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Problem: Will a larger blower motor help my air conditioning? My air conditioner does not seem to be blowing air very hard.

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Problem: Will a larger blower motor help my air conditioning? Can I adjust the speed on my blower motor to blow more air? My air conditioner does not seem to be blowing air very hard.

Answer: I would like to recommend that you check your furnace’s blower motor capacitor to make sure the capacitor is not weak. A weak motor capacitor can cause the blower to run slow. Please click here if you would like to see the capacitors that we sell. Some small appliance shops will test capacitors free of charge. Yes, you can change your blower motor’s speed to try and improve your airflow if your blower motor is not already at the highest speed. On most blower motors the black wire is the high-speed wire. Below we have a really good YouTube video made by AC Service Tech LLC about changing blower motor speeds. Thanks to AC Service Tech for making this great video! I would also recommend that you check to make sure your blower wheel (squirrel cage) and the bottom of your air conditioner evaporator coil is clean before trying a larger motor.  I would recommend checking your refrigerant charge to make sure your AC is charged up properly. If your AC system is low on charge it will cause the coil to freeze up and cause a restriction in the airflow. The rule of thumb is the blower should produce 440 CFM (cubic feet per minute) of air per ton. On a two-ton system that is 880 cfm (cubic feet per minute). This usually calculates out to about a 1/4 to 1/3 HP blower motor. If you get too much cfm it is hard on the air conditioner, because it robs the air conditioner of the cool gas going back to the compressor to keep it running cool and you have to over-charge the AC unit to get the cool gas going back to the compressor. I usually need to add refrigerant to a system that has too large of a blower motor. You want to charge your system so that there is cool gas going back to the compressor and the suction line feels like a cold coke can right out of the refrigerator. The air conditioner should make a 15 to 20-degree difference in the ambient air. If your home is 75 degrees inside, the air coming out of the registers should be between 55 to 60. I hope I have answered your question. I have installed oversized blower motors before to get more airflow. I would not recommend going over 1/3 horsepower in your case. You would need to check the charge after you install the new motor to make sure you are getting the needed cool gas back to the compressor. Below we have a real good YouTube video produced by hvacrepairguy which shows how to replace a blower motor. Thanks to hvacrepairguy for making this informative video! Please click here if you would like to see other DIY videos on how to test capacitors and clean AC evaporator coils. If you have any questions please email us anytime at or comment in our comments section below. We would love to help you out and have your business!

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48 thoughts on “Problem: Will a larger blower motor help my air conditioning? My air conditioner does not seem to be blowing air very hard.

  1. Hi, I recently change my return air ductwork in order to refinish my basement. When I first turned the furnace back on, everything was working fine, but I now notice the return vents are drawing less air; before, I could hold my hand over one of the return vents and hear the furnace struggling for air. Now, even if I cover all the return air ducts, the furnace seems unaffected and does not make that noise. Could this be caused by the blower motor?

    1. Hi Daniel! It would depend on how large of a return duct you installed in the basement. If the return is too large then maybe most of the return air is being taken out of the basement and very little air from your upstairs returns. If that be the case you might consider making the return in the basement smaller or installing a damper to cut down the airflow from your basement return. Yes, this could be a blower motor problem. I would like to suggest that you check your blower motor capacitor to make sure that the capacitor is in good condition. Also, turn off the power to the furnace and feel to see if the motor is running hot. If the motor is hot then you might need a new capacitor or you might have a bearing dragging and going out in the motor. Yes, you might need a new motor. If you have an Amprobe meter see how many amps the motor is running and compare it with the FLA (full load amps) or RLA (running load amps) on the motor label. If the motor is running over FLA or RLA then it is on its way out. I hope that you can find and fix the problem soon! Steve

  2. Hello, I have a very old legacy system that has a failed blower motor. Was told that the motor is so old and outmoded that a replacement is not available. Therefore they said I must replace the entire system. I’m wondering if it is possible to replace just the full blower assembly (housing, wheel, motor) to a modern version and simply install the new blower unit to my old furnace? It may not have the exact air flow, but if it’s close enough, is this possible? What measurements/specs/features are needed to find a blower assembly that will physically work with the old furnace?

