by Calculated Risk on 12/11/2007 03:47:00 PM

Renting is a substitute for owning, and to understand the current excess housing inventory, we also need to consider rental units.

Click on graph for larger image.

This graph shows the number of occupied (blue) and vacant (red) rental units in the U.S. (all data from the Census Bureau).

In an earlier post, Home Builders and Homeownership Rates, I discussed the decade long decline in the total number of rental units - from 1995 to 2004 - and how that related to the rising homeownership rate.

The builders didn't stop building apartment units in 1995, instead the decline in the total units came from rental to owner conversions, and units being demolished (a fairly large number of housing units are demolished every year).

And even though the total number of rental units was declining, this didn't completely offset the number of renters moving to homeownership, so the rental vacancy rate started moving up - from about 8% in 1995 to over 10% in 2004.

The total number of rental units (red and blue) bottomed in Q2 2004, and started climbing again. Since Q2 2004, there have been 2.6 million units added to the rental inventory. This increase in units almost offset the recent strong migration from ownership to renting, so the rental vacancy rate has only declined slightly (from a peak of 10.4% in 2004 to 9.8% in the most recent quarter).

Where did these 2.6 rental units come from?

The Census Bureau's Housing Units Completed, by Intent and Design shows 773K units completed as 'built for rent' since Q2 2004. This means that another 1.8+ million rental units came from conversions from ownership to rental.

These could be older out-of-service units being brought back to the rental market, condo "reconversions", flippers becoming landlords, or homeowners renting their previous homes instead of selling. But this shows the substantial excess inventory in 2004 and 2005 that didn't show up in the new home or existing home inventory numbers at the time.

Back in 2006, I estimated the excess housing inventory at 1.1 million to 1.4 million units. The number is higher now since the home builders have continued to build too many homes. Note: of course price is a factor. With the rental vacancy still above the normal range, there are probably 700 thousand excess rental units in the U.S. (assuming the vacancy rate falls back to 8%).

Here is a rough estimate of the excess inventory:

Source	Units
Rental Units	700,000(1)
Vacant Homeowner Units	750,000(2)
Excess Builder Inventory	250,000(3)
Total	1,700,000

(1) calculated based a decline in the rental vacancy rate from 9.8% to 8%.

(2) based on the homeowner vacancy rate declining from 2.7% to 1.7% on 75 million units.

(3) Based on a return to 5 months of hard inventory (completed or in process). This includes an extra 100,000 units based on rising cancellation rates.

Note: this is another step towards my housing forecast for 2008.