Unscrew the heat pump floor register vents with an appropriate screwdriver. Set the screws in a safe location so they don't get lost.
Fill a bucket with 1 quart of warm water and 1 quart of white vinegar. Moisten a clean cloth with the vinegar solution. Wring out the cloth to remove excess solution.
Wipe out the inside area of the floor register to remove nicotine and cigarette smoke smell. Wash the heating vent, too, to remove cigarette stains that harbor the unpleasant odors. Dry the surfaces with a clean cloth.
Dampen one cotton ball for each floor register with two to three drops of cinnamon essential oil. Secure the cotton ball to the underside of the floor register vent with a piece of silver tape. As air comes out of the register, the cinnamon scent will waft through the home. Freshen the fragrance each week by adding one or more drops of oil to the cotton ball.
Screw the register vent back into place. Close the vents during times when the cigarette smoke smells the strongest.
Open your windows and run exhaust fans as needed to draw out stale cigarette smell and keep fresh air circulating through your home.