Using a Mini Split in a Garage: Pros/Cons & Considerations

Garages in residential houses can be repurposed into a workshop, gym or other uses. As the time spent in the garage increases, heating and cooling are needed as much as the rest of the house. Mini splits seem like a viable choice but what are the potential downsides?

Mini splits are generally good for heating and cooling the garage. However, the potential downsides must be weighed against the upsides based on your needs for the best outcome.

Pros and Cons of Mini Split in a Garage

Mini splits are a type of heating and cooling system that have many advantages over traditional central air systems and room air conditioners such as portable and window ACs. When used in garages, their pros are as follows:

Pro #1: Zoned Climate Control

Zone control is also known as independent or standalone control. It refers to a heating and cooling system that can change the temperature settings in a particular room without affecting other rooms, effectively creating two or more thermal zones in the house.

When extending your existing central air system to serve the garage, you’re still relying on the same thermostat to control the room temperature. It is impossible to change the temperature in the garage without affecting the rest of the house.

Garages are typically not insulated or partially insulated. Hence, the heat loss/gain is more significant than the rest of the house. Thus, you may find the garage is too cold in the winter and too hot in the summer. If you change the thermostat temperature settings to suit the garage, the rest of the house may experience the opposite.

With a mini split or other independent air conditioning units, you can ensure that the garage and the rest of your house always stay at the desired temperature.

Using a mini split also reduces energy wastage. You can choose to turn on the unit in the garage only when you need it, unlike a central air system where the garage will be heated/cooled regardless if you need it or not.

Pro #2: Rapid Cooling

The central air system in your house is likely to be sized based on the house’s square footage minus the garage. If the garage is tapped into the central air system, it’ll take several hours to cool down the space. Not to mention, the rest of the house will also be affected.

In an event where you need to open the garage door, the temperature and humidity in the garage will shoot up in an instant. As a result, you need to wait a long time before the garage can return to its previous comfort level.

A properly-sized mini split can cool the garage within an hour. A one-size bigger mini split can even bring the cooling time down to 30 minutes.

Many homeowners convert their garage into a workshop where they spend a few hours on some hobby projects. Such a use-case scenario requires a rapid cooling system like mini splits to cool the garage down to a comfortable level within a short period.

Pro #3: Energy Efficient

The energy efficiency of air conditioning units is measured by SEER (seasonal energy efficiency ratio) for cooling and HSPF (heating seasonal performance factor) for heating. Mini splits often have higher SEER and HSPF ratings than other types of air conditioning units.

Old central air systems are not operating efficiently due to wear and tear, dirty ductwork and overall mechanical degradations. New central air systems are more efficient thanks to variable-speed compressors and general technological advancement. However, they are still not as efficient as ductless mini splits.

Wall-mounted, ceiling cassette and other forms of ductless mini splits are high in energy efficiency. Their form factor and the fact that they don’t use ducts for air distribution allow them to operate efficiently.

Ductless mini splits are also superior to portable and window air conditioners in terms of energy efficiency. However, the difference may be insignificant considering that you don’t use them 24/7.

But, if you do use the garage for long hours, then a mini split may save you a noticeable amount of electricity than portable and window air conditioners.

Pro #4: Simple Installation

Extending the existing central air system to serve the garage is arguably more complicated than installing a new mini split.

Depending on your existing system, you may need to check if the system capacity is sufficient, rebalance the airflow and redo the settings to ensure the system functions well with the additional space.

On the other hand, the installation of mini splits is straightforward. Some homeowners even successfully install one by themselves. Many mini split brands favor DIY installation and they provide all the information you need for a smooth installation.

Pro #5: Modernization

Having permanent climate control in the garage is likely to increase your home value. However, some buyers may look for a more efficient and modern heating and cooling solution system. Mini splits are seen as a premium solution and could appeal to buyers who value efficiency and modern HVAC solutions.

While a mini-split in the garage might not universally increase home value, it can enhance marketability by appealing to specific buyer demographics.

Although mini splits have many upsides even when used in the garage, they too have a few downsides. Some of the downsides apply to mini splits in general and some specifically to garage applications:

Con #1: High Upfront Cost

Currently, the cost to purchase and have an authorized dealer to install for you is still unjustifiable by many homeowners. Many times, extending the ductwork of your existing system is cheaper than installing a new mini split unit in the garage.

The cost of a new mini split can be reduced by going for the DIY route. Homeowners with good hands-on skills can save thousands of dollars by installing the mini split themselves. However, certain mini split brands don’t provide a warranty if it is not installed by their authorized dealers.

When compared to other solutions such as portable and window ACs, the cost of purchasing and installing a new mini split is also higher.

Con #2: Less Impact on Home Value

Many buyers consider the garage primarily a storage or parking space, so they may not see heating and cooling as a necessary upgrade. Buyers who don’t intend to use the garage as a workspace, home gym, or hobby area might not value the addition as much.

Some buyers may see the mini-split as an unnecessary luxury and not a functional improvement that justifies a higher purchase price. If the system is outdated or poorly maintained by the time of sale, it could detract from its value.

Besides, if the mini-split is installed in a way that detracts from the aesthetics of the garage or limits usable wall space, it might be less appealing.

Con #3: Required Supplemental Heating

At locations where the winter temperature is freezing cold, mini splits may require supplemental heating which further increases the cost. Meanwhile, your existing central air system is proven to be reliable in the harshest conditions.

Although certain mini split models like arctic and cold climate are designed to operate in extreme climates, many homeowners are still not confident to operate them without a supplemental heating source. This results in additional cost and added complexity.

Con #4: Need Wall Space

Garages are typically full of cabinets and tool hangers, leaving no wall space to hang a mini split head unit. On the other hand, extending the ductwork of your existing system allows you to conveniently place the vent on the ceiling level.

Although you can use other types of mini split head units like a ceiling cassette unit where you can hang it on the ceiling level as well, or a floor-mounted unit, the upfront cost will be further increased and the added complexity may not justify the effort.

Considerations for Using a Mini Split in the Garage

A mini split unit is an appealing option to heat and cool your garage. However, the setup and installation must be done correctly. Below are several considerations for using a mini split in the garage:

• Proper Sizing – The mini split must be appropriately sized for the garage. A unit that’s too small will take a long time to heat/cool and struggle to maintain temperature. Meanwhile, an oversized unit will short cycle, reducing efficiency and potentially leading to high humidity in the garage.
• Installation Cost – While mini splits may be more affordable than extending ductwork in some cases, they still have a higher upfront cost compared to simpler heating or cooling solutions, such as portable units.
• Ventilation Needs – If you use the garage for activities that generate fumes (eg: vehicle repair, painting), you need to ensure proper ventilation. Mini splits are not designed to handle air filtration or exchange in these scenarios.
• Building Codes – Ensure that the installation complies with local building codes, especially in attached garages where carbon monoxide concerns may arise.

When a Mini Split is an Ideal Solution?

If you’re looking for a solution that won’t compromise the climate control in the rest of your house, an independent heating and cooling system like a mini split is ideal. Or, if you like simplicity and the idea of having one unit to provide both heating and cooling, a mini split is perfect.

However, if your existing HVAC system has spare capacity and you find that extending the ductwork is much easier and cheaper, then a mini split may not be the best choice.

Conclusion

A mini split system is a highly effective and versatile option for heating and cooling your garage, provided the system is sized and installed correctly. It’s an investment that enhances comfort and usability, particularly for those who use the garage as more than just a storage space.