Despite the extremely low interest rates, housing may not be as affordable now as many think, according to UBS.

The National Association of Realtors has said housing in the United States is very affordable right now. Covid-19 has put restrictions on viewing and showing homes, but it has not affected the selling prices nor the availability, according to the association.

However, UBS said Friday it is concerned that the affordability of housing is overrated by the association and others because all of the factors are not being considered.

Jonathan Woloshin, head of U.S. real estate for UBS Global Wealth Management, said in a statement, “We are concerned that the methodology behind the association’s conclusion is overstating affordability and is masking the true cost of homeownership.”

However, “rising home prices, combined with flattening and declining apartment rents, are beginning to reverse the trend of the past few years, when the monthly cost of homeownership was below that of renting an apartment in many markets.”

The National Association of Realtors bases its calculations on home buyers putting down a 20% down payment, but many home buyers only put down 10%, UBS said. The buyer is then required to purchase mortgage insurance.

UBS also warned potential home buyers that they need to consider all costs associated with home ownership when calculating whether they can afford a home, including real estate taxes, homeowner’s insurance, and regular maintenance.

“Once these factors are included, home ownership is substantially less affordable than” some might think, the UBS said.

There also is no “typical” or “average” home price, as costs vary widely by region and are substantially higher on both the East and West Coasts, UBS said.

The strength of housing market has continued throughout the coronavirus crisis, mostly because “extraordinarily low mortgage rates have helped fuel demand despite continued rising prices,” UBS said.

Elevated student debt hinders many first-time buyers, the financial firm noted. In addition, “rapidly rising lumber prices represent a potential headwind to the recent strength in housing demand.”