ERV vs HRV vs Positive Pressure: What to Compare in India
Ventilation choices involve both outdoor-air supply and the energy needed to condition that air. HRV, ERV and supply-only positive-pressure systems make different tradeoffs. No single category is automatically right for every Indian home.
Understand the distinction
| System | Basic arrangement | What to assess |
|---|---|---|
| Heat recovery ventilator (HRV) | Supply and exhaust with heat exchange | Heat-recovery performance, airflow, filtration and installation |
| Energy recovery ventilator (ERV) | Supply and exhaust with heat and moisture transfer | Recovery performance under local temperature and humidity conditions |
| Supply-only positive-pressure ventilation | A fan supplies outdoor air; air leaves through other paths | Intake treatment, room distribution, exit paths and conditioning load |
The US Department of Energy explains that energy-recovery ventilation can reduce the energy needed to condition incoming air. An ERV also transfers water vapour; an HRV transfers heat. These benefits can matter during cooling as well as heating. DOE energy-recovery overview.
Filtration is a separate specification
An HRV or ERV label does not tell you how well its filters remove particles. Nor does “positive pressure” automatically mean H13 filtration. Ask for the actual filter specification and effective airflow with the filters fitted.
Avoid comparisons that call filtration secondary for an entire category or promise that positive pressure blocks every outdoor pollutant. The complete system and installation determine the result.
Compare the whole energy requirement
Fan power is only part of the calculation. Outdoor supply can add cooling, heating and moisture loads. Recovery equipment may reduce some of those loads, while adding its own fan power and maintenance requirements.
Do not assume a fixed percentage increase in an AC bill or a fixed payback period without the local climate, operating schedule, airflow and equipment data. Ask the designer to state those assumptions in the comparison.
Retrofit questions for your home
- Where can the intake and any exhaust outlets go?
- How will air reach occupied rooms when bedroom doors are closed?
- What space is available for equipment and routes?
- How will kitchen and bathroom extraction operate alongside it?
- Can filters and internal components be reached for service?
- What permissions and work are included in the installed quote?
These are more useful than choosing solely by the number of fans or a generic national price range.
What aqi0 offers
aqi0’s whole-home air purifier is a standalone positive-pressure fresh-air system with its own intake and supply path, a washable pre-filter and H13 HEPA filtration. It is not an HRV or ERV. HVAC integration is not currently offered, and this guide does not promise a later heat-recovery retrofit.
The system costs ₹82,600, fully installed. For the actual airflow basis, coverage, service requirements and performance conditions, read the technical note and pricing. Cooling and humidity requirements are assessed separately from particle filtration.
Read how positive pressure works at home and the filter-care schedule.
FAQ
Is aqi0’s system an HRV or ERV?
Neither. It’s PPV — single-direction supply with H13 HEPA filtration. The right design for Delhi conditions.
Could I add heat recovery later?
Yes, technically. The PPV intake can be retrofitted with a heat exchanger. The cost rarely justifies the benefit in NCR. For Himachal or Uttarakhand homes, more reasonable.
Does PPV waste cooling energy in summer?
Slightly. Bringing in 500 m³/h of 35°C outdoor air when indoor is 25°C adds a small cooling load. In a properly sized 1.5-ton split AC home, the impact is ~5–8% extra cooling. The trade-off (clean air vs. tiny energy cost) is well worth it.
Does PPV use more energy than HRV/ERV?
No, less. PPV runs a single fan at low speed (~30W). HRV/ERV run two fans plus motor for the heat exchanger wheel (80–150W). PPV is the lower-energy option once you factor in the actual climate.
Can I run AC and PPV at the same time?
Yes, that’s the standard configuration. AC handles temperature; PPV handles air quality. They are complementary, not in conflict.