HVAC Calculation

HVAC system design and calculation blueprint
HVAC Calculation

Size Your HVAC System with
Real Physics, Not Rules of Thumb

Enter your building details to get an instant system recommendation and load estimation across central heating, heat pumps, and split systems. When you’re ready, apply for a full detailed engineering project.

  • Instant Suggestion
  • Multi-System Comparison
  • ASHRAE Aligned
System Suggester

Instant HVAC Recommendation

Enter your building's basic parameters. We'll calculate the thermal load and suggest the most efficient system topology for your specific climate and scale.

Method

From floor plans to precise climate control

01

Data intake & weather

We analyze your architectural plans, orientation, and local TMY weather files to understand the exact thermal behavior of your building.

02

Room-by-room load calc

Using ASHRAE, EN 12831, or Manual J standards, we calculate the exact heating and cooling load for every single zone.

03

System selection & sizing

We select the optimal topology (Heat Pump, VRF, Chiller) and size the equipment perfectly to prevent short-cycling and energy waste.

04

Distribution design

We design the ductwork, piping, and terminal units (fan coils, radiators) ensuring optimal airflow, pressure drop, and acoustic comfort.

05

Documentation & BOM

You receive detailed schematics, a vendor-neutral Bill of Materials, and clear installation guides for your contractor.

Deliverables

What lands in your inbox

Thermal load report

Room-by-room heating and cooling loads calculated to ASHRAE, Manual J, or EN 12831 standards.

Equipment schedule

Exact capacities, airflow rates, and a vendor-neutral Bill of Materials ready for procurement.

Distribution schematics

Ductwork layouts, piping diagrams, and pressure drop calculations for perfect airflow balance.

Control & wiring

Thermostat placement, control logic sequences, and wiring diagrams for the automation integrator.

Acoustic & airflow

Noise criteria (NC) checks, CFM/L/s airflow balancing, and diffuser selection for silent comfort.

Install & commissioning

A step-by-step manual for your contractor, including testing protocols and final balancing guides.

Case file · RW-HVAC-0089

The office that froze and overheated

A 400m² commercial space suffering from a legacy oversized boiler and an undersized, short-cycling AC system. We recalculated the zone loads and engineered a variable refrigerant flow (VRF) solution.

  • Baseline: 185 kWh/m²/yr energy use, constant tenant comfort complaints.
  • The Fix: Right-sized VRF system with dedicated zone controls and heat recovery.
  • Result: 38% drop in energy bills, zero thermal complaints, and a 12-year projected ROI.
Request a Detailed Project

Ready when you are

Tell us about your building. We'll reply with a tailored scope, timeline, and a fixed quote for your detailed HVAC calculation.

Reply < 48h · Fixed-fee scope · ASHRAE / Manual J aligned
FAQ

Common questions

Why do I need a professional calculation? Can't my installer just size it?

Installers often use "rules of thumb" (like 1 ton of cooling per 600 sq ft), which frequently leads to oversized or undersized equipment. An oversized system will short-cycle, causing humidity issues, temperature swings, and premature failure. Our calculations (Manual J / ASHRAE) guarantee the exact capacity your building's physics demand.

What engineering standards do you use?

We strictly follow internationally recognized standards. For residential, we use ACCA Manual J (load), Manual D (ducts), and Manual S (equipment selection). For commercial or European projects, we use ASHRAE fundamentals or EN 12831. This ensures your design is compliant, efficient, and defensible.

Do you sell the HVAC equipment?

No, we are strictly vendor-neutral. We do not sell hardware, and we do not take commissions from manufacturers. We provide a detailed, vendor-neutral Bill of Materials (BOM) with exact specifications. This allows you to get competitive bids from any local supplier or installer without being locked into a specific brand.

Can you design a system for an existing home (retrofit)?

Absolutely. For existing homes where adding ductwork is impossible or too expensive, we specialize in designing high-efficiency ductless solutions (like multi-split or VRF systems). We calculate the exact placement of indoor heads to ensure perfect airflow and aesthetic integration.

How long does a detailed HVAC calculation take?

A standard residential calculation and design package typically takes 5 to 10 working days from the moment we receive complete architectural plans and window schedules. Larger commercial projects or complex retrofits are scoped individually based on the building's footprint.