Synopsis: we are replacing our current boiler which has exceeded its service life and electrifying. We've had mini-splits on our previous two homes. One of the local installers is recommending a 'hybrid' system with a single 9,000btu head unit in our bedroom (which is over an unconditioned crawlspace) and with ductwork combined with a three-zone branch box to deliver heat to our kitchen, main living space, bathroom and DD's bedroom.
This would all run off a 3-ton multi-unit heat pump, with the branch box where the current boiler sits in the basement, and ductwork running through the conditioned basement.
House is a single level, will be 1,250 sqft (upcoming renovation) built in 1944, heating zone 6A. We are upgrading the air-sealing and insulation throughout to at least current stretch codes as part of the renovation.
Main Questions: I have no experience with branch boxes on a heat pump - any input on their reliability, efficiency, other aspects?
the alternative is 3 mini-split heat pumps (primary bedroom, secondary bedroom and main living space). Simpler but it would not heat the bathroom or the farthest corner of our home.
Scope of work (links embedded):• 36k BTU Mitsubishi Electric
MXZ-SM36NAMHZ inverter driven heat pump outdoor unit (23 SEER rating)
• Mitsubishi Electric
PAC-MKA32BC three zone branch box in the basement to connect the outdoor unit to the indoor units.
• Mitsubishi Electric
SVZ-KP18NA ducted indoor unit serving the kitchen, living room, dining room, bathroom, and daughter’s room.
• 8 KW supplemental electric heating module (supplemental heating when temperatures drop below -10ºF / -19ºC).
• 9k btu Mitsubishi Electric
MSZ-EF09NAW wall mount indoor unit in the primary bedroom.
• Mitsubishi Electric MHK2 wall mount wireless thermostat
• Provide and install all required ductwork and grilles (Two in kitchen, one in bathroom, one in bedroom, one in main living room)
