I have recently moved into a home in southern Ontario. It is a bungalow/rancher duplex. I am renting. The house is approx 50 years old. There was a sewage back up resulting in a complete reno. Half of the basement is finished with new sump pump and the other half has a small hatch in the wall leading to crawl space where the furnace is located. The crawl space is encapsulated, however half of the dirt floor has been dug up down to bottom of foundation and not refilled and therefore no plastic in that area. The furnace is new (high efficiency) in past two years, has been recently maintenanced and air ducts cleaned. They have spent a lot of money making home efficient and dry.
My issue is when furnace and AC are on there is a significant musty/dirty smell that fills the house and causing breathing issues. I feel it in my lungs and my 10 year old is coughing. Not to mention the smell is nauseating. When we go outside we have immediate relief. When the furnace is off, no smell and no symptoms. Im confident the air in the crawlspace is being circulated through the home and the air is "dirty". Both the contractor and HVac pro who installed furnace disagree. They say there is nothing they can do.
Ive noticed half the ductwork (return portion) is cardboard and not very well sealed, is this an issue in a crawlspace with dirt floor? There is currently one return air vent in the house from main floor. The crawl space feels dry, save for the gaping hole in the ground. Is there anything I can do to reduce the the amount of air from crawlspace being circulated through the home? Should the hole be covered back up with vapour barrier? Should the ductwork be taped and sealed? (it isnt, there are many gaps), will another vent help? They spent a lot on sprayfoam insulating the crawl space and adding plastic to floor, wouldnt the hole negate all that? Neither the contractor nor hvac guy seem to think so. Would appreciate some other professional opinions. We currently can not run the furnace without symptoms and sleepless nights and we are heading into November.
Thank you in advance.