If your home doesn’t have an existing central HVAC system, then you don’t have many options for effectively heating your house during the winter. In this situation, most people use either electric heating options like baseboard heaters and space heaters or a radiant heating system with a boiler and radiators or underfloor heating. There is also a relatively newer option that many people don’t know about, and this is a ductless mini-split. Mini-splits are a type of self-contained heat pump that runs on electricity and can be used to provide both heating and air conditioning. We’ll now take a closer look at what mini-splits are, how they work, and whether they are an effective option for heating an entire home.

An Introduction to Ductless Mini-Splits and How They Work

Ductless mini-splits are similar to central AC and heat pump systems in that there is an outdoor condenser unit and an indoor air handler. The difference is that the air handler in a ductless mini-split system is standalone and works without needing any ductwork. Instead of being connected to a duct system, the air handler is just mounted on a wall or possibly in the ceiling so that it provides heating and cooling to that room. As with a central system, copper lines run from the mini-split condenser to the air handler to supply the air handler with heated refrigerant.

The outdoor condenser unit uses a coil filled with extremely cold refrigerant that can capture heat energy from the air. A fan blows air over the coil, and much of the heat energy flows out of the air into the refrigerant. The process works naturally because the refrigerant is always colder than the air temperature.

Absorbing heat energy raises the temperature of the refrigerant, which then flows through an expansion valve before it is pumped into the air handler. This process instantly decreases the refrigerant pressure, superheating it and turning it into a hot gas.

Inside the air handler is a second coil that the hot refrigerant flows into. A fan draws cold air from the room into the air handler and blows it over the coil. This results in the heat energy flowing out of the refrigerant to heat the air before it is blown back out into the room.

The process works in mostly the same way when a mini-split is cooling. The difference is that cold refrigerant is used to remove heat from the air inside and release it back outside.

How Many Rooms Can a Mini-Split Heat?

A typical mini-split system has a small outdoor condenser unit and one air handler, which means that it can only heat and cool one room or space. If you want to heat your entire home, you would need a larger, more powerful system that can run multiple air handlers from the same condenser unit, and these are sometimes referred to as a multi-split system.

Most of these systems allow you to run up to four air handlers, but there are also more powerful systems that can run up to eight or even 12 air handlers. This means that theoretically, you could use one of these systems to heat your entire home, but there are some limitations that we will now look at.

Limitations to Heating With a Ductless Mini-Split

Ductless mini-splits can definitely heat a smaller home, but for larger homes, it is often necessary to install two separate systems, each with its own outdoor condenser unit. The main reason is that the condenser can only pump the refrigerant a certain distance, which is usually around 100 to 150 feet. This means that every air handler needs to be located within that distance of the condenser, which isn’t always possible in a large house and especially if you have multiple levels. In this case, you would often need to have one condenser that supplied one side of the house and a second condenser for the other side.

Another limitation to heating with a ductless mini-split is that its effectiveness decreases the colder the outdoor temperature is. Mini-splits are most energy-efficient and effective in temperatures above 40 degrees. At 5 degrees, a mini-split will usually only produce around 80 to 85% of its normal heating capacity.

There are cold-weather mini-splits that are designed to still function in temperatures well below 0 degrees, but their energy efficiency and effectiveness are still decreased the colder it gets outside. This means that a mini-split system may not function effectively enough to keep your home sufficiently warm during extremely cold weather. As a result, there may be times throughout the winter when you will still need to use space heaters or other supplementary heating options.

This usually isn’t ever a problem in warmer climates. However, in colder northern areas, a mini-split system alone may not always be enough to keep you warm throughout the entire winter.

Mini-splits are definitely a great option if your home doesn’t have an existing duct system. However, if you already have central air conditioning but not heating, you are probably better off installing a furnace instead.

Benefits of Heating With a Ductless Mini-Split

Even though there may still be times when you need to supplement your heating, ductless mini-splits are still a great choice for any home without central heating. A ductless mini-split will always be two or three times more energy efficient than any other type of electric heating. Baseboards, space heaters, and other electric heating options directly convert electricity to heat at a one-to-one ratio, which means every unit of electric energy is used to create one unit of heat energy.

Ductless mini-splits are far more efficient than this due to the nature of the heat transfer process that they use. In milder temperatures, ductless mini-splits are typically at least 300% efficient. This means that for every unit of electricity that they use, three or more units of heat energy are created. At temperatures around 10 degrees, the energy efficiency typically drops to somewhere around 220%.

Mini-splits are still far more efficient than other electric heating options, even in below-zero temperatures. The only issue here is that they often won’t produce enough heat to keep a home sufficiently comfortable when it is very cold out.

Another major benefit of installing a ductless mini-split is that it also enables you to keep your home cool during the summer. A mini-split will be far more effective and use much less energy than using window or portable air conditioners for cooling. You’ll also never need to worry about hauling those bulky units around since a mini-split is permanently mounted.

If you’re considering a ductless system, Apollo Plumbing, Heating & Air Conditioning can help you choose the right system for your home and your needs. We carry a wide range of mini-splits, and we also repair and service all types and models of existing systems. Our team also installs, services, and repairs furnaces, air conditioners, heat pumps, and indoor air quality equipment. We also offer a full range of drain cleaning and plumbing services for residents in Portland, Vancouver, Boise, and the surrounding areas. If you have any questions about mini-splits or want to schedule a consultation to find out if a mini-split is right for your home, give us a call today.

Meet the Author
Brandon Bird
Brandon Bird

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