Everyone -- well, practically everyone -- applauds lower mortgage rates. And why not? Lower rates mean homebuyers have more buying power.

In May, the average 30-year loan rate was 3.6 percent -- the lowest it has been in 36 months. But there is a downside.

When rates slip, points out Jonathan Smoke, chief economist at Realtor.com, the availability of credit declines. Lenders pull in their horns because it becomes more difficult to make a profit. "With little margin, lenders become more risk-averse," says Smoke.

While Smoke believes mortgage rates are likely to remain under 4 percent through the summer and into the early fall, they could spring up to more than 4 percent by the holidays. His advice: Stay on top of rates, work closely with your lender, and become familiar with options like interest rate locks and float-downs (a type of rate reduction).

"Given how volatile rates have been this year," he says, "borrowers are likely to see both lower and higher rates from time of application to time of closing, which is what makes these options potentially attractive. However, they do come at a price, so you need to weigh the potential gains against the costs with your lender."

There is garden-variety customer service, as practiced by many real estate professionals. There is great customer service, practiced by some. And there there's Jeff Miller.

Miller, a loan officer with PrimeLending in Tucson, Arizona, outshone them all in April, when he officiated the wedding of clients Donovan Riley and Rebecca Noreen.

When working to secure the engaged couple's mortgage in January, Miller half-jokingly told the pair that he was ordained, and that if they needed an officiant for their wedding, he would be happy to step in. He said he never expected to actually receive a call, but in March, he did: Riley and Noreen were experiencing difficulty lining up an officiant. So they reached out to Miller to see just how serious he was.

The pair was married, by their mortgage officer, on April 9.

A mortgage is definitely a long-term commitment, but this one came with an "until death do us part" rider. Now that's customer service.

President Herbert Hoover promised "a chicken in every pot." Now, South Florida real estate developer Tim Lobanov is promising a jet with every condo.

To boost sales at the Aurora development in Sunny Isles Beach, Florida, Lobanov -- managing director of the Verzasca Group -- is offering complimentary one-year memberships with JetSmarter, a service that allows members to charter private jets.

Surprisingly, prices at the 61-unit "boutique" condominium on the famed Collins Avenue seem fairly reasonable, at least for South Florida: $840,000 for a two-bedroom apartment, $920,000 for two bedrooms and a den and $1.4 million for a three-bedroom unit.

There's no doubt that the internet has allowed would-be homebuyers to do much of their searching online. There are about 123 million unique visitors per month to the top three real estate web portals, most of whom are seeing what's available and reading the latest "how-to" articles.

Now, QValue, a Denver technology company, has developed a formula that allows the computer to actually find specific houses based on what buyers say they want. In a test in April, a buyer told the computer and an agent what he liked, and the machine and the real estate professional went about the task of finding just the right house.

The experiment went on for three consecutive days, with the buyer entering different requirements each day. And each day, the computer turned in the buyer's favorite.

The difference: The QValue algorithm runs on "emotionally triggering" qualitative criteria, as opposed to quantitative measures such as price and number of bedrooms.

Chinese investment in the U.S. real estate market has surpassed $300 billion and is still growing, despite China's economic weakness and increased currency controls, according to new research.

Between 2010 and 2015, Chinese buyers bought $93 billion worth of residential real estate, nearly $208 billion of mortgage-backed securities and roughly $17 billion of commercial real estate, including office towers and hotels. The data comes from a report by the Rosen Consulting Group and the Asia Society.

Despite those eye-popping numbers, direct investment from China still makes up only 10 percent of all foreign investment into U.S. real estate.

Ever wonder how much the folks who build, sell and finance houses earn? How much of what you paid went right to their bottom line?

If so, you've come to the right place. Now it can be told who makes what in the typical real estate transaction. Let's take a look, starting with the companies that build houses.

BUILDERS: According to the National Association of Home Builders' (NAHB) latest "cost of doing business" study, builders averaged just a tad over $3 million in gross profit in 2014 on $16.23 million in revenue. That's an 18.9 percent gain.

But after accounting for operating costs that averaged $2.02 million, their take was just 6.4 percent, or $1.04 million.

The remarkably detailed report goes further, though, breaking down the data by type of builder: those who build solely on their own lots, those who build on lots owned by their clients and those who do both. It also details earnings by region and by volume, and by builders who put up fewer than 25 houses a year and those who build more.

Since there is not enough space here to go into each category, let's just concentrate on the two largest segments: builders with land costs, also called speculative builders, who make up 38 percent of the total respondents to the NAHB survey; and combination builders, who build on their customers' lots as well as their own land, and make up 37 percent of respondents.

According to the survey, speculative builders' net profit averaged 5.9 percent. So if you paid $356,200 for your new house -- the average price for new homes in March, according to the latest figures from the Census Bureau -- figure that your builder pocketed $21,016 on your deal, give or take.

Combination builders netted more -- 7.6 percent per house, on average -- which works out to $27,071 in pure profit on the typical house. Not bad, except that it sometimes takes years to obtain the necessary government approvals to build, and then 90 days or so more to actually construct the place.

Breaking the profit picture down another way, small-volume builders, who comprised 65 percent of survey respondents, earned 5 percent on average, while their larger colleagues, aka production builders, made 6.8 percent.

REALTY AGENTS: The men and women who sell houses earn anywhere from under $10,000 annually to more than $250,000, depending on experience, hours worked and education. A deeper dive finds that the median yearly pay for a sales agent in 2014, according to that year's National Association of Realtors' annual member profile, was $23,300.

