HACKENSACK, N.J. — If you’re looking for improvements that can boost a home’s sale price, start with the outside.

That was the finding in a recent Remodeling magazine survey. Though most home improvements don’t pay for themselves at resale, the survey found that the projects with the greatest return on the dollar are those that improve a home’s curb appeal, such as new siding, decks and windows.

Overall these days, home sellers recover about 70 cents for every dollar they’ve spent for home improvements. That’s down from more than 80 cents in 2005. The survey’s authors say this is the result of higher costs for home remodeling and declining sale prices. But in areas where home prices have not dropped as much as in other regionsm, sellers can recoup a higher percentage of their home improvement expenses, the study found.

Still, as a general rule, sellers don’t get back the full cost of improvements.

“In a market that’s flat to declining, which is the kind of market we’re in now with home prices, I’m counseling sellers not to dump tremendous amounts of money into their homes,” said Sal Poliandro, an agent with Re/Max Properties in Ridgewood, N.J. He cited one recent seller who had spent $200,000 on a pool and landscaping. “He had a 45-foot waterfall,” Poliandro said. “It was very nice, but no one is going to pay extra for that.”

The least profitable projects are a backup generator, sunroom addition and home office remodel.

One of the most popular jobs — a kitchen remodel — returns about 80 percent of its cost nationwide.

The “Remodeling Cost vs. Value Report” is based on surveys of remodeling professionals and real estate agents. It was conducted by Hanley Wood LLC.