The Federal Building in downtown Youngstown, Ohio, features an extensive use of natural light to illuminate offices and a white roof to reflect heat.

It has LEED certification, the country’s most recognized seal of approval for green buildings.

But the building is hardly a model of energy efficiency. According to an environmental assessment last year, it did not score high enough to qualify for the Energy Star label granted by the Environmental Protection Agency, which ranks buildings after looking at a year’s worth of utility bills.

The building’s cooling system, a major gas guzzler, was one culprit. Another was its design: to get its LEED label, it racked up points for things like native landscaping rather than structural energy-saving features, according to a study by the General Services Administration, which owns the building.

Builders covet LEED certification  it stands for Leadership in Energy and Environmental Design  as a way to gain tax credits, attract tenants, charge premium rents and project an image of environmental responsibility. But the gap between design and construction, which LEED certifies, and how some buildings actually perform led the program last week to announce that it would begin collecting information about energy use from all the buildings it certifies.