Choosing the right AC system for your Phoenix rental unit can be a daunting task! There's no easy answer - you need to consider your budget, climate and personal preferences. (But) With a little bit of research, you can find the perfect fit for your home that will keep you cool in the scorching Arizona summer.

First off, it's important to understand how air conditioning works and determine what type of cooling system is best suited for your needs. Central air conditioning systems are an efficient option as they distribute cooled air throughout the entire house via ductwork or vents. Alternatively, window units provide localized cooling but may not have enough power to cool down an entire house in hot climates like Phoenix.

Additionally, think about what kind of energy efficiency rating you want in an AC unit. The higher the SEER rating (Seasonal Energy Efficiency Ratio), the more energy-efficient it will be and the lower your utility bills will be! It’s also crucial to check whether or not any rebates or incentives are available from local governments or retailers when selecting a high-efficiency model.

Next, take into account size and capacity: The bigger your space is, the bigger capacity unit you'll need to properly cool it down; conversely, if you choose one too big for the area it won't work efficiently either. A professional technician should do a load calculation before recommending one specific system; this way you can make sure it meets all of your needs without overspending!

Finally don’t forget about maintenance – regular tune-ups and filter changes will ensure optimal performance as well as improve its longevity. So when looking at different options, make sure to inquire about warranty terms and service contracts which could save you money in case something goes wrong with your system down the line.

Overall, choosing an AC system for your Phoenix rental unit may seem overwhelming at first but with some thoughtful planning and research, finding one that fits all of your needs should be achievable!