I know this is not the season for air conditioning.  But here in Texas, it got up to 112 deg for several days.  I had electric bills that were nearly $500 for 4 months and my AC ran 24 hours a day.   I do not want to live through that again.  My home and air conditioning unit were built/ purchased in 2004.  I feel that the unit is undersized but most contractors have disagreed because they are going by some EPA recommendation.  The unit is a 3 ton Carrier, I think 8 seer.  The home is 1987 sq ft, two story.  Here is my quesiton:  How can I determine how much electricity will be save if I upgrade to a 4 ton 13 seer unit? Not what you were looking for ?Welcome to the community. I remember seeing news reports last summer about the truly smoking hot weather down south. Since you have SEER, (Seasonal Energy Efficiency Rating), ratios for both old and new units, a rough estimate is fairly easy.  The new larger unit will hopefully not have to run 24/7 like your current one does.

Based strictly on output per watt of power in and assuming all other conditions are the same, the new A/C will use about 8/13 as much electricity.  This is about 38% less energy use. Hopefully next summer won’t be as hot either! I hope this helps, In November 2010 we replaced a 4 ton Lennox 1992 8 seer with a 4 ton XR 15 Trane 16 seer (including compressor, air handler and UV lights. trane home ac condenserUnder air we have 2045 SQ feet (two story) Cost installed was about $4600.00 After installation the KW usage dropped so dramatically the Electric company sent out a meter reader to check  :-) air conditioning units gautengIn Florida the hottest months are usually July-August-SeptemberJuly -August 2010 temps were an average of 90 degrees,  we used 3353 KW hours that month.gree split air conditioner e1

In comparison the July -August 2011  KW hours usage at average temps of 93 degrees was 1842 KW hours. My last bill received was $132.00 with budget billing as opposed to the average of  $300.00 we were paying prior to installing the new unit. Made a big difference, you will notice it within 30-60 days. I hope this helps.  THank you for the info.  My high kilowatt usage was Aug 4-Sep 5 at 4712.8 kwh. If I am calculating correctly, 38% less kilowatts, that would be around 2929 kwh.  So that would be good.  You gave me even more good information with the numbers on the kw usage.  From Aug 4- Sep 5 we used 4712.8 kwh and Sep 6-Oct 5 3859 kwh.  If I can reduce usage like you did to 1842 kwh, I would be happy. Newf - is the calculation you are using 8/13 referring to the 8 seer vs 13 seer systems?  So if I get a 15 seer the calculation would be 8/15 ?  Thanks in advance for the info.Mathematically, comparing pure ratios the numbers work out that way. Going from 8 to 15 you would use 8/15 as much power (53%), saving 47% compared to what you used to use.

While your mileage may vary due to real world factors like fan motor run-time, changes in weather from one year to the next, etc. the savings are still substantial.  floridalife57's real world examples show the energy savings. I should add that anywhere you can improve on insulation will also reap rewards. Programmable thermostats can also help when there are periods of time the home is unoccupied. Hello floridalife57 and welcome to the Community! We are glad to have you join the forum. Thanks for the real world information on your energy savings. Let’s keep the meter readers busy. Please keep us updated on your projects and feel free to join in helping others. Hi Newf, Is it better to replace the AC Unit during the fall and winter months? If so, what are the advantages of doing so?  The only advantage I can think of is that in the "off" season you MAY be able to get a price break. While the same people that install A/C units generally also do furnaces, there is no hurry to install an A/C unit now in much of the country. 

As a result, the install can be timed when crews are not busy.  Add to that the occasional clearance sales from manufacturers at this time of year and there is at least the potential of saving some money. Also a cost issue, if you need to replace your furnace then adding in a new A/C unit at the same time can result in some savings. Hi Newf - I am still planning this project and I am down to deciding on heat pump or electric furnace to go with my new AC.  Can you tell me which one uses less electricity?  Heat pump or electric furnace?Asking an air conditioning guy why your air conditioner won’t cool is kind of like asking a mechanic why your car won’t run – there are a million reasons.  Since we are asked this question so often though, we do have a few good answers ready to go.  So when asked about “why an air conditioner won’t cool,” or “why an air conditioner won’t cool below 80,” the short answer is that you’ll have to call up your local HVAC technician if you want it done right. 

But then, you’re not on the internet looking this up because you want to drop a few hundred bucks to call one of us out there, now are you?  If you are a return reader to the ASM air conditioning blog, then you know that we are a small, U.S. Veteran-Owned business in Southern California, and like to keep it honest, simple and efficient.  In this article, we will discuss the most common causes for why an air conditioner won’t cool your house properly, including the do-it-yourself troubleshooting tips you can use to get your AC unit up and running properly. With any troubleshooting method, it is important to first understand that safety comes first.  Know your limitations – don’t go poking your head into an attic if you’ve never crawled in an attic before, don’t mess with electricity if you don’t know what you’re doing, and if you have any doubts at any time about what you are doing or whether or not you should be doing it, the answer is “no you shouldn’t.”  

Call the professional out – it’s just not worth it, trust me.  I can’t tell you the hours I’ve spent in an attic trying to figure out what someone was thinking when they did something to their unit.  Fortunately, the most common causes for when an air conditioner won’t cool are pretty simple. If you’ve checked our blog before, then you know that this isn’t the first time I’ve said this – the simplest answer is usually the right answer.  Without going on a tangent about Occam’s Razor, trust me when I tell you that you’d be surprised at how often I get called out to a house only to find out that it was, in fact, the wife that kept turning the thermostat up.  I am far from a marriage expert, as my wife can attest to, but please ask your significant other before you call us out…then make sure that your thermostat has power, is on, is set to auto and displays the desired temperature setting. Also take note of your thermostat’s position in your house. 

