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- Airflow and velocity calculators
- Duct sizing and geometry calculators
- Ventilation and air balance calculators
- Duct component selection calculators
- Pressure loss and static pressure calculators
- System estimation and checks calculators
- Fans and energy calculators
- Duct thermal and materials calculators
- Noise, installation and procurement calculators
- Airflow measurement and conversion calculators
Guides
- ACH vs. outdoor-air ventilation rate
- ACFM vs. SCFM: actual airflow, reference conditions, and density
- Measured airflow balancing: compare, adjust, and remeasure
- Available static pressure, TEL, and design friction rate
- Bathroom exhaust airflow and installed duct resistance
- Blade-pass frequency: a frequency check, not a fault diagnosis
- Blower-table airflow: an estimate, not a measurement
- Closed-door return-air pathways and transfer airflow
- CO₂ ventilation estimates: steady state vs. decay
- Commercial hood exhaust and louver selection from matched data
- CFM, FPM, duct area, and airflow capacity
- Aspect ratio, clearance, and selecting a constructible duct size
- Dew point, duct condensation, and insulation limits
- Duct design workflow: from airflow to a pressure check
- Duct heat loss, fan heat gain, and outlet temperature
- Duct leakage testing: CFM25, leakage class, and operating leakage
- Duct material takeoff: area, weight, wrap, and sealant
- Trace a duct sound path: branch division, breakout, and end reflection
- Add system losses and identify the critical path
- Duct thermal expansion and free movement
- Plan duct transitions and offsets from clear dimensions
- Equal-area vs. equal-friction duct conversion
- Fan balance and vibration criteria: what the readings can establish
- Compare fan energy cost across a full operating schedule
- Fan laws and density: when operating-point comparisons apply
- Fan power: match pressure basis with efficiency
- Fan speed, belt ratios, pulley geometry, and tip speed
- Fan and system curves: operating point and installation effects
- FEI vs. FEG: what the rating represents
- Use matched filter and damper performance curves
- Fitting K-factor vs. equivalent length
- Flexible duct sizing, sag, compression, and installed performance
- Select grilles, registers, and diffusers using free area, pressure, and throw
- Heat-recovery temperature ratio vs. effectiveness
- Choose the duct calculation that matches the job
- How to read a duct calculator result
- Makeup-air flow balance vs. building pressure
- Mixed-air temperature and outdoor-air fraction
- NC vs. dBA: sound pressure, sound power, and frequency bands
- Plan and interpret a duct traverse
- Round and rectangular duct sizing use different decisions
- Select a silencer using insertion loss, generated noise, and pressure drop
- Single-zone vs. multizone outdoor-air calculations
- Static, velocity, and total pressure: where TESP fits
- What an airflow pickup K-factor means
- VAV terminal selection across operating states
- Target velocity vs. equal-friction duct sizing
Calculators
Airflow and velocity
Duct sizing and geometry
Ventilation and air balance
- Room Airflow from ACH Calculator
- Bathroom Exhaust Fan CFM Calculator
- Makeup Air Balance Calculator
- Mixed Air Temperature and Outdoor Air Fraction Calculator
- Sensible Heat Recovery Calculator
- CO₂ Ventilation Estimate Calculator
- Single-Zone Ventilation Rate Calculator
- Outdoor Air Load Calculator
- Return Air Pathway Calculator
- Whole-Dwelling Ventilation Calculator (2019 Method)
- Multizone Ventilation Calculator
- Outdoor Air Louver Performance Calculator
- Commercial Kitchen Hood Exhaust Calculator
- VAV Terminal Airflow and Selection Calculator
Duct component selection
Pressure loss and static pressure
System estimation and checks
Fans and energy
- Fan Laws Calculator
- Fan Power Calculator
- Fan Energy Cost Calculator
- Fan Belt Drive and Pulley Calculator
- Fan and System Curve Calculator
- Series and Parallel Fan Curve Calculator
- Fan Energy Index and Efficiency Grade Calculator
- Fan Balance and Vibration Calculator
- Fan Installation System Effect Calculator
- Fan Tip Speed Calculator
- Fan Heat Gain Calculator
- Fan Static and Total Pressure Calculator