What Is 97% Heat Recovery and Why It Matters

When we say the AirPro V2.0 achieves up to 97% heat recovery, we mean that 97% of the thermal energy in the outgoing stale air is captured and transferred to the incoming fresh air. This is not a theoretical maximum — it is a measured, certified performance figure. But what does it actually mean for your building, your energy bills, and the environment?

How Ceramic Regenerative Heat Exchangers Work

The technology behind 97% heat recovery is the ceramic regenerative heat exchanger — a dense matrix of ceramic balls or honeycomb elements packed into a cylindrical core inside the ventilation unit.

The unit operates in two alternating cycles, each lasting about 60–70 seconds:

1. Extract phase: Warm, stale indoor air (say, 21 degrees C) is drawn out through the ceramic core. As the air passes through, it heats the ceramic elements, which absorb and store the thermal energy. The air exits the building at close to the outdoor temperature.
2. Supply phase: The fan reverses direction. Cold outdoor air (say, 0 degrees C) is drawn in through the now-hot ceramic core. The ceramic elements release their stored heat to the incoming air, warming it to approximately 20.4 degrees C (97% of the 21-degree difference recovered). The ceramic core cools down, ready for the next extract phase.

This cycle repeats continuously, with paired units operating in opposite phases to maintain a constant flow of fresh air. The ceramic material has extremely high thermal mass relative to its size, which is why recovery rates reach 97% — far higher than the 75–85% achievable with counter-flow plate heat exchangers used in most centralised systems.

Energy Savings: A Real-World Calculation

Let us calculate the annual energy savings for a typical home in Northern Europe.

At a gas price of EUR 0.10/kWh, that is EUR 359 per year in heating savings. At a heat pump COP of 3, it is equivalent to 1,196 kWh of electricity saved, worth approximately EUR 358 per year at EUR 0.30/kWh.

The electrical consumption of the units themselves is minimal: 4 units x 3W average x 8,760 hours = 105 kWh/year, costing about EUR 32. Net annual savings: approximately EUR 327.

Comparison with Competitors

Most competing ventilation systems use counter-flow plate heat exchangers or enthalpy wheels, which achieve 75–85% heat recovery under ideal conditions. Here is how the numbers compare for the same Copenhagen apartment:

The difference between 75% and 97% recovery costs the building owner an extra EUR 1,230 in heating over 15 years — for just 4 units. For a school with 40 units, that difference rises to over EUR 12,000.

Environmental Impact

Every kilowatt-hour of heating energy saved is a kilowatt-hour of fossil fuel not burned (or renewable energy freed for other uses). For our Copenhagen apartment example:

• Gas heating: 3,588 kWh saved = 0.74 tonnes CO2 avoided per year (at 0.206 kg CO2/kWh for natural gas)
• Over 15 years: 11.1 tonnes CO2 avoided from a single apartment
• For a 20-apartment building: 222 tonnes CO2 avoided over the system lifetime

The embodied carbon in the ceramic cores is recovered within the first few months of operation through heating energy savings. After that, every hour of operation delivers net carbon reduction.

When you multiply this across thousands of buildings — which is what the EU Renovation Wave aims to achieve — the aggregate impact is substantial. Ventilation with high heat recovery is one of the most cost-effective decarbonisation measures available for existing buildings.

Why the Extra 12–22% Matters

Some may argue that the difference between 75% and 97% recovery is only 22 percentage points. But in practice, this difference is magnified because:

• It compounds over time. The savings accrue every hour of every day throughout the heating season, year after year.
• It scales with building size. A 20-unit installation saves 20 times more than a single unit.
• It reduces peak heating demand. Higher heat recovery means smaller radiators, smaller boilers, or smaller heat pumps — reducing capital costs as well as running costs.
• It improves comfort. Incoming air at 20.4 degrees C (97% recovery) feels comfortable. Incoming air at 16.5 degrees C (75% recovery) creates cold draughts near the unit.

Conclusion

97% heat recovery is not a marketing number — it is a transformative performance level that delivers real, measurable benefits. It saves hundreds of euros per year in heating costs, eliminates cold draughts, reduces carbon emissions, and pays for itself within a few years. When choosing a ventilation system, heat recovery efficiency should be at the top of your evaluation criteria.