A ductless mini-split system can be a great alternative to a traditional central HVAC system. You can also use a mini-split to add supplementary air conditioning to your house or to heat and cool a home addition.
When choosing a ductless mini-split system, selecting the right size and configuration is crucial to ensure it effectively cools (or heats) the intended space. The capabilities can vary significantly depending on the system. In this article, we’ll explore the most important factors that impact a mini-split’s performance so you can find the perfect solution for your needs.
Single-Zone vs. Multi-Split Systems
There are two main components in a ductless mini-split system: an outdoor AC condenser or heat pump and an indoor air handler, also known as a “head.” The air handler unit typically hangs on a wall but can also be mounted on the floor or inside a ceiling. Unlike a central HVAC system, the air handler in a mini-split directly draws air from the room it’s in and delivers conditioned air back into the same space.
A single-zone system consists of one outdoor unit and one indoor air handler, designed to cool or heat a single room or section of the house. This simplicity makes it an excellent choice for individual spaces, such as bedrooms or offices. A multi-split system, on the other hand, has one outdoor unit connected to two to eight indoor units. Depending on the size of the system, a multi-split setup can potentially serve an entire house.
Calculating the cooling capacity for a multi-zone system can be more complex. You need to account for the outdoor unit’s total BTU output and ensure each air handler is appropriately sized for its designated space. For example, a system may have a 32,000-BTU outdoor unit paired with four 8,000-BTU air handlers. Alternatively, you might have a larger air handler for an open living area and smaller ones for bedrooms. Proper sizing ensures optimal comfort and energy efficiency.
Primary vs. Supplementary Cooling
Another factor that determines the size of a mini-split system is whether it will serve as the primary source of air conditioning or supplement an existing system. Single-zone systems are often used to cool specific areas, such as home additions, garages, or workshops, without connecting them to a central HVAC system.
Mini-splits are also ideal for supplementing central air in spaces with higher cooling demands, like rooms with large windows or skylights. If a mini-split is the primary cooling source, you’ll need a system with a higher BTU capacity compared to a setup designed for supplementary cooling.
Location and Climate
Your local climate plays a significant role in determining the cooling capacity you’ll need for a mini-split system. In Farmington Hills and throughout Southern Michigan, where summers are warm but not extreme, a general guideline is to allocate 35–40 BTUs of cooling power per square foot.
For example, a 12’x12′ bedroom would typically require a 5,000 to 6,000-BTU air handler. When planning a multi-zone system, calculate the requirements for each space individually and ensure the outdoor unit can handle the combined BTU load.
Layout and Air Handler Placement
The layout of your home and the placement of the air handler can also influence how much space a mini-split system can effectively cool. For example, in open-concept spaces where airflow isn’t obstructed by walls, a single-zone system may be sufficient to cool connected areas like a kitchen and living room.
However, if walls or other obstructions block airflow, a multi-split system with multiple air handlers may be more effective. Proper placement of air handlers is crucial for even cooling. For larger rooms, mounting the air handler centrally is ideal. If the unit must be placed on a wall at one end of the room, you may need a higher-capacity air handler to ensure it can circulate air throughout the entire area.
Additionally, avoid placing the air handler near objects that could block airflow, such as cabinets or tall furniture. Restricted airflow reduces the system’s efficiency and may require a higher-capacity unit to compensate.
Wall Height
Ceiling height is another important consideration when sizing a mini-split system. The BTU guidelines mentioned earlier are based on spaces with standard 8- to 9-foot ceilings. Rooms with higher ceilings require larger systems to account for the increased air volume.
If the room has ceiling fans, they can help improve air circulation and reduce the strain on your mini-split system. Smart ceiling fans can even be integrated with your HVAC system through a smart thermostat for optimal efficiency.
Your Local Home Service Experts
Since 1925, AJ Danboise Plumbing, Heating, Cooling & Electrical has been the leading home service provider in Farmington Hills and the surrounding areas. Whether it’s heating, air conditioning, electrical, indoor air quality, or plumbing, you can count on our team to deliver prompt, professional service for all your needs.
Our certified HVAC technicians have extensive experience in installing ductless mini-split and central HVAC systems. We’ll evaluate your home’s layout, cooling needs, and budget to recommend the best solution for your space.
Call AJ Danboise Plumbing, Heating, Cooling & Electrical today to schedule a consultation and learn more about how a ductless mini-split system can enhance your home’s comfort and energy efficiency.
