Combination Boiler/Water Heater

[Rosalie DiPietro]

I'm in the process of getting quotes to replace my existing gas boiler (for baseboard heating) and gas water heater with a combi boiler.  Specifically, the Navien NCB-H.  It's a two family property whereby each tenant controls their own thermostats....each apartment has it's own pump.

Has anyone installed this type of combi boiler and what has been your experience in terms of efficiency in providing heat and hot water and the cost savings.

Has anyone installed such a combi boiler in the NYC area and who have you used?  Have you installed smart thermostats that you can control through wifi or the landlord thermostat by CCF?

Finally, I'm having difficulty in determining if a permit is needed from the Department of Buildings to replace an existing gas boiler....it's replacing the existing boiler and water heater in the same area of the current units.  The company I'm thinking about using, run by a Master Plumber, says I should get one to avoid any DOB possible surprise inspections...this is at a cost of $2,500.  I can't find anything on the DOB site that says I need a permit especially if I use a licensed Master Plumber.  So confusing!!!

Thanks!