Central Air Conditioning Units: 7 Easy Maintenance Tips

To be honest, I have a love-hate relationship with our central air conditioning unit. That is to say, I love the central air conditioner when it's hot outside and fills the house with refreshing, cool air, but hate it when it's hot outside and quits working.


Simple ways to keep your central air conitioner running efficiently

As a homeowner for more than twenty years I have had a few repairs done on the central air conditioner that we rely on so heavily during the summer months. This much I know without a doubt, it's far cheaper to maintain this appliance on a regular basis than it is to repair or replace it.

In fact, Carrier, a leading manufacturer of air conditioners, states:

Proper air conditioning maintenance can help your unit last decades. On the flip-side, a neglected air conditioner loses roughly 5% of its efficiency each year that it operates without upkeep.

Fortunately, there are some very simple things that any homeowner can do to keep their A/C unit running efficiently and perhaps even less often throughout the warm months.

A/C unit needs room for airflow

Trim plants away from air conditioning unit
Trim plants away from air conditioning unit | Source
These plants need to be trimmed around A/C
These plants need to be trimmed around A/C | Source

1. Keeps plants cut back around unit

Let's face it, outdoor air conditioning condensers are ugly and it seems that homeowners will do their best to hide them from sight. Plants, fences and trellises tend to be popular ways to go about doing this cover-up.

Yet, air conditioners need an adequate amount of air flow around all sides in order to perform at peak efficiency. This is why experts recommend that landscaping and other objects be placed about three feet away from the unit itself.

Cleaning up leaves and other debris on a regular basis, as well as trimming or cutting back bushes, trees and other plants all help increase the air that your unit needs to draw into its system.

2. Wash pollen and other debris off condenser unit

If your outdoor air condenser unit is in an unnoticeable location, it's very easy to forget about cleaning it regularly. But you don't want to neglect this very easy chore. The condenser pulls in air, and when it does, pollen and other debris often cling to its exterior. This will restrict airflow and cause a decrease in cooling efficiency and perhaps even cause the unit to overheat.

The solution...

Pull out your garden hose and with a hard stream of water, working top to bottom, hose off each side of the condenser.

Pollen like cottonwood can easily accumulate on the A/C, blocking airflow
Pollen like cottonwood can easily accumulate on the A/C, blocking airflow | Source

Closed registers can freeze A/C coils

Keep registers open or partially open
Keep registers open or partially open | Source
Do not completely close registers
Do not completely close registers | Source

3. Do not close any registers completely

With a two-story house the upper level is often warmer than the lower level even with the central air running. This is the case with our home, and knowing that hot air rises and cool air falls I figured I could easily balance the air temperature by adjusting the register (air vent) openings.

The mistake:

It is true that closing some registers on the cooler lower level forces more air out of the registers upstairs. The cooler air then works its way downstairs and the air temperature becomes more even throughout the house. However, by doing this the air conditioning unit may completely shut off!

In fact, when I totally closed some lower level registers, the coils in the unit froze and the A/C quit functioning. Luckily, by shutting off the entire cooling system and giving the coils time to thaw, the A/C was up and running again within a few hours.

The lesson:

Do not completely close registers. To balance the air temperature, registers can be slightly closed, but do not close them completely. (It took me two times to learn this lesson.) Additionally, make sure supply vents are not blocked.

4. Change the filter regularly

Maintaining a central air conditioning unit is all about maintaining airflow. That is why it is important to regularly change the air filter on the system. Filter packages usually state a recommended schedule for replacement (i.e. every 90 days or so) but it really depends more on how much the unit is running and how dirty the air is. During hot months it may be beneficial to change the air filter more frequently. The process is often as simple as sliding the old filter out and sliding in the new one.

According to Trane air conditioner manufacturers,

...regular cleaning/changing of your filter will ensure the best filtration, increase the life of your machine, and give you peace of mind that you’re breathing easier.

Remove dirty filters regularly to ensure proper airflow to air conditioner
Remove dirty filters regularly to ensure proper airflow to air conditioner | Source

5. Set temperatures in a programmable thermostat

It stands to reason that the less the air conditioner is actually in use, the less wear and tear it endures. For anyone with a programmable thermostat, setting the temperature by day and time is a good way to reduce the unit's overall usage.

