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

Ductless mini-split heat pumps aren’t as common as central HVAC using ducts. However, many homeowners are now choosing ductless heating and cooling systems for different reasons.

So, you may wonder if using a ductless mini-split is worth it.

Assessing mini-splits vs. central air conditioners and furnaces isn’t akin to comparing apples and oranges—several variables complicate the real-world scenarios. 

This article will explain if and when it’s worth using ductless heat pumps.

Is Using a Ductless Mini-Split Worth It?

Ductless mini-splits are generally worth it, as they provide both heating and cooling and are more efficient than traditional HVAC systems. They don’t need ductwork, are very quiet, reliable, and you can adjust the temperature by room or by zone.

In 2021, the total ductless heating and cooling systems market expanded to $98.4 billion. This subset is poised to be worth $145 billion in 2026. This growth is expected to sustain through 2032 as mini-splits become more prevalent.

Ductless mini-splits are already a default option for many homeowners who want space heating and cooling. Now, numerous consumers consider mini-splits as an alternative to traditional HVAC systems.

However, whether or not they are worthwhile for you depends on the pertinent factors in your house, the heating or cooling requirement, the climate, and many other variables. 

When It’s Worth It To Use a Mini-Split

Choosing a heating and cooling system is simpler if you have a clean slate. For instance, if your house has no existing provisions or installations, every heating or cooling system requires you to start from scratch. However, your home probably has some requirements and limitations.

The limitations could be based on several things, including: 

  • Infrastructural 
  • Energy-related 
  • Climate-based 
  • Personal needs and preferences 

So, we’ll try to cover all these factors in the following scenarios.

You Need To Heat or Cool Only One Room

Irrespective of all factors, a ductless mini-split is ideal if you need a unit for only one room.

Suppose you need an air conditioner to cool a room. The conventional options are window, split, and portable air conditioners.

However, none of these is a heat pump unless a model has the reversing valve to switch the refrigerant flow as you toggle the heating and cooling modes. Thus, ductless mini-splits are the most worthwhile option for heating and cooling one room using the same outdoor unit and an independent indoor head.

You Want Zonal Heating and Cooling for Different Rooms

Suppose you need space heating and cooling for more than one room. A mini-split can serve multiple rooms or spaces, depending on its capacity and the square footage or meterage of the area.

You’ll have only one outdoor unit and multiple indoor head units or air handlers. Each indoor component will have a conduit carrying the refrigerant or coolant coils to the outdoor installation. You can get as many indoor heads for an outdoor unit as the capacity model can support.

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

For instance, a 2.5-ton (24,000 BTU) ductless mini-split can simultaneously serve two to four rooms. However, you don’t need to use all the indoor heads if you don’t need them at a time.

Instead, you can use only one indoor head to heat or cool a chosen room and keep the others off.

A traditional HVAC system, including an air conditioner and furnace, cools and heats the entire house. However, you may not need to cool or heat the whole property at certain times. This unnecessary heating or cooling of a much larger space than you want is a waste of money and resources.

Many homeowners modify their ductworks to have dampers to somewhat regulate the warm or cool airflow to the zones they want. Still, the central air conditioner or furnace will circulate much more cool or hot air than necessary for the selected zone.

In effect, you will have significant energy loss through the ducts, regardless of the dampers inhibiting the airflow.

You Want Specific Temperatures in Different Zones

You are perhaps familiar with the practice of using multiple thermostats in different rooms and spaces to maintain the desired temperature. These thermostats, including the smart variety, work with both furnaces and central air conditioners. However, this system isn’t better than mini-splits.

Using multiple thermostats for various zones with an HVAC system can regulate the forced-air handler units. Still, the central air conditioner or furnace will cool all the air in the ducts and vents.

Contrast that to the indoor heads of a ductless mini-split. You turn on only that indoor unit which you need. The heat pump is not heating or cooling any excess air, and there is no ducting.

You also don’t need multiple thermostats, air handler units, ducts with dampers, or other such modifications. Every indoor head has a remote, so you can select the exact temperature to the degree you want in a room or space, and all the indoor units work independently.

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

So, you can have 68°F (20°C) in one room and 74°F (23°C) in another. Since every indoor unit is an independent and dedicated air handler, you don’t have to worry about your rooms or zones heating or cooling inaccurately.

In contrast, regular HVACs don’t have air handlers for every room but a central one or one on every floor.

Furthermore, some of the latest ductless mini-splits are Wi-Fi-enabled. This characteristic means you can use the heating and cooling functions remotely and the other settings whenever you want.

Your Home Doesn’t Have Ducts and Air Handlers

Central air conditioners and furnaces require ducts and air handlers. Gas furnaces also require chimneys or flues and combustion air intake ducts.

You must undertake a major reconstruction or home renovation project if you need supply and return ducts, combustion air intake vents, etc.

Ductless mini-splits require only one hole per indoor head. This hole is typically three inches (7.62 cm) in diameter. So, this single, tiny hole is all you must drill for every room you choose to have such a unit. Installing ductwork is an enormous task in comparison.

You may have read about the slightly lower costs of central HVAC systems compared to mini-splits. Some online quotes cite a substantial difference. However, this difference doesn’t account for ductwork. You may also need more than one air handler.

