From a 1986 atmospheric to a modulating condensing furnace — Junction Triangle row house

The owners called us after a third no-heat call in two winters. The furnace wasn't broken — it was just badly matched to the house.

What we found

An atmospheric 100k BTU furnace from 1986, lined chimney, single-stage gas valve, original 1" filter. Heat-loss calculation said the house actually needed 48k BTU. The furnace was nearly 2x oversized — which is why it was short-cycling and never really getting the upstairs warm.

We also found two return ducts that had been disconnected at some point during a basement reno and stuffed with newspaper. Cold air return upstairs was running at 24% of design airflow.

What we proposed

• Replace with a modulating condensing furnace, 60k BTU output, ECM blower
• PVC venting through rim joist, abandon chimney connection
• Reconnect both upstairs returns and add a damper for balancing
• Install a smart thermostat with two-stage logic and remote sensor in the upstairs bedroom

How it went

Two technicians arrived at 8 AM. By 1 PM the old furnace was out and the new one was set in place. PVC venting was completed by 3 PM, gas line pressure-tested, and combustion analysis completed by 4:15 PM. The duct rework was done the following morning while the homeowner was at work.

Results

“We thought we needed a bigger system. Equinox put in a smaller one and the house has never been more comfortable. The bedroom is finally usable in winter.”

— P. & S., Junction Triangle

Estimated annual gas savings of 18 – 24% based on year-over-year degree-day data, though we'll know more after the first full winter.