By USGBC MA Communications
The Residential Green Building Committee gathered on November 13th, 2017. We had a guest presentation from Rick Nortz, Manager of the Utility and Efficiency Program at Mitsubishi Electric.
Rick gave an overview of advantages of ductless vs. ducted heat pumps and dove into the health and environmental benefits of such appliances. Rick explained that just as we saw the switch from incandescent light bulbs to CFLs, we will now experience ductless heat pump swaps as the next low hanging fruit to increase efficiency in our buildings.
Generally speaking, a heat pump absorbs heat from outside and discharges it inside, as opposed to an air conditioner which reverses the process by absorbing the heat inside and discharging it outside. With a ductless heat pump, it actually acts as both a heating and cooling unit. The distinction between ductless and ducted heat pumps has to do with the refrigerant distribution. Dispersing the refrigerant through thin pipes with a ductless solution can be more efficient than through ductwork. With ductless systems, you can distribute heating or cooling to different zones within a building, without having to supply the same temperature throughout the entire building, thus improving efficiency. Of course, if the building already has ductwork, it makes the most sense to swap in a ducted heat pump, but for new homes without ductwork, ductless air pumps are highly recommended.
As heat pumps use electricity for the refrigerant distribution, Rick explained that some places consider heat pumps to be a form of renewable energy, and especially if the building already pulls from a renewable energy source such as solar PV.
Mitsubishi is a market leader as a supplier of both ductless and ducted heat pumps, and particularly, the Cold Climate Heat Pumps. Rick explained the evolution of heat pump operations, as they formerly only functioned up to 32 deg. F with the need for backup heating, and now they operate at -13 deg. F. These Cold Climate Heat Pumps are commonly deployed as the primary heating system while keeping the existing heat in the home as a secondary source. However, they can be the primary source depending on how much heat the building needs.
We all learned a lot from Rick’s presentation. Please join us at our monthly chapter meetings to hear more from experts in the green building space, and get a chance to mingle with like-minded individuals! See you next time!