You Require Supplemental Heating or Cooling

Suppose you have an HVAC system and require some supplemental heating or cooling. In such scenarios, a ductless mini-split is more than worthwhile.

Many homeowners add new rooms, expand their living areas, and renovate their houses in many ways. If the HVAC’s heating or cooling isn’t sufficient or unavailable for a space, ductless heat pumps are the most convenient, effective, and efficient option.

Consider a basement that doesn’t have ducts or is beyond the HVAC coverage. Or, you carve out a room by partitioning an existing space, and the ducts may not cover the new area. Installing new ducting or upgrading a central air conditioner and furnace is a financially-pressing endeavor.

Instead, a mini-split for only that new room, basement, or any other space is a wise choice. Besides, the installation is straightforward and independent of the HVAC system.

You Want an Energy-Efficient Heating and Cooling System

As explained, central HVAC systems account for a significant energy loss through the ducts. You may also have additional loss of energy if the ductwork has leaks, damages, general deterioration, or quaint alignment.

Ducting near the ceiling reinforced with metallic tape to cover leakage

Apart from these issues, a central HVAC system isn’t as energy-efficient as ductless heat pumps. The traditional split systems aren’t as good as mini-splits as per their CoP, HSPF, and SEER ratings.

Consider the following facts:

  • Old central air conditioners don’t have a SEER rating of more than 14 or 15.
  • Recently manufactured central air conditioners have a SEER rating of 14-20.
  • The absolute maximum SEER rating for a split air conditioner system is 25.
  • The SEER ratings for ductless heat pump mini splits are between 21-30.

The SEER ratings of most contemporary central air conditioners are rarely 20. However, the best split systems (standard splits, not to be confused with ductless mini-splits) have a SEER rating of around 20.

In contrast, ductless heat pump mini splits’ cooling capacity and energy efficiency start from 21, and can go as high as 30. Let’s put this SEER rating into the context of the Coefficient of Performance (CoP).

The CoP tells you how much heating or cooling output you can expect from a ductless mini-split for every unit of electricity it consumes.

This CoP is equal to the SEER rating x 0.293.

So, a 22 SEER rating means the CoP is 6.5. Thus, a ductless heat pump will deliver 6.5x the equivalent cooling output per unit of energy.

Compare this to a central air conditioner with a 14 SEER rating or a split unit rated 16. These CoPs will be ~4 and ~4.7. Hence, you are likely to save much more on electricity consumption with a ductless mini-split than with a conventional split and a traditional or central HVAC.

Like SEER, which implies cooling efficiency, HSPF rates the heating capacity of the energy a unit consumes. Heat pumps, ductless or ducted, have the highest HSPF ratings among all types of heating appliances.

An HSPF rating of nine or more is deemed energy-efficient by the industry. So, a 10 or 12 HSPF rating is excellent.

Ductless heat pumps have HSPF ratings of 10 and higher. Thus, you can expect these units to be the most energy-efficient at heating.

When It’s Not Worth It To Use Ductless Mini-Splits

Mini-splits have numerous strengths that make them worthwhile. However, no system is perfect in our world. Thus, all ductless heat pumps have some shortcomings, depending on what your objectives are.

You Have a Large House

Ductless heat pumps aren’t worth it if you have a large house and need to cool or warm the entirety of the space. A 3,000 sq ft (~279 sq m) house is beyond the scope of most mini-splits.

Also, the models with maximum heating or cooling capacity available right now can support up to five indoor heads. Thus, if you want to heat and cool six or more rooms, one heat pump won’t suffice.

Your House Has Ductwork

A central HVAC system may cost less than a heat pump of equivalent capacity if your house already has the ducts. Combine this convenience with your home’s size or the number of rooms you need to cool or heat, and you will find traditional HVAC more worthwhile.

Mini-splits also have only one outdoor unit. So, even if you have two to five indoor heads, you must route all those coils and drain lines as necessary. Of course, you can have these conduits as long as 50 feet (15.24 meters), but such extended installations can be expensive.

The Climate Is Extreme

Air source heat pumps don’t fare efficiently in frigid weather. The CoP or Coefficient of Performance drops significantly when the ambient temperature dips below 40°F (~4°C). The CoP plummets further when the outdoor temperature is below 32°F (0°C).

A mini-split compressor unit outside a home in wintery conditions

Even if you have a cold climate air source heat pump, which is ductless and a mini-split, the unit may not deliver anywhere close to the 4-5 CoP. The CoP can drop to two or lower if the outdoor temperature is around 14°F (-10°C).

A few ductless mini-splits can operate in temperatures as cold as -13°F (-25 °C). However, you won’t have the same energy efficiency or heating effect.

The available air source heat pumps rarely perform well at around -4°F (-20°C), even if they operate. But, of course, this issue isn’t a problem with geothermal heat pumps.

Conclusion

Using a mini-split is worth it, and you will likely save some money on your cooling and heating needs. However, one ductless heat pump unit isn’t sufficient for large houses.

In addition, sub-freezing conditions aren’t ideal for air source mini-splits.

Sources

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One Comment

  1. This is an amazingly informative and comprehensive guide; a fabulous mini-course. It’s more than timely with respect to energy efficiency, targeted heating and cooling management, financial considerations, and the option to install in the first instance or retrofit just the right unit size for whatever are the space needs. Great article!

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