Air condition unit doesn't get house cooled efficiently?

Almost everyone seems to answer this based on the assumption that your techs are wrong about the the unit working properly, or they assume it is undersized. I will try to answer this by assuming that everything is in fact how it should be:

1) Look at the position of your thermostat - is the unit turning off because the thermostat says the house is the right temperature, but really just the hallway where the thermostat is located is cool? If this is the case, move the thermostat, or install a remote sensor on it. The thermostat may also be faulty. Also, just because the air is blowing does not mean that the compressor is running - to determine if the thing is on or off, check the outdoor fans. They will come on or off approx. in sync with the compressor.

2) If the unit is just running non-stop, and it is just not getting cool enough anywhere, then look at your window coverings, doors, leaks around your ducts in the attic (A good way to check the attic is to to see if the attic is cool when the A/C is running during the day - if the attic is cool, you have a duct problem .

3) The duct work may not be sufficient to to move the air where it needs to go. This is a sub-specialty of A/C work that is beyond the scope of a regular HVAC repair guy. You may need to find an air flow specialist. Not a dig against your techs, it is just a whole different thing.

4) Check your attic vents (Gable or whirlybirds)

5) If one part of the house is getting cool, balance the vents by opening up the ones in hot part of the house, and closing off those that are too cool.

6) If you have replaced the floors in your house, make sure that all the interior doors have a gap at the bottom to allow air OUT of the room. Walk your house and think about the air coming OUT of the registers, and how it finds it way back to the return duct. If the inside doors are tight fitting with no way for the air to flow, then the pressure in that room will raise, and little air will come out of the duct.

6A) Check your clothes dryer and make sure the exhaust duct is hooked up right. If it is dumping the exhaust to the inside of your house, this will sometimes cause this symptom. The vent could be clogged, or have a rip in it.

6B) Roof leaks that have caused your attic insulation to get damp can reduce the insulation value quite a bit. If you had a roof leak, even if it is fixed, look at the attic insulation. If it is crushed down by wetting and drying, or if your A/C installers moved it or flattened it, this could be a contributing factor.

6C) Check ALL your windows! I have been on more than one call where the problem turned out to be an overlooked window in a bathroom or rarely used storage room that was left open or is broken.

6D) Change in habits or people living at your house. Leaving doors open, leaving lights on, can prevent proper cooling.

7) The "rule of thumb" is 1 TON of A/C per 400 Sq. Ft. This is BALLPARK ONLY and many, many factors affect it. Things that make you need more:

Vaulted ceilings

lots of windows

single pane windows

old house with less insulation

no attic vent

lots of heat producing appliances (refrigerators, big TV's lots of lights, etc.)

Southern exposure windows

Single story houses

Hot,humid climate

Things that make you need less:

Two story home

Concrete roof tiles

Newer house with lots of insulation

Few double pane windows

Heavy drapes and window coverings

low ceilings

Cool or dry climate

Lots of shade trees

The trick is to size it so that the it runs long enough to take out the humidity as it cools. if you oversize the unit, the house will be cool, but wet. Not comfortable. Undersize it, it will be dry, but not cool enough. The most common mistake is to OVERSIZE the unit.

Likely, you may have more than one problem. Leaving light on by itself will not cause you temp. to go up 6 degrees, but six little things together might.

Leave some more information! Size of house, size, brand, model of A/C unit, description of house (style, humidity levels if you can measure them and size and number of supply ducts, and size of the return air filter. Also your location, lot description would help.

Here are a couple things to check on your own. 1) On the outside unit you have very thin fins that go all the way around the unit, they should all be straight and/or not dinged up, don't touch them, you can bend them. A couple dings here and there are fine but they should also be clean, you can use a garden hose to spray the fins off. 2) The smaller diameter copper refridgent line, this should not have the insulation on it, the bigger one should have pipe insulation on it, the smaller one should feel warm to touch with your hand, not hot and not cool or room temp. 3) Where the ductwork connects to the furnace right on top, this is where the A coil sits (unless you have a downflow furnace) and you should see the two copper lines coming from the outside connecting at this point. Use a meat thermometer and place the probe into the ductwork as close as you can ABOVE the A coil, about 18"-24" above the top of the furnace. Usually you can get it in at a seam or corner of the ductwork, leave it in there probably about 10 minutes to get a good reading and write it down. Then do the same for the return air, usually right near the filter along the bottom side of the furnace (unless it's a downflow furnace). You should have a temperature difference of 14F-22F degrees. 4) Another item to check is your filter, do not use the cheapy $.50-$1.00 filters you can see through, at least use a pleated style which is only a few bucks a filter. Or you may have a Space-Gard type which is 4"-6" wide versus the cheaper ones about 1/2" wide. Make sure the filter is clean. 5) Some house layouts just do not work efficently for heating & cooling, the 2nd story on a cape cod style are pretty difficult to heat/cool well, basically long duct lines. If that's the case having a in-line duct bootser may help with that. Good Luck!

