Are you considering installing a ductless mini-split system but not sure whether it can effectively cool your entire house? A zoned mini-split system is a great way to keep cool if your home doesn’t have a central HVAC system. However, there are some limitations in terms of how much area a mini-split can cover and how many total zones you can have. Here, we’ll explain all you need to know about zoned mini-splits to help you determine whether this type of system will work for your home.
An Overview of Zoned Mini-Split Systems
A zoned mini-split system can potentially be a good alternative to a central HVAC system and may be capable of cooling and heating an entire house. This type of system has multiple indoor units known as air handlers that are all connected to a single AC condenser or heat pump unit located outside.
The difference between a system with an AC condenser and a heat pump is that heat pump systems can also heat in addition to cooling. While having the ability to heat also can be quite useful, you probably won’t be able to rely on this type of mini-split system as your only source of heating. That’s because heat pumps can’t always work effectively enough when the outdoor temperature is extremely cold. They also need to defrost occasionally and stop producing heat during this defrost cycle.
As of now, the biggest mini-split system available can run up to eight air handlers and have eight separate zones. If you wanted to rely on a mini-split system as your primary source of cooling, you’d obviously need one air handler in each room or space. That means one in each bedroom, another in the living room, kitchen, etc. If you have a larger home with more than eight rooms, your only option would be to install more than one mini-split system.
One thing you need to understand about a zoned mini-split system is that each of the air handlers works independently. That means that the AC condenser or heat pump will run if even one zone is warmer or cooler than it should be. This the case if the air handler in that zone is calling for cooling or heating. It also means that you can program each air handler to whatever temperature you wish and turn each one off and on as needed without affecting any other zones. This has the advantage of giving you far greater control over the temperature in each part of the home and also minimizing how much energy the mini-split uses.
Understanding the Limitations of a Zoned Mini-Split System
While you can potentially have eight zones with a mini-split system, whether or not it’s actually possible depends on the layout and size of your house. The primary reason is that mini-split systems are limited in terms of the maximum distance that the outdoor unit can pump the refrigerant to each air handler.
With most systems, each of the air handlers usually can’t be located more than 100-150 feet away from the outdoor unit. Some systems are capable of pumping the refrigerant a greater distance than this. However, the energy efficiency of the system decreases the further away the air handlers are from the outdoor unit. There is also a limitation in terms of the total combined length of all of the refrigerant line sets that run to each of the air handlers.
Another limitation is that you generally want to install each air handler on the inside of an exterior wall. The reason is that condensation is produced when the system is cooling, and you need to have a way for the water to drain outside. If your only option is to install any of the air handlers on an interior wall, each one will need a condensate pump to pump the water outside. This isn’t necessarily a major issue, but it does mean that the system will cost more and use more energy.
The Importance of Choosing the Right Location for the Outdoor Unit
The distance limitations we just looked at mean that the location of the outdoor unit can be hugely important. Ideally, you want the unit as close to the middle of the house as possible to minimize the distance between it and each air handler. If the unit is on the side of the house, you’d usually need to run the refrigerant lines in the crawl space, attic or basement. This is in order to reach the air handlers in the rooms on the opposite side of the house. Depending on the distance, you could also run the lines along the exterior of the house to cut down on the cost and time of the installation.
One possible option for limiting the distance between the outdoor unit and the air handlers is to install the outdoor unit on the roof. In this case, there would be a conduit that sticks down through the roof into the attic and contains all of the refrigerant lines. The lines would then branch off in the attic and then extend down through the inside of the wall in each room that has an air handler. Going this route is possible. However, it requires a bit more work since the technicians will have to cut holes in the walls so they can run the lines to the air handlers.
While installing the outdoor unit on the roof option may allow a mini-split system to cool and heat your entire house, there are a few drawbacks with this option. One is that you may need to first have your roof reinforced to support the weight of the unit. Another is that it will make the process of replacing the roof more difficult and expensive. This is because the unit will need to be removed first and then reinstalled after the new roof is in place. One other thing to consider is that having the unit on the roof will make the system more difficult to repair and maintain.
Your home might not have a ducted HVAC system and there may not be a suitable location where the outdoor unit will be close enough to the air handlers. In that case, the best option is to install two smaller mini-split systems. That usually means having one outdoor unit on each side of the house so that one system works for one side and the other works for the opposite side. While this will cost more, it’s nothing compared to the cost and difficulty of trying to retrofit your home with air ducts. Having two separate systems can also help to limit the distance to each air handler to allow each system to work more efficiently.
Reliable HVAC Professionals
At TR Miller Heating, Cooling, Plumbing & Electrical, we’ve been serving Plainfield and the Chicago area since 2008. We offer expert HVAC services and are ready to help if you want to install a mini-split system or any type of central heating or air conditioning. If you’re considering a mini-split system, our team can evaluate your home to help you decide whether it’s a good option. When you choose us for any cooling, heating or plumbing service, you can be certain you’ll receive honest, upfront pricing and prompt, reliable service. If you want to schedule a consultation to determine if a mini-split is the right choice for your home, give us a call today.
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