We own a house in the PNW built in 1900. Despite retrofitting the insulation it is still quite drafty. He currently have an old, oversized gas furnace and 40 gallon gas water heater. The plan is to install the Navian NP-240 on demand gas heater for domestic and heating. These will be sperated by a heat exchanger. We will run a 1/2" line to a Turbonix MVB-8 to the attic and from there run 4" insulated ducts to the ceiling of each bedroom. In the basement we will have another MVB-8 unit and will split the four zones into 8 ducts and vent these under the windows through 4" insulated ducting.
That's the plan anyways. The house is 1500 sf and we are south of Seattle, so have a very temprate climate.
I'm looking for any concerns about this system related to it's ability to heat our house and any installation tips.
Down the road I would likely install an air filtration system using the current return ducts.
Thanks all in advance.