Look there could be several reasons.1st I need more info did they change both the indoor and outdoor units. If just the outdoor unit was changed did they install the metering device that came with the outdoor unit into the old indoor unit. The new equipment may have a higher seer rating then the existing air handler (indoor unit).Have you made any additions to your house prior to replacing the equipment that would have lead to the contractor believe that the old equipment was sized correctly, and did a direct replacement instead of calculating a new heat load.Are you using the Service technicians from the installing contractor.Try using service tech's from another company for an unbiased report.The bottom line is that if the system is sized correctly it should work.There are a number of other problems that only Qualified technicians could determine like correct refrigerant piping sizes, correct duct work sizing and installation,propper charge, clean filter, fan speed set correctly.Are you turning the unit completely off during the day while at work and returning it to the desired temp when you get home. the suggested set beack temp is 6 degerees ie. 72 when home 78 when not home. Do not turn it completely off.Is the indoor coil Icing up? My Best Advice is to get another company to look at it, in the past 20years in the field I have found many times that a unit was incorrectly sized or installed wrong and it was not until a 2nd company came to look at it was the problem found.So spend a few dollars get another opinion.Your quetion was vague more technical info needed to give a more direct answer.Go get a good thermometer prefer digital reading. Turn your unit on measure the air temp sucking into the return grill(the biggest grill in the home) let the unit run for 10 minutes then measure the air temp blowing out of a grill. there should be a 20 - 25 degree difference between air in and air out. 76 in 56 out = 20 dif. If you have this and the house still does not cool good indictor unit too small. If you do not have this then there is a good chance of a mechanical problem. Take 1 sheet of toilet paper put it up againsnt the return grill (big grill) the paper should stick to the grill all by itself if it does not then there is an airflow problem.Ductwork not tight or too small. these are basic answers for a homeowner to use to check system. good luck

You changed the outside unit but did you do anything to the inside coil? Remove your filter and look up (depending on your setup) at your coils. Are they clogged with gunk and grime? If so, they need to be cleaned.

Foamy Cleaner made by DiversiTech is what I use but there are others out there. It's a very caustic chemical made specifically for cleaning a/c coils and is only available at a/c supply stores. Invest in a good quality garden sprayer (the kind with a pump built into the lid) and a pair of chemical resistant rubber gloves (available at any hardware store).

You start by turning off the breaker or main a/c disconnect switch and remove the screws holding on the coil cover. You will need to have plenty of water ready to spray down the coils since the acid in the foam will 'eat' your coils if you leave it on too long. You should also have something to catch the excess water since the drain pan probably won't be able to handle the flow. Spray the coil cleaner according to the directions and leave it on ONLY as long as recommended. Use plenty of water to rinse the cleaner off. This will make a huge difference in the amount of cold air flow if there is alot of crud in the coils.

Contrary to what other posters say, change your filter with a 'cheap' filter every month. The expensive filters restrict too much air to get the most from your a/c. If you change it regularly, you won't have to worry about the coils getting clogged again.

If your inside unit is setup where you can't get to the coils, call an a/c company to do it. They can remove it and clean it.

Where the copper lines come into the inside unit, you can see if the larger line has condensation and is 'cold beer' temperature to get a good idea if the refrigerant level is ok (just pull the insulation back a bit). If there's no condensation and the line isn't cold, you will need refrigerant added.

If your fan, coils and refrigerant are all ok and the system is designed correctly, it should keep the house at whatever temp you like. This of course is assuming that you haven't made any major changes to the house (such as adding rooms or putting on a different style of roofing material).

Make sure all windows are covered with curtains or blinds. Caulk any air gaps in your windows. Use weatherstripping for any gaps around doors and evaluate your attics insulation and upgrade if needed. Ceiling fans help also.

By the way, any worthwhile AC person should have checked to see if your inside coils were cleaned. Good luck to you, I hope this helps.

Hi.. Air Conditioner has become an essential electrical item in every household during summer. So, proper maintenance of air conditioning is very much important. I would suggest you to call an air conditioning repair service provider to fix your air conditioning unit.

This sounds like a classic case of improper size. Before the new unit was sold to you, your dealer should have performed what's called a load calculation. That is the only way to properly size an ac unit. With out doing this they just guessed at the size. It sounds like they guessed wrong.

We had a similar problem however, it didn't take much to fix it...our coolant was low. Did any of the repair guys check the levels? Our unit is only a couple years old so it shouldnt have even been low in coolant.

Hope your problem is something as simple as this!

Could be the air handling system isn't big enough for the house. Try closing off whatever rooms you can (shutting the air off at the register and down the basement at the duct).

Perhaps the unit is too small for your house.

could it be your thermostat,or your filter needs to be changed or cleaned perhaps,try that and see if that is it.