HVAC Engineering Suite
A practical HVAC design workspace for load screening, air and water systems, psychrometrics, interactive 3D building analysis, Carrier HAP comparison and documented engineering review.
Choose an HVAC calculator
Select a tool from the list to begin.
Design review & warnings
Calculate a tool or edit the room/building models to collect assumptions, design warnings and validation flags here.
Warnings are screening prompts, not automatic code-compliance approval. Review the underlying inputs, calculation scope and applicable project standards.
Saved calculations on this device
Saved locally in this browser only; this is not cloud storage or a project backup.
Room-by-Room Cooling Load Schedule
Build a transparent room schedule with separate envelope, orientation-adjusted solar screening, people, lighting, equipment, outdoor-air and infiltration components. Estimate room supply airflow from sensible load and the entered supply-to-room temperature difference. Results update as you edit rooms. A separate outdoor-air check compares the entered outdoor-air flow against user-specified per-person and per-area criteria.
Calculate the schedule to see total sensible, latent and preliminary cooling loads.
Preliminary steady-state worksheet only. Solar gain uses entered irradiance × window area × SHGC × user-entered orientation/time multiplier × external shading factor. These modifiers are not a solar-position/weather model. Supply airflow is screened from sensible load and entered supply-to-room ΔT. Thermal mass, thermal bridges, detailed infiltration, ventilation effectiveness, diversity/coincidence, design-day weather and hourly heat balance are not modelled. Ventilation screening calculates required outdoor air as occupancy × entered L/s-person rate + floor area × entered L/s-m² rate. These rates are user-defined, not embedded code requirements; confirm the applicable standard, occupancy category, ventilation effectiveness, diversity and local authority requirements. Do not use as a substitute for a validated HAP/ASHRAE-based design.
3D HVAC Building & Airflow Lab
Adjust building geometry, glazing, envelope properties and operating assumptions. The isometric model, zone heat indicator, preliminary envelope load and airflow estimate update live.
Early-stage conceptual model only. Solar gain, thermal mass, orientation, shading, infiltration, detailed ventilation, latent load, schedules and hourly weather are not simulated.
Carrier HAP workflow & technical references
Use the suite for preliminary calculations and QA organization, then compare matching project scopes against a properly configured HAP model and approved manufacturer data. These references guide the workflow; they do not imply equivalence with Carrier HAP.
Carrier Hourly Analysis Program
HAP combines system design/sizing with energy modeling; published capabilities include room/zone/system loads, ventilation sizing, coil/fan/plant sizing and psychrometric reports.
Carrier HAP official overview ↗HAP sample reports
Use report headings and matching scope to structure review: air-system sizing, zone sizing, ventilation sizing, heat balance, hourly load profiles and system psychrometrics.
Carrier sample reports ↗ASHRAE Handbook—Fundamentals
Reference psychrometrics, thermodynamics, heat transfer, climatic design data, ventilation/infiltration, non-residential loads, energy methods, duct design and pipe design.
ASHRAE 2025 contents ↗EnergyPlus engineering reference
For advanced whole-building simulation workflows, review EnergyPlus documentation and its model assumptions separately; it is not a substitute for validating inputs and results.
EnergyPlus documentation ↗- Match weather/design day, building orientation, schedules and indoor setpoints.
- Match room/zone/system scope; distinguish sensible, latent and total loads.
- Reconcile envelope, glazing/solar, people, lighting, equipment, infiltration and outdoor air.
- Review ventilation method, system airflow, fan heat, coil entering/leaving states and plant loads.
- Compare selected equipment at actual design conditions—not nominal catalogue capacity alone.
- Document deviation, tolerance, source report, assumptions, reviewer and unresolved differences.
HVAC calculators and engineering references
Explore practical HVAC calculations for thermal loads, air distribution, psychrometrics, hydronic systems, equipment efficiency and energy management. Each calculator states its units and calculation method; verify assumptions before professional use.
