Chimney Services in New Milford, NJ

What the numbers suggest for chimneys in New Milford

Census estimates put about 26% of New Milford's 6,376 housing units in buildings with two to four units. Another 62% are detached houses and 11% are in buildings with five or more units. In a two-family or three-family house, separate boilers or water heaters may each vent into the same chimney, either through their own flues or into a shared one.

The housing is mostly mid-century. About 54% of units were built from 1940 to 1959 and 20% from 1960 to 1979, with 15% older. Utility gas heats about 81% of occupied homes, electricity about 11%, fuel oil about 4% and propane about 2%.

Those numbers point toward one practical topic: knowing which appliance uses which flue, and making sure every household under the roof is protected if one of them stops venting properly.

Mapping which flue serves what

You can start the map yourself without climbing anything.

1. Count the appliances.In each unit's basement or utility area, note every boiler, furnace and water heater that has a metal vent pipe running toward the chimney. Add any fireplace.
2. Count the flues.From the ground, with binoculars if needed, count the flue tiles or caps on top of the chimney. Our guide to multi-flue chimneys shows what to look for.
3. Compare the two numbers.If there are more appliances than flues, some appliances share a flue. That can be acceptable when the flue is sized and arranged for it, and it is exactly what an inspection should confirm.
4. Label the pipes.A tag on each connector naming its unit and appliance makes every later service call faster.

Sharing has a known weak point. DuraVent's relining guide notes that condensation may occur when a furnace and water heater vent into the same flue and the water heater runs while the furnace is off. If one unit's boiler was replaced with a high-efficiency model that vents out the wall, the remaining appliance may now be orphaned in a flue sized for two.

Alarms and access in a shared house

When several households depend on one chimney, a venting problem from one appliance can affect people who never touch it. The CPSC recommends carbon monoxide alarms with battery power or battery backup on every level of the home and outside sleeping areas. In a two-family house, that means both units. See our guide to CO alarm placement and testing.

An inspection of a shared chimney usually needs access to each unit's appliance area, and sometimes to an attic. If you are the owner and rent out a unit, arrange that access with your tenants ahead of time so the whole system is seen in one visit. Our furnace and boiler flue cleaning covers heating flues for each appliance.

Keep the inspection report where both households, or the owner and the tenants, can find it. When one unit's equipment is later serviced or replaced, the installer can see which flue it uses and what condition that flue was in.

Local questions

Sources

1. U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates (tables B25034, B25040, B25024), via Census Reporter
2. DuraVent: Relining Chimneys for Gas Appliances (technical guide, PDF)
3. U.S. CPSC: Carbon Monoxide Information Center