A sharp increase in consumer sales in Brewer and Bangor has experts saying that the coming inrush of new or revamped big-box stores such as The Home Depot, Lowe’s and Wal-Mart will stiffen competition among the businesses and reduce the prices on some items.

“These stores are coming in an overlap fashion, to be able to sell to as many consumers as possible,” said James McConnon, professor of resource economics and policy at the University of Maine and a business and economics specialist at the UMaine Cooperative Extension. “It doesn’t surprise me to see Wal-Mart locate in Brewer and Wal-Mart locate [another Supercenter] in Bangor given their strategy of saturation.”

That strategy has been adopted by Lowe’s as well.

In Brewer, a Lowe’s home improvement store is under construction on outer Wilson Street. In Bangor, Wal-Mart and The Home Depot, both of which already have stores in the mall area, are building new, larger ones off Stillwater Avenue. A second Lowe’s is proposed for the Springer Drive site now occupied by Wal-Mart. The site is expected to become available next spring after Wal-Mart moves into its new home behind the Blue Seal farm supply store.

Shaw’s Supermarket at 46 Springer Drive in Bangor will be replaced with a new store at 461 Stillwater Ave., across the street from the Bangor Parkade shopping center.

Both Bangor and Brewer pull in customers from very far away, McConnon said.

“The spending that’s been going on in Brewer indicates a growing retail sector,” the professor said.

Statistics from Maine Revenue Services strongly support McConnon’s statement. From 2000 to 2006, sales of taxable goods in Brewer increased by 65.3 percent, from $130.6 million to $215.8 million. Total taxable spending statewide grew by 23 percent during the same period, from $12.2 billion in 2000 to $15 billion in 2006.

In Bangor, taxable sales grew at a pace similar to the state’s, with an increase of 22.8 percent from 2000 to 2006. In 2000, customers spent $935.7 million in Bangor, and in 2006 they spent $1.1 billion.

The numbers were not adjusted for inflation, which usually is estimated to be about 3 percent a year, McConnon said.

General merchandise sales, which do not include restaurants, hotels and other taxable purchases not made in stores, grew a whopping 152 percent in Brewer from 2000 to 2006, totaling $74.4 million last year.

“A big chunk of that is because of Wal-Mart,” McConnon said, referring to the Supercenter on Wilson Street.

In Maine, there are now 12 Wal-Mart Supercenters, which include a full grocery store, and 10 Wal-Mart discount stores.

“We decided to make [the new Bangor] store into a Supercenter because, overwhelmingly, that is the format our customers want,” said Wal-Mart spokesman Philip H. Serghini. “Our existing store in Bangor is one of our busiest stores in Maine. We believe both [the Bangor and Brewer] stores will continue to be very popular.”

Construction on the Bangor store is expected to start in the spring of 2008, with an opening in early 2009.

McConnon said he has developed a model to indicate whether a market area has a “leakage” or “surplus,” meaning customers are either leaving or entering the area to shop.

Given Brewer’s population, income and general spending patterns, it was expected to generate about $4.2 million more than what it generated in building supply sales in 2005, which means Brewer residents probably left the city to shop for building supplies elsewhere, according to McConnon’s calculations.

Bangor, on the other hand, took in $70 million more than was forecast in building supplies sales in 2005, which indicates people came from other markets to shop in Bangor, McConnon said.

“Bangor has been a relatively protective market for Home Depot. Lowe’s probably figured … this is a market for them and did market studies,” said Craig Johnson, president of Customer Growth Partners, a retail growth consulting firm in Connecticut.

Because they will be going head to head in Bangor, there’s likely to be increased price competition between The Home Depot and Lowe’s, McConnon said.

“For those items where consumers are price-sensitive, that’s where you’ll see prices fall or decline,” McConnon said.

Johnson said Lowe’s, based in Mooresville, N.C., is aggressively expanding in almost every state, and its store design contrasts sharply with The Home Depot, based in Atlanta.”Lowe’s is more female-friendly. The stores are newer, better lit, better signed. If you think about it, women are choosing the new kitchen, the new bathroom. … They’ve become a very important part, if not the most important part, of the consumer buying process,” Johnson said.

The Home Depot corporate office declined to comment on why it was expanding, but Johnson speculated it is an effort to improve its appearance in light of the coming Lowe’s.

“An older store that’s been there awhile is going to be most vulnerable to competition,” Johnson said. “It [the expansion] helps to hold off the competition a bit longer and reduces the contrast between the new, sparkling store and the older Home Depot.”

The Home Depot, which now has 11 stores in Maine, plans to open its new store in Bangor in 2008.

There are now six Lowe’s stores in Maine. Another three are under construction. Lowe’s in Brewer is targeted for opening in the spring of 2008, and the store has not yet announced plans for its Bangor location.

Economic development officials in Bangor and Brewer are not surprised at the proximity of the big-box stores.

“Most businesses like to be near the critical mass, which is the mall area. They like to be as close to each other as they can,” said Rodney McKay, director of Bangor’s Department of Community and Economic Development. “If you can’t find what you’re looking for in one store, you can go to another.”

D’arcy Main-Boyington, director of economic development in Brewer, said retailers consider Bangor and Brewer to be two separate markets, drawing from towns on either side of the Penobscot River. Brewer tends to attract shoppers from as far away as Ellsworth, she said.

“The Brewer Wal-Mart is not taking customers from the Bangor [Wal-Mart],” Main-Boyington said. After Lowe’s is erected, Main-Boyington said, she would not be surprised if The Home Depot comes to town.

Lowe’s said it considers hundreds of factors when determining where to build a new store. A few include homeownership in the area, population, access to major roadways, easy access into and out of a parking lot, and growth in the community, said Karen Cobb, a spokeswoman for Lowe’s.

“Approximately 78 percent of Lowe’s stores operate within a 10-mile radius of its major competitor,” said Cobb. The Home Depot is widely recognized as the top competitor of Lowe’s. “When there is competition in the marketplace, the customer is ultimately the winner, for they will decide where to spend their home improvement dollars.”