The smell or smoke coming down the chimney is a result of your house loosing too much air from the unsealed attic.
Attic fan fireplace smell.
In the basement the same problem can occur.
New furnace boiler and or water heater.
Stove range exhaust fans.
A neighboring structure s height increase.
Attic and or whole house fans always bring fireplace odor in when used.
Some causes of pressure change a fireplace smell in your home.
A change in your roofing ventilation attic fans.
New windows and or doors.
Every cubic foot of air that passes into the attic is one more cubic foot of air to heat and one less for your chimney.
How to stop fireplace smells from stinking up the place during summer correction.
The best way to get rid of this smoke is by placing a box fan in the same room as the fireplace.
This can happen when a dryer or other exhaust fan runs or if there are leaks in heating and air conditioning.
Whatever the situation is you are still left with a smoke filled room.
When you turn on both fans this will pull out the smoky air while you are drawing in new fresh air.
An attic hatch recessed can lights bathroom exhaust fans without baffle unsealed windows and air conditioning ducts coming out of ceiling are typical causes of the smelly problem.