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Haier AS 4.8 kW (1U50MERFRA-3) vs Midea MFAU 4.8 kW (MOX330U-18HFN8-Q(GA)): which is quieter and cheaper to run?
Midea MFAU 4.8 kW (MOX330U-18HFN8-Q(GA)) is ≈1.0 dB quieter outside (passes England's 37 dB limit from 8.9 m vs 10.0 m for Haier AS 4.8 kW (1U50MERFRA-3)); Midea MFAU 4.8 kW (MOX330U-18HFN8-Q(GA)) costs ≈£2.47 less per summer at 400 hours and 26.32p/kWh. Pick Midea MFAU 4.8 kW (MOX330U-18HFN8-Q(GA)) if the unit goes close to a neighbour's window; pick Haier AS 4.8 kW (1U50MERFRA-3) if the running-cost figures matter more.
manufacturer-declared, EPREL
Where the registered figures differ
The marker that opened this page: lwa, scop, pass_distance. Both columns use the same tariff and the same noise setting.
| Field | Haier AS 4.8 kW (1U50MERFRA-3) | Midea MFAU 4.8 kW (MOX330U-18HFN8-Q(GA)) | Difference | Source |
|---|---|---|---|---|
| Outdoor sound power | 65.0 dB(A) | 64.0 dB(A) | +1.0 dB | manufacturer-declared, EPREL |
| SEER | 6.3 | 6.5 | −0.2 SEER | manufacturer-declared, EPREL |
| SCOP | 4.0 | 3.8 | +0.2 SCOP | manufacturer-declared, EPREL |
| Refrigerant | R32 | R32 | same | manufacturer-declared, EPREL |
| GWP | 675 | 1150 | −475 GWP | manufacturer-declared, EPREL |
| £ per summer, 400 h | £80.21 | £77.75 | +£2.47 | calculated: capacity ÷ SEER × 400 h × price-cap rate |
| Distance to pass 37 dB | ≈10.0 m | ≈8.9 m | +1.1 m | calculated, MCS 020a, Q=2, no barrier |
| Cooling capacity | 4.8 kW | 4.8 kW | ≈0 kW | manufacturer-declared, EPREL |
Sound at a neighbour's window
Each distance is one outdoor unit, Q=2, no barrier, scored against England and Wales at 37 dB(A).
| Distance | Haier AS 4.8 kW (1U50MERFRA-3) dB(A) | Haier AS 4.8 kW (1U50MERFRA-3) vs 37 dB | Midea MFAU 4.8 kW (MOX330U-18HFN8-Q(GA)) dB(A) | Midea MFAU 4.8 kW (MOX330U-18HFN8-Q(GA)) vs 37 dB |
|---|---|---|---|---|
| 1 m | 57.0 | over | 56.0 | over |
| 2 m | 51.0 | over | 50.0 | over |
| 3 m | 47.5 | over | 46.5 | over |
| 4 m | 45.0 | over | 44.0 | over |
| 5 m | 43.0 | over | 42.0 | over |
| 8 m | 39.0 | over | 38.0 | over |
| 12 m | 35.4 | pass | 34.4 | pass |
EPREL manufacturer-declared registrations · snapshot 25 Sep 2026 · n=2 · pair source tier is the weaker of the two cards; noise via contract_engine MCS 020a Q=2, no barrier · updated 25 Sep 2026 · version 1.0.0 · CSV of the values on this page
How this page was calculated
If the calculated sound pressure level at all assessment positions is equal to or lower than 37.0 dB(A) then the heat pump will comply with the Permitted Development noise limit Estimated by MCS 020a Issue 1.1 for one unit, Q=2, no barrier, via contract_engine. £ per summer is capacity ÷ SEER × hours × 26.32p/kWh (2026-10-01 to 2026-12-31). The pair row lives in the compare index CSV.
Open the two cards
Better than a spec-sheet glance: the gap is scored at the same distances against the 37 dB line, and £ per summer uses one tariff.