Today's heating, ventilation and air conditioning units are more energy-efficient than their predecessors. New air conditioning and heating equipment lasts longer than ever. The end of a furnace's or air conditioner’s service life depends on more than just chronological age. Energy-efficiency issues and the price of any necessary repairs versus the cost of upgrading to a new unit all enter into that determination. Furnace Lifespan The average service life of a new furnace is 15 to 20 years. Most furnace parts that fail during that span are replaceable at a cost that makes repair a better call than replacing the entire furnace. The exception is the heat exchanger, a furnace's single most expensive component. A cracked heat exchanger in a unit that’s already out of warranty is usually a tipping point that means it’s time to shop for a new furnace. Central Air Conditioners Central air conditioners typically last from 10 to 15 years. The lifespan of a central cooling unit may be reduced if its capacity is not properly matched to the cooling load of the home.

Oversized air conditioners “short-cycle,” turning on and off rapidly, inflicting excessive wear and tear on the compressor. Like the furnace heat exchanger, the compressor is the most costly part in the system. A worn-out compressor in a unit that’s outlived its warranty is usually a deal-breaker that warrants upgrading to a new, more energy-efficient air conditioner rather that repairing the existing unit. References National Association of Home Builders: Study of Life Expectancy of Home Components Photo Credits Comstock/Stockbyte/Getty Images Suggest a Correction Yesterday's high was 106.0F, low of 79.2F, full sun all day. AC set at 78F, indoor temperature reached about 85F. Today's high was 105.4F, low of 81.1F, full sun all day, now about 102 at 7pm. AC set at 78F all day, temperature climbed steadily through the day, and is now 89F. Is it reasonable to expect an AC unit to maintain 78F in this weather? A properly functioning and properly sized central air conditioning unit should be able to maintain the temperature of your house at any reasonable temperature you select.

The amount of cooling available is related to the size of the system, insulation in the house, and finally outside air temperature. From your description I would guess either you don't have a big enough compressor, or you don't have enough airflow through the house. It's also possible the cooling element in the system has become dirty and no longer transfers enough heat from the air into the element.ac unit direct llc The first thing to check is the return air filters. general air conditioner split unitIf they're dirty, your system won't be able to keep up. ac unit keeps clickingAlso, if the coils are dirty or the refrigerant is low, you will not get efficient cooling. You can clean your condenser coils (the outside unit) yourself using a jet of water from a hose.

Contact a service company to clean your evaporator coils, do a system check, replace refrigerant and do repairs. The amount of in and out traffic you have, shade trees, insulation, type of windows, etc., all play a part in how well your system works. It's been about 100 degrees F here the last couple of days and the thermostat is set at 78 and has had no problem maintaining that. We had the same problem in our house, and we've simply lived with it - having had HVAC companies come out and inspect or evaluate it. They all said the system was in good working order, and was appropriately sized for our house. This year we replaced 3 windows and a doorwall in the first floor of the house, and suddenly we can not only maintain a temperature, but go lower if we want. The air conditioning is doing fine, even though we've still got three old aluminum frame windows upstairs. It was about 80 square feet of window surface that was cheap double glazed aluminum frame, and is now cheap composite framed, double glazed with low-e coating.

So if you've checked the interior coils, the exterior coils, and the system performance and it is still not cooling your house to your satisfaction, it is likely that you need a bigger air conditioner, or you need to better insulate your house - windows might be a big part of that loss. As others have said, if the unit is properly sized for the house, and the insulation is good enough to keep the heat out, and there is enough airflow in the house, the A/C should be able to handle almost any temperature you set it to. There is a point where it gets so hot outside that air conditioners simply can't do anything to get rid of the heat (the outdoor coil temp equals the outdoor air temp). This is extreme though, >110 deg F. You're getting pretty hot, but shouldn't be at that point yet. (Most A/C units will have specs on this. You can try looking up some specs for it online.) You indicated the system is turning on and off, so I don't think it's your thermostat. How cold is the air coming out of your vents?

If the system is working properly, it should be as cold as your fridge. If it isn't cold (not cool, cold), you have a problem. Look at the lines on the outdoor unit. Are they frosting up at all? Is there excessive dripping from your indoor air handler? If your lines are freezing up, turn the system off and call a service company. That means you are probably low on coolant, and running the system without will burn up the compressor. Other problems that would prevent cold air would be crud on the coil, or the fan on the outdoor unit not working properly. If the airflow is weak, then you have an airflow problem. Check the air filters in the system. Make sure your ducts aren't plugged somehow. Check for closed dampers or closed vents. Make sure a duct didn't pop loose somewhere (blowing air into the attic instead of out the vents). Make sure your air handler is blowing air. To get a measure of your air condition performance , try to get a temperature reading, just in front of the inside unit.