Air Conditioner Reviews, HVAC info and Buyers Guide

Residential AC: DIY or Hire a Pro?

Whether or not to hire a professional installer for a residential air conditioning system is up to each homeowner to decide, based on their own skill set and budget. Here are some guidelines for when to call an HVAC pro.

Common DIY Installs

For portable or window air conditioner units, manufacturers expect homeowners to put the equipment in themselves.1 These “do it yourself” installs are usually pretty straightforward. That doesn’t mean there aren’t some tricks to keep you out of trouble… (Window AC buying guide here. –Dave)

  • Read before you buy — You can often find installation guides or owner’s manuals available online.2 Major online retailers will often link to an owner’s manual and you can also find them at the manufacturer’s website. This gives you an idea of what to expect before you unpack a box, only to find out the unit won’t fit your windows, or needs a special bracket.
  • Ask questions — especially when you purchase from a big box store. Does the unit require special wiring, such as a high voltage power supply? Are replacement filters available? Does the store offer a service contract, free delivery or installation, or an extended warranty? Take advantage of anything offered that suits you.
  • Don’t be afraid to call a pro, even if you are installing yourself. AC dealers and service shops can help you choose the right size and model, even if you aren’t buying from them. Not all will do it for free, but they have the experience to help you calculate the correct size unit (in BTU’s) and may be able to get you a unit at a better price than you can find on your own. It doesn’t hurt to ask for help, and if you can’t get your questions answered locally, there are forums on the internet where you can ask.
    Not all forums allow Do It Yourself questions, so read what they say about it. For example, doesn’t3, but DIY chatroom does. Even those that don’t allow DIY will still offer general advice.
  • Get a second opinion. Before you spend your money, have someone check your calculations, even if it’s not a pro. This is especially important if you are buying online and having something shipped. You don’t want to make a mistake and have to deal with a return. On the same topic, read the reviews for the product you intend to buy.

Beyond the Basics

Borderline cases, that require more home remodeling experience but can be tackled by home owners are split units – units that have compressors outside and refrigerant lines running to indoor cassettes. So called “mini-splits” are often installed by non-pros and some units are marketed as DIY.5

There are a couple of hurdles that may decide the issue of whether or not to hire a pro. The first is how long the “run,” or length of hose you’ll need from the outside compressor to the indoor unit. Longer is more difficult. Next is how tricky the path will be, for example, if you run behind the walls on the inside, or run outside and just drill a single hole. Second floors also present problems because of the ladder work needed to run the line.

Another consideration is handling refrigerant. Read the installation guide – you may find that a licensed professional is needed to charge the system and test for leaks. The manufacturer may require a pro-install for their warranty, or you may run into zoning requirements in your area that insist on a licensed HVAC tech for any type of split unit. Running the electrical outside and having the proper ground is also an area where permits are sometimes required — don’t risk a fine or having to pull everything out just because you didn’t check your local ordinances.

In some cases, you can do most of the install yourself and get an HVAC pro to recharge and check your work. Doing it this way may mean significant savings, especially if you offer to sign a service contract with them for any repairs down the road. The important thing is to plan this out before you buy. That way, you aren’t stuck making a false assumption that costs you money and time.


Many systems are too complex or just too much for the homeowner to deal with. Central air conditioning systems fall into this category, since expertise is needed in heating (duct work and furnace), air conditioning (duct work and outside AC unit), and ventilation (while house air distribution).

Even smaller units can fall into this category when there is a business involved. Business owners don’t want to deal with environmental or liability issues, so hiring a pro makes sense.

What about repairs?

Keeping an air conditioning system running smoothly starts with good maintenance. Whichever type of system you have, there will be user-level maintenance you can take care of yourself, even if it’s just changing a filter or cleaning the unit. Naturally, you don’t want to spend the money on a professional if you don’t have to.

Larger central AC systems can benefit from a professional check-up at the beginning of the air conditioning season to catch any problems early, before the real heat hits. For other problems, repairs depend on your level of expertise. Most repair information is available online, and fixing an air conditioner is no harder than doing your own auto repair.

However, unlike auto repair, parts for air conditioners may be hard to find and you may end up hiring a pro just because you can’t get the parts you need. Some DIY’ers will pay for a diagnosis from a pro and then take on the repair themselves, since diagnosis is often the hardest part. Homeowners may not have the specialty equipment to track down a problem – pressure sensors, electronic testing equipment, or leak checking instruments. It’s quite possible to pay for a pro by the hour to diagnose your system; shops will give you an hourly rate before they show up.

For smaller units – window and portable – it’s easier to take the unit in than to pay for the expense of having someone come out. This is one advantage of buying locally at a store that offers warranty work or repairs.

One important point: repairs you take on yourself will almost always void the manufacturer’s warranty. Keep this in mind.


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