American homeowners are wasting more space than ever before.

There may not be many homes for sale these days, but there is plenty of vacant housing. In fact, the most in recorded history.

The number of additional bedrooms, which is defined as more bedrooms than the number of people in the home, and even includes an office, began recording this metric in 1970 according to the U.S. Census. has reached the highest level since New report from Realtor.com.

Last year, the most recent census data available, the number of additional bedrooms reached 31.9 million, up from 31.3 million in 2022. In 1980, there were only 7 million additional bedrooms.

The fourfold increase comes as the number of people in any household has declined, from a high of 3.1 people per household in 1970 to a record low of 2.5 per household in 2023.

“We’re seeing more guest rooms for two main reasons: homes are getting bigger and home sizes are getting smaller,” said Ralph McLaughlin, senior economist at Realtor.com. “What’s more, we’ve found that spare rooms are more popular in affordable areas where it’s more affordable to buy a home with extra bedrooms.”

The average size of a new home grew during the popular “McMansion” era, which began in the 1980s, when builders went big. But they stopped growing about a decade ago. Much of this has to do with rising costs, as well as the energy efficiency and environmental needs of consumers.

So over the past 50 years the average number of bedrooms per house has increased from an average of 2.5 rooms in 1970 to 2.8 rooms in 2023, but has not changed in the last 10 years.

Look regionally, since all real estate is local, the trends for more space are greatest in the Mountain West and South. According to the report, this is simply because there is more land, and homes are built with larger floor plans. Urban homes have the opposite dynamic.

“If people value extra space, then we wouldn’t have built much in the McMansion era. But if homebuyers are putting up with these big houses just because they’re available, then maybe we’ve built a lot in the past. A few decades may have built a little too much,” added McLaughlin

The 10 markets with the highest share of total bedrooms that could be considered high are:

1. Ogden, Utah (12.2%)
2. Colorado Springs, Colorado (12.1%)
3. Salt Lake City, Utah (12%)
4. Memphis, Tenn. (11.8%)
5. Atlanta (11.6%)
6. Cleveland (11.3%)
7. Wichita, Kan. (11.3%)
8. Columbia, SC (10.8%)
9. Charleston, SC (10.7%)
10. Jackson, Miss. (10.7%)

The 10 markets with the lowest share of total bedrooms that could be considered high are:

1. Miami (5.9%)
2. Sarasota, Fla. (6.4%)
3. New York (6.5%)
4. Los Angeles (6.6%)
5. New Haven, Conn. (6.7%)
6. Worcester, Mass. (6.9%)
7. Stockton, California (6.9%)
8. Bakersfield, California (7%)
9. Honolulu Region (7%)
10. Providence, RI (7.1%)