It is well understood that agents work on commission, typically 6 percent. But what is not so well understood is that they don't get all of that. Rather, they split their fee with their brokers, under whose licenses they work.

Nearly 80 percent of all agents work under a split-commission arrangement, generally 50-50. But the more productive they are, the better the split. And 13 percent keep the entire commission and pay their brokers a so-called "desk charge."

Income varies widely in the industry: After taxes and expenses, appraisers take home about $46,200, and brokers take in $96,200 if they don't act as agents themselves ($45,500 if they do). Experienced agents with 16 or more years on the job net a median of $42,000, but 3 percent walk away with more than a quarter-million dollars.

LENDERS: In 2015, independent mortgage lenders -- those unaffiliated with larger banks or with the mortgage subsidiaries of chartered banks -- earned an average of $1,189 in profit on each loan they originated, according to the Mortgage Bankers Association's (MBA) annual performance report. But in the first quarter of this year, their net gain on each loan slipped to $825.

A closer look shows that net production profits in 2015 were 55 basis points, or 0.55 percent of the loan amount. So multiply that times the amount you borrowed, and you'll have a good idea of what your lender made off of your deal, before expenses.

Because of larger loan balances last year -- $239,265 vs. $223,108 in 2014, a jump of 7 percent, and up 22 percent since the housing market collapsed in 2008 -- lenders' bottom lines rose nearly $450 per loan in 2015.

To show you how volatile the mortgage market has become, at least for lenders, the average pre-tax profit per loan in the first quarter dropped to 33 basis points, or 0.33 percent of the loan amount. Since the MBA began keeping records, net production income has averaged 52 basis points.

Houston lost its locally famous Bullock-City Federation Mansion in 2014 to a developer who plans to erect townhouses on the site.

The house may not have been worthy of a place on a list of historically significant structures. But the 5,000-square-foot structure that was erected in 1906 on a 30,000-square-foot lot was the first in the sweltering Texas city to have air conditioning. And its demise was mourned by more than a few people.

"It's a beautiful building," Ernesto Aguilar, general manager of KPFT Radio, which sits next door, told the Houston Chronicle at the time. "It is sad to see a piece of Houston history going the same way as many others do."

Teardowns -- in which builders or private individuals purchase an aging, outmoded house, then demolish it and replace it with a modern home that will suit today's homeowners -- are currently on a tear in Houston. Permits for teardowns are up by 22 percent in the city this year.

And that phenomenon isn't limited to Houston. Barry Sulphor, a real estate agent in the Los Angeles area, counts no less than 100 teardown sites in the so-called "beach cities" where he plies his trade: Hermosa Beach, Redonda Beach and Manhattan Beach. "And I'm sure there are just as many in Venice, Santa Monica and Beverly Hills," Sulphor says.

According to the National Association of Home Builders' (NAHB's) best count, nearly 8 percent of all single-family housing starts in 2015 were attributable to teardown-related construction. That's roughly 55,000 older houses gone forever, and that's on top of the 31,800 single-family teardown starts in 2014.

In some instances, the houses that are destroyed are outmoded, functionally obsolete relics that no longer serve a useful purpose. But in other cases, they work just fine and simply lack up-to-date amenities. And some have historical significance that may or may not be worthy of saving.

Usually, the places that replace a teardown are larger, covering more of the lot and rising higher than the old place -- often to the maximum height allowable under local zoning rules.

Sulphor recently sold two lots where the old houses were taken down. One was bought for $1.35 million by a builder who plans to put up a house with a nearly $4 million price tag. The other was purchased for $2.15 million by a retired couple who "love the creativity of working with architects to design luxury beach properties," according to Sulphor. "When the new place is completed, it will fetch close to $5 million."

Not everyone sees the benefit of teardowns. The leading opponent is the National Trust for Historic Preservation, which argues that they are an "epidemic" that is "wiping out historic neighborhoods one house at a time. As older homes are demolished and replaced with dramatically larger, out-of-scale new structures, the historic character of the existing neighborhood is changed forever."

Says Richard Moe, a former president of the National Trust: "From 19th-century Victorian to 1920s bungalows, the architecture of America's historic neighborhoods reflects the character of our communities. Teardowns radically change the fabric of a community. Without proper safeguards, historic neighborhoods will lose the identities that drew residents to put down roots in the first place."

But the NAHB, which admits that teardowns "have become a significant modus operandi" for its members in some parts of the country, counters that the new houses often "breathe new life into older communities."

Because teardowns are sometimes controversial, folks considering buying an older place with the idea of taking it down and putting up a new house should proceed cautiously. Often, these old homes are not advertised for sale on the open market or in the multiple listing service, so the challenge begins with finding out about one, says Sulphor. And once you do, the agent suggests making absolutely sure the condition of the current home is such that it cannot be salvaged.

Would-be buyers should also determine, before making an offer, whether what they plan to build conforms to local restrictions. Preservationists often use -- or try to change -- local building codes to push back against teardowns.

On the other hand, people trying to sell old properties that are teardown candidates should make sure whatever offers they receive are legit, Sulphor advises. Look for the proof that they have the funds to close the deal, especially if they say they will pay with cash and have no need of a mortgage.

Sellers should also realize that selling a property "as-is" does not insulate them from their obligation to disclose any issues that might impact value. The term "as-is" means only that the house is being offered and sold in its present condition.