    1. Hi Mo! They make universal blower motors. We sell a direct drive universal blower motor on the following page: If you have a belt-driven motor then they sell these motors too. We do not stock any universal belt-driven motors. The only reason why you would consider replacing the entire blower assembly would be if the assembly is rusted really badly and dangerous (will not hold the blower motor in place). To replace the entire housing you would need to know the size of the hole in the furnace where the blower blows air up (up-flow furnace) or down (downflow furnace) into. You would need to know the length and width of the housing so it would fit in your furnace’s blower compartment. Many blower housings could be drilled with new holes and made to fit. Your best bet would be to take the measurements then go to a nice local HVAC company and see if they would allow you to purchase an old used blower out of one of the furnaces that they have removed. It might be hard to find a company that would let you do this because of liability if someone got hurt on their property. There are a few companies on the Internet that sell complete blower housings. Here is one of them: I hope this helps you out. Steve

      1. Hi Steve, thank you so much for your helpful answer! I would like to get clear on a couple of things, maybe you could help me understand.
        1. From my reading and searching, it is my understanding that the size and design of the fan and housing dictates the power and specs of which motor can drive it. I believe the old motor is something like 15 amps and the blower is oversized for the unit (replaced before with a salvage from a bigger machine). Is it true that the motor must match the casing/fan itself? If yes, that would explain why such a heavy energy hog motor is no longer made, and why they say you cannot substitute a newer motor in the unit.

        2. If get a motor that would physically fit, will it technically work with any electrical air handler/system regardless of the power specs? I know the blowing force might not be right, but as far as connecting it to power, wouldn’t it turn on and spin no matter what? Or is there a “secret” to which motors can be plugged in beyond simply matching the voltage (115, 220 etc)??

        Thanks again!

      2. Hi Mo! Yes, the size of the blower wheel dictates the size, horsepower, amps, and rpm of the motor that can be used. Too small of a motor then it will draw too many amps and over-heat and burn up the motor over time. Too large a motor the motor will not what they call, “Load-up” and it will burn the motor up over time. My suppliers have a chart that matches motors with blower wheel diameters and sizes, but I do not have one. That is why it would be best if you try to get a complete blower housing and motor already matched with a motor. The motor would need to match your system voltage either 110 volts or 220 volts. Here is a link to one of our posts on how to replace a blower motor: I hope this helps you out and you can have a great day and a blessed week! Steve

      3. Hello Steve,

        Just wanted to give you an update. We resolved this by a form of your suggestion. The tech was able to locate a used full blower that would fit the furnace. The motor was old and he replaced it with a new one of similar type.

        But here is my question. I still don’t understand why a compatible replacement couldn’t be supplied. The old motor is a Fasco D2818, and if you look it up, most places show it as obsolete, discontinued, no replacement available. No cross reference. Nothing. What is it that makes it such that NONE of the new universals or generics will work or can be made to work? Could it be the shape or size of the shaft?? That’s the only thing I can think of. And even if so, doesn’t anyone make a shaft adapter as they do for plumbing fittings and similar things?

        Thanks for all your advice. I’m hoping this helps others and maybe gives you some clues as to why this situation happened.

      4. I am so very glad to hear that you were able to find a full replacement blower motor. Great! I search Google for “Fasco D2818 motor” and found lots of places that sold the motor. Maybe this is the wrong motor that I was searching for that you are referring to. You should most always be able to find a universal motor replacement if you can find the RPM, Horsepower, rotation, frame, shaft size, and amperage on the motor you are replacing then try to match that information up with a universal motor. Thanks for letting me know that you got your furnace fixed. Steve

      5. Hi again. Yes, you got the part number right. I see the same listings, but if you do a deep dive, you will see that those pages show “discontinued” or “out of stock”. Some do not say this, but the price is extremely high, and they still may not have it when you actually place an order. There are some people selling it on ebay, new old stock, but we saw this later and no tech wants to install questionable ebay parts (plus wait for it to be shipped). It is definitely discontinued, but my question still stands. What if you couldn’t find it? What makes it unable to be duplicated? I see one page says “keyed shaft”. Is that the reason? Is there an adapter? I’m just trying to arm myself with knowledge before the next time, when delays are not welcome!
        See below

      6. I am sorry, Mo, but I have never had any problem replacing a motor with some kind of a universal motor. I am not familiar with the Fasco D2818 motor so I do not know why it is different and hard to find. I am sorry that I can not help you out in understanding why this motor is so hard to find. Steve

  3. Hey Steve,

    Thank you for fielding these questions.

