21A, The Polygon, Southampton has an Energy Performance Rating (EPC) of D. This is based on the most recent assessment, dated 01 Jul 2020.

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

According to HM Land Registry, 21A, The Polygon, Southampton was last sold on 6th October 2020 for £237,000 and was recorded as a leasehold flat.

The property has only had this single sale since 1995.

Since October 2020, the market for similar properties has dropped by 9.0%.

• Sold Oct 2020£237,000

According to the Land Registry and our network of Estate Agents, there have been 24 sales of properties similar to 21A, The Polygon, Southampton within a radius of 370 metres since 2017.

The most recent example is Flat 23, Osborne House, Grosvenor Square, Southampton, SO15 2DA, a leasehold flat which sold for £283,000 on the 19th December 2025.

Read more about house prices in SO15.

• Sold Dec 2025£283,000 | 3 Bed FlatFlat 23, Osborne House, Grosvenor Square, Southampton, SO15 2DAFlat 23, Osborne House, Grosvenor Square, Southampton, SO15 2DA
• Sold Oct 2025£250,000 | 3 Bed FlatFlat 28, Osborne House, Grosvenor Square, Southampton, SO15 2DAFlat 28, Osborne House, Grosvenor Square, Southampton, SO15 2DA
• Sold Oct 2024£325,000 | 3 Bed FlatFlat 16, Osborne House, Grosvenor Square, Southampton, SO15 2DAFlat 16, Osborne House, Grosvenor Square, Southampton, SO15 2DA
• Sold Jul 2024£222,500 | 3 Bed FlatFlat 62, Parkview 5, Handel Road, Southampton, SO15 2NZFlat 62, Parkview 5, Handel Road, Southampton, SO15 2NZ
• Sold Jun 2024£285,000 | 3 Bed FlatFlat 19, Osborne House, Grosvenor Square, Southampton, SO15 2DAFlat 19, Osborne House, Grosvenor Square, Southampton, SO15 2DA
• Sold Apr 2024£275,000 | 3 Bed FlatFlat 13, Osborne House, Grosvenor Square, Southampton, SO15 2DAFlat 13, Osborne House, Grosvenor Square, Southampton, SO15 2DA
• Sold Jul 2023£265,000 | 3 Bed Flat21B, The Polygon, Southampton, SO15 2BP21B, The Polygon, Southampton, SO15 2BP
• Sold May 2023£292,500 | 3 Bed FlatFlat 7, Osborne House, Grosvenor Square, Southampton, SO15 2DAFlat 7, Osborne House, Grosvenor Square, Southampton, SO15 2DA
• Sold Mar 2023£250,000 | 3 Bed FlatFlat 35, Osborne House, Grosvenor Square, Southampton, SO15 2DAFlat 35, Osborne House, Grosvenor Square, Southampton, SO15 2DA
• Sold May 2022£285,000 | 3 Bed FlatFlat 8, Osborne House, Grosvenor Square, Southampton, SO15 2DAFlat 8, Osborne House, Grosvenor Square, Southampton, SO15 2DA
• Sold Dec 2021£315,000 | 3 Bed FlatFlat 5, Osborne House, Grosvenor Square, Southampton, SO15 2DAFlat 5, Osborne House, Grosvenor Square, Southampton, SO15 2DA
• Sold Sep 2021£250,000 | 3 Bed FlatFlat 77, Parkview 5, Handel Road, Southampton, SO15 2NZFlat 77, Parkview 5, Handel Road, Southampton, SO15 2NZ
• Sold Mar 2021£209,000 | 3 Bed FlatFlat 29, Osborne House, Grosvenor Square, Southampton, SO15 2DAFlat 29, Osborne House, Grosvenor Square, Southampton, SO15 2DA
• Sold Mar 2021£200,000 | 3 Bed FlatFlat 30, Parkview 5, Handel Road, Southampton, SO15 2NYFlat 30, Parkview 5, Handel Road, Southampton, SO15 2NY
• Sold Jan 2021£270,000 | 3 Bed Flat21, The Polygon, Southampton, SO15 2BP21, The Polygon, Southampton, SO15 2BP
• Sold Dec 2019£235,000 | 3 Bed FlatFlat 36, Osborne House, Grosvenor Square, Southampton, SO15 2DAFlat 36, Osborne House, Grosvenor Square, Southampton, SO15 2DA
• Sold Nov 2019£248,000 | 3 Bed FlatFlat 9, Osborne House, Grosvenor Square, Southampton, SO15 2DAFlat 9, Osborne House, Grosvenor Square, Southampton, SO15 2DA
• Sold Apr 2019£252,000 | 3 Bed FlatFlat 20, Osborne House, Grosvenor Square, Southampton, SO15 2DAFlat 20, Osborne House, Grosvenor Square, Southampton, SO15 2DA
• Sold Jul 2018£265,000 | 3 Bed FlatFlat 14, Osborne House, Grosvenor Square, Southampton, SO15 2DAFlat 14, Osborne House, Grosvenor Square, Southampton, SO15 2DA
• Sold Dec 2017£220,000 | 3 Bed FlatFlat 26, Osborne House, Grosvenor Square, Southampton, SO15 2DAFlat 26, Osborne House, Grosvenor Square, Southampton, SO15 2DA

The Polygon, Southampton, SO15 has a total of 60 addresses. According to our analysis of all the public data, 21A, The Polygon, Southampton is the 17th largest and the 16th most expensive property on the street.

When compared to the postcode district it is £9k more expensive than the average property in SO15.

• Springhill Catholic Primary School

  500 m away
• Banister Primary School

  800 m away
• Freemantle Church of England Community Academy

  1.1 km away

• St Anne's Catholic School

  700 m away
• Upper Shirley High School

  2.4 km away
• Regents Park Community College

  2.6 km away

• Southampton Central

  |

  300 m away
• Millbrook (Hants)

  |

  1.6 km away
• St Denys

  |

  2.1 km away

According to data from the Environment Agency, the flood risk in this area is considered to be Very Low.