When inflation is low, its impact on changes to house prices is low. Nominal changes like demand and supply pressures are the main influences.
But when inflation is high, it masks the 'real' rise in house prices. Mortgages are always nominal and are always repaid in nominal terms, but asset prices do get set with some reference to inflation levels.
Community discussion of house price changes has avoided reference to "real" inflation-adjusted changes, focusing instead on "nominal" prices which are unadjusted for the likes of seasonality, inflation or other modifiers such as interest rates.
From 1995 to 2020, a quarter century span, inflation averaged only 2.0%, peaking only very briefly in this period at 5.3%.
But inflation has suddenly risen well above that level. It hit 7.3% in the June 2022 quarter and it could come in higher in the current September quarter when these levels are reported in about three weeks.
For almost all those 25 years, house prices have been rising, in nominal terms at least. Sure they flatten out, even dipped minorly in 2008, but that didn't turn out to be much of a correction. Certainly at that time inflation remained modest.
But recently we have a unique situation: house prices are falling and inflation is roaring. The combination eats away at 'real' house prices quickly.
The following two charts paint the picture. We have set January 2012 as the base, being a 10 year timeframe.
Nationally, nominal house prices were down 5.9% in August from year ago levels. But on an inflation-adjusted basis the decline is down 16.5% from a year ago.

Over the past decade, after inflation, median prices have risen from $355,000 to only $595,100 in 2012 dollar terms. We see $800,000 as the median price if we ignore inflation.

Most of this impact has been since the start of 2022. Not only have house prices retreated since then, inflation has jumped to levels not seen in a generation or more.
The impact in Auckland is even more pronounced.

The 8.3% retreat in August house prices from August 2021 isn't something we have seen for many generations. From the November 2021 peak, the decline to August has been 15%.
But when you adjust for inflation these changes are much more. On a year-on-year basis Auckland house prices have retreated 18.6%, and from the November peak they are down 23.1%.
By conventional definitions, Auckland housing is in a fast-building bear market.

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