Choosing between a single-zone and a multi-zone system will depend upon your intended application.
If you wish to provide air conditioning for all areas of your home, a multi-zone system will best serve your needs.
However, if your goal is to provide air conditioning for just one under-served area of your home, you only need a single-zone mini split system.
There are some other factors to consider as well, so take your time and decide what will suit your needs best.
Single-zone mini split systems are a great way to deliver heating and cooling to a single room or area in your home. If you have central air or another form of air conditioning already in place, but there's a new addition or other area of your home that's under-served and never seems to get cool enough, you could add a single-zone mini split system to serve just that area.
A single-zone mini split is also a fine way to condition the air in your garage or workshop, providing more efficient cooling and heating than a window unit. And with a mini split, you'll still maintain use of any windows you have.
Another reason you may want to choose a single-zone system is if you have a very small home, such as a cabin with only two or three rooms. The single unit may serve to cool the entire home if it's small enough, however you'll need to have good air flow to evenly distribute the air. Using fans will work fine to circulate the air.
Installation is another factor to consider. Single-zone systems consist of an outdoor unit and a single indoor unit, one line set, one cable, and one drain line. Once the outside condenser and indoor unit are mounted, the refrigerant lines need to be installed. These are typically attached to the exterior of your home via line-hide tubing, then inserted through a 3-inch hole to the interior where your unit is located.
Multi-zone mini split systems are capable of cooling multiple rooms or areas in your home, and the temperature in each room can be controlled independently. For example, you can set one bedroom to 68 degrees and another to 72 for different sleeping temperature preferences. You can also turn select units off in rooms you're not using. If you have a guest room with a mini split unit, you can leave it turned off when you don't have guests.
This allows you to be even more efficient with your energy spending, since you can adjust the temperature or turn certain zones off, unlike with traditional forced-air systems that cool your entire home regardless of which spaces you're actually using. And unlike traditional systems that only control the temperature accurately in the room with the thermostat, mini splits will control temperature accurately in each room that has a unit.
A perfect example of why you'd want to set separate temperatures in different zones is your bedroom. A lot of people prefer a cooler temperature when they're going to sleep than they do when they're awake and no longer under the covers. Keeping your bedroom temperature set a few degrees lower than your family room will help to customize your comfort.
With multi-zone systems, you still have only one outdoor unit, but multiple indoor units. In addition to multiple indoor units, you'll also need a set of installation accessories for each indoor unit. The outdoor unit will run the refrigerant to the various indoor units to cool the air being blown through them. Some systems will require a branch box to split up the refrigerant and send it to the various different indoor units. If you're planning to install ceiling cassette units or concealed duct units, they may require more invasive installation methods, taking more time and possibly costing more in labor.
However, don't let any of this discourage you. Just remember the efficiency and savings you'll get in return for installing a mini split system in your home.
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