    I own a 3 story 1250 sq ft home that has few interior doors and has a centrally sited spiral staircase . Im wondering if i were to install a 30k mini split at the highest point in the stairwell and upgrade my blower with the largest appropriate unit would i achieve a reasonably even comfort level throughout by way of cool air circulating via the blower and ducts? Im in SE PA.

    1. Hi Gil! I am sorry, I do not know if this would work for you or not. You would need to do a manual J calculation which shows the heat gain and heat loss for your home to determine if a larger blower and min split would work. We have posts about this question on the following pages: and on the post where you asked this question I talk about needing a Manual J calculation to determine the right size heating and air conditioning system and the ductwork sizes. I am sorry but without the calculation, you and I would be guessing. Thanks for asking this question. Steve

  4. My Carrier unit was installed 2001. It has held its Freon beautifully. but when I moved into the house, after my mother passed away, I found the airflow had stopped and found it was due to 1″ of compacted grey cat fur underneath the evaporator coils.. Plus the squirrel cage had 1/4 inch of grime buildup. I cleaned that and wow, like brand new again. shortly thereafter the outside condenser blower motor failed and I replaced it with an Emerson 208 vt 1/4 hp. /875 Rpm; that was 9 years ago.. now 2020 they both get replaced : I used a retrofit motor the same specs 208 vt, 1/2 hp. for the inside, but it was 3/4″ taller/ longer, which I was able to adjust the length outward of the squirrel cage I replaced the capacitor: It ( inside) works fine. However Outside they sent me a 1/2 hp 1075 RPM replacement w/ capacitor, and just to save shipping and headaches, I retrofitted it to this Puron 3 ton condenser unit. I was thinking ok, 3.3 amps instead of 2.4 amps, not a big deal, But boy does it turn the crank! I calculated its 25% more RPM, airflow, and maybe it will be less run time, and more efficient in the summer as we get very hot july to august. I had some concerns that it might work the compressor harder leading to early fail, but its almost 20 years old anyway. I’m just thankful Its still oldie goldie. My other concern is that it being heavier with more torque, power, it stresses the entire unit/case, it might not hold up as long. Nothing is built to last it seems.. I’ve added some extra screws around the top and side panels. the top rack made up of lightweight (alum?) rods seems to vibrate and make noise, and haven’t figured how to tighten them. I did use some clear rubber damper material between the motor and the rack and it seems to let the motor hum fairly quiet for the time being/.. Note, It seems the manufacturers would engineer the frame top racks with heavier materials, just to reduce rattling, and provide better support for the motors. I carefully read your earlier posts and I understand now how to adjust the speeds / HP by going Lower or higher, but this unit only has one speed, although it can be easily reversed in rotation. Its weird how I got it right on the inside specs, but missed on the outside, and then pretty amazing to go ahead and use what I bought. and why the outside unit was originally less HP than the inside unit. 1/4 hp 875 RPM outside versus 1/2 hp 1075 RPM inside. I do know from years of school maintenance jobs that 208 motors generally are longer lasting and less expensive to run, at least those under 1 HP. But now mine are pretty much matched up inside and out. Another interesting fact is that the newer motors have much smaller size wires, due to technology is all I can say about it.. insulation is better. btw, I will be checking out your website.

    1. Hi Michael! Thank you so very much for taking the time to write the problems and solutions with your furnace and air conditioner! Yes! cleaning that cat fur off the evaporator indoor coil and cleaning the blower wheel I am sure made a super great difference in efficiency and airflow! Way to Go!!! This sounds like you are very good with your hands and fixing things! You are very blessed! God Bless you and your family today and always! Steve

  5. I have a carrier air handler that has a bad 1/2 hp 1400 rpm motor variable speed motor, can I change it out with a variable speed 3/4 motor also 2.3 version module ? the rpm,s on the 3/4 is rated up to 1500

    1. Hi Ken!
      If you are referring to an ECM motor that you have then I am not familiar with what would be compatible with changing and replacing ECM motors. I am not done any service since 2005 and there were not that many ECM motors when I quit doing service. I would suggest that you stay with an OEM motor with the same specifications. If you would like to send me your Carrier product number then I will be glad to look it up for you and see what the part number is that Carrier recommends. I hope you have a great and blessed day! Steve

  6. Hi Steve,
    I have a living room of 516 Sq.foot, I was checking for few split Air conditioners and the costs of maintenance and services, I luckily found this website. I was going through your answers, if I need to cool my living room I may need 500-550 cfm(15,000 btu/h or 1.25 ton), which motor is well suited for this condition(1/2 HP motor?) and out of curiosity I want to know why 440 cfm is required for 1 ton of AC unit ?
    Thank you!!

