So much has changed in the world of air conditioning in recent years that if your system has almost any significant breakdown — or if it’s just not keeping you as cool as it used to — it may be worth replacing it instead of repairing it.As of 2010, for example, manufacturers must use a new kind of refrigerant that’s not an ozone-depleting chlorofluorocarbon. And a new system can use less than half the electricity of your old one while doing a far better job of keeping you cool and comfortable.If your air conditioner is more than eight years old, repair is probably not worth the expense, unless it’s a simple problem like debris clogging the condenser unit or a worn fan belt. Still, to best weigh your repair-or-replace decision, ask your contractor to assess not just the condition of your existing equipment, but also the ducts that deliver the cool air and the overall quality of the insulation in your house. Improving those elements might increase the effectiveness of the system as much or more than installing new machinery.

Even if your central air conditioner is just eight to 10 years old, it could suck up to twice the electricity that even a low-end new one would use. That’s because it operates at or below 10 SEER, or Seasonal Energy Efficiency Ratio, which is the amount of energy needed to provide a specific cooling output. Until 2006, 10 SEER was standard, but these days, the minimum allowed by federal law is 13 SEER. That translates to 30% less electrical consumption and 30% lower cooling bills than equipment installed just a few years ago.For an 1,800 square foot house, a new 13 SEER unit will cost $3,000 to $4,000. You can double your energy savings by jumping up to 16 SEER, which will reduce cooling expenses by 60% over a 10 SEER unit. At $5,000 to $6,000, these super-efficient units are more expensive, but they qualify for a federal tax credit of up to $300 and possibly local incentives, too.“Your installer can run the numbers for you to see whether it’s worth the additional cost,” says Ellis Guiles of TAG Mechanical in Syracuse, New York.

“If you’re south of the Mason Dixon line, certainly, you can make up those dollars pretty quickly.”outside ac unit for saleYou could upgrade to the highest efficiency gear available and still not feel comfortably cool on hot days. how to install central ac unitThat’s because the mechanicals are only part of the central air system. air conditioning unit for floorThe average house’s ductwork leaks 10% to 30% of its air before it can reach your living space, according to Pacific Gas & Electric. Before deciding whether to repair or replace your condenser and blower units, your technician should run a duct-leakage test, by sealing the vents and measuring how much air escapes the system. If the ducts are inefficient, he can locate and seal the gaps, typically for $25 to $35 per vent (per “run” in industry jargon), or replace the ductwork entirely with new, insulated pipe for around $100 per run, according to Guiles.

Your technician may recommend doing the duct improvements in conjunction with replacement of the mechanicals or may recommend only one or the other job.Related: Do You Really Need to Clean Your Air Ducts?If your house is poorly insulated, it’s putting a strain on your aging air conditioner. Resolving the house’s flaws may mean that your old system will have enough cooling power to continue to do the job for a few more years. Or it may enable you to buy a smaller replacement system, lowering your upfront and ongoing energy costs significantly. Your heating and cooling contractor should assess and, if necessary, upgrade the building envelope. For example, he might seal gaps and cracks in the outer walls and attic floor, or he might blow insulation into the walls, either of which could knock as much as 30% off your heating and cooling costs. Insulation also may get you a $500 federal tax credit, and in some cases, it may be a more effective solution to your cooling problems than replacing your equipment.

If you decide to replace, make sure the contractor’s bid includes a load calculation, which is a computer printout showing how big a system you need and why. Air conditioning is measured by the ton, which is the cooling power of a one-ton block of ice melting in 24 hours. Some old-school installers use a ballpark estimate for sizing equipment—say, one ton for every 400 or 600 square feet of living space. But that typically leads to systems that are too big, according to Greg Gill of Action Air Conditioning and Heating in San Marcos, Calif. Not only do oversized systems cost more, but they also do their cooling work too quickly, which means more frequent on/off cycles, wearing out components and gobbling electricity. Plus, they don’t have a chance to effectively dehumidify the air. Good contractors use load-calculating software that factors in such data as the number of windows in your house, the thickness of insulation, the configuration of the attic, and the building’s orientation to the sun.

It produces not only an exact tonnage requirement, but determines how much cool air each room needs. All bids (get at least three, from licensed, well-regarded companies) should include this one-page printout. 10,857 posts, read 7,425,116 times Our house is on the market and an inspection by a prospective buyer says the outside unit, central air/heat, would probably need replacement in about 5 or 6 years. I would probably agree with that as it is older for sure. We are considering just replacing/upgrading it as maybe being a plus but does anyone know what the approximate cost will be? It isn't something we can look up on the internet and probably will vary some from area to area but "ballpark" figure would help us sort it out. Plus, the temps have been about 20 degrees above normal so far this year! 17,825 posts, read 24,764,727 times Originally Posted by AnywhereElse No one can tell you that without more information. Not sure what that has to do with the size and cost of a replacement....

Originally Posted by Pitt Chick This has to do with why it might make sense to replace it at this time rather than wait until it starts having problems. It heats/cools 1400 square feet, will I need more information on that if I make inquiries? 48,527 posts, read 64,619,551 times 2,737 posts, read 2,688,444 times 2 years ago I had a new 2-1/2 ton central air unit installed on a rental house for a total cost of $2300. The SEER Rating was good, so I went with it. Get 3-4 bids & compare them as closely as you can. 2,901 posts, read 4,700,020 times 2,376 posts, read 4,177,108 times Impossible to quote without an idea of the size of the unit your looking for. I had a HVAC friend buy a compressor for me for $800 and install it for another $200, but it was only a 1 ton unit for a 800 sq ft house. This was about 7 years ago, prices could have changed since then. I purchased my 2003 Honda Civic new and tires were 30 bucks a pop each then, 6 years later when I needed new tires, they were over $80 each.