Heating Retrofit in a Victorian Multi-Family House
I am looking for a suggested path to take regarding heating in a very large 6 family Victorian house North of Albany NY. It has old windows with storms and blown-in insulation. The house currently has 1 large antiquated Natural Gas boiler for radiators, probably some kind of conversion from coal or who knows what.
The efficiency rating must be scraping the bottom of the charts and the house has only 1 thermostat for all 6 units and common areas. I want to move towards dividing up the heat for each unit. For a separate house, I had installed direct vent Rinnai units. They are great but were expensive to purchase.
Iím not against investing some money to make this work but donít know where to start. I donít mind running the old system while I gradually install separate direct vent heating in each unit. Iím not even sure if that is practical or possible. And the truth is, I am already assuming that direct vent NG units are the way to go. Is there a better heating source for this type of application?
I am looking for suggestions regarding the approach and also brand names you have had success with, I may own this house for a while.