How to Keep Your Ductless Mini Split Heat Pump System Running Smoothly

11 Proven Tips from HVAC Experts

By James K. Kim

If you’ve already made the wise decision to invest in a ductless mini split heat pump system for your home or business, then you’re also probably looking for ways to get the most “bang for your buck” out of it to maximize your ROI.

The good news is that today’s modern mini split heat pump systems are engineered and designed to work more efficiently than traditional split HVAC systems (e.g. furnaces/boilers, air handlers, condensers, etc.)

However, a large factor in maximizing efficiency savings and overall performance from mini splits is in their proper control and seasonal maintenance schedule.

To help make things easier for owners, contact Cottam Heating & Air Conditioning today, or keep reading to learn 11 simple tips to help maximize the efficiency of mini split heat pump systems.

11 Tips to Maximize the Efficiency of Your Mini Split Heat Pump System

1. Check Home Energy Efficiency

The condition of your home has a significant impact on the efficiency of your HVAC equipment.

You can have the most modern mini split system in the world with all the bells and whistles…but it’s a waste if your home acts like a leaky bag by letting out conditioned air while letting outside air infiltrate it.

The most efficient way to run a mini split is in a home that’s properly sealed and insulated, so it doesn’t let warm or cool air escape.

This includes ensuring your home has:

• Sufficient insulation in the walls, attic, basement, etc.
• Windows and door are properly installed and sealed
• There are no interior or exterior wall openings

2. Get Your Mini Splits Maintained Regularly by a Reputable Local HVAC Company

Regular maintenance of ductless mini split heat pump systems is the key to keeping them running efficiently. Be sure to contact your trusted local HVAC company to book your seasonal maintenance appointments.

Aside from checking system operation and measuring refrigerant levels and pressures, during the maintenance an HVAC technician will run through an extensive list of mini split heat pump system maintenance check items, which may include the following:

• Cleaning the reusable filters and inspecting for any visible wear and tear
• Testing the condensation drainage functionality of the ductless mini split heat pump system to ensure it is draining properly during system operation
• Visually inspecting and cleaning the condenser coil on the outdoor heat pump unit. Also keeping the area surrounding the heat pump unit clean to ensure no airflow blockage from vegetation, debris, etc.

3. Be mindful of indoor unit locations

One of the most important factors in maximizing mini-split proficiency is its placement.

When installing your indoor unit, choose a spot that allows for unobstructed airflow.

Avoid placing furniture or curtains directly in front of the unit, as this can hinder its ability to distribute cool air effectively.

Additionally, one should also consider the height of the unit.

Mounting a mini split slightly above eye level can help ensure even cooling and heating throughout the room.

4. Don’t forget the importance of outdoor locations, too

There are two major considerations here: Space for service access and the provision of plenty of airflow.

Manufacturers may have requirements for things like how far away the refrigerant pipe and wiring connections should be, so pay attention to this because it could void your warranty.

Units can be mounted on the exterior of a home or on the ground.

For ground installation, make sure that the unit is placed on a concrete slab or other sort of stand that’s at least 4 inches above ground. This will help protect it from sitting in puddles and snow.

It’s also a good idea to position the unit on top of rubber pads to eliminate vibration noise. Finally, consider protecting it with a cover in the wintertime.

5. Optimize Your Mini Split’s Settings

Another useful way of increasing efficiency is by optimizing your mini split’s settings.

To do this, begin by choosing your comfort level. You can adjust your temperature settings until you like the comfort level you are feeling.

It’s important to know that a ductless mini split unit measures the temperature closer to the ceiling where it is installed. This means you may need to set the temperature a few degrees higher in heating mode or a few degrees cooler in AC mode than what you are used to.

Another setting option to consider using is the “Auto” fan setting.

This mode allows the system to change fan speed according to the outside weather conditions combined with your selected temperature setting.

6. Manage mini split run times properly

Most traditional central heating and air conditioning systems cycle on and off in approximate 15-minute time periods. However, mini-split heat pump systems are different.

It may be tempting to power on and off the mini split heat pump system or set very high (in AC mode) or very low (in heat mode) temperature set points in order to conserve energy. This may seem reasonable because that’s what a lot of people are used to doing with other types of central HVAC systems.

However, this is not recommended if you are looking to maximize the efficiency of your mini split heat pump system.

That’s because mini splits are designed to operate at their highest efficiency when used consistently.

One can think of this using the analogy of a vehicle getting better gas mileage when it is running at a constant speed.

Similarly, instead of dramatic and abrupt changes, a better cost-saving alternative lies in making smaller adjustments.

So you may be saying to yourself, “Does this mean I should run my mini split heat system all the time?”

