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50 Expert Quotes About Common AC Installation Mistakes

50 Expert Quotes About Common AC Installation Mistakes

Air conditioning is an important and pricey component of your home’s HVAC system. Therefore, ensuring correct AC installation offers homeowners peace of mind. As a result, we rounded up 50 expert tips and quotes about common AC installation mistakes to avoid. We hope these tips help ensure the job is done right the first time!

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1. Choosing a company that does not have NATE-certified technicians.

“Consumers can rest assured that with a NATE-certified technician, they are getting the best installation and service for maximum comfort and economy in their heating and cooling system. Better installation and service mean longer life for your heating and cooling equipment and increased energy efficiency.” – Why Should I Choose a Contractor with NATE-Certified Technicians?, North American Technician Excellence (NATE); Twitter: @NATEtechnicians

2. The ceiling saver kit is missing.

“Drip pans are responsible for collecting water that forms through condensation, another process necessary for successful air conditioning. When this small supply of water has no exit route, it collects inside of the home and the air conditioner itself. Be sure to ask your HVAC technician to supply and test a secondary drip pan, which we call a “ceiling saver kit”, to prevent any potential for water damage.” – Common Mistakes Found in AC Installations, Service Champions Heating & Air Conditioning; Twitter: @ServiceChampsS

3. Not working with a bonded company.

“A contract license surety bond is needed as a precaution against unfair dealings as well as a kind of financial insurance in case something with the agreement goes wrong.” – Svetlana Guineva, 6 Tips on Choosing a HVAC Contractor,; Twitter: @BuildingsMedia

4. Installing refrigerant pipes that are too long.

“The pipes that connect the indoor and outdoor units of a central AC should be kept short. If an inexperienced installer puts in pipes that are too long, it will make it difficult for the air conditioner to complete the cooling cycle. This will lead to a compressor that runs continually, draining energy and rapidly wearing itself down.” – 4 Common AC Installation Mistakes Amateurs Make, Malek Heating & Cooling; Twitter: @MalekHVAC

5. Not having the correct permits in place.

“Most companies will file permits on your behalf at the local building codes office. But don’t assume that it has happened. Check with the permitting office first. Work done without proper permits could result in a fine and time delay.” – How to Choose an HVAC Company,; Twitter: @NewsInTheBurg

6. Not enough consideration to airflow.

“Airflow plays a major role in the installation of air ducts. Contractors who don’t take airflow into consideration during air duct installation fail to ensure a correctly sized system.” – Is Your HVAC Contractor A Hack?, On Time Experts; Twitter: @TheOnTimeExpert

7. Not having a contract in place before work begins.

“Important details to ask for in writing are the dates on which the work will be performed, the cost of all fees, labor, and equipment, potential future fees such as upgrades, and payment due dates.” – How to Choose a HVAC Contractor, WikiHow; Twitter: @wikiHow

8. Leaving your AC installation to your contractor.

“Many times you’re installing air conditioning as part of a larger renovation project. If that’s the case, make sure your building contractor is bringing in a qualified HVAC company for installing the air conditioning. Your air conditioning is a complex system that needs to be installed and configured by trained experts. A qualified HVAC installer who understands both the equipment and your needs will adjust and tune the system according to the manufacturer’s specifications and the requirements of your space.”– Michael C. Rosone, Installing Air Conditioning? Don’t Make These 5 Mistakes, Arista; Twitter: @AristaAir

9. Your thermostat is in a bad position.

“If the sun or a nearby lamp blasts your thermostat for big chunks of the day, that could throw off its readings and cause it to crank your AC even though your place is pleasantly cool. Especially if you’re away during the day, you may not realize your system is working overtime due to a misplaced thermostat, Braun says.” – Markham Heid, 8 Big Mistakes You’re Making With Your Air Conditioner, TIME; Twitter: @TIME

10. Not removing the drip pan for vertical installations.

“Because this would add an additional step to the air conditioner installation process, the vast majority of A/C installers just don’t do it. Leaving this pan in the unit can cause a reduction of airflow up to 2% causing the system efficiency to drop by about 1%.” – Nathan Orr, Common Air Conditioning Installation Mistakes That Could Cost You $3500, Kalos Services; Twitter: @KalosServices

