Odd odors in semi-basement and kitchen.

Could also be that one or more of your floor drains Traps have dried out ( no water seal ) so that it's allowing this smell to reverse back into living space. Quick fix is to locate floor drains and pour some water in them to create a seal and monitor the smell over a few days? Would not hurt?

Hi, from what you’re describing (chimney room + HVAC + intake nearby), there are a few quick questions that would help narrow it down: Is the smell constant, or does it come and go? (for example, worse when HVAC is running)? Does it get stronger with weather changes (rain, cold, wind)? Is the chimney currently in use, or sealed? Have you noticed any moisture, drips, staining, in the basement area? Look in corners or at the base of the walls... Do you know if the HVAC system brings in outside air near that chimney area? The smell could actually be due to your neighbours. If it smells like coal, it could be the chimney backdrafting, combined with moisture/mold, the filter on your furnace might be old or something is stuck in the ducts. I would contact an HVAC pro, and go from there —Noemi Treetop Urban Gardens

A standard home inspector will likely not be able to identify this cause. Traditional home inspections are visual only, general assessments meant for real estate transactions. They do not possess the specialized diagnostic tools or the indoor air quality certifications required to trace hidden particulate or gas emissions. Because you are dealing with two distinct scents a generalized intake odor and a specific coal-like aroma near a fireplace you should approach this by contacting a certified chimney sweep / WETT inspector first, followed by a professional duct cleaning and HVAC specialist.

A home inspection can be a good starting point, especially if the source of the odour is not obvious. A coal, smoky, or musty smell near the chimney room could be related to the chimney itself, negative air pressure, HVAC ductwork, combustion appliances, or even an old unused flue allowing odours to enter the home. If you're also noticing the smell near HVAC vents or air intakes, that could point to the ventilation system distributing the odour throughout the house. It may be worthwhile to have the chimney, HVAC system, and any fuel-burning appliances inspected to rule out issues with venting or airflow. Identifying when the smell is strongest — for example during certain weather conditions or when equipment is running — can also help narrow down the source. A systematic inspection is usually the fastest way to identify and resolve these types of issues.