Weatherization (American English) or weatherproofing (British English) is the practice of protecting a building and its interior from the elements, particularly from sunlight, precipitation, and wind, and of modifying a building to reduce energy consumption and optimize energy efficiency.
Weatherization is distinct from building insulation, although building insulation requires weatherization for proper functioning. Many types of insulation can be thought of as weatherization, because they block drafts or protect from cold winds. Whereas insulation primarily reduces conductive heat flow, weatherization primarily reduces convective heat flow.
In the United States, buildings use one third of all energy consumed and two thirds of all electricity.[1] Due to the high energy usage, they are a major source of the pollution that causes urban air quality problems and pollutants that contribute to climate change. Building energy usage accounts for 49 percent of sulfur dioxide emissions, 25 percent of nitrous oxide emissions, and 10 percent of particulate emissions.[2]
Typical weatherization procedures include:
The phrase "whole-house weatherization" extends the traditional definition of weatherization to include installation of modern, energy-saving heating and cooling equipment, or repair of old, inefficient equipment (furnaces, boilers, water heaters, programmable thermostats, air conditioners, and so on). The "Whole-House" approach also looks at how the house performs as a system.[5]
Weatherization generally does not cause indoor air quality problems by adding new pollutants to the air. (There are a few exceptions, such as caulking, that can sometimes emit pollutants.) However, measures such as installing storm windows, weather stripping, caulking, and blown-in wall insulation can reduce the amount of outdoor air infiltrating into a home. Consequently, after weatherization, concentrations of indoor air pollutants from sources inside the home can increase.[6]
Weatherization may have a negative impact on indoor air quality, if done improperly, exacerbating respiratory conditions especially among occupants with pre-existing respiratory illnesses.[6] This may occur because of a drastic decrease in air exchange rate in the home, introduction of new chemicals, and poor management of indoor moisture due to a poorly performed weatherization work. Low air exchange rates may lead to higher concentrations of pollutants in the air when ventilation is not sufficiently addressed during weatherization work. However, the situation may be different in case of a house situated in an area with high outdoor air pollution levels such as in close proximity (<200 m) from a busy major road. In such a scenario, a more airtight building envelope can actually offer protection against infiltration of outdoor air pollution.[7] The same is true for the protection offered by tighter building envelopes during wildfire events that cause elevated levels of outdoor air pollution.[8]
Weatherization is a set of measures and practices aimed at improving the energy efficiency of a building or home, primarily to reduce energy consumption and lower utility bills. The main goal of weatherization[9] is to make a structure more comfortable and cost-effective to live in, especially during extreme weather conditions. It involves making various improvements to a building's insulation, air sealing, and overall energy systems.
The American Council for an Energy-Efficient Economy estimates that over 7 million homes have been weatherized, giving yearly savings of 2.6 TWh of electricity, 27e12Btu of fossil gas and 3.5abbr=offNaNabbr=off of reduced carbon dioxide emissions.[10] The US Department of Energy estimates weatherization returns $2.69 for each dollar spent on the program, realized in energy and non-energy benefits. Families whose homes are weatherized are expected to save $358 on their first year's utility bills.
Low Income Home Energy Assistance Programs in many states work side by side with WAP to provide both immediate and long-term solutions to energy poverty.[11]