11. Not spelling out payment terms clearly.

“Stagger payments and tie them to specific stages of the project, so you can hold back if the work is progressing slowly, and outline this payment schedule in the contract.” – Rachel Wray Thompson, How to Work With a Contractor and Not Get Ripped Off, Apartment Therapy; Twitter: @AptTherapy

12. Installing the wrong drainage system.

“If this water is not drained safely and effectively, it can spill over to other components and cause damage. The drain system design flaw is a mistake that is commonly made by the armature installation contractors, but can cost you a lot of money.” – 3 Of The Most Costly AC Installation Mistakes You Can Avoid By Hiring Qualified Professionals, Crystal Air and Water, Inc.; Facebook

13. Improper insulation on your indoor tubing.

“Tubing that is not insulated properly “sweats,” leading to dripping and water damage during the use of the air conditioner. Floors and walls can become warped and stained. By the time you notice, you may have a costly repair bill to pay. It’s worth it to thoroughly check everything both inside and outside once the split air conditioner installation is over.” – Split Air Conditioner Installation: Mistakes to Avoid, Do It Yourself; Twitter: @DoItYourselfcom

14. Blocked return vents.

“In some older homes, you may find return air vents in closets and other out-of-sight places where they often end up covered up with boxes or furniture. When return air supply is restricted, the blower fan will try harder to pull the air in, which may shorten its lifespan significantly.”– 3 COMMON HVAC INSTALLATION MISTAKES TO AVOID, Cool Breeze; Twitter: @CoolBreezeMD

15. Poorly installed electrical wiring.

“If the installation professional is not too experienced, then he could easily do sloppy wiring work which may not only prove risky but may even create faults in the working of the unit. Make sure there are no exposed wires as well.” – Shipra Mangla, 5 most common AC installation mistakes to be informed about, Ideas by Mr Right; Twitter: @MrRightIndia

16. Installing your air conditioning in a poor position.

“The location of your air conditioner has a big impact on its energy efficiency. While it may seem convenient to put your bulky HVAC system in an unused corner on the west side of the house, that placement will force the machine to work harder to cool your home. Instead, find a shady spot to put the air conditioner; the less direct sunlight it gets, the less power it will need to cool your home.” – 10 Air Conditioning Mistakes to Avoid, AC South East; Twitter: @ACSouthEast

17. Not installing the correct sized unit.

“The primary consideration when deciding what size to buy would be the area and the number of people using the room. First, you must determine the area in your house which you want to be cooled. This should determine how much power you need. Your room area should match the BTU or the British thermal unit value and the strength (capacity) of your air conditioning (ac) unit. It becomes a recommending guideline that a cooling capacity of 2000 BTU be required for every space of 50 square meters.” – Tom Pittenger, Six (6) Common Factors To Consider When Installing Air Conditioning Units, EzineArticles; Twitter: @EzineArticles

18. Not using a qualified technician for your installation.

“A lot of businesses advertise that they install A/C’s but are not licensed to do so. If your A/C is not installed by a licensed technician it can void your Manufacturer’s Warranty.” – Worst Air Conditioner Installation Mistakes, K&J Burns; Facebook

19. Not properly sealing the ductwork.

“When the ducts are not properly sealed, the chance a leak may occur at any time is bigger. Most installers use low quality products, and they also cut corners when installing the duct system. This will eventually lead to many issues, which are very expensive to fix. Make sure you hire a reputable AC contractor in order to get the most out of your AC installation project.” – Top Common AC Installation Mistakes, Futch Heating and Air Conditioning; Twitter: @kanimol42

20. Not questioning a deal that’s too good to be true.

“Make sure that company isn’t cutting corners just to get the work and always get two prices. It costs a lot of money to buy and install the best equipment and hire quality installers. Be sure the company you choose is not using second-rate equipment or taking shortcuts. Always ask for a step by step explanation of how the installation will be done.” – 5 BIG Mistakes Homeowners Make When Replacing Their Heating and A/C Systems, Horizon Services; Twitter: @HorizonServices

21. Not checking the system for leaks.

“When doing aircon installation it’s important to check for the level of coolant or Freon level in the aircon system. Any leakage can cause many health problems, and only 10 percent loss of Freon or coolant can result in 20 percent extra electricity bills. Many times installers don’t check for leakage because they think it’s a new aircon system, but sometimes system is damaged during installation, which can cause leakage.” – 7 Common Aircon Installation Mistakes To Avoid, Aircon Servicing; Twitter: @irconservicesg

