21, CELYN ISAF, TONYREFAIL, PORTH, CF39 8AN - £350,000

The information on this page is based on a number of underlying datasets, most of which are updated monthly. We maintain an update schedule which explains which version of each dataset we are currently relying on.

21 CELYN ISAF is a midsized detached house of 112m², built sometime between 1976 and 1982, which could now be worth an estimated £362,919. It was last sold for £350,000 in July 2025, which was around 27% above the average July 2025 detached price in the Rhondda Cynon Taf local authority area. The most recent EPC inspection was October 2016, where the current energy rating was D, and the potential energy rating was B.

21 CELYN ISAF Sold Prices

Land registry data shows two sales for 21 CELYN ISAF since 1^st January 1995. The below table shows the price paid for the two sales, along with the average detached price in the Rhondda Cynon Taf local authority area for the corresponding sale date. Both of the two 21 CELYN ISAF sales were for above the average price. The average price is sourced from the Office for National Statistics' House Price Index (HPI).

Date	Price	HPI Price	Variation from HPI
2025 18 JUL	£350,000	£276,335	27% above HPI
1997 4 AUG	£73,000	£54,732	33% above HPI

21 CELYN ISAF Price Paid vs. HPI Average

The below graph shows the average detached house price in the Rhondda Cynon Taf local authority area over time, sourced from the HPI. The two 21 CELYN ISAF sales from August 1997 and July 2025 have been plotted on the graph. A line has been extrapolated to show what the value of the property might have been over time, following each sale, had it maintained the same margin above or below the HPI (as a percentage). For example, the August 1997 sale was for 33% above the HPI. So the extrapolation line tracks at 33% above the HPI over time, until the July 2025 sale, where it falls to 27% above the HPI. The line then continues to track at 27% above the HPI.

What might 21 CELYN ISAF be worth now?

21 CELYN ISAF might now be worth an estimated £362,919.

This is based on house price inflation of 3.7%, between July 2025 and July 2026, for detached houses, in the Rhondda Cynon Taf local authority area, as calculated by the Office for National Statistics and published in their UK House Price Index (HPI).

The 3.7% inflationary increase is applied to the most recent sale price for 21 CELYN ISAF of £350,000 on 18th July 2025. For the value to have increased from £350,000 to £362,919 over the one year to July 2026, the following assumptions must hold true:

• The value of 21 CELYN ISAF has moved in line with the HPI for detached houses in the Rhondda Cynon Taf local authority area.
• The July 2025 sale price of £350,000 represented a fair market value for the property.
• The size, condition, and specification of 21 CELYN ISAF has not materially changed since July 2025.

How Large is 21 CELYN ISAF?

21 CELYN ISAF is 112m² according to the EPC inspection conducted in October 2016. This puts it in the smallest 50% of detached houses houses in Tonyrefail, based on EPC data. The below chart shows the distribution of detached houses houses by size in Tonyrefail, and where 21 CELYN ISAF lies on this distribution: 44% of detached houses houses are smaller than 21 CELYN ISAF, and 53% of houses are larger. Note that EPC data is not available for all properties in Tonyrefail.

21 CELYN ISAF: Plot and Title Map

21 CELYN ISAF sits on a plot of roughly 0.087 of an acre, or 351m². The below map shows the location of 21 CELYN ISAF, an approximate outline of the building(s), and the indicative extent of the property. The plot extent is a Land Registry INSPIRE Index Polygon, and it is important to note that a title may include more than one polygon, whereas only one polygon is shown on the map (the polygon which intersects with the position of 21 CELYN ISAF). The full extent of the land contained in any registered title can only be identified from the individual title plan. The maps on this page should not be relied upon to establish the extent of a title.

Where is 21 CELYN ISAF?

21 CELYN ISAF is located in TONYREFAIL, in the CF39 postcode district. The below map shows the position of No. 21 on CELYN ISAF.