A homeowner sits at a desk against a wall below a mini-split's head unit near the ceiling

Mini-split heat pumps are getting a name for themselves as one of the most efficient and cheapest options for heating and cooling your home.

The experts tell us we can all help mitigate the impacts of climate change by reducing our carbon footprints and that switching to mini-split heat pumps is one of the best ways to do this.

The good news is that making the switch shouldn’t be a sacrifice. In fact, these more efficient and cheaper-to-run systems are also quieter and more controllable than many alternatives.

If you’re interested in how much energy mini-splits require, you can read our article here.

We get a lot of questions about how mini-splits work and what makes them so efficient, which comes down to several factors.

Are Mini-Splits More Efficient Than Traditional AC?

Variable speed mini-split heat pumps are more energy efficient than traditional central air systems, partly due to the absence of ductwork, which is responsible for around a 30% energy loss. The other big reason is mini-splits’ ability to modulate their output using variable speed compressors.

You might have heard that mini-split heat pumps with inverter-driven variable-capacity compressors are the future of HVAC.

They are certainly what we’re seeing specified for high-performance, eco-friendly homes more and more these days.

How Does a Mini-Split Work?

A mini-split heat pump is a clever system that homeowners can install to provide year-round heating and cooling.

It has two main elements, an outdoor unit housing the compressor that pumps refrigerant around the system and one or more indoor units that blow conditioned air into each room or zone, known as air handlers, evaporators, or head units.

A mini-split air handler in the corner of a room just below the ceiling with a vent installed
A mini-split’s head unit component

The heat pump collects heat from the cold side of the system and moves it along the refrigerant lines that connect the two units to the warm side of the system, where the heat is released.

In heating mode, heat is collected outside the building and moved inside to heat the home. In cooling mode, the system is reversed and operates like a standard air conditioner to collect heat from the living space and dump it outside via the condenser coil in the outdoor unit.

The mini-split makes use of the refrigeration cycle to move heat very efficiently. The refrigerant absorbs the heat in the evaporator coil and carries it along the refrigerant lines between the outdoor and indoor units.

An illustrated diagram of how a ductless mini-split system functions

To make this happen, the refrigerant fluid is taken through a series of steps that alter its phase, changing it from gas to liquid and back again by compressing, condensing, expanding, and evaporating it.

This process is the refrigeration cycle. The speed the compressor runs at governs how quickly these processes take place, determining the rate of cooling or heating that the heat pump provides.

Therefore, the compressor is a vital element of the heat pump, and its performance significantly impacts the system’s efficiency.

Why Is a Mini-Split Heat Pump More Efficient?

Efficiency is relative, so before we talk about why a variable speed mini-split is more efficient, we need to look at the alternative.

Fixed Speed HVAC

In the past, HVAC systems operated at a single speed, or perhaps two speeds. There are still plenty of systems operating in this way.

A friend of ours who we visited recently has a central air system powered by a standard single-speed compressor. During the cooling season, his system kicks in when the temperature rises above a certain point, which he can set using a thermostat.

The compressor in the AC unit starts up and cools the air, which is blown into the living areas of his home via central ductwork.

Ducting is inefficient, resulting in around a 30% energy loss due to leaks from damaged or worn ductwork, poorly insulated ducts, and the energy required to blow air through the system.

Each bend in the ductwork adds to energy losses and sometimes ducts can become kinked, causing constrictions that further reduce the system’s efficiency.

Ducting near the ceiling reinforced with metallic tape to cover leakage

But that’s not the only thing impacting the efficiency of his system. Another source of inefficiency is the single-speed compressor that chugs away in his AC unit.

The only way he can control the output of the AC unit is by turning the compressor on or off. This is incredibly inefficient compared to a variable speed compressor because each time the compressor starts up, it must overcome the initial inertia of its moving parts.

The compressor starts up when the temperature rises above the setpoint by a certain amount. When the temperature is brought down to a certain point below the setpoint, the compressor shuts off.

This operation is not the most efficient way to control the unit’s output. Variable speed compressors are much more efficient.

Variable Speed Inverter-Driven Compressor

Mini-splits usually have inverter-driven variable-speed compressors. Some units, particularly older ones, might have a single-speed version, but they are a rarity these days. The overwhelming majority of mini-splits will be variable speed.

Most mini-splits are also ductless, so the energy losses due to ductwork, which are the source of the inefficiencies mentioned above, are not present in ductless heat pumps.

A homeowner sits on the couch in her living room, appearing satisfied while adjusting her mini-split evaporator with a remote control

We’ve established that single-speed compressors are inefficient, but why is it that variable-speed compressors are more efficient?

The principle can best be illustrated by way of a motoring example.

With the current price of gas going through the roof, many people have started using “hypermiling” techniques to make their tank of gas go further. These techniques have long been used by environmentally-conscious types who want to minimize their carbon footprints, but recently more people have gotten involved to save money, too.

The concept of hypermiling involves driving more carefully and thinking ahead to avoid braking. Simply by maintaining momentum and driving along at a more or less steady speed, you can increase the efficiency of your car and save some serious cash.

This is why you get more MPG from your car when driving on the highway than in and around town. In town, you are constantly starting and stopping, using the brakes, and driving with higher revs in a lower gear.

The compressor in your AC unit or heat pump is subject to the same laws of physics as your car and will perform much better when operating at a steady speed than if it is continually turning on and off.

The outdoor compressor component of a ductless mini-split

Mini-splits with inverter-driven variable-speed compressors can ramp up and down according to the heating or cooling output demanded. Once the temperature has reached the setpoint, the compressor will be modulated down to a much lower speed that maintains the desired temperature.

This is much more efficient than a fixed-speed compressor, which turns on and runs at high speed, overshooting the setpoint until it turns off. It then sits idle until it is needed again to bring the temperature under control.

