8 big mistakes first-time homebuyers make

The housing market is hot, thanks to favorable interest rates and home prices that remain relatively low around much of the country.

According to the National Association of Realtors, pending home sales rose sharply in May, with lower mortgage rates and increased inventory pushing home sales upward in all four regions of the U.S.

And as underwriters start to ease their standards—the secondary mortgage market is starting to come back for buyers with "squeaky clean" finances, according to John Barrentine, co-founder and CEO of RED Real Estate Group—industry experts are expecting the market to continue to make significant gains in the second half of the year.

But along with a hot housing market comes increased competition for homes.

"There's not a high volume of home inventory out there," said David Norris, president and COO at non-bank mortgage lender loanDepot. "And many of the lower-priced homes are going for cash."

Given the complexities associated with the costs of buying a house, jumping into the market and effectively competing with aggressive bids can be daunting. If done wrong, a home purchase can result in enough financial regrets to last a lifetime for first-time homebuyers.

Here are eight of the most common mistakes made by first-time buyers—and how to avoid them.

Despite all the good that comes with owning a house—home equity, tax benefits and comfort in knowing what your housing costs are going to be over a period of time—when it comes to the heap of costs associated with buying, it may be a better deal financially to rent. (Buyers can find help with online calculators that compute home costs into equivalent monthly rents.)

The first question is, "How long do you expect to be there? The average young person is at their job for two to four years, and when you start to amortize closing costs over that period of time, it just doesn't make sense," said Brad Wheelock, a senior vice president and branch director at RBC Wealth Management. "What's the likelihood that you'll get out of that home without too much financial damage?"

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Buyers need to realize that all of the expenses renters never have to worry about, such as homeowner's insurance and closing costs, may end up being as much as a down payment. And that's not even including all the unseen maintenance fees.

"Lawn care can be fun, but you may decide that it's not a good use of your time and you need to find someone else to pay to do it," said Art Carden, assistant professor of economics at Samford University's Brock School of Business.

Not every homebuying market today is as competitive and expensive as New York, L.A. and the San Francisco Bay Area, where housing prices are exorbitant, demand far outstrips supply and all-cash offers are common. But given the expectation that mortgage rates and home prices will continue to rise around the country over the next few years, the most important thing prospective buyers can do is be financially prepared as early as possible.

Buyers must be ready to make very quick decisions as their markets heat up. "Much of the lower-priced stuff goes quickly," said loanDepot's Norris.

Before even starting your search, save as much as possible for a down payment, clean up any blemishes on your credit report and get preapproved for a loan. "The first-time homebuyer needs to be very savvy and have an upfront preapproval letter that will help give the seller confidence that [the buyer] can close the loan and obtain the funds," Norris said.

A fault of many first-time buyers is impatience, said Cara Pierce, a certified housing counselor with ClearPoint Credit Counseling Solutions. "[Buying a home] is really like finding a job—it's going to take a lot of time to prepare. That way, when the deal comes along, you're ready to pounce on it."

Your debt-to-income ratio is one of the first things lenders look at when it comes to assessing how well you'll be able to afford mortgage payments. "It's a big deal for folks not to load themselves with debt before they buy a house," said Glenda Gabriel, a neighborhood lending executive at Bank of America. "[Debt] could be the difference between approval and not being approved."

According to loanDepot's Norris, customers' debt—attributed today mostly to student loans followed by things like car payments—has gone on average from $40,000 in 2010 to $51,000 today. "It would be much easier to own a home if you can show a history of saving and not have gotten yourself into too much debt," he said.

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While many credit counselors and financial advisors advocate researching mortgages online—it's a good place to check with the city or county where you want to buy to see if you qualify for products like VA loans and FHA loans—interviewing and working with lenders in person can greatly help demystify the lending process. The process can differ based on a buyer's qualifications, how a mortgage company operates and current market economics.

Although half of borrowers claim to grasp basic loan terms and conditions, more than 2 out of every 5 bad experiences stem from misunderstandings over fees, terms and ownership costs, according to a recent survey by PricewaterhouseCoopers.

"Go to different places and talk to loan officers to get a feel for what the differences are between similar types of loans," said ClearPoint's Pierce, who suggests attending first-time homebuying classes. "Sometimes a company won't charge an origination fee, but then the interest rate is higher … and in some cases you can put many of the upfront costs—closing costs, title insurance—into the loan, which makes your balance larger."