    1. Hi Makam! If you have not already you would need to get a heat gain and heat loss calculation (Manual J Calculation) on your living room to see how many BTU’s you would need to heat and cool the room. The mini-splits have real small motors in them (probably 1/6 horsepower or smaller. The motor and blower are sized by the manufacturer of the mini-split to get the right air flow required for that specific mini-split unit. A 1/2 horsepower motor would be way to large for a mini-spit. The 1/2 horsepower motor that I am referring to in the post is for a whole house furnace blower. On most gas furnaces a 1/2 horsepower motor will handle up to 3 to 3 1/2 tons of air with the right blower wheel. The 440 cfm per ton is a rule of thumb calculation that is made by engineers when figuring out how much airflow is needed for one ton of air conditioning. The duct worked is sized based on the 440 cfm value too. This is in the Manual J calculation book. I hope you have a great day and week! Steve

  7. Hi Steve,

    I just purchased a house with a York TG8S06A12MP11B A/C unit. The air blows cold but not very hard. There is a lot of water coming out of the condensate drain and at times the air vents will start to sweat. I have replaced the air filter and it did not seem to help. I noticed from the product manual that this unit has a 4 speed blower. Could that be the issue? Are there any tests I can run with my multi-meter before having to call out a service company?

    Thanks so much,

    1. Hi Conner! I would make sure that your blower motor capacitor is in good condition and up to specs. If you do not have a capacitor tester you might be able to take the capacitor to a small appliance parts shop and they will hopefully test it for you. Yes, you might be able to get more airflow by changing the blower speed to a higher speed. The Black wire is usually the highest speed. Another problem could be that your ductwork is not large enough to support the airflow. We have a post on the following page that might help you out because not getting enough airflow can cause freeze-ups and can cause other problems that are discussed in this post. Here is the link to the page: It will cause the air conditioner to freeze up and also cause restricted airflow. I would suggest that you test the capacitor first and make sure the blower is on high speed for AC. I hope you can get more air flow soon! Steve

  8. Hello Steve, I have an older model Comfort Air System model NTG9075FGA3, with a 3 ton AC unit. My Home is a Split level 1900 sq ft. in Ohio. Last summer I noticed the blower seemed to be getting weaker. So I replaced the Capacitor. Not really much changed. I read a few forum boards and decided to move some speeds around on motherboard. I moved a (medium High)wire to the cool on board and the blower increased. Went through winter, spring just fine, and now this summer it has declined once again. It’s not keeping up with the thermostat settings on the hot days in the house. Its blowing very low…Is it possible that this blower motor is just getting weaker and weaker on each voltage supplied by board? I asked this question to a hvac fella neighbor, and he said it sounded like the “high sides of the motor were going” …does that sound right? The motor is pretty expensive and would like your insight on this if possible. Thank you for your time.

    1. Hi Mark! I would like to suggest that before you replace the blower motor that you makes sure everything is clean and not impeding airflow. If the blower wheel, filter or evaporator coil are dirty this can cause the airflow to be weak. I have seen the underside of evaporator coils become partially stopped up and really hurt airflow. If your air conditioner is low on charge and is icing up the evaporator coil then this will mess up the airflow. I would suggest that you check the capacitor again to make sure it has not weakened any since the last time you check the capacitor. You might try to move the black wire (high-speed wire) to the cool position on the control board and see if this helps. If everything checks out then it sounds like the only solution would be a new motor. I hope you have a great day and week! Steve

      1. Will Do! Wheel, Filter all clean, I will slide panel off plenum and check the coils, and drip plate Thank you!!!

      2. Hi Mark! Just make sure that you check the underside of the evaporator coil because this would be the side that gets stopped up if you have an upflow furnace. Thanks so much for your response and kind words! Hope you find something to resolve the problem. Steve