For example, we set our temperature higher during the daytime and colder during the hours when we sleep. It's far more efficient to program in desired temperatures than it is to shut the unit off completely and then turn it on after a day of work.

6. Keep the sun out

Another excellent way to keep the air conditioner from needing to run as often is to block the sun during the hottest part of the day. During the hours when the sun shines in the most, blinds or drapes should be closed. This way the home's interior temperature will not rise as much. Additionally, consider planting trees or installing awnings to diffuse some of the sunlight.

Filter out the sun with blinds, drapes, and even shrubs and trees
Filter out the sun with blinds, drapes, and even shrubs and trees | Source

7. Get a professional inspection and cleaning done annually

Before each cooling season it is a great idea to get a regular maintenance check and cleaning done on the unit by an HVAC professional. Service professionals usually inspect the control box; coils; fan motor and blades; and compressor and tubing; among other things. Additionally, refrigerant levels are inspected and adjusted if necessary, and the unit cleaned.

As the old saying goes, an ounce of prevention is worth a pound of cure. If you've ever had your central air conditioner quit working on the hottest day of the year, you fully understand that preventative A/C maintenance is definitely preferable to repairing or replacing it due to neglect.

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Comments 66 comments

Victoria Lynn profile image

Victoria Lynn 4 years ago from Arkansas, USA

Such a useful hub! I need to open up some of those registers a bit; some are completely closed off. Great tips. I don't know the last time my unit was inspected. Is that expensive? But worth it, I'm sure. You write such informative, helpful hubs. Thanks!

ktrapp profile image

ktrapp 4 years ago from Illinois Author

Thanks Victoria. Not only can closed registers cause the coils to freeze, so can low freon. Freon levels is one thing that is checked in an annual maintenance and must be done by a professional. Obviously the cost of an annual inspection varies, but it is usually in the neighborhood of $100. Some companies offer packages to come out once before the cooling season and once before the heating season at a discounted price. But when it comes to a central air conditioner, small repairs can prevent costlier problems from occurring. It's definitely worth it in the long run.

MarleneB profile image

MarleneB 4 years ago from Northern California, USA

This is very helpful information. My husband does all the maintenance around the house; I never really paid much attention to what he does. But, I have learned after reading your hub, I need to open up a few registers.

ktrapp profile image

ktrapp 4 years ago from Illinois Author

MarleneB - Glad to have been able to help.

mts1098 profile image

mts1098 4 years ago from InsideTheManCave

Glad I read this as the summer season is beginning to heat up...I change the filters every two years but I think I have to go and trim the surroundings...thanks and cheers...

ktrapp profile image

ktrapp 4 years ago from Illinois Author

Oh no mts1098. I think you need to leave your man cave (that is where you said you lived in your profile, right?) and head out to the store to get some filters. Changing them every two years is way too long. It should be closer to every 90 days. (Maybe you meant to write two months.) Anyway, it's real important to trim back plants around the air conditioner too - anything to improve airflow is what's needed.

randomcreative profile image

randomcreative 4 years ago from Milwaukee, Wisconsin

Great topic for a hub! I will definitely take some of these suggestions into consideration!

Victoria Lynn profile image

Victoria Lynn 4 years ago from Arkansas, USA

I opened up my closed vents, today, if not all the way open! thanks for the valuable information!

ktrapp profile image

ktrapp 4 years ago from Illinois Author

Thanks randomcreative. All of these suggestions are quick and easy, so it makes sense for homeowners to do them and extend the life of their air conditioners.

ktrapp profile image

ktrapp 4 years ago from Illinois Author

Thanks for letting me know Victoria. If you find the air temp is too uneven from room-to-room or perhaps from downstairs to upstairs you can balance the registers by closing some a little bit. There's good information out there on how to balance registers (easy to do).

Victoria Lynn profile image

Victoria Lynn 4 years ago from Arkansas, USA

ktrapp, In the rooms I don't use a lot, I just opened them up a little bit to let some air flow through. Think that's okay?

ktrapp profile image

ktrapp 4 years ago from Illinois Author

I guess it really depends more or less on the percentage that is closed throughout the house. Heating and air conditioning systems need that air flow to operate efficiently and to extend the longevity of either the furnace or the air conditioner. So you have to be careful when closing the supply registers. I have seen where some professionals say it's OK to close 20% of the airflow off and others say not to do it at all since there are risks involved.

catgypsy profile image

catgypsy 4 years ago from the South

Excellent hub ktrapp. I do all of these things, but it reminded me that I need to go wash it off and trim some weeds away from it! Thanks!

ktrapp profile image

ktrapp 4 years ago from Illinois Author

Thanks catgypsy. You should definitely clean up around your A/C.

