Ductless Heat Pumps have become increasingly popular in the pacific northwest. Marr’s Heating & Air Conditioning has installed and serviced many of these systems. Ductless heating and cooling systems serve a unique purpose and provide the following benefits to homeowners

  • No ductwork needed, therefore less labor to install
  • Provides both heating and cooling
  • One outdoor unit can feed up to 8 indoor zones
  • No ductwork means less dust
  • Quiet operation
  • Most efficient heating and cooling system available
  • Simple and easy operation
  • Zoning capabilities for “room by room comfort”
  • Variable capacity operation (always the right amount of heating or cooling)
  • Sizable rebates available in certain applications

System Design

Ductless heat pumps typically require less labor to install then a traditional heat pump system. Most Ductless systems can be completed and operational in just one day! Though the ductless heat pumps and their operation is relatively simple, it requires some serious though that must be put into designing the perfect system.

1. Sizing
Our sales representative first must start by performing a Heat loss/Heat Load calculation of the space we are trying to temper. This process involves using the square footage, window size and type, insulation levels, and air infiltration. From this calculation our designer will arrive at the proper unit size for your space, not too big, and not too small

2. Airflow
After we arrive at the size needed for the space, our designer will then find a location for the indoor unit that will maximize air distribution. A single ductless head or zone may or may not be sufficient for the space because after all, tempered air doesn’t make its way through walls and around corners very well. You’ve probably heard it before, but we will say it again…location! Getting this portion correct is crucial to the performance and your overall comfort levels.

3. Location
As mentioned before, location is extremely important to the proper design of a ductless heating and cooling system. Below we have outlined a few placement mistakes and why they will yield a poor result:

  • Ductless head in a room with tall ceilings: This system will likely overwork to try and maintain temperature. Without the addition of a reversible ceiling fan (which can drive the air down in heating mode, and pull the air up in cooling mode), you will likely be unhappy with the placement of a ductless system in this application.
  • Ductless head in a large room with a small heat loss: Your estimator did all their homework and your new house such little heat loss that you can get away with a smaller system. Great right? Yes, but in a larger room, we need to consider the fact that we may need an indoor unit with a large enough fan to distribute our tempered air evenly. If the air handling unit is too small, you will likely be unhappy with the results.
  • Ductless head in a bedroom: In certain situations we may be able to place a ductless head or cassette in a bedroom, generally we try to avoid doing this. We have found that in the majority of cases there is simply not a unit small enough for the small heat loss in a bedroom. On top of that underlying issue, humans operate on a different set of needs when we need to sleep. Though the noise from a ductless system is small and relatively minor, when we are trying to sleep and there is no other noise in the home, even small noises become amplified and can wreak havoc on your ability to fall asleep.
  • Ductless head in a position that will blow on occupants: In certain situations, this may be unavoidable and we may be able to counter this issue using the adjustable air diverters in the unit…that being said, the human body responds and does fine with warm air blowing directly upon it, but when it comes time for cooling season and we are distributing 50 degree or colder air on you, you will regret the feeling of sitting in an icebox.

4. Serviceability
This point may again lead us back to the importance, but it deserves its own section. As a rule we never install a system in a position that makes it impossible or inconvenient for future maintenance or repair. We are not just an installation company, we are a service company. Over the years our service and installation team have worked together to develop the do’s and don’ts of ductless equipment placement. This small extra step will save you money long term, and it makes our technicians happier too!

Though the installation of a ductless Heat Pump may seem simple there are many complexities involved with getting the job done correctly the first time. Some of these details include but are not limited to the following

  • Properly leveling the indoor unit on the wall
  • Achieving proper drainage for the condensation lines
  • Setting the outdoor unit pad on a gravel base to avoid the unit coming out of level
  • Properly flaring and torqueing refrigerant line connections to ensure a leak free seal
  • Properly pressure testing the system using high pressure dry nitrogen gas
  • Properly evacuating the system to sub 500 micron levels
  • Properly adding and releasing the refrigerant to the system
  • Proper running of paintable Line covering for an aesthetically pleasing look
  • Surge protector to protect sensitive electrical components of the system
  • Proper wiring gauge and type to achieve manufacture recommended installation

If you would like to learn more about how we do things, watch a few of our installation videos below, or ask your estimator to see our ductless installation standards manual. All ductless heat pump installations come with a 100% satisfaction guarantee and a Lifetime workmanship guarantee.


Our team is highly trained and familiar with how to service and maintain ductless heat pump systems. We offer and suggest our annual Preventative maintenance on these systems in order to keep them running at their absolute best. The best thing you can do as a homeowner is remember to clean your filters at regular intervals (we recommend every month). Watch our video below to get a sneak peak into a full ductless cleaning by one of our service technicians

To learn more about our product offerings for ductless Heat Pumps, visit our product page by clicking here!

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