  9. I am sick that the technician that ruined my A/C unit will be sent out to repair it! After ascertaining the fan motor was shot he proceeded to remove the soft start device that made the unit run great for 15 yrs! Without telling me either! then he installed the new matching fan motor and I told him the blades were too close to the motor and that they needed to be spaced out and that even though he was “the expert” I have seen the working of this yearly for maintenance and know where the blades lie in the design. He started to mock me and later moved it an inch closer to the mark I mentioned and after tightening it up said is that good enough? Are you happy with this? I was sick at heart by then and he completely closed it up before test running it… It was immediately obvious the blowing air was circulating behind the fan guard instead of out and beyond and I immediately said so…. his disgust was immediately obvious and he said “it is done correctly MAM!” it was completely dark by then and an unfortunate water leak in the basement shorted out the furnace circuit board so we could not test it until morning…. In the morning it ran 10 minutes with the air not blowing enough to cool the fins and it stopped running. Out he comes AGAIN and this time he changes out the motor to 1/2 hp (not according to specs) and he berates me that he is out the cash from his pocket for this motor (like he is a good guy tho putting in wrong sized motor) again he completely closes it up before turning it on… he heads to his van to leave and this time it stopped running before he could pack up his tools! It also blew the double breaker and now is when I find out the soft start had been removed and now he says the compressor has shorted out and the A/C is dead for all purposes… So my assumption is that the higher hp and no soft start device caused a over draw of power and a short in the compressor which had easily chilled every time we fired the A/C up until now, but the fan wasn’t working. Now I must pay $200 to recap refrigerant and dispose of the compressor and pay extra $150 to install a new one with no guarantee that this guy can make it work. We have been without A/C for a month now… Home Warrantee service!! Sheeesh!

    1. So very sorry to hear that you have been subjected to all this bad workmanship and trouble!!! I wish that I could do something about it but I can not. I would like to suggest that you contact the BBB, Better Business Bureau about all the trouble that you have had with this company and the trouble that you had with trying to get your air conditioner fixed. I hope you can get a reputable company to get your air conditioning system fixed right away. So very sorry this happened to you! God bless you and your family. Steve

      1. Sometimes being a voice for us little guys just has to be enough thx!

      2. Thanks for your kind words! God bless you. Steve

  10. I realize the question is from YEARS ago, but if I had to guess, if anyones air conditioner is not “blowing hard enough” it is not likely the motor to blame, as I’m sure the equipment was installed with a proper sized motor. The most common problem for lack of airflow is the owner of the equipment using an air filter that is overly restrictive with a high MERV rating. If you use an air filter that claims to filter out extremely small particles it is going to also inhibit the blower motors ability to blow air through the ducts or actually suck air back through the return ducts. If you want more air movement/blowing use a filter with a very low FPR or MERV rating…fiberglass filters work best. However, because these filters may let through more dust, be sure to have your equipment cleaned and inspected at least every year or every other year to help prolong it’s useful life.

    1. Fantastic advice! I agree 100%! Thanks so much for taking your time to write this! I hope this will help other people who are having poor air flow problems. God bless you and your family. Thanks! Steve

    2. If the system was installed by a good qualified company then maybe you could assume that. But there are plenty of people who inherit lousy systems. Quick check is to just yank the filter. If the airflow doesn’t change then you’ve ruled it out. Honestly these days it’s hard to find an honest and knowledgeable tech.

      1. Sorry, to hear that you are having trouble finding a good, honest and knowledgeable company. I would check with Angie’s List, Home Advisor or companies with an A+ rating with the Better Business Bureau. I hope you can find a good company.

  11. Hello Steve,

    Hope you could help me here and sorry for the write up.
    I have a few concerns about a furnace blower motor replacement.

    An HVAC contractor came to my home to do a furnace tuneup on my older Heil unit.
    The unit is under the house (crawlspace). He removed the motor, wheel and housing in order to wash it off.
    When he put everything back together, the motor burnt out and he ended up replacing it with one he had in his truck.

