or the gas utility's emergency line is made from there.
Want a tune-up that covers this checklist? Call any hour and say which systems you have. You will be put through to a local company; ask it for its task list and price before you book.
About this line: Houston Air & Heating is a free phone line, not an HVAC contractor. It answers your call and connects you with an independent local heating and air conditioning company, which inspects, quotes and does the work, and which you pay directly. Companies may pay a referral fee. You never pay the line. Read how the line works.
Verify the license before work begins. Texas requires anyone contracting to do air conditioning, refrigeration or heating work to hold an Air Conditioning and Refrigeration (ACR) Contractor license from the Texas Department of Licensing and Regulation (TDLR). Ask the company for its ACR license number, then confirm it on the TDLR license search (opens in a new tab). The line does not check this for you.