This unit replaces an electric boiler or gas geyser. It does not replace a full space-heating heat pump — for that see the Altherma 4 H or GEO. If you are looking for hot water only, the Altherma M HW is a strong, quiet and well-documented choice.
1. Specs that matter
- 200 L tank (EKHHE200CV37): COP 3.23 (profile L), recharge time 497 min, 50 dB(A) Lw — catalog p.150.
- 260 L tank (EKHHE260CV37): COP 3.38 (profile XL), recharge time 614 min, 50 dB(A) Lw.
- Operating range: -7 to 35 °C ambient. Below -7 °C, electric backup takes over.
- PCV37 variant: integrated Smart-Grid input for PV surplus (catalog p.149).
2. Family overview
Daikin offers 4 SKUs in this family across the standard and PCV37 (smart-grid) variants. Choose 200 L for 1-3 people, 260 L for 4-6.
3. Verdict
Solid 4.4 / 5. The Altherma M HW is exactly what it claims: a quiet, efficient, ISDE-eligible alternative to an electric boiler. It is not a space-heating system, and anyone marketing it as such is misleading you.
FAQ
Is a heat-pump water heater the same as a full heat pump?
No. A heat-pump water heater only produces domestic hot water (showers, taps). A full heat pump such as the Daikin Altherma 4 H also heats the home through radiators or underfloor heating. Use a heat-pump water heater only when your space heating still works satisfactorily and you only want to replace a separate boiler or geyser.
Which tank size (200 or 260 L) fits my household?
Rule of thumb: 200 L for 1–3 people or a household with light shower routines. 260 L for 4–6 people or a household with daily baths. The Altherma M HW recharges fairly slowly (8–10 hours in heat-pump mode), so the tank must buffer the full morning peak.
How long does it take to heat the tank?
Per the Daikin 2026 catalog (p.150): the 200 L tank takes 8h 17m in heat-pump mode, the 260 L tank 10h 14m. In boost mode (heat pump + electric backup) about 30 % faster.
Can I install it in an unheated garage or attic?
Yes, provided the air temperature stays above -7 °C (catalog operating range). During longer cold snaps the unit falls back on the electric backup element and efficiency drops. Also factor in sound (50 dB(A) Lw) — installation under a bedroom is not recommended.
How much do I save versus an electric boiler?
An electric boiler runs at ~0.9 efficiency. A Daikin Altherma M HW reaches COP 3.2-3.4. Practical: a household of 4 that used ~3,500 kWh/year on an electric boiler drops to ~1,000 kWh/year. At €0.31/kWh: from €1,085 to €310 per year, a saving of about €775.
Does the Altherma M HW qualify for Dutch ISDE subsidy?
Yes, per the Daikin catalog (p.149) all Altherma M HW heat-pump water heaters qualify for the Dutch ISDE subsidy. The exact amount depends on the ErP tap profile and your home's build year — ask an installer for a personalised figure.
Does the PCV37 variant work with my solar panels?
Yes. The PCV37 has an integrated Smart-Grid function (catalog p.149) which automatically heats water when your PV system produces a surplus. With an average 4 kWp PV install this can save up to €100-€200 per year on feed-in losses.
Read the Dutch original at /altherma-m-hw-review. Specifications and citations are identical.