Hi, this is my space for Heat Pump selection and analysis while I make progress to go low-carbon in my 1930s detatched house in the south of England, UK.

This is very much an ad-hoc selection of notes so far but you may find some of it useful…

  • Jul 7, 2026 ~ Jul 7, 2026

    Comparison of 5-6kW Heat Pumps (2026)

    This is the 2026 refresh of the heat-pump SCOP comparison. The current focus is the 5–6kW range (suitable for a well-insulated ~4–5kW-demand property), but the table is now a single filterable master table driven from a shared dataset, so larger outputs can be added over time — use the search box and the kW column to filter/sort.

    The data now lives in _data/heat_pumps.yml as a clean single source of truth, so figures can be de-duplicated, re-ranked and checked by tooling rather than hand-edited in the table.

    Criteria / methodology (unchanged from the 2024 table):

    • Target property demand ~4–5kW; units may cycle if oversized (8kW+).
    • EN 14511/14825 Average Climate. Low temp = 35°C, Medium = 45°C, High = 55°C.
    • Ordered by SCOP@35°C where higher is better; ambiguous ranks fall back to 45°C then 55°C (we prefer mild-weather performance which gives greater yearly SCOP).
    • MCS Product Database figures are the source of truth and replace datasheet figures where they differ — see MCS Product Directory.
    • Where a model has no MCS certification, published manufacturer/datasheet figures are used instead and flagged 💔 (unverified). Note many manufacturers publish only COP, not the SCOP@35/45/55 trio, so some newly launched models show no SCOP until they are MCS-certified.
    • A * on SCOP@45°C means it was estimated as mean(35,55) because the datasheet omitted it (a conservative underestimate).

    Status column legend

    Badge Meaning
    💎 Datasheet matches MCS-verified figures
    📗 MCS-only or a close match to datasheet
    📘 MCS present but not close to datasheet (MCS used) — hover the ds≠ marker for datasheet claims
    💔 Not validated / unknown — may be mis-ranked

    MCS verified, Datasheet only and Rumoured / no data in the Status column are searchable terms — type one into the search box to isolate that confidence tier.

    # Make/Model kW SCOP@35°C SCOP@45°C SCOP@55°C Gas Status MCS Cert. Sound Power (dBA) Wall Date Valid Links
    1 Lambda 8kW 8 5.66 5.07* 4.48 R290 💔 Datasheet only — 42-56 ✖ 2024-12 site datasheet
    2 Ovum AC208P 8 5.53 4.89* 4.0 R290 💔 Datasheet only — 41-54.5 ✖ 2024-07 site datasheet
    3 LG ThermaV HM093HF 9kW 9 5.04 3.74 3.75 R290 📘 MCS verified ds≠ 011-1W0831_04 48-49 ✖ 2024-01 site
    4 EBac H1A05WG-GB 5kW 5 4.91 4.38 3.96 R32 💎 MCS verified HP0369/01 64.5 👍 2024-02 site
    5 Nibe 6kW 6 4.87 4.07 3.46 R32 📘 MCS verified ds≠ 012-C700141 53 ✖ — datasheet
    6 Samsung Gen7 5kW 5 4.84 4.14 3.43 R290 💎 MCS verified 011-1W0686_2 55 ✖ — datasheet
    7 Baxi 5kW 5 4.77 4.06 3.39 R32 💎 MCS verified HP0033/10 58 ✖ — site
    8 Stiebel Eltron WPL-A 07 7 4.66 4.21 3.69 R454C 📘 MCS verified ds≠ 011-1W0393_02 48 ✖ 2024 site datasheet
    9 Aira 6kW 1.0 6 4.62 4.1 3.58 R290 📗 MCS verified HP0372/06 57 ✖ 2024-03 datasheet
    10 Bosch CS5800iAW 5kW 5 4.53 3.9 3.28 R290 📘 MCS verified ds≠ HP0329/06 42 ✖ — site
    11 Viessmann Vitocal 151.A06 6 4.53 4.03 3.61 R290 📗 MCS verified ds≠ 011-1W0590_06 51 👍 — datasheet brochure
    12 Vaillant aroTHERM plus 5kW 5 4.48 3.77 3.06 R290 💎 MCS verified KIWA 00016/018HP 51-55 👍 — site datasheet
    13 Daikin Altherma 4kW 4 4.43 3.72 3.2 R32 📗 MCS verified ds≠ 011-1W0527_3 60 ? — site
    14 Mitsubishi Ecodan R290 5 4.42 3.9 3.53 R290 📘 MCS verified ds≠ 037-0135-23-1 — 👍 — site
    15 Ideal Logic Air 5kW 5 4.39 3.83 3.06 R32 📘 MCS verified ds≠ KIWA 00027/023 HP 52 ✖ 2023-06 site
    16 Ecoforest ecoAIR+ 230 (6-24kW) 6 4.38 3.49 3.11 R290 📗 MCS verified 011-1W0921_6 — ✖ 2024-10 site
    17 Octopus Cosy 6 6 3.98 3.36 3.06 R290 📗 MCS verified HP0255/03 53.8 ✖ 2024-05 site MCS
    – Grant Aerona 290 (R290) 6 — — — R290 💔 Rumoured / no data — — ✖ — site datasheet
    – Panasonic Aquarea R290 (5kW) 5 — — — R290 💔 Rumoured / no data — — ✖ — site
    – Warmflow Zeno R290 6 — — — R290 💔 Rumoured / no data — — ✖ — site
    – CTC Ecoair 700M 7 — — — R290 💔 Rumoured / no data — 46 ? 2024-03 site
    – Wondrwall DR-HP-006-UK 6 — — — R290 💔 Rumoured / no data — 60 ? 2024-03 site datasheet

    Notes:

    • Figures are refreshed from the MCS Product Database using tools/fetch_mcs.py; links are validated with tools/check_links.py (see tools/README.md).
    • The older 2024 5kW table is retained for history.

    ToDo / research backlog:

    • Vaillant aroTHERM plus 2025/26 (improved-spec model expected to reach the UK market in 2026).
    • Confirm SCOP + MCS certs for newly announced 2025/26 models and move them from Rumoured / no data up into a verified tier as figures are published.
  • Mar 8, 2024

    HeatPünk - Free web based heat-loss calculator

    If you are looking to do your own heat-loss calculation to compare against 3rd party quotes or do some preliminary research. Then there are many options out there. I would recomend HeatPünk https://heatpunk.co.uk/ is actually a sureprisingly simple tool. Being fully web-based its easy to get setup with a free acount and setup your floor plans in a visual and intuitive manner. I currently have no point of reference to compare but will be looking to get professional heat-loss survey in future to compare. Noteable though is there is much debate over Air Changes/hr which on its own will dramatically affect your heat-loss estimates.

  • Mar 7, 2024

    Are ASHP datasheets reliable?

    This is an open question of mine, questions the datasheet SCOP figures for many products.

  • Feb 15, 2024

    Comparison of 5Kw Heat Pumps