Embracing the Comfort and Convenience of Air Source Heat Pumps: Tips for Optimal Living

Whether you have solar or not, there are plenty of things you can do to maximize your ASHPs, or mini-splits, so you can enjoy optimum comfort and efficiency out of your system. NES lead designer and product specialist Fana loves to get technical with our clients and works hard to create custom designs that meet individual needs and efficiency considerations. Since joining Northeast Solar in 2022 to head up our ASHP product rollout, Fana has worked with over 150 clients to build 121 ASHP systems. Part of his work is sharing his experience with them throughout the process, from the initial consult and design to installation and follow-up.

My immediate neighborhood offers a great example of the nuances of these design options at work. NES has installed mini-splits in two similar houses with two very different Fana designs — each with big benefits for the homeowner. First, my own home’s installation, which I outlined in my previous 7-part series, Creating Your Own Personal Power Plant, was informed by several factors. I have two outdoor compressors, one on each side of my house. But they are both single-zone systems — one single zone powering the unit in the master bedroom and another in the living room. This setup works for me, my home’s design, and my lifestyle. I could have conditioned all the rooms, but that would have required a lot of work in the attic to run lines and drains, and truthfully, I didn’t need it. I am mostly the only occupant of the home, work in a single office, and travel several months of the year. During the design phase, therefore, we settled on the two single zones. For me, simplicity and convenience won out.

My wonderful neighbors, N and S, also have two outdoor multi-zone compressors that power six, not two, indoor heads. During the design phase, Fana walked through the options for them. They settled on multi-zone systems that could condition their whole home. Every room, excluding the bathrooms, is conditioned.

Powering this multi-zone, two-compressor, six-head system will take N and S more electrical energy to heat and cool their house than it will for mine, but because their solar array produces more energy than mine, they will come out ahead. Their system had a higher price point and installation expense than my installation, but they received a $10,000 MassSave Whole Home Rebate, while I received a $3,125 MassSave Partial Home Rebate.

Two different houses, two different designs, but the outcome will be the same — a comfortable house, and a significantly reduced heating and cooling expense with an equivalent ROI. Ultimately, in the consultation with Fana, each client decides which system is the best to fit their lifestyle and budget.

Fana enjoys working with our clients to share his tips for optimizing their systems. The most important thing to remember is that ASHPs are designed to operate most efficiently at a steady temperature. After selecting the optimal air source heat pump (ASHP) system for your home, the best approach, then, is to find your ideal temperature setting, and then set it — and forget it. This advice diverges from the habits many homeowners might have developed with traditional propane or fuel oil heating systems, where adjusting the thermostat at night or before leaving the house was a common practice to save on energy costs. Unlike older systems, fluctuating the settings of your ASHP — such as turning it down at night or when the house is empty — doesn't necessarily lead to significant energy or cost savings. In fact, maintaining a constant temperature can be more energy-efficient and cost-effective. This strategy eliminates the need for your system to work harder to return to your preferred temperature, conserving energy over time. For those looking to align with the U.S. Department of Energy's recommendations, setting your heating to 68 degrees and cooling to 78 degrees offers an effective balance between comfort and efficiency. Trust in the consistency: your ASHP, your comfort, and your wallet will benefit from this approach.

Here is another tip: the temperature you set on a mini-split remote will likely not be the final temperature you reach in your room. In my living room, while the temperature on the remote is set to 74 degrees, the actual temperature in the living room is closer to 68 degrees. Find the temperature that feels comfortable to you regardless of what the remote — or the thermostat — says the temperature is or should be.

Mini-Splits generally come with four different operating modes. These are designed to enable the most comfort depending on the season, weather conditions, and particularities of your home. Understanding this versatility and adaptability can enhance the comfort and convenience of your mini-splits system. Whatever mode you’re using, when turning the system on, be patient and give it time to do its thing; you can keep making adjustments to the temperature as you go, but it will take several minutes to start conditioning the air.

Heat mode: This is the standard mode for warming your home during colder months. ASHPs are most efficient when maintaining a consistent temperature, so find a comfortable setpoint and stick with it.

Cool mode: Use this mode to keep your home cool during warmer months. Similar to heating, it is best to maintain a consistent setpoint for optimal efficiency.

Dry mode, also known as dehumidifier mode, is a feature on many mini-split air conditioners that removes humidity from the air. It works by reducing fan speed, which allows humid air to move more slowly over the cooling coil and lose moisture. This can make the air feel more comfortable, especially in warmer climates with high humidity. Dry mode can also help create a more healthy indoor environment, as high humidity can lead to negative health effects. As our climate shifts to hotter, more humid summers, dry mode has become a go-to for many people.

Fan mode: This mode circulates air without heating or cooling. It can be used to improve air circulation and filtration when temperature control isn't necessary. Fan mode is most effective when used in conjunction with open windows for natural ventilation.

Auto mode: While auto mode can be convenient, it may cause your ASHP to switch frequently between heating and cooling, reducing efficiency. It's generally more efficient to set your desired temperature and mode manually.

I know it might not be the most exciting topic, but taking care of your ASHP is key to keeping it running smoothly for years to come. The good news? It's super easy. The most important thing is to keep those filters clean. I recommend checking them every month and using a vacuum cleaner with a soft brush attachment to remove dust and debris from the filters gently. If the filters are excessively dirty, wash them with lukewarm water (below 40°C or 104°F) and a mild detergent. Rinse the filters thoroughly to remove any soap residue. Allow the filters to air dry completely before reinstalling them. Do not use a hair dryer or expose the filters to direct sunlight, as this may cause damage. You can replace them as needed. The filters are readily available on Amazon. It's a small task that makes a big difference in maintaining system efficiency, airflow, and good air quality.

Before shifting modes when transitioning into a new season, Fana recommends making sure all units are in the same mode, even if some of them are “off” and not currently being used. As well, taking the time to replace batteries once a year will help ensure your system is working at its best.

Another simple maintenance tip: keep the area around your outdoor unit clear. Making sure there's no debris, leaves, or snow blocking the airflow will help your ASHP work its magic without any unnecessary strain.

There are two other options that you should consider. Have your indoor units professionally cleaned, and have NES perform an annual service check on your system.

For professional cleaning, we recommend our partner, We Clean Heat Pumps. You can schedule your cleaning with them. Ideally, this should be done annually, depending on where you live and how much you use your system.

For an annual service check, just call us. For a flat service fee of $250, our team will come out and inspect all the fittings, indoor units, outdoor compressor, and check the pressure in the lines. A great time to do that is in late fall early winter just before the heating season, or early spring before the cooling season.

That first year with your ASHP can help you get to know your system and, in particular, how seamlessly they integrate into day-to-day living. You might notice how quietly these systems operate compared to traditional heating and cooling units. Say goodbye to the constant hum and rattle of window air conditioners! With an ASHP, you'll enjoy a peaceful, comfortable home without noise pollution — and you won’t be lugging those window units up and down the stairs twice a year.

Another perk? ASHPs are incredibly efficient at maintaining consistent temperatures. No more hot and cold spots throughout the house! And with the ability to control each zone separately, you can customize your comfort level room by room. It's like having a personal climate control system at your fingertips. Once you have your system set to what works for you, it is really a set-it-and-forget-it technology, except for recommended maintenance and setting the mode.