Change in Housing Affordability Indicators

Renting a home 

The change in rental affordability indicator compares changes in rental prices for new tenancies with the growth in median household disposable (after tax) income. 

Factors that can affect rental affordability are:  

• Rental prices 
• Household disposable income 

Saving for a deposit 

The change in deposit affordability indicator compares changes in house sales prices with the growth in median household disposable (after tax) income. 

Factors that can affect deposit affordability are:  

• House sales prices 
• Household disposable income 

Servicing a mortgage 

The change in mortgage serviceability indicator compares changes in the purchasing power of mortgage interest payments for new home loans with the growth in median household disposable (after tax) income. 

Factors that can affect mortgage serviceability are: 

• Mortgage interest rates 
• House sales prices 
• Household disposable income. 

Individual experience of affordability will vary, for example if household income doesn’t change in line with the national median.  

Limitations

CHAI shows experience of those on median incomes, not individual experiences of affordability  

The indicators compare the change of median incomes with overall house and rent movements, and average interest rates. Households not experiencing median income growth or paying different interest rates will experience different changes in affordability. 

CHAI reflects change in affordability, not relative affordability 

The indicators track whether affordability is improving or worsening in an area but not how affordable an area is at a point in time. This means it is not possible to compare the level of affordability between areas. Affordability in one area can improve more than another’s over a period of time, while the level of affordability remains worse.  

Seasonal Series 

Some of the indicators are affected by seasonal change. For example, rent prices tend to peak in the first quarter of each year. For short term analysis, it’s best to use the same time of year for the start and end of your comparison. 

Modelled Income Series 

The median household income data for recent periods is estimated using tax data and are revised as further income data becomes available. 

About the dashboard

Contents 

The indicators are displayed across multiple tabs: 

• Affordability indicators present the annual and cumulative Change in Housing Affordability Indicators (CHAI) over time for a selected geographic area. 
• Indices present the annual and cumulative changes over time for the indices that make up the CHAI. 

• Area comparison allows users to choose multiple geographic areas and compare the change in affordability.  

Using the dashboard 

You can select the geography and time period you’re interested in by using the filters at the top of each page.  

To see individual values, you can hover over the time series.  

Download the Concepts, sources, and methods paper(external link)

The House Price Index (HPI) is provided by Cotality New Zealand and is provided subject to Cotality’s Terms and Conditions(external link) 

Data download

For easy ad-hoc analysis of measures featured on this dashboard, we have created a data download file linked below. This .xlsx file encompasses comprehensive statistics from all previous months featured in the dashboard.

Within this sheet, please read the “Instructions” tab on how to filter and use the data appropriately.

Change in Housing Affordability Indicators data download (XLSX, 1.6 MB)