Simone Smith profile image

Simone Smith 4 years ago from San Francisco

What a thorough, useful, practical, clearly-written guide! This is SO helpful! I love the original photos, and really appreciate the tips. Most of those would not have been at ALL obvious to me, so should I ever find myself living in a house with central air conditioning, you'll have saved me a lot of trouble!

ktrapp profile image

ktrapp 4 years ago from Illinois Author

Thanks Simone. A lot of these tips fall under the category of "live and learn." Air conditioner and furnace repairs can be pretty costly, and being without either isn't too pleasant either.

moonlake profile image

moonlake 4 years ago from America

Lots of good information. I love our central air. People hearsay it's crazy to have it but I don't think so, we have never been sorry we put it in. If we need it fixed we call our son. He's a has a heating and air business. Voted up on your hub.

ktrapp profile image

ktrapp 4 years ago from Illinois Author

How wonderful for you, moonlake, that your son has a heating and air conditioner business. I don't think you're crazy to have central A/C; when it's hot it's nice to be able to cool off indoors. Thanks for commenting and voting.

Cre8tor profile image

Cre8tor 4 years ago from Ohio

Congrats on HOTD ktrapp!

myownlife profile image

myownlife 4 years ago from london

its really a useful tips of each and every one. Great job

ytsenoh profile image

ytsenoh 4 years ago from Louisiana, Idaho, Kauai, Nebraska, South Dakota, Missouri

Excellent hub! Great step by step instruction guide in how to care for your AC unit. Thanks.

ktrapp profile image

ktrapp 4 years ago from Illinois Author

Cre8tor - Thanks so much. You've got the most helpful hubs on this topic too.

myownlife - Glad you found each of the tips to be useful.

ytsenoh - Nice to know you found this to be an excellent guide. I appreciate you letting me know that.

kelleyward 4 years ago

Awesome Hub Ktrapp! Thanks for the useful information on this subject! Congrats on winning HOTD!!! Take care, Kelley

ktrapp profile image

ktrapp 4 years ago from Illinois Author

Thanks Kelley. It's so easy to forget to do some of these tasks (out of sight, out of mind), so I'm glad you found this useful.

Happyboomernurse profile image

Happyboomernurse 4 years ago from South Carolina

Great tips to keep central air conditioners running and lasting longer through regular maintenance. Most I knew and already do but some I didn't, like the importance of hosing off the pollen and debris around the unit.

Congrats on earning Hub of the Day for this excellent article.

Voted up, useful and interesting.

kthix10 profile image

kthix10 4 years ago from IL

Thanks for the tips - some of them we already did but I really do need to clean the filter. We have duct work in the floors and ceiling of our one level house and I do have some blocked because I am not sure if they are part of the system or not - I really need to have a profession tell me about it

VirginiaLynne profile image

VirginiaLynne 4 years ago from United States

Good information. I do copywriting for a number of HVAC companies and have written on this subject before, but not for Hubpages. It is also important to look into the type of MERV filter you use because some need to be cleaned more often and reduce efficiency. Another thing to consider is that sometimes replacement is cost effective if your unit is older (10 yrs or so) because the older units used so much more electricity. Congrats on Hub of the Day!

Victoria Lynn profile image

Victoria Lynn 4 years ago from Arkansas, USA

You are the Hub of the Day Queen, ktrapp! Congratulations, once again!

joaniebaby profile image

joaniebaby 4 years ago

Great Hub. I didn't even realize an A/C unit had a filter. We always clean our furnace filter. Is this the one the A/C uses, or is there another one in the A/C unit itself? Thanks for the info.

ktrapp profile image

ktrapp 4 years ago from Illinois Author

Thanks happyboomernurse. The pollen can get really bad if left unchecked. I didn't put a photo of the back side of the condenser up, but it was completely covered in pollen from just a couple months of spring. It's funny, but when I've watered neighbors' outdoor plants while they are on vacation, I have also hosed off a few dirty A/C units; clearly they had no idea they should do this - no charge of course :) Thanks for the nice comment and votes.

