I have a HWG on my ClimateMaster 4 ton. I have a 50 gallon buffer that feeds an early generation tankless. The tankless froze on Sunday night it was -23 and a steady wind. I was able to defrost it and it worked fine. However it froze again later that day and is now destroyed. Heat exchanger cracked and water ran into the electronic controls. My breaker panel is full unless I install a sub panel. I am not sure I want another tankless or if I can afford another one. What should i do? The last time I filled propane in October it was $4.00 per gallon I currently have hot water directly from the buffer tank, so I have a little bit of time to decide.