Flat 8, 20, Onslow Square has an Energy Performance Rating (EPC) of E. This is based on the most recent assessment, dated 20 Dec 2022.

The property is connected to mains gas and has partial secondary glazing. It is heated using community scheme.

The most recent sale of Flat 8, 20, Onslow Square completed on 23rd December 2025 at £2,280,000 and was recorded by HM Land Registry as a leasehold flat.

Since 1995 this is the property's only sale.

Values of comparable properties have dropped by 1.8% over the period since December 2025.

• Sold Dec 2025£2,280,000

Since 2008 31 properties similar to Flat 8, 20, Onslow Square have sold within a radius of 280 metres, per the Land Registry and our network of Estate Agents.

The latest, on the 20th November 2025, was Flat 2, 11, Onslow Square, London, SW7 3NJ, a leasehold flat which sold for £2,750,000.

Read more about house prices in SW7.

• Sold Nov 2025£2,750,000 | 3 Bed FlatFlat 2, 11, Onslow Square, London, SW7 3NJFlat 2, 11, Onslow Square, London, SW7 3NJ
• Sold Jun 2025£2,200,000 | 3 Bed FlatFlat 9, 14, Onslow Square, London, SW7 3NPFlat 9, 14, Onslow Square, London, SW7 3NP
• Sold Sep 2024£1,275,000 | 3 Bed FlatBasement, 109A, Onslow Square, London, SW7 3LUBasement, 109A, Onslow Square, London, SW7 3LU
• Sold Jul 2024£1,900,000 | 3 Bed Flat3, Rose Square, London, SW3 6RS3, Rose Square, London, SW3 6RS
• Sold Jul 2024£1,975,000 | 3 Bed FlatFlat 10, 14, Onslow Square, London, SW7 3NPFlat 10, 14, Onslow Square, London, SW7 3NP
• Sold Oct 2023£2,600,000 | 3 Bed FlatFlat 6, 89, Onslow Square, London, SW7 3LTFlat 6, 89, Onslow Square, London, SW7 3LT
• Sold Sep 2023£2,750,000 | 3 Bed FlatFlat 8, 61, Onslow Square, London, SW7 3LSFlat 8, 61, Onslow Square, London, SW7 3LS
• Sold Jun 2023£2,650,000 | 3 Bed FlatFlat 3, 6, Onslow Gardens, London, SW7 3LYFlat 3, 6, Onslow Gardens, London, SW7 3LY
• Sold Oct 2022£3,100,000 | 3 Bed Flat42, Rose Square, London, SW3 6RS42, Rose Square, London, SW3 6RS
• Sold Sep 2017£632,000 | 3 Bed FlatFlat 1, 81, Onslow Square, London, SW7 3LTFlat 1, 81, Onslow Square, London, SW7 3LT
• Sold Mar 2017£2,500,000 | 3 Bed FlatFlat 2, 89, Onslow Square, London, SW7 3LTFlat 2, 89, Onslow Square, London, SW7 3LT
• Sold Jan 2017£3,000,000 | 3 Bed Flat63, Onslow Square, London, SW7 3LS63, Onslow Square, London, SW7 3LS
• Sold Jul 2016£3,600,000 | 3 Bed FlatFlat 8, 14, Onslow Square, London, SW7 3NPFlat 8, 14, Onslow Square, London, SW7 3NP
• Sold Feb 2016£2,550,000 | 3 Bed FlatFlat 1, 46, Onslow Square, London, SW7 3NXFlat 1, 46, Onslow Square, London, SW7 3NX
• Sold Dec 2015£2,850,000 | 3 Bed FlatFlat 4, 5, Onslow Square, London, SW7 3NJFlat 4, 5, Onslow Square, London, SW7 3NJ
• Sold Nov 2015£3,200,000 | 3 Bed FlatFlat 6, 14, Onslow Square, London, SW7 3NPFlat 6, 14, Onslow Square, London, SW7 3NP
• Sold Dec 2014£3,950,000 | 3 Bed FlatFlat 6, 81, Onslow Square, London, SW7 3LTFlat 6, 81, Onslow Square, London, SW7 3LT
• Sold Jul 2014£1,999,000 | 3 Bed FlatFlat 4, 14, Onslow Square, London, SW7 3NPFlat 4, 14, Onslow Square, London, SW7 3NP
• Sold Mar 2013£1,850,000 | 3 Bed FlatFlat 7, 89, Onslow Square, London, SW7 3LTFlat 7, 89, Onslow Square, London, SW7 3LT
• Sold Nov 2008£2,400,000 | 3 Bed Flat50, Rose Square, London, SW3 6RS50, Rose Square, London, SW3 6RS

Of the 321 addresses on Onslow Square, London, SW7, Flat 8, 20, Onslow Square comes out as the 177th largest and the 123rd most expensive in our analysis of the public data.

It is also £122k more expensive than the average property across the SW7 district.

• Oratory Roman Catholic Primary School

  300 m away
• Our Lady of Victories RC Primary School

  500 m away
• Marlborough Primary School

  500 m away

• St. Thomas More Language College

  700 m away
• Chelsea Academy

  1.7 km away
• The London Oratory School

  1.8 km away

• South Kensington

  |

  200 m away
• Gloucester Road

  |

  700 m away
• Knightsbridge

  |

  1.1 km away

The flood risk here is rated Very Low, based on Environment Agency data.