Replacing the AC: what happens from the estimate to the first cool night

Most replacements are finished in a day

A typical central air conditioner replacement takes one day: the crew arrives in the morning, removes the old equipment, installs and tests the new system, and you have cooling again by evening. The job takes longer when ductwork has to be extended or rebuilt, when electrical work is needed, or when extra work is done to improve efficiency, and a good estimate tells you that ahead of time. From the first estimate visit to installation, the timeline depends mostly on the season and on how quickly you decide.

I am Brandon Quigley, and my family's company, Quigley Heating & Air, has been replacing heating and cooling systems from Farmers Branch since 1945. Most homeowners only go through this once or twice in their lives, so it helps to know what is coming. Here is the whole process, start to finish, as we run it.

Before installation day: from estimate to calendar

It starts with a free estimate. Our comfort consultant visits the house, looks at the existing equipment, the ducts and the rooms that bother you, and prepares a tiered estimate with clear options. ENERGY STAR recommends getting a written proposal before work starts that lists the costs, model numbers, job schedule and warranty information, and that is what you should expect from any contractor. If you want to compare companies, my guide on questions to ask an HVAC company covers what to ask at this stage.

Once you choose, our install coordinator schedules the job and confirms what equipment is needed. If you are financing, Wells Fargo financing with approved credit is arranged before the work. Timing depends on the season. Early spring and fall are the easiest times to schedule with little wait. In the middle of a heat wave, when a failed system forces the decision, we still move quickly, but you have fewer options for picking a day.

If you are still deciding whether to replace at all, that decision comes first, and it deserves real numbers rather than a hunch. My guide on an air conditioner that runs but does not cool explains how we weigh a repair against replacement on an older system, including the age, the repair history and the cost of the part that failed.

Getting the house ready

You do not need to do much, but a little preparation keeps the day on schedule. The crew will be going in and out of the house many times, carrying equipment to the attic or closet and to the outdoor unit, so clear paths save time and protect your belongings.

If you are moving the outdoor unit to a new spot, or adding equipment that will be visible from the street, check your HOA rules first. Some Dallas-area neighborhoods have rules about where outdoor equipment can sit and how it is screened, and it is easier to settle that before the crew arrives than after the equipment is set.

• Clear a path to the indoor unit, whether it is in the attic, a closet or the garage
• Move stored boxes away from the attic access and around the equipment
• Clear the area around the outdoor unit, including hoses and planters
• Keep pets in a closed room or out of the house for the day
• Tell us where you would like the crew to park
• Plan for several hours without cooling, and keep fans or a cool room ready on a hot day
• Make sure someone can be home at the start and for the walkthrough at the end

What the crew does, in order

Every house is a little different, but the order of work is consistent. The crew protects floors and work areas, shuts off power to the equipment, and recovers the refrigerant from the old system with recovery equipment rather than releasing it. Then the old outdoor unit, indoor coil and, if it is being replaced, the furnace or air handler come out.

The new equipment goes in next: the outdoor unit on a level pad, the indoor coil and furnace or air handler in place, the refrigerant lines connected or replaced as the new equipment requires, and the condensate drain line, drain pan and safety float switch installed. The electrical connections and disconnect are completed, and the thermostat is connected or replaced. Before any refrigerant is released into the new system, the lines are tested for leaks and evacuated. Only then is the system charged, started and tested.

On our jobs, a lead installer runs the crew and is the person to ask questions during the day. Our install coordinator handles scheduling and equipment behind the scenes, so the installer's attention stays on the work. If something unexpected turns up once the old equipment is out, such as a damaged duct connection or a drain line that was never properly sloped, the lead installer explains it and gives you the options before anything changes from the plan.

• Protect the house and shut off power
• Recover refrigerant and remove the old equipment
• Set the new outdoor unit, coil and furnace or air handler
• Connect refrigerant lines, drain, float switch and electrical
• Leak test and evacuate the lines, then charge the system
• Start up, test and adjust

The tests that separate quality from speed

The last hour of the day matters more than the first seven. ENERGY STAR warns that improper installation can reduce a system's efficiency by up to 30 percent, which means a new high-efficiency system installed carelessly can perform like a much cheaper one. ENERGY STAR describes a quality installation as one where the equipment is properly sized for the home, airflow is optimized, the right amount of refrigerant is installed and the ducts are evaluated.

In practice, that means the crew should test and adjust the refrigerant charge, confirm the airflow matches the manufacturer's specifications, check that the drain carries water away and that the float switch works, and measure the temperature of the air going in and coming out. Ask the crew to tell you what they measured. You do not need to understand every number, but a crew that can explain them is a crew that took them.

When one day turns into two

Some jobs need more time, and the estimate should say so before work begins. The most common reason is ductwork. If ducts need to be extended, rebuilt or resized, or if a return has to be added so the new system can breathe, that work adds hours. Electrical upgrades, a tight attic that makes equipment hard to move, a new zoning system with dampers and extra thermostats, or a switch from one type of system to another can do the same.

Some of that work is exactly what fixes long-standing comfort problems. If your upstairs never cools, a replacement is the best moment to address it, and my guide on a hot second floor explains the duct, insulation and zoning options. If the job runs past one day, the crew should leave the house with working cooling or heating overnight whenever possible, and tell you exactly what is left.

The walkthrough before the crew leaves

Do not let the crew leave without a walkthrough. It takes a few minutes and saves calls later. You should know how to work the thermostat, where the filter is and what size it takes, and where the drain line runs. You should also have the paperwork that matters for the life of the system.

• Thermostat settings explained, including any schedule or app
• Filter location, size and how often to check it
• Where the condensate drain and float switch are
• Model and serial numbers for every new component
• Equipment and labor warranty terms, and whether registration is needed
• Who to call if anything seems off in the first weeks

The first few weeks with a new system

A new system often behaves differently from the old one, and that is usually a good sign. Variable-speed equipment, our top recommendation for replacements, runs longer at lower speed instead of blasting on and off. People sometimes worry it is running all the time. That longer, quieter run is how it holds steadier temperatures, removes more humidity and uses less electricity than older units.

If something does not feel right, call. A room that is suddenly warmer than the rest, water near the indoor unit, or a thermostat that will not hold its setting are worth a quick visit while everything is new. After that, the system's long-term health comes down to maintenance. Our Q Club plan adds two tune-ups a year and extended repair warranties, and it is the easiest way to protect the investment you just made.

Check the filter after the first few weeks as well. Installation stirs up dust in the attic and ducts, and the new filter catches much of it. A quick look a month in, and a replacement if it is already gray, gets the new system off to a clean start.

Planning your replacement

If your system is aging and you would rather replace it on your schedule than in the middle of a July breakdown, now is a good time to start. Call our office for an estimate, and our comfort consultant will walk you through the options. If cost is the first question on your mind, my guide on what drives the price of a new system explains each line of a replacement estimate.

We install Lennox and Trane equipment, we service all brands, and we work across Dallas, Farmers Branch, Carrollton, Coppell, Frisco, Garland, Highland Park, Plano, Richardson and University Park. Our Texas license number is TACLA23686E.

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