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What Size System Do I Need?

If you're considering a ductless split system installation, you probably have some questions. Using highly advanced technology, Mitsubishi Electric Cooling and Heating makes some of the best ductless air conditioning systems on the market. These innovative cooling devices are highly efficient by delivering a consistent, quiet flow of cool air to keep you comfortable and conserve energy. However, split systems must always be properly sized to accommodate the indoor spaces they are designed to cool.

Advantages Of Mini Splits

The primary advantage of Mitsubishi Electric ductless air conditioning systems is that you don't need the duct work required by a central air conditioner. Another benefit is that, unlike central air conditioning systems, ductless systems are much easier to install. Other benefits include:

  • High efficiency equals lower utility bills
  • You can create zoned areas for even more efficiency
  • Attractive indoor units boast super quiet operation
  • No bulky exhaust hoses are required
  • Split systems cost less overall than central AC systems

How Do Split Systems Work?

Split systems consist of an outdoor unit and one or more indoor units (air handlers). The compressor and condenser coil are located in the outdoor unit, while the evaporator coil is situated in the indoor unit. A small hole of less than 3 inches in diameter is made in the wall to accommodate electrical wiring and copper tubing that connects the outdoor unit to the indoor unit. The outdoor unit transfers refrigerant from the compressor and condenser coil via the tubing to the evaporator coil in the indoor unit. Cooled air is then blown indoors by a fan that's virtually silent.

The sleek and inconspicuous indoor units can be mounted on the wall or ceiling. You can regulate the temperature of each indoor unit with a remote control or a wall-mounted thermostat. Multiple indoor units can be connected to the same outdoor unit. Each indoor unit can then be programmed to maintain a different temperature, thus creating separate cooling zones. This differs from central systems where the thermostat setting determines the temperature in every room.

Why Is Ductless Heat Pump Sizing So Important?

Proper ductless air conditioner sizing is essential for high efficiency performance and the level of cooling capacity. If the sizing is too small or too large, the system won't cool properly, and it won't operate efficiently. And if the system is improperly sized, if the indoor units are mounted in the wrong locations, or the installation itself is done incorrectly, you'll be left with an expensive problem to fix. Systems that are incorrectly sized and improperly positioned can seriously interfere with humidity control and cost a bundle in high electric bills.

Sizing a split system will depend on existing insulation levels, the area you want to cool and on how many indoor air handlers you plan to include. The more indoor units you want, the more precise the sizing must be. Because you're investing in a high performance system, technicians at Mitsubishi Electric Cooling and Heating recommend professional sizing and installation. That way, you'll know the job will be done properly and that your investment will be protected.

Ductless splits cool a larger area at the same BTU level than do window air conditioners and portable air conditioners. Below is an approximate sizing guide:

350 square feet = 9,000 BTU

500 square feet = 12,000 BTU

750 square feet = 18,000 BTU

1000 square feet = 24,000 BTU

1250 square feet = 30,000 BTU

1500 square feet = 36,000 BTU

Can I Install A Mini Split System Myself?

The expert contractors at Mitsubishi Electric Cooling and Heating do not recommend installing a mini split system yourself. Although these systems are easier to install than central air conditioners, it's best to hire a licensed and insured contractor who employs NATE-Certified technicians. There are safety risks involved, and the installation process requires high-tech tools and specialized techniques. The installation must be performed in accordance with HVAC guidelines or it won't be covered under warranty. And although split systems come pre-charged, your technician may need to add more refrigerant to establish the correct charge.

What Makes Ductless Air Conditioners So Efficient?

Mitsubishi Electric ductless systems have Seasonal Energy Efficiency Ratios (SEERs) of at least 13, while some inverter units boast SEERs of from 20 to 22. The higher the SEER rating, the more efficient the system will be. For maximum efficiency, Mitsubishi Electric Heating and Cooling recommends installing an air handler in every room. However, one indoor unit can certainly cool multiple rooms if the BTU capacity of that unit is sufficient to cool the area of the corresponding space.

There are two additional reasons why Mitsubishi Electric split systems are so efficient:

  • An air handler in each room provides maximum efficiency because you need only cool the rooms you use -- and only while you're using them.
  • Because the cooled air is released directly from the indoor units instead of traveling through a system of ducts, it retains and releases maximum cooled temperature.