HTHOMETALLYTHE PRACTICAL HOME GUIDE

Insulation/ CALCULATOR

Ventilation heat loss

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

Use the design or measured outdoor-air rate.
The indoor heating setpoint.
The outdoor design condition for this estimate.
Use a tested value appropriate to the operating condition.
Use equivalent hours at the entered average temperature difference, not automatically the full heating season.
Cost of one delivered kWh of heat from the actual heating system, in any currency.
Load without heat recovery

1.25 kW

Load after heat recovery

0.31 kW

Heating load avoided

0.93 kW

Seasonal heat after recovery

935 kWh

Seasonal heat avoided

2,804 kWh

Estimated seasonal cost avoided

336.47 currency units

Interpretation:Across the entered equivalent hours, heat recovery avoids about 2,803.95 kWh of heating and 336.47 cost units. Fan energy and defrost are not included.

Constant dry-air properties, balanced airflow, sensible heat only and the entered equivalent operating hours. Fan electricity, infiltration, defrost, leakage, humidity, changing weather, heating-system efficiency changes and equipment performance changes are excluded.

FROM ESTIMATE TO ACTION

Use the result, not just the number.

01

Verify the inputs

Measure or document each input. If a value is only an estimate, record its source and test a conservative alternative.

02

Keep the calculation traceable

Save the input link or copied result together with the date, units and assumptions. A number without its inputs cannot be checked later.

03

Confirm the decision

Compare the estimate with the related guide, current product data and requirements that apply at your location before buying or building.

Inputs to verify

Outdoor airflow (m³/h)
Use the design or measured outdoor-air rate.
Indoor temperature (°C)
The indoor heating setpoint.
Outdoor temperature (°C)
The outdoor design condition for this estimate.
Sensible heat recovery (%)
Use a tested value appropriate to the operating condition.
Hours at this average condition (h/season)
Use equivalent hours at the entered average temperature difference, not automatically the full heating season.
Useful heat cost (currency units/kWh)
Cost of one delivered kWh of heat from the actual heating system, in any currency.

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