Big Foot Heating & Cooling completed an HVAC ductwork modification project in Madison County, Montana, to address uneven airflow between the basement and upstairs living spaces. Instead of replacing the home’s entire HVAC system, the project focused on modifying the existing ductwork and zoning arrangement to redirect conditioned air where it was needed.

The existing system served both levels of the home, but the way several supply runs were connected meant the zones could be adjusted to better suit the layout of the house. The project included relocating existing supply runs, adding new basement ductwork, installing additional supply registers, and moving a thermostat to better coordinate with the updated zoning arrangement.

HVAC Ductwork Modification and Airflow Adjustments

The main portion of the HVAC ductwork modification involved changing how several supply ducts were connected between the home’s upper and lower zones.

Technicians disconnected six existing duct runs from the smaller zone and reconnected them to the larger upstairs zone. Additional work was completed on the basement supply ductwork, including two new 8-inch duct runs for the alternate zone and the reconnection of an existing 6-inch run serving the downstairs stairway.

The existing main supply trunk was also modified to accommodate three new 12-inch by 6-inch supply registers in the basement.

The ductwork modifications included:

• Relocating six existing supply runs to the upstairs zone.
• Disconnecting and rerouting dampered supply duct connections.
• Installing two new 8-inch duct runs for the downstairs zone.
• Reconnecting a 6-inch supply run serving the downstairs stairway.
• Cutting in three new 12-inch by 6-inch supply registers.
• Sealing unused duct openings.
• Taping and securing ductwork connections.
• Adding duct supports and fittings where needed.

The purpose of these changes was to redistribute the existing supply airflow between the two levels and make better use of the home’s existing zoning configuration.

Thermostat Relocation and Zone Control

The HVAC ductwork modification also required an adjustment to the thermostat location.

The existing thermostat was located in the master bedroom. As part of the updated zoning arrangement, technicians relocated the thermostat downstairs to the wall designated for zone two.

New thermostat control wiring was routed across the ceiling and down the wall to reach the relocated thermostat. The wiring was secured as part of the installation.

Changing the thermostat location was coordinated with the ductwork changes so that the control location better corresponded with the updated zone arrangement.

Ductwork, dampers, and thermostats all work together in a zoned HVAC system. When the distribution of supply air changes, the control configuration may also need to be adjusted to match the new arrangement.

Sealing and Supporting the Modified Ductwork

Once the supply connections were changed, technicians sealed the openings that were no longer being used and secured the modified ductwork.

The project included taping duct joints and adding supports and fittings where needed. These details are an important part of completing an HVAC ductwork modification, because the newly routed sections need to be properly connected and supported within the existing system.

The work was completed around the home’s existing HVAC equipment rather than requiring a complete equipment replacement.

For general information about ductwork, airflow, and duct sealing, homeowners can also review guidance from ENERGY STAR. ENERGY STAR notes that ducts distribute conditioned air throughout a home and that poorly connected or leaking ducts can contribute to comfort problems.

Results of the HVAC Ductwork Modification

With the HVAC ductwork modification and thermostat relocation completed, the Madison County home has an updated zoning arrangement intended to improve how conditioned air is distributed between the basement and upstairs areas.

Rather than replacing the home’s heating and cooling equipment, Big Foot Heating & Cooling concentrated on the existing ductwork and zone controls. The completed work included relocating supply runs, adding basement supply connections, installing new registers, modifying duct connections, and moving the thermostat for zone two.

Projects like this demonstrate that airflow concerns can sometimes be addressed by modifying the way an existing ductwork system is configured. The appropriate solution depends on the home’s layout, existing ductwork, zoning arrangement, and the specific airflow issues identified during evaluation.

If certain rooms are consistently warmer or cooler than others, or temperatures vary noticeably between floors, the cause may involve the ductwork or zoning configuration.

Big Foot Heating & Cooling provides professional heating services and furnace repair and installation throughout the surrounding communities.