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

Original Article ↗ Hacker News Discussion ↗

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.