I live in a cape cod style house from the 1930s, and while it's comfortable in the winter, summer is rough due to the lack of hot air returns on the second floor. I'm considering a change: there's a chimney that currently only vents the hot water heater, which I'll need to replace soon. What if I vent the new water heater directly outside from the basement (the furnace already does this)? That would leave the chimney unused, and I thought it could be repurposed for a hot air return system, with the vent located in the upstairs hallway. Since I'm also replacing the roof, I could stop the chimney in the attic to keep everything flush. Would this setup help improve my HVAC situation?
3 Answers
Your idea could work, but make sure the duct size is appropriate for the airflow. Also, if the HVAC vents in the rooms are behind closed doors, consider ways to let air flow to the return, like grates or jump ducts. Using the chimney as a duct might not be the best idea; installing a proper duct inside would likely be more efficient.
Instead of using the chimney for ductwork, I’d recommend demoing it entirely if it’s not a structural part of the house. This way, you have a larger void to work with for running ducts directly to where you need them.
I can't comment on the return aspect, but when I removed a chimney from my own cape cod, it took me about three days. It was easier once I figured out I could toss bricks out a window instead of dragging them through the house. Also, if you do go this route, be prepared for plenty of soot—cover everything!
How did you get to the inside of the chimney? Did you have to tear down walls to reach it?
Is it because the void would be bigger without the bricks? That makes sense.