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Before You Go Ductless, Make Sure Your Pro Correctly Determines the Right Size

With versatile installation, precise temperature control and smooth operation as quiet and manageable as the energy bill, going ductless definitely has its benefits. Before you go ductless with your remodel, new addition or new energy-efficient home, enlist the help of your specialized Mitsubishi Electric contractor. Correctly sizing a ductless system ensures the best performance of your Mitsubishi system, warranty and long-term value and return for your home-comfort investment.

Why Sizing Is Important

For supplemental heating and cooling in a single room, or for multiple rooms to an entire home via a multi-split system, sizing a ductless system correctly is necessary to leverage any and all energy-efficiency savings, and to maximize home comfort and system performance through the years.

Ductless mini split systems deliver efficient heating and cooling to the living spaces by using refrigeration principles. Heat energy naturally seeks a cooler location, which is both good news and not-as-good news for ductless systems—or any heating and cooling system for that matter.

The good news is that Mitsubishi ductless systems are unmatched in engineering to manipulate refrigerant under pressure and temperature changes to effectively and consistently cool the living spaces. The units do so by extracting and releasing heat outside, even during sweltering Virginia heat waves. During the heating months, the same Mitsubishi technology and design delivers ductless systems that can provide comfortable heating in a home when outside temperatures fall below zero degrees.

The not-as-good news is that the rate of heat movement through a home's insulation barrier is the very definition of a home's heat gain and heat loss properties. No matter how well sealed and insulated a home may be designed, heat gain and heat loss are inevitable. This can make life uncomfortable and more expensive if your contractor doesn't follow Mitsubishi installation procedures and HVAC industry best practices for correctly sizing a ductless system. 

Load Calculations

The first step for sizing a ductless system correctly is performing a heating and cooling load of the spaces where the system will be installed. A heating and cooling load calculation should be performed by a qualified HVAC contractor using the Manual J publication from the Air Conditioning Contractors of America (ACCA). Manual J is the tested and proven method by which credible and responsible HVAC industry companies and leaders evaluate heat gain and heat loss, measure the load, and match and install a correctly-sized heating and/or cooling system.

When you consider all the possible situations for upgrading or installing supplemental heating and cooling and take into account each home's design and occupant preferences, it's no wonder a manual was developed to provide accurate information for the design and installation of HVAC systems, rather than relying on square footage alone. These are just a few examples: 

  • Garage: Perhaps you would like to cool and heat an attached garage to keep stored household items safe from the cold, heat and humidity. Is there a room above the garage? Is the garage finished, or is there substantial air leakage through the walls and ceiling to other spaces in the house structure?
  • Attic: Attic space is often converted to a bedroom or other living space. Even though it's a single room, you'll need to calculate the shape of the ceiling, amount of insulation, number and size of windows, potential heat gain from the roof and much more. Attics and second-floor spaces may reach temperatures 10 to 15 degrees higher (or more) than the ground floor and basement.
  • Upper-floor bedrooms: Perhaps you've had enough sleepless nights in stuffy upstairs bedrooms, and you're installing a ductless multi-split for the entire floor. You'll need a room-by-room load analysis, as one room is likely different from the next regarding sun orientation, occupant temperature preferences, room size, shape and more. Sizing a ductless system correctly is vital for installing an outdoor compressor/condenser unit which can handle the total load, and for installing the right size indoor air handlers in the right locations.  


Matching Load and Capacity 

With the load calculation completed, the ductless system can be sized and designed correctly. Your contractor will discuss the correct system size and design for your home improvement project, the efficiency ratings of various ductless models and the features you're seeking for the best home-comfort experience from your investment from one season to the next, and year after year. 

If you're tempted to go ductless, your home comfort investment is in good hands with a Virginia Mitsubishi Electric contractor. Contact a trained Mitsubishi Electric contractor near your Virginia home today for the best service, installation and for sizing a ductless system correctly.

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