    I had:
    GE 1/3 HP 2.9 FLA, 2 speed Permanent Split Capacitor, 1075 RPM, 208-230 Voltage, Frame 48YZ

    He replaced it with:
    FirstChoice Direct Drive Furnace Blower Motor, 3/4HP, 3 Speed, 208-230 Volts, 1075 RPM, 5.4 Amps Frame 48Y

    He stated that I was getting an upgrade and that my old blower motor was using one speed and now the 3/4hp motor he installed will be at medium speed for heat and full speed for cold.
    He also replaced the relay and capacitor.

    I am concerned that this higher HP and almost double AMPS motor may cause some premature failure somewhere in the system as it is at least 18yrs old.
    I am also worried that the higher amps motor will consume a lot more electricity and my bills will be higher as I tend to keep the fan on circulating mode to move the air in the house.
    The motors are the same RPMs, so not sure if it is pushing more air even with a higher HP? and that will be bad for my system somehow or my ducts?

    Please let me know if I should have these concerns, expect a much higher elec bill or premature failure, or what to look out for and keep an eye on.
    Thanks a lot for your insight.

    Relevant info:
    My unit outside is a 3 Ton older Heil Heatpump NHP036AKA1 with a compressor UPKA-035jaz
    Fan motor at the Condenser unit (if this helps) is a 1/3HP 208/230 volts 1075rpm 1 speed 48Y 1.9amps

    Note: There was a sticker on the furnace from the original factory installed furnace blower motor and it reads that it once had a 1/2HP 208/230volts FLA 3.2 MODEL NUMBER BH3036SKB1 MFR NO: NBH3036SKB1 STYLE BEA36A
    This makes me think that this unit originally had a furnace 1/2 HP motor and then the previous home owner had it replaced with the 1/3hp GE motor at some point before I bought the home 15yrs ago. I never had and issue with the Furnace GE 1/3 motor even if it was less HP and 2.9 instead of 3.2amps that the originally installed motor had and lasted the full 15yrs until yesterday.

    Also, the fan motor at the condenser unit was replace about 10 years ago and it was replaced with the 1/3 HP 208/230 volts 1075rpm at 1.9amps. I am not sure if the condenser fan was chosen to match close to the 1/3HP furnace motor the previous home owner installed.

    Sorry again for the long write up!

    1. Hi Jay! Great question and concern! The furnace and air conditioner in your home are manufactured, sized and based on the amount of air flow that the furnace or air handler produces. Since you have a 3-ton air conditioner you should have a blower that produces 440 cfm (cubic feet per minute) of air per ton or 1320 cfm for a 3-ton system. I would think that installing a 3/4 horsepower motor might harm your heat pump in the air conditioning mode because with the stronger blower motor the increased airflow can boil off more refrigerant and cause the compressor to not get enough cool gas back to the compressor to keep it running cool. You would need to have your unit checked out with gauges and thermometers to make sure you are getting the proper superheat and subcooling for your unit’s design with the new blower motor. I would think that your tech would need to over-charge the unit slightly to get the proper subcooling with the larger blower motor. I would think that you would hear more noise of air flow in your home with the stronger blower. Most of the time 3/4 horsepower blower are used on 4 to 5-ton units. I usually think of 1 amp as like one 100 watt light bulb burning. So if you increase your amps by 2 then it would be like burning two 100 watt light bulbs and this would increase your electric bill to compensate for the extra power for the 3/4 horsepower motor. If you were having trouble heating and cooling your home because of poor airflow in your home, then I might consider going up to the 1/2 horsepower, but I would not recommend the 3/4 horsepower. Some of the universal motors have the speeds rated in horsepower. Like low speed is 1/3 horsepower, medium speed is 1/2 horsepower and high speed is 3/4 horsepower. If this is the case on the 3/4 horsepower motor then I would say that is great, but if you had a straight 3/4 horsepower with low, medium and high speeds then I would not recommend this. I hope I have answered your question. Hope you have a great day! Steve

  12. I have an older home that is 2200sqft + 1000sqft of basement that the central air also feeds to.
    My AC unit is from 1985. It runs and cools the air slightly, but basically stays running all the time, and never gets the house below 75 on the first floor. Upstairs is about 78. The air coming out of the vents doesn’t feel that cool and there is not a lot of air flow.

