# Heat-Recovery Ventilation Planning Guide

> Plan balanced ventilation from required outdoor airflow and climate conditions. Includes measurement workflow, a worked example, decision table, ordering checkpoints, common failures and professional boundaries.

- Canonical URL: https://buildmeter.net/guides/heat-recovery-ventilation-planning-guide/
- Category: Energy & Electrical
- Author: Liron Elimeleh
- Publisher: BuildMeter, developed by ELStudios
- Published: July 30, 2026
- Last reviewed: August 19, 2026

## Direct answer

Plan balanced ventilation from required outdoor airflow and climate conditions.

## Primary calculator

- [Heat Recovery Ventilator Calculator](https://buildmeter.net/heat-recovery-ventilator-calculator/)

## Plan airflow and recovered heat as separate quantities

A heat-recovery ventilator (HRV) exchanges stale indoor air for outdoor air while transferring part of the temperature difference between the two air streams. The planning inputs are ventilation airflow, indoor/outdoor temperatures, sensible recovery efficiency and operating time—not packages or generic material allowance.

### HRV planning inputs

| Input | Meaning | Why it matters |
| --- | --- | --- |
| Outdoor-air flow | cfm or L/s | Sets ventilation volume and fan duty |
| Temperature difference | Indoor minus outdoor temperature | Sets sensible heating/cooling load |
| Sensible recovery efficiency | Fraction of temperature load recovered | Reduces ventilation heat loss |
| Run time | Hours/day or duty cycle | Converts rate to energy |

## Worked recovery example

Assume 100 cfm of outdoor air, indoor air at 70°F and outdoor air at 30°F, a 40°F temperature difference. Using the common sensible-air approximation 1.08 × cfm × ΔT, untreated ventilation would represent about 4,320 Btu/h of sensible heat. At 70% sensible recovery, roughly 3,024 Btu/h is recovered and about 1,296 Btu/h remains as ventilation heating load, before fan power and frosting/defrost effects.

## Recommended workflow

1. Establish the required outdoor-airflow basis for the home and local requirements.
2. Use the [Heat Recovery Ventilator Calculator](https://buildmeter.net/heat-recovery-ventilator-calculator/) to compare airflow, temperature difference and recovery efficiency.
3. Check fan power and annual run time separately from recovered thermal energy.
4. Verify duct size, balancing, intake/exhaust placement and condensate handling from the selected equipment instructions.

## Common mistakes

- Using advertised maximum airflow instead of the balanced design airflow.
- Treating sensible recovery efficiency as total system efficiency in every climate condition.
- Ignoring fan electricity when comparing annual energy impact.
- Assuming an HRV replaces bathroom/range exhaust requirements or dehumidification strategy.

## Professional limits

Ventilation rates, duct design, combustion safety, frost control and balancing require system-specific design and commissioning. The calculator is a planning model, not an HVAC design approval.

## Sources

- [U.S. Department of Energy — Ventilation](https://www.energy.gov/energysaver/ventilation)

## Related calculators

- [Humidifier Size Calculator](https://buildmeter.net/humidifier-size-calculator/)
- [Duct Air Velocity Calculator](https://buildmeter.net/duct-air-velocity-calculator/)

## Related guides

- See the BuildMeter Guides directory.