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ductless air conditioner

Ductless Split System Air Conditioners: What you Need to Know

Updated Dec. 1, 2017
By Gary Sprague

If you own a home without air conditioning, or one with older window units, you may want to consider adding a ductless split system air conditioner. This is also a good option for homes without ductwork, which can be difficult and costly to install. Ductless split systems (also known as "mini splits") cost more than window units and can be more expensive than central air- conditioning systems, although the expense of installing ductwork could balance the cost difference between these two options.

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Although ductless split systems can cost more upfront than central systems, they can save energy dollars by allowing consumers to heat and cool specific areas, as well as eliminating the cooled air normally lost through ductwork. Benefits of a ductless split system include ease of installation and the ability to cool and heat individual rooms as needed.

What Are Ductless Air Conditioners

A cooling option for homeowners, ductless air conditioners, also known as mini-splits, are smaller and easier to install than central or window units. Similar to a window unit, mini-split systems are most effective at temperature control in a single room. However, mini-splits are more energy efficient, offer greater temperature control, make less noise, and make life easier for allergy sufferers.

Mini-splits utilize an outdoor condenser that is similar to a central air system but is far more size-efficient than central air conditioning units. The condensers work by pumping air through refrigerant lines that are connected to the indoor unit.

Indoor units are compact, aesthetically pleasing, and easy to install. Indoor units require a small hole in the wall for installation and can be mounted or suspended from the wall or ceiling.

Conduits, which are system connectors, contain refrigerant tubing, which cools the air as the condenser coil pumps it through. Conduits, which connects come in a variety of lengths, making installation flexible and efficient.

Split systems can be used in single zone or multi-zone applications. A single zone has one indoor and outdoor unit and are designed for use in a single room or area. A multi-zone split system combines a single outdoor condensing unit with up to four indoor units, usually located in separate rooms and each with its own control. Multi-zone systems are most often used to cool multiple areas in a home or business.

Factors to Consider Before Purchase

Number of Zones

The difference between multi-zone and single-zone ductless air conditioners is the amount of rooms that they are required to cool. If your home or business requires more than one room to be cooled with a mini-split, consider a multi-zone mini-split.

Capacity

According to the Sylvane website, a single-zone mini-split's cooling power is determined by indoor BTUs only. BTUs are used to determine the amount of energy that must be added or removed from the environment. To determine the right mini-split, simply compare the BTU output with the square footage of the home. BTU output ranges from 5,000 BTUs for a 150 sq. ft. zone to 18,000 BTUs for a 1,000 sq. ft. zone.

Multi-zone units include the outdoor unit's BTU output. Outdoor unit BTU output typically averages around 12,000 BTUs for multi-zone systems.

Energy Efficiency and Environmental Impact

Mini-splits run no risk of energy loss that units with ducts suffer. The US Department of Energy states that the energy lost from conditioned air seeping through ducts can account for 30 percent of said unit's energy consumption.

Mini-split systems also reduce negative environmental impact. Information from Mitsubishi Electric explains that this is due to "a refrigerant called R410A, known for its zero-ozone depletion potential."

Installation

Installation typically takes around a day and requires no more than a three-inch hole in the wall. Units are lightweight, making for a manageable mounting or suspension process. Although installation is quicker and more efficient, mini-split systems still require professional installation. This guide on selecting a heating or cooling contractor provides a detailed outline of the entire process for dealing with contractors.

Warranties

Warranties on top mini-split systems from Mitsubishi and LG range from five to seven years, with companies offering extensions to 10 years. Some companies, like Daikin, offer warranties for separate parts and compressors.

Additional Features

  • Wifi Control: Mini splits are compatible with the AirPatrol smart controller.
  • Auto Restart: Major brands like Mitsubishi feature auto restart.
  • 24 Hour Timer: 24-hour timers allows for custom conditioning schedules.

Brands

  • Mitsubishi: Mitsubishi offers a variety of different mini-split air conditioning units. Their models are some of the most efficient in the industry, and they can operate in the most varied weather conditions.
  • Daikin: Daikin mini-splits are known for their quiet productivity. Like the Mitsubishi, they are also extremely efficient, touting a SEER rating of up to 26.1 on their more efficient models.
  • LG: LG mini-splits are known for their aesthetic appeal. However, LG also produces powerful mini-splits, with some models producing 36,000 BTUs.

