10 Things You Should Know Before Replacing Your Central AC System

Couple happily reviews electricity bills that lowered since they replaced their HVAC system

Maybe your old central air conditioner has quit working, and you think you need a replacement.  Maybe you want to upgrade to a more energy-efficient or environmentally-friendly system. Maybe you’re not sure what to do.

Whatever the reason you’re considering a new air conditioner or furnace, you’ll want to go through this handy checklist to make sure you are shopping for the right equipment and asking contractors the right questions.

1.  How much time do I really have to replace my system?

Click here to learn how to put time on your side to get the right equipment for your needs.

2.  Do I really need to replace my entire system or can it be repaired?

Click here to see the many factors facing the repair vs. replace decision.

3.  How much space am I trying to cool (and has it changed since the old AC was installed)?

Click here to learn how you might need more or less cooling and heating power based on changes in your home or workspace.

4.  Do I want something more than “just cold air”?

Click here to read about how improvements in comfort, energy costs and the environment can make you feel better and save you money.

5.   Do I really need to cool the whole house all the time?

Click here to see how some common suggestions can actually lead to bigger problems.

6.  Is there really anything new in air conditioning?

Click here for an overview of new technologies available today and what they mean to you.

7.  Are there unique needs in my region of the country?

Click here to see how where you live might determine the type of equipment you should buy.

8.  Should I replace my furnace if I replace my air conditioner?

Click here to learn how your air conditioner and furnace work together… and apart.

9.  Should I invest in a programmable thermostat?

Click here to see how you can save 20-30% on your energy bill without changing your routine.

10.  How do I know which contractor to hire?

Click here for insights into how to ask the right questions and select the best contractor for your situation.

Was this helpful?
Vote This Post Up 84 Loading...

52 thoughts on “10 Things You Should Know Before Replacing Your Central AC System

  1. I really like that you remind people to think about the space that they need cooled when they’re looking to replace their HVAC system. A lot of people tend to forget about that and it can really come back to bite them later. After all, if you don’t get an new system that fits the size of your home just right, you could see a rise in your energy bill. http://www.modernair.biz/residential.html

  2. Does the dryer lent trap and vent have anything to do with my central Air Conditioner/ Freon? Sounds strange to me but my landlord is saying it does .My heat is electric. Thank you

    • Some homes have heat exchangers in the electric drier exhaust line to capture the waste heat and use it to help with heating spaces in the home. That is the only thing that comes to mind but you can ask the contractor for further clarification.

  3. Central air is very old, compressor went out, it used to use the now illegal freon. Is it impossible to get a modern compressor put into it?

    • The refrigerant restriction currently only covers new equipment. You can still repair an existing system and recharge it with the old refrigerant as long as it is still available. If your system is older thought it might be better to just replace the whole system. We recommend getting a few quotes from different contractors for both repairing and replacing before deciding.

  4. The refrigerant or ‘freon’ in the cooling system has nothing to do with whether or not the furnace is going to heat or not. If I’m understanding correctly, you want to heat up your house, not cool it down?

    • Hi Eric – we were assuming that Tonya’s system was a “heat pump” system which works as an AC system in the cooling season and runs in reverse (using refrigerant) in the heating season. There are many articles on this site about heat pump systems and you can search for that that term if you want to learn more about them. Heat pumps are commonly used in the southern US where the winters are mild. They are pretty efficient heating systems down to around 15F.

  5. Hello,
    My heating unit on the first floor isn’t heating. I’ve had multiple companies come out and say they can’t find anything wrong other than putting freon. As an example it’s 42 degrees outside and the indoor temp is 60 and I have the thermostat set to 80 (I replaced the thermostat a month ago) no heat is coming out. Can you provide any possible causes for the issue?

    • If the multiple companies have continued to add refrigerant, there is a good possibility that there is a leak in the system. The leak must be identified and repaired for the unit to operate properly.

