Based on industry pricing data, a new central air conditioner typically runs $4,000 to $7,000 installed for a smaller home, $5,000 to $9,000 for a mid-size home, and $6,500 to $12,000 for a larger home that needs a bigger system. Stepping up to a high-efficiency unit rated 16+ SEER2 typically adds $1,000 to $3,000 to those figures. These are typical installed cost ranges for the region, not a quote from 717 Mechanical. The actual price for your home depends on an in-home assessment of the cooling load, the condition of your ductwork, and what the existing electrical and refrigerant lines can support.
717 Mechanical LLC has installed central air conditioning across Lancaster County from our shop in Marietta since 2012. This guide explains what those ranges include, what pushes a job toward the low or high end, and how to tell whether the air conditioner you have is worth one more repair. When you want a real number, we measure the house and put a written price in front of you before any work starts.
Ready to skip ahead? See our AC installation in Marietta, PA page or call (717) 468-9567.
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Central air conditioners are sized in tons of cooling capacity, and the size your home needs is the single biggest driver of price. The table below shows typical installed cost ranges by home size, based on industry pricing data. "Installed" covers the outdoor condenser, the indoor evaporator coil, labor, removal of the old equipment, and the standard connections. Ductwork changes, a new line set, and electrical upgrades are extra when a house needs them.
| Home size | System capacity | Typical installed range (national) |
|---|---|---|
| Up to 1,200 sq ft | 1.5 to 2 tons | $4,000 to $7,000 |
| 1,200 to 2,000 sq ft | 2.5 to 3.5 tons | $5,000 to $9,000 |
| 2,000 to 3,000 sq ft | 3.5 to 5 tons | $6,500 to $12,000 |
| High-efficiency upgrade (16+ SEER2) | any | add $1,000 to $3,000 |
Ranges are national averages for context: your home's size, ductwork, line set, and electrical service change the number. 717 Mechanical quotes your exact price upfront before any work, and that quote comes from an in-home assessment, not a table.
Square footage is only a starting point. Two homes of the same size can need different tonnage depending on insulation, window area and orientation, ceiling height, how many people live there, and how much of the house sits under an attic that bakes all afternoon. A load calculation settles it. Guessing from the old unit's nameplate, or going one size bigger "to be safe," is the most common sizing mistake we see, and an oversized air conditioner short cycles, leaves the house clammy, and wears out early.
When two quotes for the same house come back far apart, the difference is almost always in one of these line items. Knowing them makes any estimate easier to read and easier to compare.
Bigger capacity means a bigger condenser, a bigger coil, and more refrigerant, and each step up in tonnage moves the price. The right size comes from the load calculation described above, not from the square footage alone. Many of the older homes around Marietta, Columbia, and Lancaster city have had rooms added, attics finished, or windows replaced since the last system went in, and the cooling load has changed with them.
SEER2 is the current federal efficiency rating for central air conditioners, and a higher number means the unit delivers more cooling per unit of electricity. Baseline equipment meets the minimum the rules allow; 16+ SEER2 equipment costs more up front and uses less power every hour it runs. In Lancaster County, where humid summers keep an air conditioner running from late May into September, the higher tier has a long season to earn back its premium. Variable-speed and two-stage compressors, which sit at the top of the SEER2 range, also run longer at lower speed, which pulls more humidity out of the air and keeps rooms from swinging between cold and sticky.
A new air conditioner can only deliver what the ducts will carry. Leaky joints in a hot attic, crushed flex runs, undersized returns, and duct systems that were sized for a furnace decades ago all show up in a quote as sealing, resizing, or replacing sections. This work is the most common reason a job lands at the top of its range, and skipping it means paying for capacity the house never sees.
The copper line set connects the outdoor unit to the indoor coil. New equipment is built for the current refrigerant standards, and an old line set may be the wrong size, contaminated with old oil, or too corroded to reuse. Replacing it is a modest line item on a short, accessible run and a larger one when the pipe has to be fished through finished walls or a long basement.
The outdoor unit needs a dedicated circuit, a properly sized breaker, and a disconnect box within sight of the condenser. Older homes that have never had central air, or that still run on a small or crowded electrical panel, sometimes need a circuit added or the panel upgraded before the equipment can be connected. That work is quoted separately and is the reason a first-time installation often costs more than a like-for-like replacement.
