The Empire State Building, New York was completed in 1931 with construction having commenced in January 1930. Whilst it is currently the tallest building in New York, you would hardly expect this iconic world landmark building would be energy efficient. Yet, the Empire State building was recently awarded a gold LEED-EB rating.

The building provides 271,036 sq m (2,917,408 square feet) of commercial office space over 76 office floors with a total of 102 floors overall. In September 2011, the Empire State building was comprehensively refurbished at a cost of $550 million.

The Leadership in Energy and Environmental Design (LEED) rating is an American energy efficiency and sustainability rating. More about LEED here.

It is estimated that the new retro-fit will result in cost savings of $4.4 million reduction in annual energy costs and a 38% reduction in annual energy use.

As a result of the retrofit, the building also achieved an Energy Star Rating of 90. More information on Energy Star ratings can be obtained here.

The Empire State building targeted reducing energy loads. Eight energy projects were undertaken to reduce the overall energy load by 40%. Some of the main projects were as follows:

1. Lighting & controls – Installing photoelectric and occupancy lighting controls will reduce energy used for lighting. By removing internal partitions and creating open plan space natural daylight is optimised. Expected saving: 2,060 tonnes of CO2 and $941,000 per year.

2. Windows – The original windows in the building were single glazed metal framed typical of the age of construction. These windows would be likely to have a U-value of circa 5.7 W/m2 K. The 6.514 windows were re-manufactured with a film and gaseous layer to reduce solar gain and heat loss. 1,150 tonnes of CO2 and $410,000 per year.

3. Installing reflective barriers behind the central heating system radiators. There is approximately one radiator beneath each window in the ESB. The ESB calculated that approximately 50% of the heat is lost to the exterior. By installing inexpensive insulation behind the radiator would save 24% of heat. Anticipated savings 480 tonnes of CO2 and $190,000 per year.

4. Sub-metered electricity to allow better monitoring & targeting. This could also identify further options to reduce energy use.

5. Chilled water to Fan Coil Units. Variable speed drives were fitted and the controls upgraded to the chiller units. Chiller renovation is expected to reduce overall energy consumption by 5%.

This project has resulted in the Empire State building being able to offer tenants reduced occupational costs with the intention being to enable rents to be at least maintained if not achieve a premium.

Note: Metro Commercial was not involved in this project and this summary of this project is provided to demonstrate energy efficiency projects taking place throughout the world.