  6. What a nice article, after reading again and again I followed a few tips that landed me at http://www.trendycoolfans.com, the reviews here helped me pick on programmable thermostat and I don’t regret, apart from the silent performance of the gadgets, my energy bill reduced by half. Thank you so much

  7. I just had a new A/C unit installed. It wouldn’t cool the house properly initially. The installer found the insulation in the coil (which was not replaced) had fallen down and was blocking the air flow. It took an extra 4 hours for him to determine and fix the problem. He said he would have to charge me extra on top of the cost of the new A/C unit and its installation. Did he have an obligation to tell me in the quote or at least verbally before installation that he would charge extra if problems were encountered with the installation? Aren’t problems getting a new A/C unit to work with existing components to be expected?

    • Hi Lynn,

      Sorry to hear about your dissatisfaction with your service. We would encourage you to refer to the terms and conditions on the quote, if provided.

  8. My AC is not cooling the house as I think it should. We just moved in a house where the AC unit is located on the side of the house and unit that it is connect too is located in the basement. I had a friend look at it and he said that the HVAC unit in the basement is leaking air when the AC is on. Since the HVAC unit is located in the basement than all of the vents are under the floor on the main floor. I’m not sure what I need to replace or do to cool down the house. The house temperature is 75 degree with the AC on when the outside temperature is around 80 degree. Our house is 1,700 square feet with 4 rooms, 2 bathrooms, a living room, a family room and a kitchen.

    • Hi Jonathan,

      There could be multiple reasons for the lack of cooling, one of which was pointed out by your friend as air leakage around the coil and/or ductwork. Some other potential causes are refrigerant undercharge or leak, reduced airflow or blockage of indoor fan, faulty expansion valve and inefficient or faulty compressor. We would suggest finding a qualified contractor to have the unit and refrigerant system diagnosed properly. The ACCA – which is a national contractor organization have a contractor locator tool which may also help you find a qualified contractor in your area.

      Here’s the link: http://www.acca.org/locator

  9. I hired 2 hvac guys from work to install a new 2 ton unit in my house. This was in addition to my 5 ton that was not sufficient cooling for my 4000 square foot house in FL. The duct lines were grabbed from the bedrooms and rerouted to the new unit. After 2 weeks of operation the unit shut down, the came out and said the would have to evacuate the lines but they don’t have a pump. Should they have done this at install?

  10. We just replaced our AC unit. 3 months later water in the basement due to the pump Not being replaced at the same time by the contractor. Isn’t the pump a significant part of replacing the new unit? Of course now told the pump not included in the warranty because it was not replaced. Should it hv been? The old unit was 17 years old. Thx

  11. W e have an HVAC unit that is 22 years old and finally quit. We have Insurance, but the contractor quoted us over $1400 when the normal fee is only $60. The contractor said it was due to changes in city codes and that he had to replace some of the piping that runs from AC to inside of home and attic unit. How on earth could it be that expensive? Why do we have to pay for all new piping? Why wouldn’t insurance cover these costs?

    • Hi Jodi – most contractors replace the refrigerant lines (piping) when replacing older units because they have to switch to the new refrigerant and oil for the new systems and it is better to start with clean pipes that have no residual oil in them. These lines also fatigue over time at the braze joints so the probability is higher for leaks and losing your whole refrigerant charge later which could be expensive to fix. I hope this helps answer some of your questions.

  12. we have a 1600 sqf house outside temp never exceeds more than 90 DEGREES. Average a/c usage is one mth out of a year. the unit is about 20 years old. I have
    a repair cost of $1200. What is the average labor cost to replace a 3-ton unit. I have asked the couple of repair people, have not got no answer or estimate on the replacement cost. Everyone is willing to repair the old unit. Can you pls advise what is involved in replacing the old unit, of course other than the cost of the unit. The main structure of the house has not changed ever since the old unit was installed.

    • Hi Faisal – typical labor associated with installing a new AC unit includes: removing and disposing of the old unit (including refrigerant reclaim), installing new refrigerant lines running to the indoor unit, brazing the lines, evacuating the lines, recharging with refrigerant, running new wiring if needed and modifying ductwork if needed, among other things. These costs vary from location to location, throughout the season and from job to job depending on the complexities involved. In most cases these can be pretty high – approaching $1,000 unless they are doing a partial replacement. I hope this helps answer some of your questions.