Recovering the refrigerant from the old system and hauling the equipment away is normally included in the installed price. Items that can appear as separate lines include a new condenser pad, a thermostat, a media filter cabinet, a whole-home dehumidifier, and the permit and inspection your municipality requires. A written quote should list each of them.
Most air conditioner replacements start as a repair call in July. The technician finds the fault, quotes the fix, and the homeowner has to decide whether that money is better spent on a new system. The $5,000 rule is a common industry shortcut for that decision: multiply the age of the air conditioner in years by the repair estimate. Under 5,000, repair is usually the sensible choice. Over 5,000, the money is usually better spent on replacement.
The rule works because it weighs the two things that matter most. A young system with an expensive repair is worth fixing, since the rest of the equipment has years left. An old system with even a moderate repair is not, because the compressor, the coil, and the fan motor are all approaching the end of their service life together, and the repair buys less time than it appears to.
A central air conditioner in Lancaster County typically lasts 10 to 15 years, and the humid summers here work a system harder than the same equipment would see in a drier climate. Inside that window, a failed capacitor, contactor, or fan motor on an otherwise sound unit is worth fixing. Past 12 to 15 years, a compressor or evaporator coil failure almost always tips the $5,000 rule toward replacement, and a refrigerant leak on an older system that uses a refrigerant no longer produced can push the repair cost past the point of sense on its own.
Some symptoms point toward replacement regardless of the arithmetic: a system that needed a repair each of the last two summers, electric bills climbing while the house cools less, a unit that runs constantly on a hot afternoon and never catches up, and a compressor that hums but will not start. If your air conditioner is showing any of these, ask for a replacement quote alongside the repair quote so you can compare real numbers rather than guessing. Our AC repair technicians give you both on the same visit.
Central air shares the blower and the ductwork with the furnace. If both are past 12 to 15 years, replacing them together as a matched system usually costs less than two separate projects, because the crew is already there, the new coil is matched to the new blower, and there is one permit and one day of labor instead of two. If the furnace is young and sound, replace the air conditioner alone; a good installer will match the new coil to the existing blower properly. Our guide to furnace replacement cost covers the heating side of that decision.
An air conditioner rarely fails at a convenient time, and most families would rather spread the cost than pay for a whole system in the middle of a heat wave. 717 Mechanical LLC offers financing through Service Finance and Wells Fargo, including 0% financing for 60 months on qualifying systems with approved credit. The application takes a few minutes and can be done from your phone. Financing is often what makes a 16+ SEER2 system practical when the up-front difference between tiers would otherwise decide the question. Terms and the application links are on our HVAC financing page, and you can ask about current promotions when you call.
We install American Standard and Armstrong Air central air conditioning, from single-stage baseline units to two-stage and variable-speed systems at the top of the SEER2 range. As a local American Standard dealer we can walk you through the lineup and match the tier to your budget and how long you plan to stay in the house. Every installation includes a load calculation, a look at the ductwork, line set, and electrical, and a written quote before any work begins. See our AC installation in Marietta, PA page for how the process runs from the first visit to the final startup.
A new system holds its efficiency only if the coils stay clean, the refrigerant charge stays correct, and the condensate drain stays clear. A spring AC tune-up handles all three before the first hot week, and most manufacturer warranties expect that annual service. Our HVAC maintenance plan puts it on the calendar automatically.
The ranges in this guide are useful for setting expectations, but they cannot see your attic or your electrical panel. A quote from a local installer accounts for the things that move the price: the actual cooling load of your house, whether the ducts can carry the airflow a new system needs, whether the line set can be reused, and what the panel can support. The right number for your home comes from an in-home assessment, and we provide that assessment and the written quote upfront, with no pressure to decide on the spot.
Call (717) 468-9567 for a QuoteAs a family-focused HVAC company, our mission is to provide honest service with a personal touch. We treat every home as if it were our own, ensuring high-quality workmanship and lasting results.
Our shop is on Maytown Road in Marietta, minutes from the river towns of Columbia, Mount Joy, and Wrightsville, and we install central air throughout Lancaster County and the neighboring communities in York, Dauphin, and Lebanon Counties. Many of the older homes in these towns got central air long after they were built, with ductwork squeezed into whatever space was available, which is exactly why an in-home assessment matters more than a national average.
Same-day service is available when scheduling allows, and every installation quote is written and explained before any work starts.
Tell us the age of your air conditioner, what it has been doing, and roughly the size of your home, and we will schedule an in-home assessment and put a written price in your hands.
Call (717) 468-9567 to talk through your options.
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