22. Running your air conditioning all day long.

“Have your HVAC company install a programmable thermostat or unit timer to turn the system off when you leave and on just before you return home. This will help save on energy bills and maximize your air conditioning system’s efficiency.” – 4 Common Air Conditioning Mistakes, B.M.C./Clower; Facebook

23. Using the wrong piping size and connections.

“Some individuals fail to use the correct diameter of refrigeration piping when running it long distances, which decreases system performance and efficiency. When installing refrigeration lines, make sure you have the correct size line based on the length of run.” – Common Mistakes Made While Installing an AC or Heat Pump System And How to Easily Avoid Them, Alpine Home Air; Twitter: @AlpineHomeAir ‏

24. Trying to hide your HVAC system.

“If you have an outdoor HVAC system, you may be tempted to camouflage it behind shrubbery. The urge is understandable – the unit probably isn’t the most appealing element of your landscaping. However, surrounding it with plants or shrubs could block proper ventilation and clog the system. Always make sure there’s plenty of open space around an HVAC unit. As well as above it.” – 10 Common Heating & Air Conditioning Mistakes, Leitch Heating & Air Conditioning; Facebook

25. Only replacing part of your system.

“A/C systems are really two different parts to a whole: the indoor and the outdoor equipment. Inside are the blowers, fans, and coils. Outside you’ll find the condenser unit. Both of these sets are designed to work together. Replacing part of the system and leaving the rest may look appealing to your budget, but you’ll end up with a mix-and-match system that won’t operate as well or as efficiently.” – Madeline Johnson, Common Mistakes to Avoid When Buying a New A/C Unit, D&D Air Conditioning & Heating; Twitter: @DD_air

26. Choosing a poor filter location or poor filter assembly.

“Many equipment systems don’t come with internal filter racks. The first reason for a filter is to protect your equipment to keep it as clean as possible so it operates properly; a) so you don’t have electrical shortage issues, b) so the equipment doesn’t overheat, or c) in the cooling, so that it doesn’t get dirty causing water issues. Other filters can improve the air we breathe, reduce allergens, or sterilize the air as it passes through. Many filters have poor access and leaky cabinets (the container for the equipment). Many systems we come across don’t even have a filter on it or no sealing. What you have is an opening that is pulling contaminated air directly from the crawl space or the attic and dumping contaminants directly into the house.” – 8 Common Mistakes of Heating and Air Conditioning Contractors, Comfort Master Heating; Facebook

27. Overcharging the refrigerant in the system.

“Each air conditioning system runs on a set charge (amount) of chemical refrigerant. Any more or less will cause the system to work ineffectively and will eventually cause malfunctions with the compressor. It’s common for amateurs to put in too much refrigerant (overcharging it) from the start.” – Here Are Mistakes Amateur AC Installers Often Make, Comfort Zone Heating & Cooling; Twitter: @czonehvac

28. Purchasing the least expensive system.

“When an AC unit is priced significantly lower than competitors, this should be a warning flag – especially if the unit in question is manufactured by a company name you don’t recognize. A cheaply priced system is often comprised of cheaply made parts, assembled by cheaply paid people, and installed by companies looking to cut corners in every way in order to save a buck. In the end, these types of systems tend to wear out quicker and will require more maintenance in order to withstand the extreme heat and temperatures.” – Chris Hays, Air Conditioner Installation in Scottsdale: 3 Costly Mistakes to Avoid, Hays Cooling and Heating; Twitter: @Hayscooling

29. Too many contractors bidding on your project.

“You may think this is a good way to do business, and it is, to some extent. However, here is why it usually isn’t a good way to deal with heating and cooling contractors. A good contractor has enough loyal customers that they don’t need to deal with price shoppers. Once you find a good contractor, make the decision to be loyal to them. If you flip-flop from contractor to contractor, a good one won’t be motivated to keep YOU as a customer.” – Eight Mistakes People Make When Selecting an HVAC Contractor—and How to Avoid Them, 1st Choice Heating & Air Conditioning; Twitter: @1stChoiceAirCo