  13. We have moved into a 1600 sf home and have a home warranty on the major appliances. The air conditioner isn’t able to keep the temp at 68 degrees without running almost constantly thru the day. It is cool by morning but not comfortable during daytime. The home warranty people have unstuck a valve and refilled the refrigerant, but the air conditioner is about 15 years old. Should we look into replacing it or keep trying to get them to find something?? Do you recommend air and furnace or just air if the furnace is doing ok…

    • On average HVAC systems in the US are about 14-16 years old when they are replaced. They tend to last a little longer in the north due to the lower AC run hours and heat pumps tend to have shorter lives since they run all year round (heating and cooling). It is a pretty common practice to replace just the AC and keep the furnace. Lately, some people have been keeping their furnace (if it is still in good shape) but upgrading the AC to a higher efficiency (16 SEER or greater) heat pump with at least two steps of capacity modulation. This could provide both comfort and energy benefits over the minimum 13/14 SEER systems. Using the heat pump in the spring and fall seasons should provide additional energy savings over your (gas?) furnace but then you can run the furnace during the coldest parts of the season when the heat pump efficiency goes down with lower ambient temperatures (below around 15F). They also call these systems “dual fuel” systems because you can use gas heat or electric (heat pump) based on the relative prices of gas or electricity. I hope this helps to answer some of your questions.

  14. I have a two story home with a single heat pump. How much should it cost to replace my single heat pump with two units. I have 2700sqft to heat and cool. I was quoted at 15k.

    • Prices vary by geography and by equipment and by installer. The price you referenced would be in line with others we have seen recently but we recommend getting a few different quotes to make sure you are satisfied with the contractor and with your equipment decision – size, capacity, efficiency, etc..

      I hope this helps to answer some of your questions.

  15. My AC runs but the flow of air varies from room to room. Some rooms feel almost as if no air is coming out. It takes an extremely long time for my house to cool down and it never really reaches the temp I want it. I had someone come out and refill the coolant but that didn’t seem to help. Does anyone know what might be the problem?

    • Hi Arturo, one simple thing you might check is to see if all your returns are working. If you have a room with only a cool air supply and no warm air return you would need to keep the door to that room open so the warm air in the room can move back into the hallway or wherever your return vent is located. If the door is closed in a room with no dedicated return it is like you are practically blocking off the supply to that room. The pressure builds up in the room and the cool air is slowed from coming out.

      You can also check for leaks in your ductwork or other blockages. Sometimes people put something on flex duct in an attic or crawl space or there are tears and holes. This can affect air flow through the house. If none of these simple checks work for you it might be best to call a local HVAC contractor to check for other problems. Most of them have tools to measure airflow and blower operation.

      I hope this helps.

    • Hi Gloria – depending on the size of the coil, your location and the other parts you might need to change this could cost between ~$1,000 and $1,500+ for material and labor to install. We also recommend getting 2-3 quotes from different contractors before deciding. I hope this helps to answer some of your questions.

  16. Hi Wanda – Our homeowner research suggests that the typical, U.S. style central AC systems are replaced when they are, on average about 14 years old. This age can vary due to climate and run times i.e. units in the south and heat pumps get replaced sooner due to longer run times experienced in each season. Repairs for an 8 year old system are not uncommon but you might ask the contractor if you can just replace the reversing valve instead of the whole outdoor unit. We also recommend getting 2-3 quotes from different contractors before deciding. I hope this helps to answer some of your questions.

  17. My home and AC unit are almost 8 years old. My home has 2 units 1 each for upstairs and downstairs. I’ve already had to replace the coil on the upstairs unit (900.00) and now i”ve been told that on the reversing valve is stuck in the middle and my unit needs to be replaced. Is this normal, so early in the life of an AC? Of course my home warranty doesn’t cover valves.

  18. I just had a new heating/air conditioning unit replace a day ago; should the tech have replaced the heating coil at the same time? He said that it may have to be replaced at a later if needed. If this is a brand new installation, should everything have been replaced. He left no instructions in writing,nor did he show me the manual. When he left, I found the instruction packet in the yard. When installing the new unit, is the refrigerant included in the entire package? Last question, should he have asked me if I wanted to keep the old unit to scrap it or do they normally take it with them?

