Ducting Systems and Air Ventilation - Do I need a return in the basement?

We purchased this home 3 years ago. The basement was partially finished. We have a forced air system (gas heat). There were 3 vents installed into the side of the main trunk to provide heat/cool to the basement. The square footage is aprox 1200. It is all open less one unfinished room that houses the furnace and water heater (gas). I am thinking that we need a return installed. If so, can I just install a grille into the existing return ductwork? Thanks

Hi andy, there are energy issues, efficiency, and safety issues, back drafting, to consider. Whenever you have more supply or return capacity in a given area, then you create a pressure difference. That difference will force conditioned air out or pull unconditioned air in depending upon the pressure. It can also pull exhaust (CO) from your heating system (back drafting) back into your home and potentially cause a serious health problem.

SO, yes you should balance the supplies with a proper return, but just cutting into the existing duct may not be the correct location. Convenient, yes, but a big hole there could reduce the return capacity elsewhere.

Since you have a separate furnace room, you could consider a combustion air source for that room.

Without being there I can't be more specific.

GL
Bud

I currently have CO2 monitors on all three levels of my home (including the basement). We have never had any issues. I think I will contact my HVAC guy and have him take a look. We just had the furnace installed 2 years ago. They never mentioned anything about the basement setup.