ktrapp profile image

ktrapp 4 years ago from Illinois Author

kthix10 - While I'm not an HVAC professional (see cre8tor who commented a few above this - he has incredibly helpful hubs since he's in the biz) you might want to open the supply vents and with the air conditioner running see if you feel any air flow. Where you have return vents (the ones that pull the warm air out of the room in the summer and cold in the winter) hold a piece of paper up to it when the A/C is on and see if it "sticks" to it from the draw of air. If those things happen then those rooms are part of the system. But I would have a professional do a quick inspection if I were you.

ktrapp profile image

ktrapp 4 years ago from Illinois Author

VirginiaLynne - I really appreciate the added information learned from your HVAC copywriting experience. Due to the cost, I have always dreaded when the day comes to replace the entire A/C unit, but you make an excellent point about electricity usage on older units.

ktrapp profile image

ktrapp 4 years ago from Illinois Author

That's funny Victoria Lynn. Thanks for stopping by this hub again.

stephhicks68 profile image

stephhicks68 4 years ago from Bend, Oregon

Great hub, Kristin! Very simple, easy to follow steps to keep the A/C running throughout the summer, without having to call maintenance or - heaven forbid - buy a new central air conditioning unit. Congratulations on HOTD! Best, Steph

ktrapp profile image

ktrapp 4 years ago from Illinois Author

joaniebaby - Our filter for our furnace and air conditioner are one and the same which is probably the case with yours since the two systems would share the same duct work throughout the house. So you probably should change it soon if you haven't in awhile. I'm glad this was info. you could use.

ktrapp profile image

ktrapp 4 years ago from Illinois Author

Thanks Steph. I'm doing everything in my power to extend the life of my air conditioner as I dread the cost of a new one. I believe our unit is about 14 years old now. I bet you might know a thing or two about "greener" air conditioners - is there such a thing?

TheMagician profile image

TheMagician 4 years ago from Tampa, FL

Wow, tons of great information that I never knew about! This will definitely come in handy. Thanks! Voted up and useful :)

ktrapp profile image

ktrapp 4 years ago from Illinois Author

I'm glad this is handy information for you, TheMagician. Thanks for letting me know.

Kristine Manley profile image

Kristine Manley 4 years ago from Atlanta, GA

What useful information. I did not know that I could hose down the condenser unit and I will be doing this. Thanks.

ktrapp profile image

ktrapp 4 years ago from Illinois Author

Kristine - It's perfectly fine to hose off the outside of the unit. After all, it gets wet in the rain, but you probably shouldn't spray the inside. Perhaps leave that cleaning to professionals if it's even necessary.

coffeegginmyrice profile image

coffeegginmyrice 4 years ago from Toronto, Ontario

Wonderful tips to keep in mind. Congratulations, ktrapp! I love the dog by the window, nice photo!

ktrapp profile image

ktrapp 4 years ago from Illinois Author

coffeegginmyrice - Thank you and I'm glad you liked my dog; I have to include her every now and then since she is my ever-present writing partner.

jpcmc profile image

jpcmc 4 years ago from Quezon CIty, Phlippines

Proper maintenance will definitely give you better output - plus less trouble in the future. Simple steps make it easy!

sammimills profile image

sammimills 4 years ago from California, USA

Very informative and useful hub! I learned and discovered a lot. Congrats on being LOTD! Deserving.

ktrapp profile image

ktrapp 4 years ago from Illinois Author

jpcmc - And better output is a money-saver all around.

ktrapp profile image

ktrapp 4 years ago from Illinois Author

sammimills - I'm glad I could help and thanks so much.

rebeccamealey profile image

rebeccamealey 4 years ago from Northeastern Georgia, USA

Great Hub to keep up to date on cooling our homes efficiently this Summer. It is extremely helpful! Congratulations!

urmilashukla23 profile image

urmilashukla23 4 years ago from Rancho Cucamonga,CA, USA

Great central air maintenance tips. Helpful and voted up.

Congratulations on Hub of the day award!

ktrapp profile image

ktrapp 4 years ago from Illinois Author

Rebecca - I'm glad to know these air conditioner maintenance tips were helpful. Thanks for letting me know.

ktrapp profile image

ktrapp 4 years ago from Illinois Author

Thanks urmilashukla23. How nice of you to read, vote, and take the time to let me know that these A/C tips are helpful.

