Mini‑Split vs. Window AC: Which Is Better for My PHX Home Addition?

Are you considering adding a room to your house or making your garage a workspace?

If so, one of the first things you need to consider is how you will cool the new room. Installing ductwork for a new room can be prohibitively expensive, which is why most homeowners choose a window or mini-split (ductless) AC system instead.

Here’s our opinion: If comfort and convenience are important to you, go with a mini-split system. If you’re on a tight budget and don’t plan on spending a lot of time in the new room, a window AC will probably suit your needs.

In this article, we’ll explore both types of air conditioners to give you a better idea of which one is best for your add-on room.

Although more common in other parts of the country, window air conditioners are sometimes used in the Phoenix area—usually to cool just one room. But they can also be a viable option for garages, sunrooms and Arizona rooms.

• Price. They’re less expensive than a ductless system.
• Easy to install. Window units are simply mounted in an open window. Wall units are a little more complicated as they require a hole to be cut in an exterior wall.

• Not very versatile. Window units require a window to the outside and wall units require an exterior wall to work.
• Ugly. Most window and wall air conditioners aren’t nice to look at. They’re big, bulky eyesores. Plus, window units take up one of your windows.
• Noisy. Window units can be loud since the compressor and condenser are in the same unit and hanging from your window.
• Security problem. A window unit could be an easy entry point into your home for a burglar.
• Only cools one room. If you need to cool more than one room, you’ll have to buy additional window air conditioners.
• Uneven cooling: Some window units leave the room feeling too cold or too warm, and can struggle to maintain a consistent temperature.
• Less energy-efficient than a mini-split system. Window and wall units generally consume more energy to cool a room, which results in higher monthly energy bills.

Ductless air conditioners have been around for decades, but are becoming more and more popular. They offer the benefits of a central AC system without the need for all the expensive and difficult-to-install ductwork.

Before we dive into the pros and cons, let’s take a quick look at how a ductless AC works.

A mini-split system works essentially the same way as a central AC system—just without the ductwork.

Like a central AC system, a ductless system consists of an indoor and outdoor unit. The indoor unit pulls in warm air from your room, removes heat from it (making it colder), then blows the cool air back into the room.

All the heat absorbed from the warm air is carried to the outdoor unit, where it’s dispersed outside. The cooling process repeats over and over again until the room reaches your desired temperature.

For more information about how a mini-split system works, read our blog “How Do Ductless ACs Work? A Phoenix Tech Explains.”

Now that you’ve had a brief introduction, let’s take a look at the pros and cons of a mini-split AC system.

• Quiet. The noisier condenser unit is located outside your home.
• Very efficient. Compared to a window AC, many mini-split systems are more energy-efficient, resulting in lower monthly energy bills.
• Size and style options. Ductless systems are small enough to be installed anywhere (rather than just exterior walls). If you don’t want to look at the indoor unit, in-ceiling mounted units are also available.
• Versatile. Mini-split systems can be placed in more areas than window units. And you can have up to 8 indoor units for each outdoor unit, allowing you to cool multiple rooms to different temperatures.
• Comfortable: Ductless systems are usually better at maintaining consistent temperatures than window units.

• Price. The cost to purchase and install a mini-split AC system is much more than a window unit (of course, you also get many other benefits).
• Requires professional installation. Refrigerant tubing and electric wiring must be run through the walls of your home.

• Are you renting? If so, the easiest option would be to purchase a window AC because you’ll need the homeowner’s consent to install a mini-split system.
• How many rooms do you want cooled? If you’re considering a cooling option for multiple rooms, a ductless system is the best choice.
• What space do you have available? If you don’t have any windows to spare, a mini-split AC is going to be your best option because it can be installed on any wall.
• What’s your budget? If you’re on a tight budget, a window AC will be the least expensive option in the short term.
• How long are you planning on living in your home? If you plan on living in your home a while longer, it’s better to get a mini-split system because it will keep you more comfortable and save you more money in the long run.

In the end, choosing between a window unit or a mini-split system depends on what matters most to you. If it’s upfront price, then a window unit will be the cheapest option. However, if you look a little deeper at the long-term benefits, a mini-split air conditioner is a better investment.