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

Smart thermostats are all the rage these days, boasting convenience, smart technology, and even money-saving features.

These products have been on the market for several years for central HVAC systems, but do they work for mini splits?

What Is a Smart Thermostat?

In residential HVAC, there are three common types of thermostats.

  • Non programmable
  • Programmable
  • Smart/Wifi-Connected

Non Programmable Thermostats are the simplest kind. They are also the most popular. The user sets the thermostat to a certain temperature and the system maintains that temperature until the user changes it. These thermostats all offer a heat and cool mode, as well as “Fan On” and “Auto.” 

Programmable Thermostats allow users to set a schedule in the thermostat. For example, you can set the system to lower the temperature of your home while you are away at work all day and raise it just before you arrive back.

Each day can be programmed individually. The program can be temporarily overridden by manually setting the temperature and pressing the “Hold” button. These thermostats are not connected to wifi.

Smart Thermostats are connected to wifi. These thermostats allow you to access your HVAC system remotely from smartphones, tablets and laptops. They use smart technology to collect information and adapt better to the patterns of a household. They can adjust the system for increased energy efficiency and savings.

A smart thermostat on the wall in our second net-zero home

What Exactly Does a Smart Thermostat Do?

One of the biggest benefits of smart thermostats is their ability to be accessed remotely. For households who take vacations, this offers peace of mind that your HVAC system is still working while you are away. 

It also allows you to turn the system on or adjust the temperature while you are away from home.

Many smart thermostats (like the Nest) have a learning feature that notices what temperatures you prefer at different times of the day and adapts automatically.

They can even use a geo-tracking feature to adjust the HVAC system when you leave the house so you can save a bit of money. This feature will turn the system back on when it sees you are on your way home.

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

Some notable features of smart thermostats are as follows:

  • Large, digital temperature displays – these can be easier to see and adjust than older models.
  • Remote access from your smartphone – change your home’s temperature any time, anywhere. Useful to stop your pipes from freezing while you’re away or to ensure your pets are comfortable while you’re out.
  • Create heating and cooling schedules using apps on your phone or tablet – these can be far easier to input schedules than traditional programmable thermostats.
  • Save money on your energy bills – smart technology can adjust your HVAC setting for maximum savings while maintaining home comfort.
  • Household pattern learning – this feature automatically learns when you are in and when you are out, so you don’t have to program the thermostat manually.
  • Weather tracking – automatically turns the temperature up or down according to local weather conditions.
  • Energy profiles – some models use information about your home, such as size, which climate zone you are in, etc., to tailor the setup to your circumstances and simplify operation.
  • Tracking energy use – get an on-demand update on your energy consumption, complete with graphs, trends, and advice on where you could save energy.
  • Voice control – compatible with Alexa and Google Assistant, many smart thermostats can be used with voice commands.
  • Motion detection – automatically detect when people are at home and active using motion sensors, which helps tailor the learned schedule to your needs.

Smart Thermostat Compatibility with Mini Splits

Smart thermostats were built for central HVAC systems. They are mounted to the wall and require a “C” wire (common) from the furnace for power. 

If you have a central HVAC system, you can likely install one yourself. In fact, the online setup with your phone will often take longer than the thermostat installation.

Mini splits are a little different.Their thermostats are tied into the remote. These thermostats are considered programmable thermostats but they are not connected to the system by any wiring.

A homeowner using the Nest Compatibility Checker to determine compatability with their mini-split system
Courtesy of Colton Crump DIY
Two mini-split compressor units outside a home in snowy conditions
The exterior compressor component of a ductless mini-split

Mini-splits already use smart technology for internal control. The indoor air handlers are in constant communication with the outdoor condenser.

To use a mini split with a smart thermostat, you would have to run the system in a non-communicating mode and this would remove much of the technology that makes a mini split so efficient.

These systems are generally not compatible with smart thermostats.

Adapters for Using Mini-Splits With Smart Thermostats

Adapters are available to allow some mini-splits to work with certain smart thermostats.

This sounds great in principle, but the models we have seen do not get good reviews. Mini splits were made with efficiency in mind and are meant to run within their own system. Even with adapters, you can run into issues undoing the performance optimizations that come built into a modern mini-split.

One reviewer’s experience highlights the pitfalls of trying to force compatibility using third-party adapters. A user named Zeke said the following of a model he had tried with a Mitsubishi mini-split.

“Works, but beware if you have a heat pump. This adapter WILL work with heat pumps however I strongly recommend against it as it will undo most performance optimizations. That’s because this [thermostat adapter interface] can’t send IR data and some other data to the outside unit. What ends up happening is that any call to heat will trigger the backup electric resistance, turning your nice efficient heat pump into a toaster.”

In fact, the product description for this adapter states that it “works with conventional systems, NOT heat pump control.” Not even the manufacturer is willing to recommend its use with a heat pump!

Smart Wi-Fi Controllers for Mini-Splits

A smart Wi-Fi mini-split controller works differently from a traditional thermostat. It is really just an upgrade to the LCD remote that comes standard with a mini-split. These controllers use the same technology as the original remote but they allow you to access the system remotely.

This is really the best option for mini split owners that want similar smart thermostat options. It might not provide complete control of all the features of your mini-split, such as dry mode or fan-only mode, but it will allow you to program schedules for heating and cooling as well as give you remote access.

There are several manufacturers of these Wi-Fi mini-split controllers. Some are marketed as smart thermostats, but they are really just wifi controllers.

The following brands manufacture “smart thermostats” for mini-splits.

  • Mysa
  • Cielo
  • Honeywell
  • Sensibo

There is some variability in terms of warranty and the range of the infrared units, so worth considering which are compatible with your home setting before you buy.

A summary of essential features is provided in the table below.

Comparison of Key Features of Wi-Fi Mini-Split Controllers (Smart Thermostats)

Mysa Smart ThermostatCielo BreezeHoneywell D6Sensibo SkyFlair Puck
Free ShippingAcross N AmericaThe US OnlyAcross N AmericaThe US OnlyThe US Only (order must be over $229)
Thermostat Display and ControlYesYesYesNoYes
Range30 feet6-12 feet30 feet20 feet30 feet
Free Access to All App FeaturesYesYesYesYesYes
Warranty2 years1 year5 years1 year1 year
Integration with Other Smart Home ProductsApple Homekit, Alexa, Google HomeAlexa, Google HomeAlexa, Google Home, SmartThingsAlexa, Google Home, IFTTTAlexa, Google Assistant

If you are looking for smart thermostat for your mini split, one of these should do the job. These wifi controllers should be compatible with most systems that use a full state LCD screen display with target temperature, fan speed, and mode settings. 

Manufacturers include Mitsubishi, Fujitsu, LG, Daikin, and several other popular mini-split companies. We recommend you use the thermostat manufacturers’ compatibility checkers or refer to their website before you buy.

Leave a Reply

Your email address will not be published. Required fields are marked *