Small calculations. Better decisions.

Dew point & surface margin

Compare an indoor surface temperature with the estimated dew point.

Assembly heat loss

Compare heat flow through a wall, roof or window area.

Extra insulation thickness

Estimate an ideal continuous layer needed to reach a target U-value.

Ventilation heat loss

Estimate the heating load associated with outdoor-air ventilation and heat recovery.

Wells & water

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Rainwater collection & overflow

Estimate one rainfall event and the amount a tank can receive.

Household water demand

Estimate daily use and an explicit buffer-storage volume.

Well drawdown & specific capacity

Interpret water levels from a recorded pumping test.

Pump head & electrical power

Combine lift, delivery pressure and friction in a first-pass pump calculation.

Water velocity in a pipe

Convert flow and internal pipe diameter into water velocity.

Water volume in a round tank

Estimate the water held in a vertical cylindrical tank from its internal dimensions.

Water pressure to head

Convert water pressure into metres of head and psi using a stated density.

Hot and cold water mixing

Estimate hot and cold volumes needed to reach a target mixed-water temperature.

Water stored above a well-pump reserve level

Estimate the cylindrical water column and volume above a protected pump-intake level.

Observed well water-level recovery

Convert a measured rise in a cylindrical well into equivalent volume and an average recovery observation.

Independent energy

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Generator running & starting load

Check one documented motor start against other running loads.

Daily electricity budget

Add three appliance groups using power and actual daily running time.

Solar array energy balance

Estimate DC array size from daily energy and a monthly solar assumption.

Battery autonomy

Convert a daily load into nominal battery capacity with stated losses.

Energy to heat water

Estimate heat and input energy for a known water volume and temperature rise.

Battery recharge time

Estimate ideal recharge time between two states of charge.

Generator fuel runtime

Convert usable stored fuel and measured consumption into a simple operating-time estimate.

Solar energy balance over a low-sun period

Compare estimated solar production with critical-load demand over several days.

Generator-assisted battery recharge plan

Estimate recharge time, generator-side demand and fuel for a stated battery deficit.

Frost & ground

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Pipe cover to trench depth

Convert an established pipe-cover requirement into a trench section.

Heat-trace energy use

Estimate connected load and energy use for a thermostatically controlled heating cable.

Foundation frost-depth screening comparison

Compare a planned bearing depth with a locally established frost-protection target.

Foundation bearing and excavation elevations

Translate final grade, bearing depth and a working layer into site elevations and excavation depth.

Wastewater

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Wastewater

Wastewater hydraulic load

Explore daily wastewater volume and a holding-time scenario.

Wastewater

Gravity drain fall

Convert pipe length and slope into vertical fall and a downstream invert depth.

Water treatment

Water treatment

Filter-media contact time

Estimate empty-bed contact time and hydraulic surface loading for a cylindrical media vessel.

Water treatment

Filter service-life planner

Turn a rated treated-water capacity into a conservative replacement date estimate.

Water treatment

UV intensity × exposure time

Show the unit relationship between ultraviolet intensity, exposure time and nominal dose.

Construction

Construction

Concrete volume and order allowance

Calculate geometric concrete volume and a separate ordering allowance.

Construction

Trench excavation volume

Estimate in-place and loosened spoil volumes for a straight trapezoidal excavation.

Construction

Roof runoff peak flow

Estimate peak roof runoff from connected area, rainfall intensity and a runoff factor.

Electrical power

Electrical power

DC cable voltage drop

Estimate copper-cable voltage drop, percentage loss and heat at a steady current.

Electrical power

Inverter DC input current

Convert an AC load and inverter efficiency into approximate battery-side power and current.

Electrical power

Battery runtime from a steady load

Estimate ideal runtime from nominal energy, usable fraction, inverter efficiency and load.

Heating