The answer, for the most part, is “yes”.

However, there are a few exceptions which we will cover shortly.

On a typical day, a ductless mini-split uses less energy when it is allowed to run continuously. Plus, this will keep indoor temperatures in the conditioned space more consistent and even.

So what kind of small changes can be made on a continuously running mini split to help save energy?

As previously indicated, having a mini split ramp up or down with major temperature setting changes can actually cause them to work less efficiently.

An alternative solution is to set the mini split to a smaller setback temperature overnight while you’re sleeping if running the system in heating mode.

In other words, just set it just a few degrees lower when you are sleeping than you normally would during the daytime.

This results in the system not needing to work as hard in the morning to bring the room back to your preferred temperature.

As an exception, if you are planning on being away from home for more than a few days, it can help you save on costs by turning off the mini split (provided the outside temperature is not extremely cold or hot).

For AC season, you may be tempted to run the mini split in cooling mode 24/7. Obviously, this adds to your electrical bill.

Unless it’s a heat wave or gets unbearably warm, then you may want to consider only running the mini split in air conditioning mode on the hot days where it’s absolutely needed.

7. Consider the Extent of the Extreme Outside Temperatures

Do ductless mini splits also provide heating when it gets cold outside?

Absolutely. But it’s also important to consider the extreme outside temperatures that impact the efficiency levels of your ductless mini split heat pump system.

Extreme subzero cold (or hot such as 115+ degrees F) can force a mini split to work much harder than normal in order to maintain a comfortable indoor temperature.

For example, if you live in a northern region that has extended periods of subzero temperatures, it may be worthwhile to supplement your mini-split system with a secondary heating source such as a boiler or electric baseboard.

8. Utilize the airflow vent controls

According to physics, warmer air rises whereas denser, cooler air sinks.

Knowing that fact, the mini split unit’s airflow can be directed accordingly to increase efficiency.

The mini split vents can be directed upward during cooling mode, letting the conditioned air descend towards the floor.

Adjust your mini split’s air handlers in summer when you’re using AC to cool your home by directing airflow upwards.

In winter, direct airflow towards the floor (since that’s where you are) to optimize your mini split’s heating efficiency.

This simple change will allow for better airflow and will help heat and cool your home more effectively.

9. Adjust your interior fixtures to help offset outside temperature influences

Try closing window shades and curtains during the day to help block the intense warmth emitted from the sun in the summer.

For most regions, the late afternoon is when temperatures are at their warmest. Help give your ductless mini split heat pump system a break from working so hard by drawing shades and curtains.

You can also help airflow by leaving interior doors open. Sometimes the difference between leaving doors open and closed could lead to as much as a 5-degree F difference.

Over time and depending on the number of rooms and conditioned square footage in your home, this will help your ductless mini split heat pump system run less than needed, helping you save on energy costs and increasing the operational lifespan of the units.

10. Smarten up your controls

“Smart” thermostat control options for your ductless mini split heat pump system offer many benefits to help increase efficiency. For example, the Kumo smart app offered by Mitsubishi Electric allows you to monitor your Mitsubishi mini split heat pump system from anywhere on your mobile device. You can set programming schedules for your mini split heat pump system to automatically adjust operation accordingly if you plan on being away from home for an extended time.

Additional monitoring features may include system run time, humidity, ambient temperatures, and other useful data to help you fully customize your mini split heat pump system according to your needs and save more money.

11. Get proper sizing and placement of your mini split units

A reputable and experienced professional HVAC contractor will properly size your ductless mini split heat pump system with a Manual J residential load calculation, the industry standard methodology for correctly sizing HVAC equipment.

That’s because heating and air conditioning equipment that’s sized too small for the conditioned space will make the system overwork to reach the set point temperature (if at all).

As a result, the functional lifespan of the underperforming equipment will be decreased, and you will not be seeing much of a return on your investment in the mini-split system.

Alternatively, one may wonder if it’s good to oversize a mini-split system.

The answer is also “No”. That’s because ductless equipment that is sized too big for a conditioned space will lead to short cycling (i.e. the oversized system will run for a brief time over and over again, quickly satisfying the thermostat set temperature, but not properly cooling or heating the space adequately).

Additionally, short cycling equipment will not properly control humidity, and you’ll basically be throwing your hard-earned money out the window due to all the wasted energy with substandard results.

Conclusion

Due to their build quality and system components, today’s modern ductless mini split heat pump systems are operationally efficient by nature.

However, by following the above steps and getting regular maintenance visits from your trusted reputable local HVAC company, there are ways you can help the system run even more smoothly while helping reduce energy bills and avoid preventable costly repairs in the future.