30. Not registering the warranty.

“Once your air conditioning system is installed, be sure to register your warranty. Failing to do so results in that warranty being void when you need it. Many manufacturers allow you to register your AC system’s warranty online, while others must be mailed in by a certain date.” – 4 Mistakes That Can Void Your AC’s Warranty, Blair’s Air Conditioning & Heating; Facebook

31. Not checking a company’s references.

“A professional heating and air conditioning company should have a list of recent customers that you can refer to in order to verify that the company in question performed the work in a timely manner and to the customer’s satisfaction.” – How to Hire an Air Conditioning Repair Professional, Hixon Heating and Air Conditioning; Twitter: @hixonheatairga

32. Steer clear of repairmen without a license.

“Hiring an unlicensed, inexperienced company or doing-it-yourself will impact the quality of your repair and has the potential of creating a dangerous situation for everyone in your home.” – The Importance of Hiring a Licensed HVAC Technician, Heritage Mountain Heating and Cooling; Twitter: @HeritageMT

33. Not focusing enough on ventilation.

“The insulting way to state this is that any HVAC contractor who doesn’t address the V in HVAC is just a HAC (read: hack). New homes are tighter than ever because of energy codes that require higher levels of air-sealing and in some cases, blower door tests to verify the airtightness. Tight homes need mechanical ventilation. All homes need spot ventilation in kitchens and bathrooms.” – Allison Bailes, The 7 Biggest Mistakes That HVAC Contractors Make, Energy Vanguard; Twitter: @EnergyVanguard

34. Not getting an estimate in writing before signing a contract.

“This will give you a good idea of how much you are expected to pay. Avoid getting estimates over the phone as the contractor can easily renege on their agreement.” – How To Find The Best AC Repair In Your City, Smith & Willis; Facebook

35. Not checking consumer review websites.

“Many disgruntled and satisfied customers share their personal experiences about specific contractors. The feedback section of the rating sites offer good insights in regards to the quality of service that the contractors provide.” – How To Hire An AC Repair And Maintenance Company, OK Heating and Air @OKHeatingAndAir

36. Drain pipes that lead to no exit.

“For example, a sidewalk is built over the drain pipe. Now, though the AC continues to run with water traveling through the drain pipe, it has no place to empty. What results is build up and back up that traces its way back to the furnace closet inside the home. Old water and even yard waste that made its way into the pipes from outside can clog the drain pipes and damage not only the system, but the home as well.” – Common Mistakes Found in AC Installations, Service Champions Heating & Air Conditioning; Twitter: @ServiceChampsS

37. Waiting too long to replace your unit.

Replacing a central air conditioning system, especially one that is more than 12 years old can result in substantial energy savings.” – Mary H.J. Farrell, Badly installed central air can make you lose your cool, Consumer Reports; Twitter: @ConsumerReports

38. Not leaving enough clearance room for the unit.

“The outside condenser cabinet of an AC needs to have about 2 feet clear on all sides. This allows the fan to properly circulate air to cause condensation and the release of heat. If this unit is placed where it lacks sufficient clearance, the air conditioner will lose energy efficiency.” – 4 Common AC Installation Mistakes Amateurs Make, Malek Heating & Cooling; Twitter: @MalekHVAC

39. Not installing a timer or programmable thermostat.

“There’s no need to blast the AC at full tilt while you’re at work. For central units, install a programmable thermostat that lets you set higher temps when you’re gone and cooler temps when you’re home. Newer window units have built-in timers and adjustable thermostats, or you can buy a timer at any home store for $10 to $20; just make sure it matches your device’s voltage.” – Sal Vaglica, 9 Things You Need to Know About Air Conditioning, This Old House; Twitter: @ThisOldHouse

40. Installing improperly sized air ducts.

“Air ducts must be large enough to distribute heated or cooled air to the entire house. Improper measurements lead to weak air delivery. As there’s no quick fix for a leaky HVAC system, the entire ductwork should be removed and reinstalled.” – Is Your HVAC Contractor A Hack?, On Time Experts; Twitter: @TheOnTimeExpert

41. Not considering style or design.

“Air conditioners have become more attractive in recent years. With a rounder shape and cleaner lines, today’s models do a better job of blending with furnishings. And while white is still popular, we’re now seeing blues, metallic greys and even natural wood! A manufacturer of mini- and multi-split models recently went so far as to create an air diffuser behind the front panel – and for a touch of elegance, these models also allow users to frame the front panel with a photograph or a painting! Manufacturers have also worked hard on the appearance of outdoor modules in a bid to harmonize them with landscape design.” – Isabelle Bergeron, How To: Buy Aa Air Conditioner, Style at Home; Twitter: @StyleAtHome

