How much does central air installation cost? 4 basic factors to consider

Image source: Consumer Reports

Jack Wisniewski

By Jack Wisniewski

October 1, 2021

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Average costs to install a new central air system in a typical home range between $3,660 and $6,488.

In extreme instances, you might pay as little as $1,675 or exceed $20,000 for central air installation.

Determining total costs depends on several cost factors, most notably the system size, efficiency rating, and whether or not you have adequate ductwork.

To recognize how these factors play into costs for your specific home, continue reading. We discuss how AC sizing, efficiency scores, and ducting play into costs.

Finally, we touch on tips to minimize costs for a central air conditioner installation.

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Central air installation factors

Size of the unit

In residential applications, central air conditioning systems typically range from 1.5 to 6 tons (18,000 to 72,000 BTUs, or British Thermal Units) in size. "Tons" doesn't refer to weight here. Rather, it denotes the amount of cooling the machine can produce.

The more tons, the more you will pay. Perhaps counterintuitively, more cooling power isn't always better for your comfort and bottom line.

Get a roof replacement estimate before installing central AC.

Why you don't want an oversized air conditioner

Oversized air conditioners cool your home too quickly. While this might seem ideal on those scorching days, an air conditioner that turns off rapidly after turning on – a phenomenon professionals call short cycling – puts undue stress on components and reduces system lifespan.

Perhaps even worse, a short cycling air conditioner will not adequately remove moisture from the air. High humidity makes it feel hotter even in relatively cooler temperatures, which essentially nullifies the benefit of your air conditioner.

For these reasons, it's essential to get air conditioning sizing right.

How do I calculate what size air conditioner I need?

The rule of thumb has long been that a 1-ton air conditioner will cool 500 square feet of space. By this standard, a 2,000 square foot home would need a 4-ton air conditioner to stay comfortably cool.

The introduction of the far more thorough Manual J load calculation procedures has since rendered the ton per square footage principle suboptimal one at best to determine cooling needs.

In particular, it neglects variables like design temperatures (which depend on your geographical region), window efficiency, and insulation values that play crucial roles in how much cooling your home needs to stay comfortable.

Manual J calculations weigh these variables among a long list of others, including the size of your home, to precisely determine the appropriate AC system size.

While you can DIY this process, proper execution requires accurate measurements and familiarity with Manual J software.

We recommend hiring an experienced contractor using programs accredited by the Air Conditioning Contractors of America – who publish the Manual J standards.

System efficiency

Energy efficiency sticker

Image source: North County Cooling Inc.

Just as efficient cars need less fuel to drive one mile, efficient air conditioners cool your home using less power.

The result? Your utility bills come back with a smaller number.

The industry uses the seasonal energy efficiency ratio to indicate energy-saving potential. The higher the SEER number, the more savings you can expect.

For instance, a 14 SEER air conditioner will deliver the same comfort using less electricity than a 13 SEER unit of the same size.

Energy Star-rated systems (14+ SEER) may qualify for a $300 tax credit until December 31, 2021, amplifying their value to an even further extent.

Ductwork

Ductwork in a residential home

Image source: Menards

Central AC units distribute cool air via a duct system.

If your home lacks this essential component, you will need to pay for a professional installation before along with the AC unit.

Even if you have existing ductwork, you should consider a replacement before the central air install to ensure optimal performance. Ductwork seams and joints tend to deteriorate over the years, which reduces airflow and increases energy demand.

The installation and replacement process can increase project costs dramatically depending on several factors, namely home size, complexity, and materials used.

In extreme cases, such as large, finished homes, new ductwork installation costs can exceed $12,000. An expensive situation like this arguably calls for a ductless mini-split system – a popular alternative to central air that avoids ductwork.

Pre-installation evaluation

A pre-installation assessment by a certified HVAC professional ensures you pick the optimal equipment for your budget and comfort.

Depending on the size and complexity of your home, you could pay as little as $250 or as much as $2,000 for a comprehensive appraisal, which should include a Manual J load calculation and ductwork inspection.

It may seem more economical to skip over this routine. However, note that you run the risk of installing an incorrectly sized unit that saps your electricity bills, comfort, or both.

4 tips to save money on a central air unit

Buy in the off-season

When homeowners notice their air conditioning isn't up to scratch in hot summer months, HVAC companies face incessant service calls. This means you will wait longer for a team to install the new air conditioner you desperately need.

On top of slower turnaround times, manufacturers also jack up their prices during the cooling season corresponding with the extreme demand for new air conditioning components.

You should therefore look to install a new system during the fall or spring months. During these times, air conditioning contractors have less on their plates and units run cheaper.

Shop around

For any home improvement project, it's good practice to see at least three contractors.

Costs can vary immensely among HVAC contractors. In addition, some contractors only work with select companies like Goodman, Lennox, and Trane. Only shopping with one brand limits your system and pricing options.

That's not to say you should always go for the cheapest bid. An especially low quote should raise concern as it could mean the contractor does not pay for insurance or provide a warranty.

At the end of the day, hearing from three installers should provide a firm grasp of the options at your disposal and the fair rate for each.

Upgrade your home’s energy efficiency

Fiberglass insulation roll in an attic

Image source: This Old House

While an air conditioner keeps your home cool, passive energy-efficient improvements prevent it from heating up in the first place.

Effectively insulating your home, for instance, can achieve energy savings of 10 to 20 percent by reducing demand on your HVAC system.

"Cool" roofing materials reflect sunlight and emit heat back into the atmosphere before it can penetrate your home to maintain colder interior temperatures.

For an additional $100 to $500 saved per year on electricity, throw in energy-efficient windows.

Upgrades such as these will reduce your demand for your air conditioning. Not only will you lower your electricity bills, but your air conditioner could last longer with less intense use.

Consider split units

Split air conditioning unit in a residential home

Image source: Tri City Heating and Cooling

Although most homes in the United States use central air conditioning, it's not the only type of system.

Professionals often compare central air with split systems.

Central air vs. ductless mini-splits

Consisting of an outdoor compressor connected to indoor air handlers via refrigerant tubes, split systems deliver cool air without ductwork.

Think of a split cooling system as a connected network of window-mounted AC units, except you can install air handlers on any unobstructed wall or ceiling surface.

Each individual air outlet only provides cooling in the zone you install it in. Therefore, you need to strategically place outlets to economically distribute cool air throughout your home.

Ductless mini-split systems can be more cost-effective than central air, especially in smaller homes without ductwork. As each indoor air blower works independently of others, you can save on electricity by only cooling the rooms you use instead of the entire house.

A ductless system increases in price as you add more air-handling units. Therefore, it pays to thoroughly compare split system pricing and central air pricing for your home to pinpoint your optimal cooling solution.

Central air installation costs: summing it up

Air conditioning unit outside a home

Image source: The Spruce

By understanding the primary cost factors, namely system tonnage, energy efficiency ratings, and ductwork, you can reach a solid starting point when the time comes to hire an installer.

Minimizing costs can be as simple as buying during the off-season, vetting several contractors, and upgrading your home’s overall efficiency. In some cases, a ductless mini-split system will prove more cost-effective in the long run.

Get in touch with a local contractor today.

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