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I need some advise on selecting the type of heating system for a small new home that will be all-electric.
I am wondering about the common refrigerants used in small scale residential heat pumps and the concern about the GWP.
Does anyone know the real world impact of this in terms of leakage? If the system is sealed and properly installed, does it leak over time?
As far as I can tell, most of the common refrigerants in small scale residential systems have a GWP of around 1100-1400 (such as R-410A used in a Mitsubishi mini-split). I know there is one company (Sanden) that makes an air-to-water heat pump that uses CO2 itself with a GWP of 1,but it involves some bulky equipment and produces a certain amount of noise, and vibration, which in a dense urban environments (like SF) is not easy to accommodate. Plus it involves a more costly water based radiant system, storage, etc.
A small mini-split system has somewhere between 2-4 lbs of refrigerant. My rough math indicates that a 1 lb leak of refrigerant equals driving about 1500 miles so want to be careful to consider the trade offs of the air-to-water using CO2 (using Sanden) or a more typical refrigerant system.
I appreciate the perspective of the group.