High Efficiency Boiler with Indirect Water Tank
I want to replace an old Burnham boiler rated at 96,000 BTU with a high efficiency Navien unit and an indirect water heater. I have received several proposals for 80,000 BTU boilers with 40 gallon indirects. The house is a 2 story Cape style house of 2000 s. f. with 2 full bath rooms. It is insulated with fiberglass batts and recently blown in cellulose from Mass Save. The knee wall is also insulated.
One contractor has proposed a 150,000 BTU boiler. We both agree that 80,000 BTU would be sufficient for heating, but he believes the bigger boiler would give faster hot water recovery. He indicated that because this boiler has a 15 to 1 turndown ratio it would modulate and run at a lower rate. He is planning on installing this same configuration in his own 2000 s. f. house.
Does this proposal make sense or should I go with the 80,000 BTU boiler?
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