Is Ventora accurate for professional work?

Yes! Our AI is trained on real-world HVAC knowledge and provides code-backed answers with specific references to the IMC, UMC, ACCA Manuals, ASHRAE standards, and EPA Section 608.

What HVAC codes does Ventora reference?

Ventora references the IMC, UMC, IRC, and IFGC mechanical codes, ACCA Manuals J/S/D/T, ASHRAE 15/34/62.1/62.2/90.1, and EPA Section 608 and the AIM Act. We update with each new code cycle.

Can I use Ventora offline?

All 6 calculators work offline. AI and photo features require internet.

How does photo analysis work?

Snap a photo and our AI identifies the equipment — nameplates, furnace control board error codes, wiring diagrams, and gauge sets — checks code compliance, and provides recommendations.

Can I cancel anytime?

Yes, cancel through the App Store anytime during or after your 7-day free trial.

Ventora is an AI-powered HVAC calculator and reference app designed for HVAC technicians, installers, and apprentices. It includes professional tools like superheat & subcooling, refrigerant charge, duct sizing, airflow/CFM & static pressure, BTU/load, and hydronic calculators, plus a comprehensive HVAC code reference and photo analysis.

What HVAC calculators does Ventora include?

Ventora includes six professional HVAC calculators: Superheat & Subcooling, Refrigerant Charge, Duct Sizing, Airflow / CFM & Static Pressure, BTU / Load, and Hydronic (water-side). Each is built for real field work with results interpreted for you.

Does Ventora have an AI assistant for HVAC questions?

Yes, Ventora features an advanced AI assistant trained on real-world HVAC knowledge. Ask about refrigerants, error codes, sequences of operation, wiring, and codes, and get instant, accurate answers backed by mechanical code and standards references.

Is Ventora free to use?

Ventora is free to try with a 7-day free trial, then $19.99/month. Cancel anytime through the App Store. The subscription unlocks the AI assistant, all six calculators, HVAC code reference, photo analysis, and guided troubleshooting.

How do I calculate superheat?

Superheat = Suction Line Temperature − Evaporator Saturation Temperature, in °F. On a TXV system, target 8–14°F. Low superheat (under about 5°F) risks liquid floodback and overcharge; high superheat (over about 20°F) usually means a starved or undercharged system. Ventora's Superheat & Subcooling Calculator looks up saturation temperatures from the PT chart for R-410A, R-454B, R-22, R-32, and R-407C.

How do I calculate subcooling?

Subcooling = Condenser Saturation Temperature − Liquid Line Temperature, in °F. Target roughly 10–18°F on most systems. Low subcooling points to an undercharge; high subcooling points to an overcharge or a liquid-line restriction. Ventora computes it automatically once you enter your liquid line pressure and temperature.

What is the target superheat for a fixed-orifice system?

For fixed-orifice (piston) metering, use the Carrier method: Target Superheat = 3 × (indoor Wet Bulb) + (80 − Outdoor Dry Bulb) − 1, in °F. Ventora's Refrigerant Charge Calculator computes target superheat from indoor wet-bulb and outdoor dry-bulb temperatures and compares it to your measured superheat.

How do I size ductwork?

Duct sizing starts with the friction rate: Friction Rate = (Available Static Pressure ÷ Total Equivalent Length) × 100, in inches of water column per 100 ft. Aim for roughly 700–900 FPM on supply and 600–700 FPM on return. Ventora's Duct Sizing Calculator recommends round diameters and equivalent rectangular sizes following ACCA Manual D principles.

How do I calculate CFM and airflow?

The core airflow formula is CFM = BTU ÷ (1.08 × ΔT). You can also derive CFM from velocity (CFM = FPM × Area in ft²) or velocity from velocity pressure (V = 4005 × √VP). A common target is about 400 CFM per ton. Ventora's Airflow / CFM Calculator handles all three methods plus total external static pressure.

What is a good total external static pressure?

Total External Static Pressure (TESP) should generally stay at or below 0.50 iwc on typical residential equipment. Readings above 0.80 iwc indicate a serious airflow restriction — often a dirty filter or coil, closed registers, or undersized ductwork. Ventora flags high static pressure automatically.

How do I calculate a cooling load?

Sensible load = 1.08 × CFM × ΔT; Total load = 4.5 × CFM × Δh; Latent load = 0.68 × CFM × ΔW; Tons = BTU ÷ 12,000. For quick estimates Ventora offers BTU/sq-ft rules of thumb by climate zone — but a full ACCA Manual J is required for real equipment sizing, since oversizing is the number-one install error.

What refrigerants does Ventora support?

Ventora includes PT data and charging guidance for R-410A, R-454B, R-22, R-32, and R-407C. It also covers the AIM Act phase-down: as of January 1, 2025, new residential and light-commercial systems must use lower-GWP refrigerants such as R-454B (GWP 466) in place of R-410A (GWP 2,088).

Do I need EPA 608 certification to handle refrigerant?

Yes. Under EPA Section 608 of the Clean Air Act, anyone who purchases or handles refrigerant must be certified — Type I (small appliances), Type II (high-pressure), Type III (low-pressure), or Universal. Ventora's code reference covers 608 requirements including mandatory leak repair, recovery, and recordkeeping rules.