Loads & capacity
- Cooling capacity estimator
- HAP load & capacity cross-check
- Room cooling-load estimator
- Four-zone load aggregation schedule
- Heating-load estimator
- Chiller capacity and chilled-water flow
- Cooling-coil sensible capacity
- Cooling-coil total capacity (enthalpy method)
Air systems
- Airflow and air changes per hour (ACH)
- Outdoor-air ventilation estimator
- Outdoor-air mixing & cooling-coil estimate
- Duct sizing by velocity
- Straight-duct friction loss
- Filter face velocity
- Fan power and fan affinity laws
Water & pumps
- Chilled-water flow and pipe sizing
- Pipe pressure drop
- Pump head and power
- NPSH available estimator
- Pump affinity laws
- Condenser-water flow
- Pipe thermal expansion
Thermal & refrigerants
- Live psychrometric chart & design feasibility
- Dew-point estimator
- Heat-transfer and insulation heat-loss estimates
- Refrigeration-cycle COP
- Cooling-tower heat rejection
- Reheat-coil duty
- Humidification water estimate
- Condensate production
- Moist-air density
Energy & operations
- COP and EER
- Energy use and cost
- Motor electricity cost
- Heat-pump heating COP
Learn the method. Check the result. Document the work.
Use guided calculators for learning and quick checks, then carry the assumptions and outputs into your professional engineering workflow.
Readable input labels, units, equations and calculation notes.
Review key outputs and compare the effect of changing inputs.
Print a report or export a calculation summary for review.
HVAC engineering calculators: FAQs
What can I use this HVAC engineering suite for?
It provides preliminary HVAC calculations and engineering checks for cooling and heating loads, psychrometrics, ventilation, ducts, chilled water, pumps, fans, heat transfer and energy use.
Are results suitable for construction or final equipment selection?
Not by themselves. Verify project conditions, local codes, standards, manufacturer performance data and assumptions, and have safety-critical or final design calculations reviewed by a qualified professional.
Does the cooling-load estimator replace a detailed load calculation?
No. The quick estimator uses area-based load intensity. The component-based room estimator adds entered envelope, people, lighting, equipment and outdoor-air loads, but it is still not a substitute for a validated hourly or room-by-room design method.
Can I print or save my calculations?
Yes. After calculating, use Professional PDF Report to open a branded, print-ready report and choose Save as PDF in your browser, or use Export CSV for spreadsheet review.
Which units are used?
Each input explicitly displays its units. The suite primarily uses SI units and provides common HVAC output conversions such as CFM, BTU/h and refrigeration tons where useful.
Is the live psychrometric chart suitable for final design?
No. It provides an approximate state plot and process screen. Verify psychrometric states with a validated method and confirm airflow, coil performance, capacity, controls and condensation risks independently.
Does the 3D lab reproduce Carrier HAP?
No. The interactive isometric model visualizes a conceptual building and gives transparent preliminary envelope/internal-load estimates. It is not a detailed heat-balance model, hourly energy simulation, BIM model or Carrier HAP replacement.
What does the multi-zone calculator do?
It aggregates four entered zone sensible and latent loads and screens capacity, SHR and sensible airflow. It does not calculate detailed room-by-room hourly peaks or coincident system loads.
Can the outdoor-air mixing tool select a cooling coil?
No. It estimates mixed-air properties and an air-side duty from entered states and airflow. Final coil selection requires validated psychrometrics and manufacturer performance data at the project conditions.
How is room supply airflow estimated?
The room schedule uses the sensible heat equation with entered supply-to-room temperature difference and assumed air density and specific heat. Confirm airflow against ventilation, latent control, diffuser throw/noise, pressurization and the selected system design.
This suite does not certify code compliance or replace competent engineering judgement. Results are only as reliable as the entered data and the selected calculation model. Do not use simplified estimates as sole authority for life-safety, pressure-boundary or final construction decisions.