Mini-splits are quickly becoming a favorite appliance among homeowners. First off, mini splits are incredibly efficient. According to the Department of Energy, it’s up to 30% more cost-effective to use a mini-split over a conventional air conditioner.
Additionally, mini-split systems are way more aesthetically pleasing than traditional air conditioners. This becomes an even bigger advantage when you consider that you can choose from a wide range of sleek and stylish mini split indoor air handlers. Recessed ceiling cassettes and vertical air handlers are particularly very beautiful.
Unfortunately, mini-splits can be highly confusing, especially if you’re accustomed to furnaces and traditional air conditioners. The technologically-enhanced features and advanced controls make the learning curve a little complicated.
This guide answers the common question – should you leave the mini-split ON through the summer months? Or should you turn them off like traditional furnaces and central air systems?
Should I Leave my Mini Split ON All the Time?
Yes, you should leave your mini-split all the time. Why? Because mini-split air conditioners are designed to run round-the-clock without wasting energy or hurting the appliance’s internal components. It’s more energy-efficient and cost-effective to let the mini-split run all the time.
How Mini-Splits Work
The following is a brief explanation of how the mini-split works to help you understand why running it all the time is better than turning it off periodically.
Mini-splits aren’t too different from traditional air conditioners, at least on working principles. They work based on a refrigeration cycle. Essentially, refrigerant flow within the unit allows the mini split to extract heat from indoor air and send (and dispose of) it outside the house via refrigerant material, typically freon.
TheThe cold refrigerant absorbs heat inside your house and circulates the now-hot refrigerant to evaporator coils located outside the house, where compression forces the heat out of the refrigerant.
The heat is then released into the outdoor air. This goes on until the thermostat setting (typically 78°F) is reached, gradually lowering the temperatures inside the house until you’re fully comfortable.
However, there are two main differences between mini splits and traditional air conditioners (central air and window/through-wall systems). First, mini-splits comprise an outdoor unit and indoor air handlers, whereas traditional air conditioners combine everything into one large body.
Secondly, unlike central air systems, mini splits don’t connect to the home’s ductwork system. Instead, they are completely independent systems that only need electric power to work.
Single Speed vs. Multi-Speed Mini-splits
Mini-splits can be single speed or-multiple speed systems. Single-speed mini spits are 0% (OFF) or 100% (running at full throttle). Meanwhile, multi-speed mini-splits typically have an extra speed setting, often 75%. So, the unit can be OFF, ON at 75%, or ON at 100%.
Of course, multi-speed units offer users greater flexibility and convenience. You can also save energy by running the unit at 75% instead of 100% on a not-so-hot day. You must manually switch the AC from one setting to another, though.
Alternatively, you can set a timer on the thermostat to automatically step the operation up or down. However, remember that not all mini splits have a timer.
Inverter Technology Mini-splits
However, newer mini-splits employ inverter technology that allows the appliances to run at any speed (technically) for even greater convenience and energy savings.
Inverter-motor air conditioners change the operating speeds automatically. So, for instance, if the unit is running at 50% and the weather gets a little hotter, the motor will self-adjust to 55%, then 60%, and so on to bring down the temperatures faster.
Then it automatically reduces the operating speeds once you’re within the desired temperature range.
The increase or decrease in speed happens gradually and in very small bits to avoid sudden indoor temperature changes.
Why Mini Splits Run All the Time
They are designed that way. Why? Because the inverter technology makes it possible to run the mini split air conditioner non-stop without adverse consequences.
You’re probably wondering how this is possible. Well, the inverter motor technology changes a few things;
Minimal Energy Wastage
As you may have experienced, single-stage and even dual-stage air conditioners consume a ton of energy. Single-stage units are particularly very expensive to run because they draw a lot of energy.
The main reason for the high energy usage is that single-stage air conditioners run at 100% as long as the appliance is ON. This can be very expensive.
Mini-splits spend most hours below 40%, thus consuming very little energy. As a result, they can run longer and still use less power than central air systems.
Reduced Wear on Moving Parts
One of the dangers of running the air conditioner at 100% for a long time is that it quickly takes a toll on the moving parts, especially the compressor motor and fan.
Imagine the fan running at 100% for eight hours non-stop! The risk of “burnout” and consequential damage is very high.
Fortunately, you don’t have to worry about such problems when using an advanced inverter motor running at 40%.
