How do I simulate an energy audit?

Open this page and use the live HVAC Duct Designer tool below — set your inputs and the simulation runs instantly in your browser using real numerics. No install, no account needed.

Yes. The simulation runs free in your browser. A one-time unlock or a Pro plan adds advanced parameters, saved presets, data import, and clean exports.

Can I use my own numbers?

Absolutely — every input is adjustable, and with data import you can drive an energy audit from your own measurements.

Use case · powered by HVAC Duct Designer

HVAC Duct Designer for an energy audit

Simulate an energy audit live in your browser. This runs the real HVAC Duct Designer solver — adjust the inputs, watch it respond instantly, and export the result. No install, no account.

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Fluid

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2D Fluid (CFD) StudioLive

Stam stable-fluids · Navier–Stokes

Controls

Speed1×

Click and drag on the canvas to inject dye and velocity.

Presets

Viscosity

Injection force

Dye amount

▶ Run in Python

Data Inspector

Grid96×96

Total dye0

Mean speed0.000

Max speed0.000

Enstrophy0.00e+0

Governing equation

\frac{\partial u}{\partial t} + (u \cdot \nabla) u = - \frac{\nabla p}{ρ} + 1.0 e - 7 \nabla^{2} u, \nabla \cdot u = 0

Reading this result: Near-zero viscosity: momentum barely dissipates, so vortices persist and the flow tips into turbulent, chaotic mixing.

Runs locally in your browser — free forever. Scale to the cloud when reality gets heavy.

↓

Sound Levels

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Sound Levels (dB SPL)Live

adding & spreading loudness

Controls

Presets

Level per source at 1 m (dB)

Number of sources

Distance (m)

Decibels are logarithmic, so loudness does not add the way you expect: two identical sources are only 3 dB louder than one, and ten are 10 dB. Meanwhile a point source drops 6 dB every time the distance doubles (the inverse-square law). Sustained exposure above 85 dB risks hearing damage.

▶ Run in Python

Data Inspector

Combined at 1 m85.0 dB

At 4 m73.0 dB

Doubling sources+3 dB

Risksafe range

Governing equation

L = 85.0 - 20 lo g_{10} (4) = 73.0 dB

Reading this result: A single source falls from 85 dB to 73 dB across 4 m — about 6 dB lost each time the distance doubles.

Runs locally in your browser — free forever. Scale to the cloud when reality gets heavy.

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Thermal Resistance

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Composite Wall Heat TransferLive

R-value & U-value

Controls

Presets

Drywall (mm)

Insulation (mm)

Brick (mm)

Inside temp (°C)

Outside temp (°C)

Heat flows through a wall like current through resistors in series. Each layer's thermal resistance is its thickness over its conductivity; adding them gives the total R-value, and the heat flux is the temperature difference divided by it. Insulation, with very low conductivity, dominates the R-value — the steep temperature drop shows where it does its work.

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Data Inspector

Total R-value2.71 m²K/W

U-value0.37 W/m²K

Heat flux9.6 W/m²

Governing equation

R = \sum \frac{L _{i}}{k _{i} A} = 2.71 \frac{m ^{2} K}{W}, Q = \frac{Δ T}{R} = 9.6 \frac{W}{m ^{2}}

Reading this result: The insulation layer carries the most thermal resistance, so the temperature falls most steeply across it. A total R-value of 2.71 m²K/W lets 9.6 W/m² flow for this 26°C difference.

Runs locally in your browser — free forever. Scale to the cloud when reality gets heavy.

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About this simulation

The full HVAC Duct Designer tool models an energy audit with the same numerics engineers and scientists use — running entirely client-side. Change any parameter and the result updates in real time, so you can build intuition, check a design, or teach the concept without spreadsheets or installs.

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Frequently asked questions

How do I simulate an energy audit?: Open this page and use the live HVAC Duct Designer tool below — set your inputs and the simulation runs instantly in your browser using real numerics. No install, no account needed.
Is it free?: Yes. The simulation runs free in your browser. A one-time unlock or a Pro plan adds advanced parameters, saved presets, data import, and clean exports.
Can I use my own numbers?: Absolutely — every input is adjustable, and with data import you can drive an energy audit from your own measurements.