How Much Is the New-Build Premium?

A new flat selling for more than the average flat nearby does not tell us, by itself, how much buyers are paying for “new”.

They may also be buying a different location, a different specification or a different kind of building.

That distinction matters when interpreting new-build premiums.

At Valtaic, our preliminary analysis of England and Wales transactions between July 2023 and June 2026 compares new homes with modern resale properties, allowing for differences in location, size and other recorded characteristics.

Across the local authorities included in the analysis, the median estimated differentials were:

• Detached houses: 2.6%.
• Semi-detached houses: 4.1%.
• Terraced houses: 6.9%.
• Flats: 13.8%.

These are medians of local-authority estimates, not national transaction-weighted averages. Nevertheless, the distinction between property types is clear: in this analysis, the estimated differential for flats was considerably larger than for houses.

The Local Variation Matters

A single headline percentage hides considerable variation.

The middle half of local-authority estimates fell between:

• 1.4% and 3.8% for detached houses.
• 2.5% and 5.5% for semi-detached houses.
• 5.0% and 9.1% for terraced houses.
• 12.2% and 16.4% for flats.

These ranges describe variation between local estimates, not confidence intervals or the range into which every individual property should fall.

A blanket assumption of a 10% premium would sit well above the typical detached-house estimate in this sample, but below the typical flat estimate. Applying the same adjustment to both would obscure an important difference.

Even within one property type, an area-level estimate should be a starting point for understanding the market, not a fixed markup for every development.

What the Premium Does, and Does Not, Tell Us

The comparison matters as much as the percentage.

Comparing new homes with the entire resale market can combine the effect of being new with differences in the properties being sold. A modern apartment scheme and an area's older converted flats are not necessarily interchangeable products.

This is why accounting for property differences is important. The official UK House Price Index also adjusts for the mix of homes sold, rather than treating every change in average transaction prices as a change in underlying value. UK HPI methodology

Our estimates describe an adjusted price differential. They do not establish that “newness” alone caused the difference.

Nor does a 13.8% estimated differential mean that a particular new flat will lose 13.8% when resold. That would require a different analysis, following properties through subsequent transactions and accounting for market changes.

The practical conclusion is straightforward: new-build premiums need to be understood by property type, location and comparison group.

Before accepting a headline premium, ask what it is measured against. That question can change the answer considerably.