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Heat pump water heaters · Compare

ASTON 300 vs Sunex DROPS D4.1

Water heating efficiency ηwh: ASTON 300 112 %, Sunex DROPS D4.1 96 %. The ASTON 300 is better on 5 of 8 comparable points.

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Who wins where

  • ASTON 300
  • Sunex DROPS D4.1

Biggest differences

Fact300DROPS D4.1
Annual electricity use, colder climate1,865 kWh1,062 kWh
Annual electricity use, warmer climate1,397 kWh1,062 kWh
Indoor sound power46 dB(A)59 dB(A)
Outdoor sound power46 dB(A)59 dB(A)
Annual electricity use (average climate)1,389 kWh1,111 kWh
ηwh, warmer climate119 %96 %
All specifications ↓

Score per area = position (0–100) relative to all 450 models in this category; higher is better.

ASTON300SunexDROPS D4.1
General
Load profileL1L2
Efficiency
Water heating efficiency ηwh112 %✓196 %2
ηwh, colder climate98 %✓196 %2
ηwh, warmer climate119 %✓196 %2
Energy labelA1A2
Annual electricity use (average climate)1,389 kWh11,111 kWh✓2
Annual electricity use, colder climate1,865 kWh11,062 kWh✓2
Annual electricity use, warmer climate1,397 kWh11,062 kWh✓2
Noise
Indoor sound power46 dB(A)✓159 dB(A)2
Outdoor sound power46 dB(A)✓159 dB(A)2

Frequently asked questions

Which is better: the ASTON 300 or the Sunex DROPS D4.1?

Water heating efficiency ηwh: ASTON 300 112 %, Sunex DROPS D4.1 96 %. The ASTON 300 is better on 5 of 8 comparable points.

What is the water heating efficiency ηwh of the ASTON 300 and the Sunex DROPS D4.1?

ASTON 300: 112 %. Sunex DROPS D4.1: 96 %.

Which is better on annual electricity use, colder climate: the ASTON 300 or the Sunex DROPS D4.1?

Sunex DROPS D4.1: 1,062 kWh. ASTON 300: 1,865 kWh.

Which is better on annual electricity use, warmer climate: the ASTON 300 or the Sunex DROPS D4.1?

Sunex DROPS D4.1: 1,062 kWh. ASTON 300: 1,397 kWh.

How we collect and check this data →

Sources

  1. European Product Registry for Energy Labelling (EPREL) – water heaters — Europese Commissie · accessed Oct 13, 2026
  2. European Product Registry for Energy Labelling (EPREL) – water heaters — Europese Commissie · accessed Oct 13, 2026