Mini Split Air Conditioners

Frequently Asked Questions

What is a mini split air conditioner?

A mini split air conditioner, also known as a ductless mini split, is a compact heating and cooling system that does not require ductwork. It consists of two main parts: an outdoor compressor/condenser unit and one or more indoor air-handling units. These components are connected by a small conduit containing refrigerant lines and electrical wiring, which only requires a single, small hole in your wall. Mini splits are excellent for cooling or heating individual rooms, home additions, or spaces where installing ducts is impractical.

What size of mini split ac do I need?

The right size for your ductless air conditioner is determined by its cooling/heating capacity, measured in British Thermal Units (BTUs). The primary factor is the square footage of the area you want to condition, but factors like room insulation, ceiling height, and sunlight exposure can affect the exact size needed. Here is a general guide based on room size：
●9000 BTU Mini Split: 0–400 sq. ft. (Small bedroom or office)
●12000 BTU Mini Split: 401–550 sq. ft. (Medium-sized bedroom or living room)
●18000 BTU Mini Split: 551–1000 sq. ft. (Large living room or open floor plan)
●24000 BTU Mini Split: 1001–1500 sq. ft. (Large living room or multi-room areas)
●36000 BTU Mini Split: 1501–2500 sq. ft. (Large rooms or open spaces)

Is it better to undersize or oversize a mini split ac?

It is crucial to have a properly sized mini split ac, as both undersizing and oversizing cause problems. An oversized unit will "short cycle," meaning it turns on and off too frequently. This leads to poor humidity control (making the air feel clammy), uneven temperatures, higher energy bills, and increased wear on the system. An undersized unit will run constantly, struggling to reach the desired temperature, especially in extreme weather, which also increases energy costs and can shorten its lifespan. The goal is always correct sizing for optimal efficiency and comfort.

Where should you not install a mini split ac?

To get the best performance and longevity from your mini split air conditioner, avoiding certain installation spots is key. Here’s a quick guide on where not to place your indoor and outdoor units.
For the Indoor Unit:
Near Heat Sources or in Direct Sunlight: Avoid installing the ductless air conditioner near appliances like ovens, stoves, or in a spot where it will be hit by direct sunlight from a window. The extra heat can trick the unit's temperature sensor, causing it to run inefficiently and work harder than necessary.
In High-Humidity Rooms: Steer clear of rooms with consistently high moisture levels, like bathrooms or laundry rooms, unless the ductless ac is specifically rated for such environments. Excess moisture can lead to internal damage and mold growth.
Where Airflow is Blocked: Do not place the mini split system behind large furniture, in a cramped corner, or where curtains could block the vents. Restricted airflow reduces efficiency, leads to uneven temperatures, and can strain the system.
Directly Over Beds or Seating Areas: Avoid mounting the mini split ac so that it blows air directly onto where people sit or sleep. Constant direct airflow can cause discomfort.
For the Outdoor Unit:
In Enclosed or Tight Spaces: The outdoor unit needs plenty of space to "breathe." Do not install it in a small, enclosed area like a narrow alley or with less than 12-24 inches of clearance on all sides from walls, fences, or shrubs. Inadequate space can reduce efficiency by over 15% and cause the unit to overheat.
In Direct Sunlight All Day: While some sun exposure may be unavoidable, try not to place the unit where it will be in direct sunlight for prolonged periods. This can cause it to overheat and work less efficiently.
On an Unstable Surface or Prone to Flooding: Do not place the unit on an uneven or unstable base, as this can lead to excessive vibration and damage. Also, avoid areas that are prone to flooding or poor drainage to prevent water damage.
Too Close to Windows or Patios: Consider noise. To avoid disturbing yourself or your neighbors, place the outdoor unit away from bedroom windows, patios, and other outdoor living areas.
General Rule of Thumb: Always ensure both units have unobstructed airflow are kept away from extreme temperatures, and are mounted on stable, level surfaces. For the best results, we highly recommend consulting with a professional HVAC technician who can assess your specific space and ensure a safe, optimal installation

Can I install a ductless mini split myself?

While some preparatory work might be DIY-friendly, the full mini split ac installation requires a professional HVAC technician. The process involves handling refrigerant, making electrical connections, ensuring a vacuum-tight seal on the refrigerant lines, and final system commissioning. Improper installation can lead to poor performance, refrigerant leaks, voided warranties, and even safety hazards. Professional installation ensures your system runs efficiently and reliably.

How much does it cost to install mini split systems?

The mini split AC installation cost varies significantly based on the system's capacity, brand, number of indoor units (zones), and installation complexity. Here's a general cost range:
Single-Zone System (one indoor unit): Typically between 1,500 and 4,000 for the unit and installation.
Multi-Zone System (one outdoor unit with multiple indoor units): Can range from 4,000 to 10,000 or more.

Do ductless air conditioner turns off when temperature is reached?

Costway mini split system with inverter technology typically do not turn off completely. Instead, once the set temperature is reached, the compressor slows down and the system operates at a low capacity to maintain the temperature. This is a key feature that contributes to their energy efficiency, consistent comfort, and quiet operation compared to traditional systems that cycle on and off.

At what temperature do mini split heat pump stop working in winter?

Standard mini split heat pump can lose efficiency as the outdoor temperature drops, typically struggling to extract heat below 15-20°F (-9 to -6°C). However, Costway now offer "cold climate" ductless ac specifically designed to provide efficient heating in much colder temperatures, operating effectively down to -15°F. If you live in a region with harsh winters, be sure to select a model with a low-temperature heating capability.

What is the most efficient way to run a mini split ac and heat in the winter?

●Set it and Forget it: Avoid frequently changing the thermostat. Find a comfortable setting and leave it. The inverter technology is most efficient at maintaining a steady temperature.
●Utilize Programmable Timers: Set the mini split ac and heat to lower the temperature when you are away or asleep to save energy.
●Keep Vents Clear: Ensure furniture or curtains are not blocking the airflow from the indoor unit.
●Regular Maintenance: Clean the air filters every month and schedule an annual professional check-up to ensure the system is running at peak efficiency

How many years does my ductless mini split air conditioner last?

With proper maintenance, a high-quality mini split system can last 10 to 15 years, and sometimes even longer. The lifespan heavily depends on regular cleaning of filters, keeping the outdoor unit free of debris, and scheduling annual professional maintenance to check refrigerant levels and overall system health.