    What is the best way to address my situation? Is the cost of a new unit ($3000) really worth it? I moved into the house a few months ago so I do not know how well it was working before. The furnace is newer and seems to do a good job of heating the house, which makes me think the A/C unit is on it’s last leg and that’s why it’s not cooling the house. Plus my electric bill is over $100 a month because it runs so much.

    Thank you for the help!

    1. Hi Doran! I would like to suggest that you have the air conditioner serviced by a reputable company. You might ask your friends if they know of a good honest HVAC company to call for service. You could check with Angie’s List or the Better Business Bureau for a good company to call. I recommend calling for service because you might just need a good cleaning or a little refrigerant charge to fix your air conditioning system. If you do get a new AC system I would recommend that your installers do a heat gain and heat loss calculation (Manual J Calculation) to make sure you are getting the right size Air conditioner and duct work to cool your home. We are required to have a heat gain, heat loss calculation here in Louisville, KY before the Housing Department will give a permit to do a new heating and air conditioning install. That way you know that you are getting the right size equipment for your home. I hope that you find an easy inexpensive solution to your problem. God bless you and your family. Steve

  13. I have a 1320 sq foot mobile home, they put a 3 1/2 ton HVAC AC unit and it runs five minutes at a time it stays humid, and ,I’ve had the coil replaced then two weeks later needed it replaced again. I’m asking them to bring it down to the 2 1/2 ton that was for this home. Can I leave the same heater and blower motor and just replace the outside AC unit and the inside evaporator coil’s? AC unit and it runs five minutes at a time it stays humid and I’ve had the coil replaced and two weeks later needed it replaced again. I’m asking them to bring it down to the 2 1/2 ton that was for this home. They want to put a 3 ton on the home. Can I leave the same heater and blower motor and just replace the outside AC unit and the inside evaporator coil‘s , My home is just now one-year-old

    1. Hi Sherry! Yes, it most definitely sounds like they over-sized your air conditioning system since it is cutting off and on so much! I do not understand why they keep on having to replace the coil. That is hard to believe they had two bad evaporator coils in such a short period of time. You can leave the same blower motor in if they can lower the speed on the blower motor to produce 440 cfm (cubic feet per minute) per ton on the air flow out of your existing blower motor. So for a 3 ton unit the blower should produce 1320 cfm air flow. They would need an anemometer to measure this or many times the furnace will show in the installation instructions how to set the blower speeds to produce different air CFM’s. So if your existing furnace or blower can be run at a lower speed then yes, they could use the same blower. If the speed can not be lowered then you will need a new furnace or blower because it would be hard on your new air conditioner to have beyond the designed air flow. Thanks for asking this question. I hope you can get this fixed soon!

      1. I want the 2 1/2 ton that’s what the house square footage requires. If they insist on putting the 3 ton, well I have the same issue with the cutting off and on. Or, will a 1/2 ton make that big a difference?

      2. Hi Sherry! If they did a heat gain and heat loss calculation and found out that your home requires a 2 1/2 ton AC then I would insist on the 2 1/2 ton because, yes you will get the same problem with the unit shutting off and on all the time and not running long enough to take the humidity out of your home. You might think about getting a thermostat that has a 2 degree difference in on off cycles. I know that some of the thermostats are real sensitive and can cause lots of cycling if not set properly. I hope you get your problem taken care of soon! Steve

  14. The back rooms in my home have always been hotter than the rest of the house. The past 2 years the whole house is hot. About 5 years ago I had to replace the furnace. I also had new ductwork done, a second air return added and a new thermostat. The AC unit is about 12 years old. 2 years ago I had the capacitator replaced. I had the insulation checked last year and it is good. They added 1 lb of refrigerant last year. Still hot. This year I had another company come out. They measured air from the vents vs air return, added another 1 lb of refrigerant, checked for leaks and everything was coming up good. Still hot. Called again and he is stumped. He is suggesting increasing the AC unit by 1/2 ton even though based on home size it should be good. However, to do that he says I would have to replace my furnace too since he feels the AC would freeze up because the furnace size would not match the AC. Is this true and could I not just install a larger blower motor on the furnace since it is relatively new?

