Combined, buildings in the United States consume 40% of all energy. But these buildings are not created equal. The important first step in reducing energy use in buildings is to understand what type of building it is, and what the occupants are there to do. A school will have different energy consumption habits than a single family home; a large office building will perform differently than a five story walkup. But what exactly are the differences, in aggregate, between the residential sector and the commercial sector?
1) In the residential sector, space heating accounts for 43% of energy use. In the commercial sector, space heating is only 25% of energy use.
2) In terms of energy used for space heating, the residential sector uses twice as much renewable energy as the commercial sector.
3) In terms of percentage of related carbon emissions, space heating is twice as much in residential buildings than commercial buildings.
4) 93% of the residential sector’s direct greenhouse gas emissions come from the combustion of fossil fuels, primarily for heating and cooking. Only 60% of direct emissions come from on-site fossil fuel combustion in commercial buildings.
5) As a percent of total energy consumption, lighting in commercial buildings is twice that of residential buildings.
6) As a percent of total energy consumption, water heating in residential buildings is almost three times that of commercial buildings.
7) Refrigeration is a larger energy consumer in commercial buildings than in residential buildings.
8) Even though space heating is the biggest energy user, lighting is the biggest cause of carbon dioxide emissions in commercial buildings.
9) Since 1985, in the residential sector, total energy use has increased while energy intensity (energy used per sq. foot) has decreased. In the commercial sector, both total energy use and energy intensity have increased over the same period.
10) There are 4.8 million commercial buildings, there are over 128 million residential buildings. In total, residential buildings only release 12% more carbon emissions.