An open source initiative to share and compare heat pump performance data

Original Article ↗ Hacker News Discussion ↗

An open data project for monitoring residential heat pump performance is being praised as a way to compare real‑world efficiency, costs, and reliability across brands, climates, and installation styles. Contributors highlight that heat pumps can work well even in cold regions and dramatically cut fuel bills, but only if systems are correctly sized, installed, and integrated with insulation and existing radiators. Others call for better tools, standards, and open hardware to address issues like noise, poor installer training, and opaque manufacturer data.

Project & Data Access

  • Strong enthusiasm for heatpumpmonitor.org as an open, crowdsourced performance database.
  • Code for the site is open source; data is crowd-submitted and can be exported (CSV from UI).
  • Some want clearer UI, better table documentation, world map views, and additional fields like noise level (dB) and more detailed efficiency/consumption context.

Metrics: COP, SCOP & Interpretation

  • COP/SCOP widely discussed; COP varies with outdoor temperature and output temperature.
  • Short-interval COPs at mild temperatures can be very high (e.g., >5), so users caution against comparing single COP numbers without conditions.
  • Seasonal COP (SCOP) is seen as more meaningful, but still depends on climate and system temperatures.

Climate Suitability & Backup Heat

  • Many report excellent operation in cold climates (down to ~–25 °C), though with reduced COP and heavy runtime.
  • Conflicting experiences: some systems keep homes warm at –25 °C; others are undersized and need frequent backup heat (gas, electric strips, wood).
  • Debate over whether you “just calculate from building + weather data” versus needing real-world testing/monitoring.
  • Ground-source systems avoid icing and perform better in deep cold but are costlier to install.
  • Hybrid systems (heat pump + boiler or electric) are popular in some regions to cover peak cold.

Design Quality, Sizing & Installer Competence

  • Recurrent theme: performance problems are often due to poor design and installation, not the technology.
  • Complaints that many installers skip proper load calculations (Manual J/D equivalents), oversize units, use excessive buffer tanks/zoning, or poor duct/pipe insulation.
  • Some training schemes and “heat geek” style programs are praised for turning bad installs into high-SCOP systems.

Costs, Markets & Equipment Types

  • Huge regional cost differences: mini-splits are relatively cheap in parts of Europe/Australia, very expensive in US/Canada due to labor and installer practices.
  • Air-to-air, air-to-water, ground-source, and hybrid systems all represented; choice depends on climate, emitters (radiators vs floor heat vs ducts), and local supply chains.

Noise, Comfort & Building Envelope

  • Noise is a major concern; some units are effectively silent, others produce intrusive hums.
  • Mounting quality and low-frequency noise transmission matter, especially in dense housing.
  • Many emphasize that insulation, draft sealing, and sometimes mechanical ventilation (ERV/HRV) are critical to comfort and heat pump performance.
  • Discussion on whether deep insulation “pays back” financially versus being justified by comfort and environmental goals.

Monitoring, DIY & Longevity

  • Systems are commonly monitored via OpenEnergyMonitor and/or Home Assistant; users value seeing as-installed performance.
  • Interest in open-source, repairable, long-lived heat pumps; frustration with disposable, proprietary units.
  • Some users self-install mini-splits or ground-source loops, but complexity and local regulations limit DIY for many.