While millennials were the largest group of home buyers in the past 12 months, many had problems with affordability and the down payment.

A significant number of millennials that were able to purchase a home, 37%, went over their planned budget; for all buyers, 29% exceeded their price range, according to the Zillow Group Report on Consumer Housing Trends 2017.

Because of increased competition for a limited supply of homes, 53% of millennials made multiple offers in an attempt to buy their first house.

By age group, those between 18 and 37 made up 42% that purchased a home in the last 12 months, while 29% were Generation Xers, 25% were baby boomers and 4% were 73 or older.

Only 39% of millennials were able to make a 20% down payment, while 21% made a down payment of 5% or less.

Friends and family members helped 29% of millennial buyers with the down payment.

More than six in 10 millennials (62%) in the market to purchase a home were at the same time were considering moving to another rental property in case their search failed.

"Young buyers often start their careers in fast-growing cities in which the market is particularly tough — and they're trying to save for a down payment while making record-high rent payments," said Zillow Chief Economist Svenja Gudell in a press release.

"Whether it's searching for a rental as a Plan B, looking outside their preferred neighborhood, or cobbling together a down payment from multiple sources, these buyers are willing to try every trick in the book in order to find a place to call home."

Finding a home in their desired price range was a leading challenge cited by 49% of millennials, along with finding a home in their desired location and finding a home with the desired amenities, each at 45%.

Determining the best mortgage product was cited by 41% of millennials (compared with 32% of all respondents), while going through underwriting was considered a top challenge by 39% (26% for all respondents) and qualifying for a mortgage by 33% (25% of all respondents).