Flat 4, 17, Onslow Square has an Energy Performance Rating (EPC) of C. This is based on the most recent assessment, dated 16 Sep 2025.

The property is connected to mains gas and has single glazed windows. It is heated using a boiler and radiators (mains gas).

Flat 4, 17, Onslow Square last changed hands on 26th August 2003, selling for £725,000. The transaction was logged as a leasehold flat by HM Land Registry.

That is its only recorded sale since 1995.

• Sold Aug 2003£725,000

Land Registry records and our Estate Agent network show 26 sales of comparable properties within 280 metres of Flat 4, 17, Onslow Square since 2011.

Most recently, Flat 8, 20, Onslow Square, London, SW7 3NP, a leasehold flat, sold at £2,280,000 on the 23rd December 2025.

Read more about house prices in SW7.

• Sold Dec 2025£2,280,000 | 3 Bed FlatFlat 8, 20, Onslow Square, London, SW7 3NPFlat 8, 20, Onslow Square, London, SW7 3NP
• Sold Nov 2025£2,750,000 | 3 Bed FlatFlat 2, 11, Onslow Square, London, SW7 3NJFlat 2, 11, Onslow Square, London, SW7 3NJ
• Sold Nov 2024£2,825,000 | 3 Bed FlatFlat 2, 23, Onslow Square, London, SW7 3NJFlat 2, 23, Onslow Square, London, SW7 3NJ
• 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 Oct 2022£3,100,000 | 3 Bed Flat42, Rose Square, London, SW3 6RS42, Rose Square, London, SW3 6RS
• Sold Aug 2022£3,600,000 | 3 Bed FlatFlat 1, 17, Onslow Square, London, SW7 3NJFlat 1, 17, Onslow Square, London, SW7 3NJ
• Sold Mar 2021£2,300,000 | 3 Bed Flat1, Onslow Square, London, SW7 3NJ1, Onslow Square, London, SW7 3NJ
• Sold Oct 2018£2,650,000 | 3 Bed FlatFlat 2, 52, Onslow Square, London, SW7 3NXFlat 2, 52, Onslow Square, London, SW7 3NX
• 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 Mar 2016£4,400,000 | 3 Bed Flat19, Onslow Square, London, SW7 3NJ19, Onslow Square, London, SW7 3NJ
• 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 Dec 2014£3,950,000 | 3 Bed FlatFlat 6, 81, Onslow Square, London, SW7 3LTFlat 6, 81, Onslow Square, London, SW7 3LT
• Sold Nov 2014£3,250,000 | 3 Bed FlatFlat 5, 38, Onslow Square, London, SW7 3NSFlat 5, 38, Onslow Square, London, SW7 3NS
• Sold Jan 2011£2,250,000 | 3 Bed FlatFlat 3, 89, Onslow Square, London, SW7 3LTFlat 3, 89, Onslow Square, London, SW7 3LT

Our analysis of the public data ranks Flat 4, 17, Onslow Square as the 179th largest and the 103rd most expensive of the 321 addresses on Onslow Square, London, SW7.

Against the SW7 postcode district average, it is £361k more expensive than the typical property.

• Oratory Roman Catholic Primary School

  300 m away
• Marlborough Primary School

  400 m away
• Our Lady of Victories RC Primary School

  500 m away

• St. Thomas More Language College

  700 m away
• Chelsea Academy

  1.8 km away
• The London Oratory School

  1.9 km away

• South Kensington

  |

  200 m away
• Gloucester Road

  |

  700 m away
• Knightsbridge

  |

  1.0 km away

Environment Agency data suggests this area has a Very Low risk of flooding.