Heat pumps, more than you wanted to know (2023)
Heat pumps are attracting intense interest as an efficient alternative to gas and electric resistance heating, but real‑world experiences reveal a mix of strong benefits and practical headaches. Commenters describe major gains in comfort and energy use—especially when paired with good insulation and solar—alongside issues like icing in cold, wet climates, noise, high upfront and installation costs, and the need for backup heat sources. A recurring theme is how local housing stock, climate, electricity pricing, and installer expertise can make the same technology economical and reliable in one region yet marginal or frustrating in another.
Cold-Weather Performance and Icing
- Multiple reports of air-source units freezing up in wet, snowy, or windy −16°C to −20°C conditions; defrost cycles sometimes fail to clear condensate before it re-freezes in the base pan.
- Suggested mitigations: base-pan heaters, heated compressor / “Nordic” models, extra or larger drain holes, snow shielding, or manually melting ice with a heat gun.
- Several people conclude air-source is good overall but shouldn’t be the sole heat source in harsh climates.
Backups, Hybrids, and Redundancy
- Common patterns: electric resistance backup elements in hydronic tanks, gas or wood stoves as independent backups, or dual-fuel (heat pump + gas furnace) systems.
- Backup is valued for rare “panic weeks,” mechanical failures, extreme cold, or in areas with weak grids.
Costs, Labor, and Regional Differences
- Huge spread in installed cost: from ~€2–3k for simple air–air mini-splits in Nordics to €15–30k+ for air–water or geothermal in Western Europe/US, and $18k+ for US retrofits.
- Labor and installer scarcity widely cited as major cost drivers; subsidies sometimes blamed for pushing prices up.
- DIY mini-split installs can be 2–4× cheaper than contractor quotes, but people worry about future service.
Insulation, Housing Stock, and System Sizing
- Repeated emphasis: poorly insulated, leaky homes (esp. older UK/European stock) make heat pumps struggle or require oversized units and extensive retrofits (windows, walls, lofts).
- Better to reduce “temperature lift” (e.g., low-temp floor/ceiling heating, larger emitters, fan-assisted radiators).
- Debate over whether heat pumps “need” insulation versus simply benefit from it more than gas boilers.
Noise and Siting
- Experiences range from “crazy silent on a concrete slab” to “unlivable” when placed in tight side yards, near bedrooms, or wooden structures.
- Defrost cycles can be particularly loud. Some report regulatory noise limits being hard to meet in dense cities.
Efficiency, Grid Mix, and Alternatives
- Many highlight COP 2–4+ and note that even when electricity comes from gas, a heat pump can beat direct gas heating.
- Others worry about high electricity prices and dirty grids; some find modern gas furnaces cheaper to run.
- Discussion of ground-source: better cold-weather COP and quiet, but much higher installation cost and uncertain payback.
- Mention of emerging thermoacoustic/helium systems and heat-pump clothes dryers and water heaters as promising niches.
User Experiences and Practical Advice
- Several homeowners report 30–60% heating-energy savings and much-improved summer comfort; others report noise, control, and comfort disappointments.
- Common advice: get multiple quotes, consider hybrid systems, prioritize insulation, be wary of oversizing and contractor bias, and account for long-term serviceability.