A residential HRV is a whole-house ventilation device that exhausts stale indoor air and pulls in fresh outdoor air while transferring most of the heat between the two streams. In an airtight modern home — where you can no longer rely on draughts for ventilation — it is the difference between healthy air and a stuffy, mould-prone box.
Why homes need it
Tight envelopes (required by modern codes) trap moisture from cooking, showering and breathing. Without controlled ventilation that moisture condenses on cold surfaces. An HRV gives you a fixed, filtered air change rate without throwing away the heat you paid to produce. In winter it pre-warms incoming air with the departing warm exhaust; in summer it can pre-cools it.
How much airflow do you need?
Whole-house rates are small compared with industry. A typical home wants about 0.3–0.5 air changes per hour, which for a 200 m² home is roughly 150–350 m³/h total supply (and a matched exhaust). That is well within a single counterflow plate core. Our CFM–m³/h converter helps translate equipment ratings.
What effectiveness to specify
For homes, aim for sensible effectiveness of 75–85%. Below 70% the comfort payback weakens; above 85% the core gets large and the fan energy grows. Note the cold-climate moisture rule from our ERV vs HRV piece: in dry heating climates an HRV is often preferred so indoor humidity is not pushed too high.
Where the core goes
- Central unit: in a mechanical room or attic, with supply/exhaust ducts to each room. Best for new builds.
- Decentral (wall) units: one core per room, no ductwork. Easier retrofit, lower total recovery.
- Demand-controlled: CO2 or humidity sensors ramp the fan only when needed, cutting both fan power and defrost energy.
Running cost and comfort case
A residential HRV fan draws 20–100 W. Against the heating (or cooling) energy it recovers — often 1,000–4,000 kWh/yr for a well-used home — the electricity cost is tiny, and the comfort (no cold drafts at the window, no condensation on the glass) is the real selling point. Estimate your own saving with the savings calculator.
Common mistakes
- No pre-filters — plates foul in a season.
- Unbalanced flows — supply must roughly equal exhaust or the house goes positive/negative pressure.
- Skipping frost control in cold regions (see frost control).
Designing HRV for a home?
Tell us the floor area, climate and ACH target — we will suggest a core size and arrangement.
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