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Aerial view of a stucco home with a dark gray shingle roof on a waterfront lot with palm trees
Professional Ventilation Calculator

Know what the job needs before you install.

From attic size to available intake, a few details can shape your recommendation. Work through them here, check your sizing, and head into the job with more confidence.

Calculate Ventilation
Before You Calculate

Start with these four details.

Take a look at the attic space, roof, sun exposure, and available intake. Having those details ready will help you get more out of the calculator.

  • Open attic with exposed wood rafters and trusses, blown-in insulation between the floor joists, a decked walkway and a gable vent

    How much attic space are you ventilating?

    MEASURE THE ATTIC SPACE.

    Use the square footage of the attic floor you’re ventilating. In a multistory home, that may be different from the home’s total living area.

    Note any separate attic spaces. Each may have different ventilation needs.

  • Five roof types: asphalt shingle, clay tile, standing-seam metal, flat membrane and a shingled gable

    What type of roof are you working with?

    CHECK THE ROOF DETAILS.

    Roof material, pitch, and layout help determine which fan and mounting options fit the job.

    Look for additions, separate roof sections, or anything that could limit where you install the fan.

  • Shingled roof partly shaded by an overhanging tree on a sunny day

    Where will the solar panel get sun?

    LOOK AT SUN AND SHADE.

    Check which direction the roof faces and where trees, nearby buildings, or other roof sections cast shade.

    Think about how that shade moves throughout the day when considering panel placement.

  • Louvered soffit intake vents set into the eave above lap siding

    What intake is available?

    CHECK WHERE AIR ENTERS THE ATTIC.

    Identify the soffit, eave, or other intake vents serving the attic. Check their listed net free area and whether the openings are clear.

    Have the available intake measurements ready to compare with the calculator’s requirements for the recommended fans.

After You Calculate

Turn your calculation into a job-ready plan.

Use your results to review the recommended fan options, confirm the required intake, and verify installation details before ordering materials or arriving on site.

  • Review the Recommended Fans

    Compare the fan models sized for the project and identify the right mounting configuration, capacity, and product series.

  • Compare the Intake

    Confirm that the planned intake supports balanced airflow and the calculated exhaust requirements.

  • Check the Installation Details

    Review model-specific mounting, flashing, clearances, accessories, and installation documentation.
Aerial view of a tan asphalt shingle roof on a waterfront home overlooking the bay
Your Next Job

Take the plan to the roof.

You’ve checked the space, roof, sun, and intake. Now size the ventilation for the job or talk through anything that doesn’t fit the usual setup.

Calculate Ventilation Talk to Our Team

Sizing results are a planning aid. Confirm field conditions, model-specific installation requirements, and applicable local requirements before finalizing the job.