How much is a great view from a condominium worth in Honolulu, and how much would it cost to lose?

Many condo owners at Sunset Towers near the Central YMCA along Atkinson Drive are nervous about the potential of significant drops in value as a proposed 350-foot condo tower is planned nearby, at a site currently limited by zoning to 150 feet.

"We really do have a very pleasant view at the moment," said Lyn Stobie, who heads the Sunset Towers resident organization’s zoning committee. "Anybody coming into our apartment is amazed at the view, and it’s a good selling point of the apartment. The channel view is between the two towers" along Ala Moana Boulevard.

This issue will not be unique to this proposed project, and, in fact, only stands to increase as Oahu’s urban building boom commences. As towers are planned throughout Kakaako, concern has begun to be expressed about prized views toward the ocean being cut off for present condo owners. But could views being cut off result in a drop in the worth of condos?

"That’s one of the things that we really should think about as we build more tall buildings," said Karl E. Kim, professor of urban and regional planning at the University of Hawaii. "We have to think about the impact on the urban landscape at multiple levels, from the perspective of individual units or buildings looking toward the views, and certainly the views are one of the things that make Hawaii a special place."

"I would think it’s very important," said Stobie, who lives on the 10th floor, two floors below the condo of Curt Carson, whose concern has spread through the building.

"I’m going to lose my view," anesthesiologist Carson testified this month to the Honolulu Planning Commission, which recommended approval of a zoning change for the proposed condo at the YMCA site. "I’m going to lose my property value."

Carson’s condo, with a view to the ocean between two towers, was appraised for a divorce settlement on Nov. 1, 2011, at $711,000. A year later, the condo was appraised for a bank loan at $530,000 — a plunge of more than $180,000.

The only major difference between the two appraisals was that the YMCA developer, MB Property Acquisitions LLC, had announced prior to the second one its plan to build the Aloha Kai tower 200 feet above the height limit under existing zoning, Carson said.

"As soon as some of the people found out, they started unloading their properties in the building," Carson said. "The reason they folded was because the building was going up and they presumed that the properties’ values would decrease."

Real estate appraiser Charlie Lum said he based the second appraisal of Carson’s condo on recent nearby sales but "it’s hard to say," specifically, why values drop.

"I took into consideration if there was any adjustment in sales that might have been affected by the news (of the development)," Lum said, "but I did not say, oh, proposed development is going to drop the development by $100,000. I do not do that."

Nor does he accept Carson’s singular reason for the price drop of Sunset Towers condos, as condo prices consist of "more than a view."

Similar concerns about blockage and sightlines have been voiced by condo residents near a 197-unit, 250-feet-high condo dubbed 803 Waimanu that is planned to come less than 40 feet at one point from Imperial Plaza’s main tower near Kapiolani Boulevard in Kakaako. MJF Development Corp. is seeking approval from the Hawaii Community Development Authority.

Most of the testimony by Imperial Plaza residents at a May 2 HCDA hearing was against the 803 Waimanu project. As resident Mike Kuhl put it, "It’s a good project — it’s just too close."

In written testimony, five area state legislators, including Rep. Scott Saiki, and two City Council members expressed concern about this "first project (in Kakaako) that proposes to construct a high-rise directly adjacent to an existing high-rise building."

HCDA responded by pointing to the two Waterfront Towers that are next to each along South Street, but Saiki pointed out that those towers were "a single project and one developer. It was very different from what’s happening at Waimanu Street, where it’s a different lot and it’s a different developer, and it’s being built with one section as close as 35 feet.

"To me, that’s not appropriate planning," said Saiki — whose concern is not limited to just views and this one project, but about HCDA’s "plan for the area" of Kakaako.

In their letter on 803 Waimanu to the HCDA, the area lawmakers also said: "We share residents’ concerns regarding the impact of this project, especially since this decision will set a precedent for the consideration of future projects. … The HCDA should disclose and explain its precise standards for review of variances and modifications, particularly with respect to height and density. The Kakaako master development plan should be presented in the aggregate, and not on a piecemeal basis."

Urban planning professor Kim agreed that the Kakaako plan should avoid blocking views from existing buildings. "Rather than treat this as sort of one building at a time and catch-as-catch-can," he said, "I think it makes more sense to treat this as a large planning project, in which we look at the visual impacts."

HCDA maintains it is doing just that. A month ago, it released its comprehensive plan for numerous skyscrapers in Kakaako, including three "exemplary iconic buildings" as high as 700 feet and other towers. Together, they "will create a skyline of views through and between towers, as well as green spaces on podiums that will enhance views down from neighboring buildings and residential areas on the slopes of Punchbowl, Makiki and Pacific Heights."

The question is whether the agency will follow what Kim said are the two primary reasons for zoning.

"The first is health and safety," Kim said. "The second reason is really quite explicit. It’s to protect the value of property. But the value of the property is affected by a host of other factors, among which include views."