42. Not doing a proper load calculation and HVAC design.

“When you’re renovating your home, a lot of things are changing: the layout, possibly the square footage, building materials used and the usage of the space. All of these factors need to be considered to determine the correct size of your new unit, and the placement of ventilation and equipment components.” – Michael C. Rosone, Installing Air Conditioning? Don’t Make These 5 Mistakes, Arista; Twitter: @AristaAir

43. Not using the correct refrigerant.

“When installing a new air conditioning system it is important to make sure there is absolutely nothing in the refrigerant system except the rated refrigerant. The wrong refrigerant can potentially cause premature parts failures and costly repairs, but the primary issue is that is lowers the power efficiency. Noncondensables in the system will not flow normally through the piping and will build up in the outdoor coil. This causes higher pressures, higher compressor electrical usage, and lower heat transfer.” – Nathan Orr, Common Air Conditioning Installation Mistakes That Could Cost You $3500, Kalos Services; Twitter: @KalosServices

44. Units or base attached to the building structure.

“It is tempting to attach the outdoor unit and/or base to the building. However, this causes noise within the structure. One of the advantages of buying a split air conditioner system is that there is less noise when installed properly. You are wasting your money if you don’t take the time to do it right.” – Split Air Conditioner Installation: Mistakes to Avoid, Do It Yourself; Twitter: @DoItYourselfcom

45. Not using UV-rated and insulated piping.

“It is proven to last longer when subjected to UV rays and won’t break down. This means that there is no chance of the insulation degrading and causing any moisture damage (mouldy) in ceiling and wall spaces, and won’t cause your air conditioner to work harder and increasing your power bill (This can begin to occur in as little as 12 months). These materials do result in a more expensive initial installation but over the lifetime of your air conditioner will save you money.” – Worst Air Conditioner Installation Mistakes, K&J Burns; Facebook

46. Trying to patchwork your equipment.

“A mistake some individuals make is mismatching their new condenser or heat pump to an old indoor evaporator coil. If you have an old AC or heat pump that is 13 SEER or less, you will need to replace the old evaporator coil with the appropriately sized new coil and orifice (or TXV). Always check your new condenser’s or heat pump’s specification sheet for the correct model coils…if the a new evaporator coil isn’t installed and the old one is used instead, this can cause a variety of poor operation symptoms including improper cooling, evaporator coil freeze-up, and high electric bills.” – Common Mistakes Made While Installing an AC or Heat Pump System And How to Easily Avoid Them, Alpine Home Air; Twitter: @AlpineHomeAir ‏

47. Not getting a guarantee in writing.

“Make sure the company is willing to stand behind the products and services it sells with a no-hassle, no-questions asked guarantee that will protect you and your family from any unseen breakdowns. Be sure the guarantee is in writing and includes a Performance Guarantee, Investment Guarantee and a real 100% Satisfaction Guarantee.” – 5 BIG Mistakes Homeowners Make When Replacing Their Heating and A/C Systems, Horizon Services; Twitter: @HorizonServices

48. Not choosing a reliable brand.

“They are assembled using quality parts, by professional technicians and are only installed by authorized installation companies that have been trained directly by the manufactures.” – Chris Hays, Air Conditioner Installation in Scottsdale: 3 Costly Mistakes to Avoid, Hays Cooling and Heating; Twitter: @Hayscooling

49. Installing the thermostat too close to appliances.

“Make sure that no lamps, TVs or other heat-emitting appliances are too close to the thermostat. Your thermostat can register the rise in temperature and respond accordingly, leading to higher bills in the summer and a colder home in the winter.” – 10 Common Heating & Air Conditioning Mistakes, Leitch Heating & Air Conditioning; Facebook

50. Rushing your installation.

“Mistakes happen when you rush! When you’re in a hurry, you may forget to tell a contractor certain instructions, or you might make an error in judgment or a poor purchasing decision because you were focused on getting it done fast—instead of getting it done right.” – Eight Mistakes People Make When Selecting an HVAC Contractor—and How to Avoid Them, 1st Choice Heating & Air Conditioning; Twitter: @1stChoiceAirCo