    • Hi Beverly – Here are my thoughts on your questions. It sounds like you have a heat pump system (that also works like an air conditioner in the summer) and had the outdoor unit replaced and did not replace the old indoor coil and air handler. My answers assume that is the case – if something else was done, please provide a little more information and I will try to answer later.

      It is fairly common to replace just the outdoor unit of an air conditioner or heat pump and leave the indoor coil and air handler if it is functioning ok and not too old. As long as your old and new unit used the same refrigerant there should not be a problem. If the refrigerant in the new outdoor unit was upgraded to a different refrigerant then there are a few additional steps that need to be done by the contractor but that approach is still pretty common as well.

      If he just changed the outdoor unit there should not be any change in the way you operate your system – it should work the same as before but reading the instructions and keeping them handy would be a good thing to do.

      Refrigerant charging or re-charging would probably have been included in the service charge as the system would not run without it.

      Most contractors include disposal of your old unit in the cost of the job unless you tell them you want to keep it for some reason. Most people just let the contractors take care of the disposal process. Some scrap dealers want the parts separated into various components – copper, steel, aluminum, etc and if you take it to a scrap dealer yourself they might not accept it – plus you have to haul it there and all. Most people just let the contractor handle it. I hope this answers your questions.

      • I hate when they take it without asking. Are you telling me they charge to take it? I hope not they should give a discount for taking it cuz its worth money

        • Hi Kato – You can ask a contractor about that but again, it is often not easy for a person to get it to the scrap dealer and sometimes the dealers charge because it has all the metals mixed up and they have to tear them apart to separate. It is always good to ask though. The contractor should be able to explain your options.

  19. Iam having my old furnace and ac replaced its from 1998.My new furnace and ac are being installed today.But my contractor is using my old copper lines for the ac?Should he replace them or wash them out .Before he hooks it up?

    • You can ask to have the copper lines replaced but it will probably cost more especially if they are difficult to access. The risk from not replacing them is basically leaks – probably at the braze joints or bends. If you keep the old lines they should be cleaned and flushed before recharging with new refrigerant. You should probably ask the contractor about this.

  20. Hi Jon – Here are a few thoughts. Our recent survey data indicates that on average, US consumers replace their HVAC systems when they are about 14 to 16 years old depending on where you are located and how many hours it runs each year (i.e. shorter life for a heat pump in the south running year round). So, at 10 to 12 years old, your system could be coming up on its useful life expectancy. Reasons for replacing it could also include likely energy savings as you upgrade to the new minimum efficiency standards as well as an upgrade to the latest refrigerant (if you have R22 now it might be more difficult to repair your old unit in the future as that refrigerant is being phased out by the EPA). This would be in addition to the home selling feature of having a brand new HVAC system.

    You could also be seeing some utility and other state/local rebates for going with a higher efficiency model than just the minimum, which is now 14 SEER in SC. One site we recommend for checking rebates is http://www.dsireusa.org/ and your contractor should be able to help you with this as well.

    On the geothermal option, the payback could be a little longer than you are expecting even after the rebates but the energy savings can be significant so it might be worth considering. In any case, we usually recommend getting 2-3 quotes from different contractors for each system type before deciding. Good luck with your HVAC project!

  21. Hi, the heating coil (replacement quoted at $1400) on my HVAC unit is cracked & needs replacing. We replaced the circuit board about 2yrs ago as well. So we are faced with replacing the whole unit ($4200 total for a Payne unit) or just the coil.

    We live in Greenville, SC & plan to move in the next year…so we don’t know which is a better decision; replace the part & wish the new owner the best or replace the whole unit & advertise that when selling our house & try to get the money back in the sale of the house? The house is in the $115,000 range, and it’s roughly 1600 sq ft. The unit that is breaking down is about 10-12yrs old.

