Ductless VRF Air Conditioning. What is it and Why is it Better Than Central Air?
Ductless air conditioners and heat pumps are one of our main specialties at Magic Touch Mechanical and we install a lot of these systems throughout the Phoenix, AZ area each year. When many people think of a ductless ac unit, they think of “spot cooling” or cooling for just one room but nothing could be further from the truth.
Although we install many Mitsubishi ductless air conditioners in homes throughout Arizona, this article is focused specifically on commercial building applications and why a VRF (Variable Refrigerant Flow) cooling and heating system is a better choice than a traditional ducted central air conditioning and heating system in many cases.
First let’s cover what Variable Refrigerant Flow is. VRF has been around since the early eighties and was first used in commercial buildings in Asia. Much like the compressor used in a residential mini-split ductless air conditioner, the compressor located in the outdoor unit known as the condenser uses inverter technology. In a nutshell, this compressor can use only a portion of the energy needed under partial load conditions. In layman’s terms; if only 60% of the indoor units or “air handlers” are being used, the compressor only operates at 60% of its capacity, meaning a 40% energy savings as compared to a conventional system which is either “on” using 100% of its power or “off”.
Another way to look at this is, say you have a VRF system on an office building and only eight of sixteen offices are occupied – that office equipped with a VRF HVAC system only needs to use 50% of its capacity to keep the occupants comfortable, whereas a conventional system would be in essence wasting 50% of the power produced.
Unique Characteristics of a Ductless Variable Flow Refrigerant Air Conditioning and Heating System
- Maximum Energy Efficiency
- Improved Comfort
- Precise “Zoning”
- Simultaneous Heating & Cooling (some VRF systems have the capability of cooling one area while heating another simultaneously).
- Easy to Operate
- Failure of one air handler will not affect the rest of the system in most cases
Besides being more efficient “out of the box” so to speak than a conventional central air conditioner and heating system with regards to common methods of measuring the energy efficiency of a heat pump or AC unit, such as; EER (Energy Efficiency Ratio), SEER (Seasonal Energy Efficiency Ratio), and HSPF (Heating Season Performance Factor) – the improved energy efficiency with regards to how these systems work in general are significant.
Energy Efficiency Benefits of a Ductless VRF HVAC System
- Eliminates Energy Waste from Duct Leakage – because VRF systems typically utilize no, or very little ductwork (hence the term “ductless”), they eliminate energy loss caused by leaky air ducts. NOTE: Magic Touch conducts hundreds of energy efficiency audits on buildings and homes annually and typically find duct leakage to be amongst the most common sources of energy waste.
- Eliminates Energy Waste from Duct Heat Gain – since air ducts are typically installed in unconditioned space (attics, basements, wall chases, and above ceiling grids) they can absorb or lose heat energy to / from the surrounding space. This “duct loss” accounts for the need to install larger capacity systems in order to cool or heat the conditioned area to make up for it.
- Condition Only Occupied Space – because each air handler only controls one area or “zone” there is no need to waste energy on cooling and heating unoccupied zones of the building. NOTE: In the residential segment of our business we often install ductless heat pumps to cool and heat master bedrooms or living rooms as auxiliary systems to homes already equipped with central air conditioning. This way the homeowner can set their bedroom unit to cool to say 72 degrees at night, while keeping the rest of the home at say 80 degrees while it’s not occupied.
- Inverter Compressor Technology – as discussed above the energy savings benefit of using the precise amount of energy is great for occupied / unoccupied portions of a building or home, but it also has an additional benefit: In Phoenix, a system is sized by completing what’s known as a load calculation (ACCA Manual N for commercial buildings and ACCA Manual J for residential homes). The ACCA design temperature for most parts of the Phoenix, AZ area is to size the unit to maintain 75 degrees indoors when it is 108 degrees outdoors. That said, we still need to cool our buildings and homes when it’s 90 degrees – but we don’t need the same capacity to do so, this is where the inverter compressor really shines and saves $$$.
Air Quality Benefits of a Ductless VRF System
- Localized Filtration Per Zone – The “zoned” application of these systems adds an IAQ (Indoor Air Quality) benefit of providing better air filtration to every conditioned room of the building. Whereas most central ducted systems are filtered at the air handler in the attic or on the rooftop, ductless units are filtering the air right in the space they condition, providing better filtration to each zone.
- No Contaminants Entering Via Air Ducts – one often overlooked cause of contaminants entering a building and affecting the air we breathe is leaky air ducts. The return air system of a central HVAC system is like one big vacuum cleaner. If these return ducts leak (and they usually do), they suck in attic dust, and other nasty contaminants and then distribute those contaminants into the building through the supply air ducts. Another benefit of eliminating ductwork is healthier air.
Comfort Benefits of Ductless VRF AC & Heating Systems
- Micro-Zoning – while it is possible to “zone” a ducted central air and heating system, which offers improved comfort over a conventional duct system. The ability to micro-zone every room of a building with a ductless air handler offers the most precise temperature control for that room.
- Precise Temperature Control – on a central ducted system, while you might set the thermostat located in the hallway two offices down to 75 degrees, the office at the end of the hall with the most sun exposure or furthest duct run may only get to 79 by the time the thermostat reaches its set-point and shuts off. It is very common in office spaces for one person to say they are freezing while someone else in another office says they’re too hot. When each office has its own individual unit, everyone can set the temperature to their perfect setting (without wasting energy). Smart CEO’s and CFO’s are starting to realize this increases the productivity of their teams, and creates a happier work environment and replacing central air systems with ductless VRF’s as an “investment” and “cost savings benefit”.
If you are a regular reader of our blog, you know that I do my best to remain as impartial as possible when it comes to HVAC brands. You also know that Magic Touch recommends and installs four of the five major manufacturers equipment and we promote Magic Touch not; Trane, Lennox, Carrier, Daikin, etc. However, when it comes to VRF and ductless equipment in general, we recommend Mitsubishi Electric.
There is a lot of “white-labeling” going on out there within the ductless manufacturing world and just because it carries the name of a major manufacturer does not mean they actually make it themselves. Mitsubishi does manufacture their own ductless air conditioners and heating systems and based on thirty years as a technician, and 20 years owning a Phoenix HVAC Company; in my opinion, they have no equal.
If you would like to experience Magic Touch Mechanical’s award winning service for yourself and see why we were named the top HVAC contractor in the USA by ACCA (Air Conditioning Contractors of America), contact us today!