Despite what you see on TV and what the conventional wisdom says, most of the home improvement projects with the greatest return on investment are unglamorous. According to Remodeling Magazine's 2014 Cost vs. Value report, you'll recoup the greatest percentage of your investment on projects such as replacing the front door with a steel one, adding a wood deck, replacing old siding, replacing the garage door and replacing old windows. Also contrary to conventional wisdom, most home improvement projects do not return more than your investment when you sell. In fact, the average remodeling project only recoups 66 cents for every $1 you spend on it. To get the highest percentage of your remodeling dollars back when you sell, here's what to improve, what not to improve and why.

Best Options: Practical, Midrange Projects

Do you want to get back 96.6% of what you spend on a home upgrade? Then replace your old front door with a new, mid-range steel door with a clear dual-pane half-glass panel and a new lockset. You'll spend an average of $1,162 for this project, but you'll get back $1,122 when you sell, Remodeling Magazine reports. Another project in the same price range is replacing your garage door for $1,534; you'll recoup $1,283, or 83.7%. You won't need a home-equity loan to tackle these projects, and their low cost and high impact on curb appeal make them smart choices.

Curb appeal is the biggest selling factor, says Diana George, founder of Oakland, Calif.,-based Bay Area real estate brokerage Vault Realty Group. If the house looks unkempt on the outside, buyers automatically assume the same will apply to the interior of the house.

If you can afford to spend more, consider projects such as adding a 16' x 20' wood deck, which costs $9,539 on average but recoups 87.4% of its cost; replacing 10 old 3' x 5' windows with new, double-hung, wood or vinyl ones, which costs close to $11,000 for wood and nearly $10,000 for vinyl but recoups about 79%; or replacing vinyl siding, which costs $11,475 for 1,250 square feet but should bring back $8,975 when you sell.

Windows, garage doors and decks aren't necessarily big-ticket items in terms of price or luxury, George says, but updating these items gives the home an instant facelift and contributes to a modern aesthetic, which is exactly what potential homebuyers want to see when they drive up to look at a new home.

Pricier Projects

Two of the priciest – but still relatively worthwhile – improvements include attic bedrooms and basement remodels. These projects will set you back tens of thousands of dollars, but are a relatively inexpensive way to increase your home's useable square footage compared with an addition. Minor and major kitchen remodels also make the cut, as do bathroom remodels. However, while it may be true that kitchens and bathrooms sell houses, forget about doubling your money. You're likely to recoup just 82.7% of your $18,856 cost on a minor remodel of a functional but dated 200-square-foot kitchen; 74.2% on a $54,909 major kitchen remodel and 72.5% on a $16,128 remodel of a 5' x 7' bathroom. These are the types of expensive projects you might be tempted to finance with a home-equity loan, but you should think twice before borrowing money and paying 6% interest or more to finance a project with a negative return.

The costs Remodeling Magazine provides are averages. If you can get a project completed well for less, you might be more satisfied with the percentage of its costs you get back when you sell your home. Costs vary by geographic region, project size and scope, and the quality of finishes you choose.

Bathroom upgrades can be done for a minimal cost using materials that look expensive, but are quite affordable, says Jeff Dumas, owner and broker at Home Ventures Realty in Tempe, Ariz., where he's rehabbed and sold residential properties for more than 10 years. Most of the time, I can take an average starter home, put in a new tub with a porcelain tile backsplash, new toilet and vanity, tile the floor, and use some decorative hardware for about $1,500 to $2,000. The results are amazing and help the wow factor when potential buyers are viewing the property, he says.

Surprising Disappointments

Backup power generators and roofing replacements are among the projects on which homeowners will recoup the least at resale. You might get back just 67.5% of the $11,742 you spend on a generator and 67.6% of the $18,913 you spend on a roof. Also at the bottom of the list are sunroom additions, bathroom additions and master-suite additions. These projects are expensive and involve weeks or months of disruptive construction, so don't take them on unless they're for your personal enjoyment and you're planning to stay in your home for years to come. Remodeling a home office is the least worthwhile project on the list, recouping just 48.9% of the $28,000 it's likely to cost.

That being said, some of these projects are more valuable if you live in areas where they're in higher demand. In the West South Central region, which includes storm-prone areas in Texas, Oklahoma and Louisiana, a backup generator will recoup 86% of its cost, on average.

Other Cases Where the Rules Don't Apply

In some circumstances, the report's findings on the most valuable home improvements might not apply to your house. For example, adding a wood deck would not be a smart investment if decks are not popular in your neighborhood. Also, if your home's overall condition is poor, one or two improvements are not likely to make a big difference in sale price.

It's also possible that you will see a return on your investment if you live in a hot market and complete a popular project. Homeowners in San Francisco will likely see huge payoffs on midrange attic bedroom, kitchen, basement and bathroom remodels; bathroom, deck, family room, second-story and garage additions; entry-door and garage-door replacement; and siding replacement. Returns range from 109.8% to 177.6%.

Even if you don't live in a hot market, you might see a significant jump in your home's resale value when you make changes that bring it in line with the majority of homes in the neighborhood, such as adding a second bathroom when yours is the only one-bathroom house. In these cases, financing the improvements with a home-equity loan or home-equity line of credit might make sense.

The Bottom Line

If improving resale value and recouping remodeling costs are important to you, don't let TV shows, your personal taste, your family's unique needs or your emotions guide your home improvement decisions. Consult with a real estate agent about the conditions in your local market, consult the Cost vs. Value Report's averages for your region, and stick to the upgrades that research and experience have proved worthwhile.