When it comes to checking out houses and neighborhoods online, real estate agents have become wary of what clients find at sites like Zillow (Z) and Trulia (TRLA), which can give buyers a false sense of home values.

"My rant of the moment is Zillow and what we have to undo," said RED's Barrentine. "If a buyer believes that the actual value of the property is $1.1 million [as listed online] when it's really $1.3 million, it's a real disservice to the client. You really should [spend time] with someone that understands the market, someone who's there day in and day out."

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Driving around neighborhoods with an agent highlights the subtleties of a given market, things not easily represented online—like how one side of a canyon gets darker earlier, making it less valuable than the other side. "How would someone [searching these sites] know that at the top of El Granada, California, there's a million-dollar ocean view when the price on Zillow is $700,000?" said Nate Serdy, a Realtor with Alain Pinel Realtors in the San Francisco metro area.

Kirsten and Darrell Becker, co-owners of Becker Studios in Santa Barbara, California, suggest buyers step out of their comfort zone and drive by prospective houses at night. "Hear what it's like when not everyone is at work ... hear the roosters and the crows" that may live in neighbors' yards, Kirsten Becker said.

About 10 percent of recently bought homes weren't inspected, according to Bill Loden, president of the American Society of Home Inspectors. These buyers were trying to cut costs, forgoing the fee that inspectors charge to perform a two- to four-hour search to flag material defects of the property, but those defects can result in thousands of dollars of damage down the road. Inspection rates start at $450, on average, and vary depending on a home's size and how it was built, according to Loden.

"It takes a trained eye to be able to see the problems that can exist in a home," Loden said. "The inspection can also give the first-time buyer a bit of a schooling on the house and how to maintain it."

While buyers should tag along with the inspector and ask questions about cracks, water stains and odd smells, Loden cautioned that there are always "latent defects that inspectors cannot see."

Buyers should inspect basements, attics and mechanical rooms to see how well maintained they are and ask about conditions specific to certain areas—radon in the Midwest, sewers in California and active clay soils in Dallas, which can cause problems for foundations.

When looking to buy a home in an area with such soil issues, home inspectors urge buyers to call on specialists who perform foundation inspections, which run from $350 to $500 but can head off costly repairs down the road.

"In a case where the home inspector recommends a foundation inspection, 85 percent of the homes are likely to need foundation stabilization," said Adam Green, president and principal engineer at Crosstown Engineering. "The foundation of the home is the most important structural component, bearing the weight of the entire structure. If it fails or is unstable, it will cause all kinds of damage. Costs [to fix foundation problems] can be high and ongoing if the cause isn't identified and remediated."

Also, don't be afraid to "follow your nose," Kirsten Becker said. Mold, gas leaks and long-term dry rot can often be detected by their smell, she said.

In a competitive market where multiple offers may essentially be the same, "the sellers will choose almost every time to sell their home to someone who [appears to] really love it," said Amy Mizner, principal of real estate firm Benoit Mizner Simon & Co. "Most buyers don't realize they are being 'interviewed' by the listing broker, and if they complain the whole time or get exasperated about what are ultimately small-ticket items, they will make a bad first impression."

While it's important to note cracks and inquire about things like potential rodent problems in wooded areas, Mizner said buyers should not become fixated on these things while seeing the home. Save those questions for a broker, who should help clients do due diligence after a home tour.

Becker said lots of factors—the house's façade isn't to your taste, for example—turn out to be relatively cheap, easy fixes. She added, "If you're being overwhelmed by red flags, often that's when you can renegotiate your deal or take advantage of an amazing location with a house that may have a functional issue that [may turn out to be] a very easy fix."

Many first-time homebuyers invest their life savings into a home, hoping to turn a healthy profit when they sell five, six or seven years down the road. "I think a lot of people got burned doing that in the 2000s," Carden said. "And while to a certain degree it's really nice to get home equity for money you'd be paying for rent, it's a large asset that's not very liquid."

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Buy a house to live in, Carden said, and be prepared for lots of unseen upkeep costs that range from mowing the lawn to emergency repairs. "Stocks are far better investments than real estate," he said. "I've never had to call a plumber because a mutual fund started leaking."

—By Maggie Overfelt, special to CNBC.com