Advantages of a Mini-Split System

Aesthetically Pleasing

Mini-split systems are considered an aesthetically pleasing ductless air conditioning option. Unlike window units, a mini-split is mounted discreetly on the wall without taking up an entire window. These units are sleek and compact, giving off a modern, minimal aesthetic appeal.

Easy to Install

Unlike duct systems, which can take weeks to install, mini-split systems can be installed in a single day. They are easily mounted, have minimal installation requirements, and a flexible, easy-to-install conduit.

Energy Efficient

Mini-splits are energy efficient thanks to their ductless systems and Energy Star ratings. Ductless systems eliminate the wasted energy that's lost through ducted systems.

Disadvantages of a Mini-Split System

Demanding Upkeep

Mini-split systems require monthly filter cleaning. If neglected, mini-splits are susceptible to malfunctions. Malfunctions must be handled by professionals, often costing hundreds of dollars in repair.

Permanent Fixtures

Unlike window units, mini-split systems are permanent fixtures. This limits the interior design possibilities in specific rooms. They cannot be moved to accommodate design changes, making them a nuisance for indecisive interior designers.

Cost

Compared to other single room options, such as window units, mini-split systems are much more expensive.

The upfront cost of ductless air conditioning tends to be slightly higher than that of central air conditioning. According to a 2012 report by the U.S. Department of Energy, mini splits cost about $1,500 to $2,000 per ton (12,000 Btu per hour) of cooling capacity – roughly 30% more than central air systems and approximately five times more expensive than window units.

According to Homewyse, the average cost to have a split system air conditioner installed is between $2,400 and $3,800, although the cost increases with each additional unit. The cost to install a central air unit (without ducts) averages between $2,900 and $4,200.

Central air conditioners cool the entire house, including unoccupied rooms, while split systems only cool certain rooms and can be individually controlled, making them more economical. Also, central air conditioners average a 30 percent energy loss through ductwork. Ductless systems save energy by eliminating this loss.

Ductless Air Conditioners vs. Central Air Conditioning

The main difference between single-zone mini-split systems and standard ducted air conditioning systems are the cooling area capabilities. Unlike ducted systems, mini-split systems cannot be used to cool an entire house. However, for those without central air, multi-zone mini-splits can be installed.

Heat Generating Mini-splits

There are two main forms of heat-generating mini-splits: heats strips and heat pumps. Each has their own advantages and disadvantages.

Heat Pump

Heat pumps utilizes electricity to move heat to the desired zones. Since heat pumps do not generate heat, they can warm rooms at a much lower cost than other systems. There are three common forms of heat pumps: geothermal, water source, and air. Heat pump systems most effective as single zone heaters.

Heat Strips

Heat strips generate their own heat rather than moving heat from room to room. This allows them to produce a greater level of heat. However, they cost more to operate than heat pumps.

Deciding if a Mini Split is the Right Choice

Consumers should consider the following questions in deciding whether or not a ductless split system air conditioner is the right fit for their cooling needs:

  1. Is there ductwork already installed in my home?
  2. Do I need to cool one room or several rooms?
  3. Is there a qualified installer in my area who is familiar with ductless split systems?

Installing ductwork involves opening up walls and ceilings and can be a messy and expensive process. If you need to cool only a few rooms and can locate a qualified installation expert, then a ductless split system air conditioner may be right for you. Potential buyers can check for a SEER rating on a ductless split system, just as with other types of air conditioners. Units with a higher SEER rating are more efficient but higher in price.

You may also want to read Is a Mini-Split Right for You?.

Finding a Qualified Installer

Because installation is critical in achieving peak performance, consumers should search for an installer who has installed ductless split systems in the past. The contractor should perform a load calculation to determine the proper size for each indoor unit and the best location in each room for installation. A system that is too large is more expensive to purchase and often wastes energy by short-cycling, while an undersized unit will run too often, resulting in higher operating costs and premature wear.

While the popularity of split system air conditioners appears to be growing, it can still be a challenge to find a qualified installer. Most heating and cooling contractors are trained to install central air systems, while far fewer have experience with mini splits. Along with a lack of training and experience, many contractors have tools and materials for central air systems but are not as readily equipped to work on mini splits.

It is important to do your research before choosing an installer. The installer should have verification of bonding and insurance. You can check with the Better Business Bureau for complaints against the installing company. In addition, some technicians are certified by trade organizations, which can show that company's commitment to providing quality service.

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