Ardie profile image

Ardie 4 years ago from Neverland

This is JUST what I need right now. The hot weather is right around the corner for us. I dislike spending a ton of money for someone to maintain my central AC when I've watched my dad do it to his own for free since I was small. Thanks for the tips!!

ktrapp profile image

ktrapp 4 years ago from Illinois Author

Ardie - I know exactly what you mean. My dad fixed everything, appliances, cars,televisions - heck, he even built the house. I cannot recall ever having one single repairman or contractor out to the house when I was a kid. So it is hard to pay when you know that with some know-how the job can be done for free labor. That's why it's nice to try to avoid costly repairs with a little bit of maintenance.

skylergreene profile image

skylergreene 4 years ago

So not surprised that you got Hub of the Day again. Hats off to you -- this really is an awesome and useful Hub. I change the filters regularly and wash the condenser off every so often, but I didn't know it was beneficial to trim plants.

ktrapp profile image

ktrapp 4 years ago from Illinois Author

Thanks Skyler. This was in response to a weekly topic inspiration which happened to coincide with some much needed A/C maintenance that I needed to do. I still need to edge and mulch around that condenser unit - such is the life of a homeowner. This certainly is one appliance you don't want to go on the fritz in your neck of the woods around Dallas. I lived there for a few years and remember all too well how incredibly hot it gets there day after day.

RTalloni profile image

RTalloni 4 years ago from the short journey

Congrats on your Hub of the Day award for a hub that will be helpful to many people!

ktrapp profile image

ktrapp 4 years ago from Illinois Author

Thanks RTalloni. I do hope this is helpful to a lot of people.

abdul ghaffar 4 years ago

good information about air conditioning please add current problems and remedy thanks abdul ghaffar from faisalabad pakistan

Howard S. profile image

Howard S. 4 years ago from Dallas, Texas, and Asia

A couple of weeks ago I noticed a problem with the drains from my indoor cooling coil pan. It's happened before and I fixed it, but I either don't remember how or it's not working. The secondary is only supposed to drain when the primary clogs. They're both dripping--and I've tried blowing out the primary. I guess I'll have to open the cooling coil unit itself and study it from that end. It probably needs cleaning anyway.

(BTW, I denied a similar spam link from @Mike on my hub.)

ktrapp profile image

ktrapp 4 years ago from Illinois Author

Hi Howard. Well you sound more capable when it comes to actual air conditioner repairs than I ever will be. Check out cre8tor. He works in HVAC and has terrific hubs of this nature.

furniturez profile image

furniturez 4 years ago from Washington

Definitely important to keep the central air clean of debris and shrubs/plants surrounding it trimmed down to a reasonable level... I learned this the hard way!

Armchair Builder profile image

Armchair Builder 4 years ago from Hawaii

Nice hub. I would also add...make sure the unit is level on the exterior of you home. Some of the new models are installed on brackets that attach to the foundation. However, the older ones need to be leveled. I walked by one that was out of level in my neighborhood the other day and it was making a horrible sound...not good.

Dolores Monet profile image

Dolores Monet 3 years ago from East Coast, United States

Thanks for the simple tips to keep that AC in good working order. The pollen around here can be heavy at times, and I just don't think of hosing it off. Will do next spring!

ktrapp profile image

ktrapp 3 years ago from Illinois Author

Dolores - Hosing the pollen off your AC unit is a really simple thing to do to help keep it running smoothly and efficiently. You will probably want to do this a few times during the spring when the pollen is probably at its peak.

vespawoolf profile image

vespawoolf 3 years ago from Peru, South America

Wow, I don't know how I missed this one. Congrats on the HOTD you won for it. This is certainly chock full of useful information. A little maintenance sure does go a long way, even on air conditioning units.

Amelia Brose profile image

Amelia Brose 2 years ago from Carlton, Victoria, Australia

Thanks for the great content! This information is very accurate and informative

Steve 17 months ago

Today my wife and I put down fill dirt on the north side of house and mulch on top to absorb rain water. We put dirt and mulch right up to the pad the air conditioner condenser sits on, the system still has airflow on all sides. Does anyone know if this is ok?

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