Whether you realize it or not, an air conditioner that won’t cool might not end up being the AC unit at all.  Your air conditioner doesn’t kick on because it thinks you are hot, and it doesn’t kick on because it’s hot in your house either – it kicks on when your thermostat gets hot and crosses whatever threshold temperature you have set.  In other words, check the location of your thermostat.  If your thermostat is in the deep dark hallway that is always cool and it is set to 72, then that doesn’t mean your house will be 72 in the front living room with the big windows that get sun all day.  Try adjusting your thermostat to start with, then read: What Temperature Should I Set My Thermostat To? Sit in your chair, relax and take a few deep breaths.  Having any trouble breathing?  Now, take the down comforter out of the closet and wrap it around your face and take a few deep breaths (disclaimer: don’t really).  Is it easier or harder for you to breathe?  Now translate this to why your air conditioner won’t cool – maybe it’s cooling, but it’s having trouble pushing air into your house. 

I say this in almost every one of our articles – your air conditioning filter isn’t really for you, it is a filter to keep contaminants from building up on your AC’s internal components.  The fact that it reduces allergens is just an ancillary benefit.  If you aren’t doing so, change your air conditioning filter no less than once every three months.  It may seem like a pain, or expensive, but your air conditioner works significantly harder when it has to push air through a saturated filter, just like you had to breathe harder through that down comforter.  So hard in fact, that this might be why your air conditioner won’t cool below 80 degrees in your house.  Change the filter and give it a try, then read: Air Conditioning Filter Change. Check the circuit breakers on your main power distribution panel (aka, your circuit breaker box).  Reset all air conditioner related breakers, including ones that are listed as “condenser,” “compressor,” “AC,” “Air Conditioning” and “HVAC.”  

People often times mess this part up – some circuit breakers won’t actually move to the “off” position if tripped.  So to reset them, move the circuit breaker to the “off” position, wait a second, then switch it back to “on.”  Do this for all of the applicable breakers. Next, go to the air conditioner itself (if it is on the roof, careful of loose leaves, etc. and don’t go up unless you know what you are doing).  If you have a “package” AC unit, then there is only one component, usually on the roof.  If you have a “split” AC unit then you have one piece outside and one inside.  Go to both and look carefully for another set of circuit breakers.  Some models have them, and some don’t.  If you see them, reset those too.  If one of these circuit breakers throughout this process keeps tripping off (making an obvious sound), then read: Air Conditioner Circuit Breaker Keeps Tripping for more information on troubleshooting this malfunction.  Don’t just keep resetting it!

If you have a split unit (see: What is a Split Air Conditioner?), then the condensing unit (or “condenser”) is the piece that’s locked outside.  For a package unit, it is all together in one unit outside (hence, “package”).  Either way, go to it.  Check it for debris.  Any leaves, branches, dirt mold and grime that have collected on it needs to be removed.  WARNING – don’t stick your hands inside that thing yet because it could kick on and hurt you!  Either call a professional HVAC specialist, or for the veteran do-it-yourself types, start by removing power from the unit using two different methods (use both, not just one): turn the thermostat to the “off” position, AND turn off the applicable circuit breakers (in HVAC, we ALWAYS turn a unit off at two separate locations for safety – that way, when someone comes along and says “oh, the thermostat is off” and turns it on while your arm is elbow deep in your condenser…get the point?).  Another word for the wise is to turn off all the power, not just the air conditioning breakers. 

Who said that whoever labeled those circuit breakers did it right?  In my experience, it’s about a 50-50 chance that it was labeled right – be safe and just turn off all the power why you do this.  After you turn them off, wait a few minutes just to make sure it doesn’t kick on, then go to work. Ok, enough motherly guidance.  Remove all large pieces of debris, then clean the heck out of that thing with a hose and a brush.  These coils are the exact location that your air conditioner releases the heat from inside your house into the outside air, so make sure they’re cleaned well.  Replace all safety panels, etc., and turn the power back on, as well as the thermostat. See if your air conditioner cools your house now.  If it doesn’t then you’re out of luck.  It is time to call the HVAC pros out.  If you live in Southern California, we ask that you keep us at ASM in mind, but chances are that you don’t live here.  Either way, here is an article I wrote on How to Choose a Reputable HVAC Contractor.

Like I said about the mechanic and your car at the beginning of this article, there are a million reasons that your air conditioner won’t cool, but you’ve honestly done everything that you can.  The number one thing that you can expect your air conditioning technician to do is to hook up to your system and check the refrigerant levels (either R-22 or R-410).  If he notices that they are low, he might opt for a Nitrogen Leak Check, where he will pressurize your system with nitrogen and wait for a while.  Then when he checks the gauge later he can tell if some nitrogen has leaked out.  If so, you have a leak and can go from there.  If not, then your Freon was probably just low.  He’ll top off your refrigerant and go from there.  Either way, call in the pro and see where it goes. I hope this has helped.  In the end, when your air conditioner won’t cool it can be frustrating, but it isn’t then end of the world.  Follow the troubleshooting steps above and go from there.