How do I troubleshoot a system that isn't cooling?

The most common causes are a dirty air filter or restricted airflow, a low refrigerant charge or leak, a frozen evaporator coil, a dirty condenser coil, or a failed run capacitor. Ventora's guided troubleshooting walks you through no-cooling, no-heat, airflow, electrical, and refrigerant faults step by step.

Does Ventora work for commercial HVAC technicians?

Yes, Ventora is designed for both residential service techs and commercial installers. It includes commercial-focused tools like hydronic (water-side) heat-transfer calculations, airflow and static pressure analysis, and a code reference covering the IMC, ASHRAE 62.1/90.1, and Manual N commercial loads.

What is the best app for HVAC technicians?

Ventora is built specifically for HVAC technicians. It combines an AI assistant, six professional calculators (superheat & subcooling, refrigerant charge, duct sizing, airflow/CFM, BTU/load, hydronic), HVAC code reference, photo analysis, and guided troubleshooting in one mobile app. Free to try with a 7-day trial, then $19.99/month.

Duct Sizing Calculator

Size supply and return ductwork instantly. Enter target CFM and friction rate to get the right round diameter and equivalent rectangular dimensions, with velocity checked against ACCA Manual D targets.

Use Calculator in App

What is Duct Sizing?

Duct sizing determines the round diameter or rectangular dimensions needed to deliver a target airflow (CFM) at an acceptable friction rate and air velocity. Proper sizing keeps total external static pressure low, delivers full airflow to every room, and holds noise down.

Undersized ducts choke airflow, drive up static pressure, and cause comfort and efficiency problems. Oversized ducts waste material and can drop velocity so low that air stops throwing across the room. The goal is a diameter that lands airflow squarely inside the velocity targets below.

Velocity & Friction Rate Targets

Residential duct design keeps air velocity and friction rate inside proven ranges. Aim for these targets when selecting a size:

700-900

Supply Velocity (FPM)

Target range for supply trunks and branches

600-700

Return Velocity (FPM)

Lower velocity keeps returns quiet

0.08-0.10

Friction Rate (iwc/100ft)

Typical residential design friction rate

Friction Rate = (Available Static Pressure / Total Equivalent Length) × 100 (iwc per 100 ft)

Round Duct Area = π × (D / 2)² (sq. in.)

Velocity = (CFM × 144) / Area (FPM, area in sq. in.)

Equivalent Round D_e = 1.3 × (a × b)^0.625 / (a + b)^0.25 (inches)

Round Duct Airflow Capacity (CFM by Velocity)

Round Diameter	Area (sq. in.)	CFM @ 700 FPM	CFM @ 800 FPM	CFM @ 900 FPM
6"	28.3	137	157	177
7"	38.5	187	214	241
8"	50.3	244	279	314
9"	63.6	309	353	398
10"	78.5	382	436	491
12"	113.1	550	628	707
14"	153.9	748	855	962
16"	201.1	977	1117	1257

Equivalent Round for Rectangular Ducts (D_e)

Rectangular Size	Equiv. Round	Rectangular Size	Equiv. Round
8" × 6"	7.6"	12" × 10"	12.0"
10" × 6"	8.4"	14" × 10"	12.9"
12" × 6"	9.1"	16" × 10"	13.7"
10" × 8"	9.8"	14" × 12"	14.2"
12" × 8"	10.7"	18" × 12"	16.0"
14" × 8"	11.5"	20" × 14"	18.2"

Duct Sizing Example

Problem:

A supply trunk must carry 800 CFM. There is 0.10 iwc of available static pressure over a total equivalent length of 100 ft. What round duct works, and what rectangular size is equivalent?

Solution:

Friction rate: (0.10 / 100) × 100 = 0.10 iwc per 100 ft

Required area at 800 FPM supply: 800 × 144 / 800 = 144 sq. in.

Round duct: D = 2 × √(144 / π) ≈ 13.5" → use 14" round (velocity ≈ 748 FPM)

Equivalent rectangular: 16" × 10" (D_e ≈ 13.7", velocity ≈ 720 FPM)

Use 14" round or 16" × 10" rectangular (both inside 700-900 FPM)

Instant Duct Sizing with Ventora

Enter target CFM and friction rate - get the round diameter and equivalent rectangular sizes with resulting velocity instantly. No ductulator wheel required. ACCA Manual D methodology built-in.

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Duct Sizing Calculator

What is Duct Sizing?

Velocity & Friction Rate Targets

Round Duct Airflow Capacity (CFM by Velocity)

Equivalent Round for Rectangular Ducts (D_e)

Duct Sizing Example

Problem:

Solution:

Instant Duct Sizing with Ventora

Explore All HVAC Calculators

Get All Calculators in One App

What is Duct Sizing?

Velocity & Friction Rate Targets

Round Duct Airflow Capacity (CFM by Velocity)

Equivalent Round for Rectangular Ducts (De)

Duct Sizing Example

Problem:

Solution:

Instant Duct Sizing with Ventora

Explore All HVAC Calculators

Get All Calculators in One App

Equivalent Round for Rectangular Ducts (D_e)