(CNN) — A new set of rules governing the business activities of most real estate professionals in the U.S. officially goes into effect Saturday — and the changes could upend the way Americans buy and sell homes.

The National Association of Realtors, the powerful industry association with 1.5 million members, has agreed to these rules as part of a $418 million antitrust settlement. The rules are designed to change how agents are paid and who pays them. It is the biggest change to the organization’s rules in at least a generation.

Impact of new regulations on home buyers and sellers in Utah

In a statement, NAR President Kevin Sears said the changes “help give consumers more clarity and choice when buying and selling a home.”

“I am confident in our members’ ability to prepare for and embrace this evolution of our industry and help consumers navigate the new landscape,” he said.

What you need to know:

Two important changes

In the past, buyers were not expected to pay their real estate agent directly. That’s because real estate agent commissions — to both the buyer’s agent and the seller’s agent — were paid by the home seller.

Commissions are typically 5 to 6 percent of a home’s sales price. So, for a home valued at $450,000, which is about the average price of a home in the U.S., the seller would have to pay $27,000 in fees. Many experts believe that these commissions are built into the list price of a home, driving up real estate prices.

But starting this week, sellers’ agents will no longer be allowed to charge commission fees to buyers’ agents on multiple listing services used by real estate agents to list and find homes for sale and facilitate transactions.

This means a buyer’s agent can no longer use the database to search for homes based on the compensation they expect to receive. This practice is known as “steering” and has led to some agents not showing their clients homes that met their criteria simply because the seller offered a below-market commission, critics say.

“With the MLS gone, it’s going to be harder to navigate because you can’t just look for a 3% commission,” said Tonya Monestier, a law professor at the University at Buffalo School of Law. “You can still call everybody and find out what the situation is, but this makes it a lot harder.”

The second change affects the relationship between prospective home buyers and their real estate agents. Buyers must now sign a legally binding representation agreement with their agent before they can begin viewing homes together.

These agreements are designed to inform home buyers how their agent will be paid, and if sellers are unwilling to pay the agent’s commission, the buyer can be responsible for that payment. They are also designed to inform buyers that this commission is entirely negotiable.

“The idea is that if buyers are aware that they can negotiate commissions and that they are actually paying them and not the seller, it could create a more competitive market and possibly, in the future, a service offering that would be more comparable to that of other developed countries,” says Norm Miller, professor emeritus of real estate at the University of San Diego.

A central element of these agreements is that the buyer’s agent cannot receive more compensation than what the buyer originally signed, even if the seller is willing to offer more.

The NAR website stated that these two changes “eliminated any theoretical steering because a broker would not receive more compensation for referring a buyer to a particular listing simply because it offered a ‘higher’ compensation.”

The final approval hearing is scheduled for November 26, but a judge had already tentatively approved NAR’s settlement in April.

Buyer beware

Some brokerages have realized that buyers get nervous about signing anything legally binding before viewing homes, so they have created shorter-term contracts that allow a week or maybe even an hour to allow buyers to get familiar with the agent before committing.

However, Monestier warned that buyers should be cautious about signing legally binding contracts without reading them thoroughly.

“You’re going to see all sorts of versions of these agreements that are going to vary from state to state and broker to broker. There could be thousands of them,” she said. “It worries me that buyers and sellers will sign something blindly and then be surprised when things aren’t the way they think they are.”

Leo Pareja, CEO of eXp Realty, one of America’s largest brokerage firms, told CNN that he focused on simplicity when drafting his company’s buyer contracts to avoid potential confusion.

“It’s designed so that the consumer can read it on the driveway without feeling uncomfortable,” Pareja said. “You don’t need a law degree to read it.”

Pareja decided to make his contracts widely available so that other companies could also use them.

“We just want there to be as little friction as possible between consumers and agents in the future, because that’s the last thing we need right now,” he said.

What impact could this have on home affordability?

Some real estate experts warn that the new rules could have a chilling effect on the home market, as more buyers may now be expected to pay their agents in cash themselves.

However, Monestier said she was confident the changes would help consumers in the long run.

“I would say it would be better for home buyers and sellers if commission rates went down over time,” she said.

However, it remains unclear whether the costs of buying and selling homes in the United States will immediately become cheaper for most people.

“I suspect that at some point, someone will say, ‘Let’s compete on price.’ If it’s a big company, that could spark a revolution,” said Miller of the University of San Diego. “But when would that happen? I don’t know.”

In the short term, Miller believes mortgage rates will have a bigger impact on home affordability than any specific rule change.

The interest rate on the average 30-year fixed-rate mortgage recently reached 6.49%, which, while still high compared to recent history, is near its lowest level in over a year.

“This has far more of an impact on affordability than anything we’re talking about here,” Miller said. “If mortgage rates continue to fall, rule changes will be just noise in the equation by comparison.”