    1. So sorry to hear that you are having all these problems getting the back rooms in your home cool. I would suggest adding at least one supply register in each room if that is possible and see if this helps. You could increase the horsepower of the blower motor and see if that helps. The motor needs to be matched with the blower wheel or if the motor is too large it will not load the motor and the motor will burn out fairly soon. The contractor maybe having trouble fitting a larger coil on your furnace due to width restrictions of the furnace. We are required to submit a heat loss, heat gain calculation for every home before Code Enforcement, the housing department will issue a permit for a new installation. If your contractor had completed the heat gain and heat loss calculation they would have know the AC was too small for your home. I hope you can get this taken care of with the least expense. Steve

  15. Hi I have twoout of 3 bedrooms 2nd floor and they do not cool or heat very well. The HVAC is in the basement and it is an electric ac and gas furnace. Unit is 18 yrs old and original from the time the townhouse was built. The ac part was replaced about 5 yrs ago. Will a new HVAC system help these rooms? One company said I should put booster fans in the duct work to push the air to those rooms.

    1. Hi Deb! You should get your contractor to do a heat gain, heat loss and duct calculation before installing the new system. Then you will know if the new furnace and air conditioner will do the job or not. More than likely you do not have the right size duct work or number of ducts to heat and cool your upstairs properly. We are required here in Louisville, KY. to submit a heat gain, heat loss calculation to our code enforcement housing department before we can start work on a new installation and get a work start permit approved. Thanks so much for asking this question. Steve

  16. I live in a 45 y/o mobile home with central air (which was installed as an afterthought). Coleman Evcon model BPCH0301BA. The 12″ diameter flexible ducting from the unit has to travel at least 6 feet before it connects with the metal ducting that delivers the conditioned air to the vents. Airflow into the house is minimal. I have to run the unit constantly and block the windows with dark curtains to achieve a modicum of cooling. Could the distance it has to travel account for the loss of pressure? Would a bigger blower help? The motor currently in the unit is 1/2 hp. Thank you.

    1. Hi Ginger! Sorry you are having trouble keeping your home cool. If your home only has one supply duct that is 12″ in diameter then this could be the problem. A 1/2 horsepower blower motor should handle 3 to 3 1/2 tons of air conditioning. Most mobile homes only have 2 to 2 1/2 tons of air conditioning not unless you have a very large mobile home. There are lots of things that can cause poor air flow and poor air conditioning such as: dirty filter, dirty evaporator coil, dirty blower wheel, dirty condensing unit, under or over charge of refrigerant, duct work too small for air conditioner, air conditioner under-sized for the heat gain of your home. The installers should have done a heat gain heat loss calculation to determine the size of the air conditioner and the size of the duct work that should be installed in your home. I am sure they did not do this 45 years ago. You might try to get some of these items checked out. A larger blower motor might help, but if you only have one supply duct it still probably will not do that much good. Sorry that I could not give you a definite answer. Steve

  17. Stumbled upon this while researching a similar issue. I have a 1700 square foot home, with a full unfinished basement that I am in the process of finishing. There are no vents in the basement. The upstairs vents put out decent air, but I’m afraid when I run vents to the two new bedrooms, bathroom and the family room it won’t be enough. Wouldn’t a larger blower solve this IF it becomes an issue? Also, how many returns should the basement have?

    1. Hi Mr. Birkemeier! A larger blower motor could harm your air conditioner since the amount of air that the blower sends out determines what tonnage Air conditioning you should have. The duct size determines the amount of air too. Too much air going through too small of duct work creates noise. Most of the time a 1/3 horsepower blower motor will handle a 2 1/2 to 3 ton AC unit and a 1/2 horse power blower motor handles a 4 ton unit and a 3/4 to 1 horsepower motor will handle 5 tons of air conditioning. The air flow should be 440 cfm per ton. You could try a larger blower motor, but test the cool gas going back to the compressor on a warm day. What usually happens is you have too much air flow and you have to over-charge the unit to get the cool gas back to keep the compressor running cool. When you have to over-charge the AC it you do not get as good cooling because it raises the evaporator temperature and it is harder on the compressor pumping more refrigerant. Just keep a watch on the pressures and super-heat going back to the compressor if you do install a larger blower motor. Rule of thumb in a basement would be one supply in every room. Probably two in the larger family room and one return that is centrally located in the basement near the floor. You probably already know this, but do not install the return in the same room as the water heater and furnace. The return should be in the largest living space if possible. Best of luck on this project. Steve

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