How should a range hood be vented in a remodeled kitchen

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Measure the duct run before choosing the hood, because the path out of the house decides which hoods can work at all. On a kitchen renovation in Scottsdale, AZ the cooking wall often moves, and the figures kept at kitchen renovation scottsdale national video game archive begin with where the air can leave, not with the hood's finish.

Wall exit or roof exit

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In Scottsdale, AZ a range on an exterior wall can vent straight out with a short, nearly straight duct. A range on an interior wall needs a run through the attic and out the roof, and that is where tile roofs complicate things. The roof jack has to be flashed under the tile, and the tile around it cut and sealed by someone who works on roofs.

Duct size and bends

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Every elbow takes airflow away from the fan. A hood rated for a given volume delivers much less through a long run with several turns. Rigid metal duct with smooth joints performs better than flexible foil, and the manufacturer lists the diameter the fan needs. Stepping down to a smaller pipe to fit a joist bay starves the fan.

Why recirculating hoods disappoint

A ductless hood filters grease and returns the air to the room. It does nothing for moisture, heat or combustion gases. In the Phoenix metropolitan area, where the air conditioner is already working hard in summer, heat from a cooktop stays inside the house instead of leaving it.

Makeup air

A strong hood pulls air out of a tight house, and that air has to come back from somewhere. Newer homes in Maricopa County are built tight, so a powerful hood can draw exhaust back down a water heater flue. Large hoods usually call for a controlled makeup air damper that opens when the fan starts. The local building department sets the threshold, and the plan is checked before drywall closes the ceiling in Scottsdale, AZ.

Attic temperatures

Summer attics in the Sonoran Desert around Scottsdale run far hotter than the rest of the house. Duct runs through them should be insulated so condensation and heat do not collect in the pipe, and the damper at the exit needs to be a type that closes fully so hot attic air cannot slide in when the fan is off.

Cleaning access

Grease collects in the first few feet of duct. A hood with a removable baffle and a duct with an accessible first section makes yearly cleaning a job for a screwdriver rather than a ceiling cut.