# Building heat recovery: What to track

Watch real-world efficiency and shifting subsidies

Source page: https://www.materialinsights.org/energy/e_building_recovery/tracking/

What this tab covers The attributes worth tracking regularly, with the latest value, the direction of travel and why each matters.

Track running hours, real-world efficiency, and policy support; carbon prices barely reach buildings yet.

| Category | Attribute | Latest | Trend | Why it matters |
|---|---|---|---|---|
| Operational | **Capacity factor and operating hours** | Hotel chiller heat recovery runs daily; home drain-water units only during showers (about 790 kWh/yr in a test house)^[2](https://sustainabletechnologies.ca/?p=5720)^[8](https://iifiir.org/en/fridoc/benefits-of-superheat-recovery-on-chillers-case-study-for-a-hotel-21304) | → stable | Coincidence of supply and demand sets savings. |
| Operational | **Thermal efficiency or COP over time** | HPWH UEF 3.3-4.0; ERV/HRV recovery 70-80%^[4](https://energystar.gov/products/ask-the-experts/heat-pump-water-heater-right-your-home)^[5](https://www.solardecathlon.gov/blog/archives/3418) | ↗ improving | Field performance falls in cramped spaces and with dirty filters. |
| Counterparty | **Host counterparty credit and utilisation rate** | Building owners and hotel operators; low stranding risk^[8](https://iifiir.org/en/fridoc/benefits-of-superheat-recovery-on-chillers-case-study-for-a-hotel-21304) | → stable | Hotel occupancy drives hot water and cooling loads. |
| Impact | **t CO2e avoided per dollar invested** | Drain-water unit about 0.57 t CO2/yr for USD 300-500, roughly 1.1-1.9 kg CO2 a year per dollar (calculated, Indian grid, electric water heating)^[1](https://www.energy.gov/node/1266061)^[2](https://sustainabletechnologies.ca/?p=5720)^[12](https://cea.nic.in/wp-content/uploads/2021/03/User_Guide_Version_20.0.pdf) | → stable | Compare with heat pump and solar water heating. |
| Operational | **Heat exchanger fouling and cleaning frequency** | Low for clean air and water; grease is the main problem in kitchens^[7](https://www.wbdg.org/FFC/ARMYCOE/COEECB/ARCHIVES/ecb_2015_3.pdf) | → stable | Kitchen exchangers need regular cleaning, so demand control is often preferred. |
| Policy | **Local carbon pricing and penalties** | EU ETS EUR 82-88/t in October 2026, but covers no buildings; the separate ETS2 for building and road fuels is due from 2028; India's CCTS covers seven industrial sectors, not buildings^[10](https://icapcarbonaction.com/en/news/compliance-obligations-under-indias-carbon-credit-trading-scheme-enter-force-seven-sectors)^[13](https://gmk.center/en/news/european-carbon-prices-rose-to-e88-t-in-october/)^[14](https://www.spglobal.com/energy/en/news-research/latest-news/natural-gas/100526-european-carbon-prices-drop-to-7-week-low-as-market-eyes-upcoming-policy-agenda)^[15](https://carbonpricingdashboard.worldbank.org/compliance-factsheet/ETS_EU2) | ↘ worsening | ETS2 will put a carbon price on gas and oil burned in buildings from 2028, improving the case for recovery in Europe; in India codes, labels and subsidies still matter more. |
| Technology-specific | **Heat-pump water heater incentives** | US 30% federal credit (up to USD 2,000) repealed for installations after 31 December 2025^[4](https://energystar.gov/products/ask-the-experts/heat-pump-water-heater-right-your-home)^[11](https://nefi.com/news-publications/recent-news/ira-equipment-tax-credits-expire-december-31-2025) | ↘ worsening | Subsidy changes move payback sharply. |
| Technology-specific | **Drain-water unit effectiveness rating** | About 26-39% for one tested coil type^[3](https://doi.org/10.3390/resources9060069) | ↗ improving | Rated effectiveness (CSA B55 tests) lets buyers compare units. |

