A dual-focus guide on water management. Part 1 dives into the physics of rainwater catchment, cistern sizing, and filtration. Part 2 covers irrigation efficiency, evapotranspiration, and calculating exact water needs for your landscape.

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plumbing

The Physics of Comfort: A Deep Dive into HVAC Sizing, Manual J, and Tonnage

HVAC sizing is not a guessing game. This comprehensive guide explains Manual J Load Calculations, the definition of a Ton of cooling, SEER ratings, and why oversizing your AC unit is the worst mistake you can make.

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plumbing

Hot Water Logistics: Sizing Tank vs. Tankless Water Heaters

Never take a cold shower again. We explain First Hour Rating (FHR) for tanks and Temperature Rise/GPM for tankless units. Compare the pros, cons, and payback periods of both technologies.

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How to Use This Calculator

Attic area.

Ratio (1/150).

Get NFA.

Understanding Ventilation Louver Size Calculations

Net Free Area.

Intake vs Exhaust.

Stack effect.

Moisture control.

Formula & Calculations

Area / 150 or 300

Key Factors to Consider

Soffit balance

Vapor barrier

Screen clogging

Roof vents

Frequently Asked Questions

11/150 vs 1/300?

1/300 if balanced intake/exhaust.