Building heat recovery: What to track
Watch real-world efficiency and shifting subsidies
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)28 | → 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%45 | ↗ 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 risk8 | → 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)1212 | → 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 kitchens7 | → 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 buildings10131415 | ↘ 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| Technology-specific | Heat-pump water heater incentives | US 30% federal credit (up to USD 2,000) repealed for installations after 31 December 2025411 | ↘ worsening | Subsidy changes move payback sharply. |
| Technology-specific | Drain-water unit effectiveness rating | About 26-39% for one tested coil type3 | ↗ improving | Rated effectiveness (CSA B55 tests) lets buyers compare units. |
Sources
- Drain-Water Heat Recovery (Energy Saver) US Department of Energy, 2024
- Evaluation of Residential Drain Water Heat Recovery Unit (study begun 2010) Sustainable Technologies Evaluation Program (Toronto and Region Conservation Authority), 2017
- Modelling the Steady-State Performance of Coiled Falling-Film Drain Water Heat Recovery Systems Using Rated Data (Manouchehri and Collins), Resources 9: 69 MDPI Resources (University of Waterloo authors), 2020
- Is a Heat Pump Water Heater Right for Your Home? ENERGY STAR (US EPA), 2023
- Technology Spotlight: Energy-Recovery Ventilation Systems (Solar Decathlon 2013 houses) US DOE Solar Decathlon, 2013
- Engineering and Construction Bulletin 2015-3: Demand control kitchen ventilation US Army Corps of Engineers (via WBDG), 2015
- Benefits of superheat recovery on chillers: case study for a hotel installation (Rane and Tandale), 21st IIR International Congress of Refrigeration International Institute of Refrigeration, 2003
- Compliance obligations under India's Carbon Credit Trading Scheme enter force for seven sectors ICAP, 2026
- IRA equipment tax credits expire December 31, 2025 New England Fuel Institute (trade association), 2025
- CO2 Baseline Database for the Indian Power Sector, User Guide Version 20.0 Central Electricity Authority, 2024
- European carbon prices rose to EUR 88/t in October GMK Center (ICE data), 2026
- European carbon prices drop to 7-week low as market eyes upcoming policy agenda S&P Global Commodity Insights, 2026
- EU ETS2 compliance factsheet World Bank Carbon Pricing Dashboard, 2026