#### Sources

1. [Drain-Water Heat Recovery (Energy Saver)](https://www.energy.gov/node/1266061) US Department of Energy, 2024
2. [Evaluation of Residential Drain Water Heat Recovery Unit (study begun 2010)](https://sustainabletechnologies.ca/?p=5720) Sustainable Technologies Evaluation Program (Toronto and Region Conservation Authority), 2017
3. [Modelling the Steady-State Performance of Coiled Falling-Film Drain Water Heat Recovery Systems Using Rated Data (Manouchehri and Collins), Resources 9: 69](https://doi.org/10.3390/resources9060069) MDPI Resources (University of Waterloo authors), 2020
4. [Is a Heat Pump Water Heater Right for Your Home?](https://energystar.gov/products/ask-the-experts/heat-pump-water-heater-right-your-home) ENERGY STAR (US EPA), 2023
5. [Technology Spotlight: Energy-Recovery Ventilation Systems (Solar Decathlon 2013 houses)](https://www.solardecathlon.gov/blog/archives/3418) US DOE Solar Decathlon, 2013
6. [Engineering and Construction Bulletin 2015-3: Demand control kitchen ventilation](https://www.wbdg.org/FFC/ARMYCOE/COEECB/ARCHIVES/ecb_2015_3.pdf) US Army Corps of Engineers (via WBDG), 2015
7. [Benefits of superheat recovery on chillers: case study for a hotel installation (Rane and Tandale), 21st IIR International Congress of Refrigeration](https://iifiir.org/en/fridoc/benefits-of-superheat-recovery-on-chillers-case-study-for-a-hotel-21304) International Institute of Refrigeration, 2003
8. [Compliance obligations under India's Carbon Credit Trading Scheme enter force for seven sectors](https://icapcarbonaction.com/en/news/compliance-obligations-under-indias-carbon-credit-trading-scheme-enter-force-seven-sectors) ICAP, 2026
9. [IRA equipment tax credits expire December 31, 2025](https://nefi.com/news-publications/recent-news/ira-equipment-tax-credits-expire-december-31-2025) New England Fuel Institute (trade association), 2025
10. [CO2 Baseline Database for the Indian Power Sector, User Guide Version 20.0](https://cea.nic.in/wp-content/uploads/2021/03/User_Guide_Version_20.0.pdf) Central Electricity Authority, 2024
11. [European carbon prices rose to EUR 88/t in October](https://gmk.center/en/news/european-carbon-prices-rose-to-e88-t-in-october/) GMK Center (ICE data), 2026
12. [European carbon prices drop to 7-week low as market eyes upcoming policy agenda](https://www.spglobal.com/energy/en/news-research/latest-news/natural-gas/100526-european-carbon-prices-drop-to-7-week-low-as-market-eyes-upcoming-policy-agenda) S&P Global Commodity Insights, 2026
13. [EU ETS2 compliance factsheet](https://carbonpricingdashboard.worldbank.org/compliance-factsheet/ETS_EU2) World Bank Carbon Pricing Dashboard, 2026

## Other sections

- [Summary](https://www.materialinsights.org/energy/e_building_recovery/index.md)
- [Overview](https://www.materialinsights.org/energy/e_building_recovery/overview/index.md)
- [Correlation](https://www.materialinsights.org/energy/e_building_recovery/correlation/index.md)
- [Science and thermodynamics](https://www.materialinsights.org/energy/e_building_recovery/rc-sci/index.md)
- [Engineering and integration](https://www.materialinsights.org/energy/e_building_recovery/rc-eng/index.md)
- [Economics and contracts](https://www.materialinsights.org/energy/e_building_recovery/rc-econ/index.md)
- [Impact and additionality](https://www.materialinsights.org/energy/e_building_recovery/rc-impact/index.md)
- [Relationships](https://www.materialinsights.org/energy/e_building_recovery/links/index.md)