This stop-start routine is inefficient compared to a variable-speed compressor that can run very slowly using only a fractional amount of energy. It is a major reason why a variable-speed mini-split heat pump is so much more efficient than a single-speed HVAC system.

Zonal Heating

Individualized heating is one of the critical benefits mini-splits offer. With this system, each room or zone in your home can have its own temperature setting. That means you can tailor the temperature to meet your needs in each space.

For example, if you want the living room to be warmer than the bedroom, you can set the thermostat accordingly. That flexibility can save you money on your energy bills, as you won’t need to heat or cool areas you’re not using.

A homeowner adjusts a smart thermostat connected to a mini-split system on the wall of her home

Additionally, it can provide a more comfortable environment for occupants, as everyone can customize the temperature to their liking. If you’re looking for a heating system that offers individualized comfort and efficiency, mini-splits are a great option.

Ductless Mini-Splits Are Quieter 

Traditional HVAC systems can be pretty loud, mainly when first turned on. That can be a significant problem for anyone who values peace and quiet.

Mini-splits have a much quieter operation, making them an excellent choice for anyone who wants to avoid the noise pollution that traditional HVAC systems can create. 

Easier Temperature Control

Mini-splits offer easier temperature control than traditional HVAC systems. Most models come with remote control, so you can easily adjust the temperature from anywhere in the room.

Additionally, many models allow you to set different temperatures for distinct areas of your home as mentioned. That means you can keep the temperature in your living room at a comfortable level while keeping the temperature in your bedrooms cooler, saving you money on your energy bills.

A homeowners points a remote control at the air handler unit of her mini-split system

So a mini-split is worth considering if you’re looking for an HVAC system that is easy to use and provides greater temperature control.

Mini-Splits Don’t Require Much Space

Ductless heat pumps don’t require much space, making them excellent for small homes or apartments. Additionally, they can be installed in various locations, including closets, attics, and crawl spaces.

Pro Tip: When shopping for a mini-split, be sure to look for a model that is Energy Star-certified. Approved units are the most energy-efficient models on the market and can help you save money on your energy bills.

For a quality mini-split, check this Senville LETO Series Mini Split Air Conditioner Heat Pump from Amazon.com. It comes with an inverter heat pump, remote control, and installation kit. 

Besides, it’s Alexa-enabled, making it easy to control the temperature with your voice.

Tips for Making Your Home More Energy-Efficient

Having looked at some of the ways that ductless heat pumps can make your home more energy-efficient, let’s now look at some general tips for making your home more energy-efficient. After all, even if you don’t have a mini-split, you can still save money on your energy bills by making your home more energy-efficient.

Here are a few tips for making your home more energy-efficient:

Get a Home Energy Audit

A home energy audit is a great way to learn about your home’s energy use and identify areas where you can improve. The audit will assess your home’s energy use and provide recommendations for improving efficiency.

Many utilities offer free or discounted audits, so check with your local provider. Once you’ve completed the audit, you can implement the recommended changes to help reduce your energy consumption and save money on utility bills.

Seal Air Leaks

One of the most significant sources of energy wastage in homes is air leaks. These are tiny gaps and cracks around doors, windows, and other openings that allow heat to escape in the winter and cool air to escape in the summer.

Fortunately, sealing air leaks is a relatively easy and inexpensive way to improve your home’s energy efficiency. Use weatherstripping or caulking to fill the gaps and cracks around doors, windows, and other openings.

Closeup on a homeowner applying window caulk to a seam at the base of a window's interior using a caulk gun

You can also use door sweeps to seal the gap between your door and the floor. By sealing air leaks, you can help reduce your energy consumption and save money on utility bills.

Install Insulation

Another great way to improve your home’s energy efficiency is to install insulation. Insulation helps keep heat in during the winter and cool air in during the summer, making your home more comfortable and reducing your energy consumption.

There are a variety of insulation materials available on the market, so be sure to choose one that best suits your needs. Once you’ve installed insulation, you can enjoy lower energy bills and more comfortable home.

Upgrade to Energy-Efficient Appliances

If your appliances are old and inefficient, upgrading to energy-efficient models can help you save money on your utility bills—energy-efficient appliances use less energy to operate, so they cost you less to run.

When shopping for energy-efficient appliances, be sure to look for models that are Energy Star-certified. Energy Star-certified appliances are the most energy-efficient models on the market.

Use a Programmable Thermostat

Using a programmable thermostat allows you to set different temperatures for the morning, afternoon, and evening, so you’re not heating or cooling your home when you don’t need to.

A homeowner adjusts the settings on their smart thermostat from their smartphone.

For example, you can set the temperature lower when you’re away at work or school and higher when you’re at home. Using a programmable thermostat can save money on your energy bills and reduce your energy consumption.

Use Natural Light Whenever Possible

One of the easiest ways to reduce energy consumption is to use natural light whenever possible. For example, open your curtains or blinds during the daytime and let the sun light up your home.

You can also take advantage of natural light by using skylights. Skylights are a great way to add natural light to your home and reduce your need for artificial lighting.

Summary

Most mini-split heat pumps are ductless, which is one of the reasons they are more efficient than central air HVAC systems.

Most systems also employ inverter-driven variable-speed compressors that allow the heating and cooling supplied by the heat pump to be precisely modulated.

This feature allows the system to run very slowly when the desired temperature is reached, thereby consuming very little energy.

By comparison, the inefficient approach of single-speed systems that turn on and off to control the amount of heating or cooling provided by the system consumes far more energy. It costs more to run as a result.

If you would like to read about more ways to save money on HVAC costs, why not take a look at our article that describes ways to save money on HVAC in your home.

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