    Also, should we look into geothermal units because of the tax breaks? Are there any tax breaks for replacing a HVAC unit? Sorry for all the questions, but we’re (like most people) in a pretty tight spot financially. Thank u

  22. I want to install a centrally controlled unit to regulate the 6 individual rooms in my house. This unit should be able to separately control the temperature of each room as well as when to turn on and off the existing heaters. Is it possible? What is the cost estimate to install such unit?

    • Hi Anthony. There are several ways to centrally control individual rooms. If you already have a ducted system (or room for new ductwork) you can install a central HVAC system with automatic duct controls that regulate the amount of conditioned air that goes into each room and this can be done with centralized control. If you use this method I would recommend getting a system with at least two steps of capacity control to allow you maintain effective temperature and humidity control in both a smaller space (many rooms closed off) or the larger space (all open). If you are planning for wide capacity variations you might be better off with a fully variable speed system which allows for that sort of capacity demand flexibility.

      Another way to achieve room by room control is with ductless mini-splits or “mulit-split” systems. However, these units are usually limited to about three separate indoor evaporator units (mounted on the walls in the space to be cooled). With this arrangement you would only have three separately controlled spaces – not six. You could install two units with three each but I do not think you would not have centralized control on all six rooms unless they have come up with a way to link them together to a central controller.

      A third way to achieve six separate zones is with ductless variable refrigerant flow system (VRF) that can handle multiple room evaporators with one, central outdoor unit. These units are used mostly in commercial buildings in the US but are also available for residential applications as well. Our research has shown that these systems tend to be more expensive than either ductless multi-splits or ducted, central HVAC systems.

      There is a lot of information in the articles and posts on this site that deal with the tradeoffs of these systems so you might want to spend some time with that material. We usually recommend getting at least 3 quotes from qualified HVAC contractors for each of the systems you are considering before deciding on a new system since some of these businesses tend to specialize in one or the other. Also, depending on the climate in your area you might want to talk to the contractors about issues related to humidity control, air flow, air filtration, winter heating, and other factors which can be affected by the type of system you choose. Our policies on this site do not allow us to recommend any particular brand of equipment or service provider but you can probably perform an internet search on some of the system types mentioned above to do more research. Good luck with your HVAC project!

  23. I have a window AC unit that needs to be recharged. Can I buy the freon someplace and do this myself? If so, where can I find the freon kit?

      • No, you cannot buy a kit. It is possible to add refrigerant to a window unit, but only by a qualified professional. I would recommend cleaning the condenser coil, and making sure the evaporator filter is clean.

  24. I have a Ge air conditioner its blows out very cold air, however it is making a loud noise. Any suggestions about what it could be.

    • Hi Rebecca. It is difficult to tell much from this without knowing the type of AC you have (window or central) but here is a link to an article on this site with some basic information about normal versus abnormal noise in central type AC systems. http://www.ac-heatingconnect.com/sound-advice-about-air-conditioner-noise/

  25. It is difficult to comment on prices for a particular job without knowing the specifics and our policy on this site is not to comment on prices anyway. However, this site does recommend getting quotes or opinions on your particular solution from at least 3 differecnt qualified contractors before you make your HVAC investment decisions. This is especially true on problem jobs or expensive ones.

  26. I have a question: An AC repairman quoted a price of $1148 to install a drain flood safety switch and replace receptor contacts on my air conditioning unit. It is located in the attic of my home. This seems terribly high and beyond my budget.

    Is there a less expensive way to take care of these two items and how do I know that I’m not being taken for a ride?

  27. What about refrigerants? ie r22 and so on? How do I know that they’re being properly disposed of when I go out and get a new AC unit?

    • Most HVAC contractors know they should not just “vent” old refrigerant to the atmosphere and now there is even more incentive for them to “reclaim” the old refrigerant because the old R22 refrigerant is not being made for sale in the US anymore so if you want to use it for replacement/recharging on an old R22 system you need to “reclaim” it from other old systems. Consequently the price has gone up so there are incentives for contractors to capture the old refrigerant when they do a replacements. I hope this helps. BTW, there are some articles on this site about refrigerants – you can use the keyword search tool. Thanks for visiting our site!

Let us know your thoughts

Your email address will not be published. Required fields are marked *