Fewer Temperature Fluctuations
Finally, one of the biggest challenges with single-speed and dual-speed systems that come ON and OFF repeatedly during cooling is sudden temperature bursts.
One second, it’s too hot, and the next second, it’s too cold. Sudden temperature bursts aren’t good for healthy living.
One of the reasons manufacturers developed the inverter motor technology was to solve this problem. Keeping the mini-split ON throughout and gradually adjusting the temperatures ensures more comfortable and healthy air conditioning.
So, Should Mini Splits Run All the Time?
The short answer is yes; mini-splits should run all the time. The benefits far outweigh the downsides.
- Comfort: Keeping the mini-split ON all the time eliminates temperature bursts common with traditional central air systems, ensuring greater indoor comfort.
- Save energy: Mini-splits are designed to run continuously without consuming more energy than central air conditioners. However, interrupting the running cycle by turning off the AC now and then negates all the gains.
Does Running a Mini Split Continuously Save Energy?
Yes. For instance, a 1.5 kWh single-stage window AC consumes 1.5 kilowatt-hours every hour that it’s running. This translates to 12 kilowatt-hours per day, assuming you run the AC for eight hours per day (US average) and 1,500 kilowatt-hours per year, assuming that you need air conditioning for 125 days per year (also the US average).
Now, assuming that you pay 11.33 cents per kilowatt-hour (also a US average), the cost comes to $1.36/day or $169.96/year.
Of course, the figure is slightly higher once you factor appliance efficiency ratio (SEER). However, we will assume a constant SEER value.
Now, consider that mini-split ACs spend most of the time on very low settings. Studies show that most mini-splits operate at about 40% for the better part of the day.
So, how much would this cost you? It is a lot cheaper. Using a 1.5 kWh mini split, it costs 0.4 (40%) x 1,500kWh = 0.6 kWh/hour. This translates to 4.8 kWh/day and 600 kWh/year. Thus, the cost comes to $0.54/day or $67.98/year.
Of course, you can’t run the mini-split at 40% all the time. Times come when the appliance shoots to 100% to compensate for a sudden increase in outdoor temperatures. However, the difference is still significant.
According to the DOE, homeowners can expect to save 30% of energy costs monthly upon switching to mini split air conditioners from traditional central air systems.
Most Energy-Efficient Way to Run a Mini-Split?
The most energy-efficient way to run a mini-split system is to set it to AUTO and direct warm air towards the floor, so your mini-split variable-speed fan automatically adjusts to maintain a consistent temperature.
When a Constantly Running Mini Split May Be a Sign of Trouble
Everything said, though, a constantly-running air conditioner may also point to a few issues.
For instance, if the unit constantly runs 100%, you may have one of the following issues (all of which are easily fixable);
- Low outdoor temperatures
- Not enough refrigerant
- Wiring issues
Best Practices for Running your Mini Split in the Summer
- Find a comfort level you’re comfortable with and stick to it.
- Run the mini-split continuously, not ON and OFF repeatedly.
- Set the fan to AUTO to minimize energy use while maximizing comfort levels.
- Keep air continuously moving with routine maintenance.
- Make sure the outdoor condenser unit drains properly.
- Leave interior doors open for maximum air circulation.
- Block out the sun using shades and curtains.
Should I Leave My Mini Split On All The Time FAQs
Should Mini-Splits be Turned off?
No. mini-splits should not be turned off manually unless you don’t need cooling (or heating) anymore. If you’re worried about energy costs, mini splits are even cheaper when you leave the appliance ON throughout.
Is it Bad to Run a Mini-Split All Day?
No. There’s no harm in leaving the mini split to run all day. The opposite is true; repeatedly turning the mini-split ON and OFF can cause faster wear and tear throughout the day.
Should I Turn my Mini-Split OFF at Night?
No, don’t turn the mini-split off at night. Instead, turn the thermostat down several degrees to lower energy consumption. With that done, you can run the mini-split the entire night while using very little energy.
Should I Leave my Mini-Split ON in Winter?
It depends on whether it’s a dual-purpose air conditioner and heat pump or explicitly an air conditioner. Leave it ON throughout the winter if it’s a dual-purpose system. However, turn it off if it’s a single-purpose air conditioner.
You should leave your mini-split ON throughout the summer months as they’re low-maintenance and highly energy efficient.
However, keep a close eye if the unit shows underperformance, such as prolonged high-speed operation and poor cooling (lukewarm air).