Retrofitting refers to the addition of new technology or features to older systems.

• power plant retrofit, improving power plant efficiency / increasing output / reducing emissions
• home energy retrofit, the improving of existing buildings with energy efficiency equipment
• seismic retrofit
  Seismic retrofit
  Seismic retrofitting is the modification of existing structures to make them more resistant to seismic activity, ground motion, or soil failure due to earthquakes. With better understanding of seismic demand on structures and with our recent experiences with large earthquakes near urban centers,...
  
  , the process of strengthening older buildings in order to make them earthquake resistant

Retrofit projects replace or add equipment to existing power plants to improve their energy efficiency,
increase their output and extend their lifespan, while decreasing emissions.

• Saving on capex
  CAPEX
  CAPEX, also known as the Kerala State Cashew Workers Apex Industrial Co-operative Society, is an organization managed by the government of Kerala to promote the cashew industry and especially the export market for cashews.-Organization:...
  
   while benefiting from new technologies
• Optimization of existing plant components
• Adaptation of the plant for new or changed products
• Increase in piece number and cycle time
• Guaranteed spare parts availability

Principally retrofitting describes the measures taken in the manufacturing industry to allow new or updated parts to be fitted to old or outdated assemblies (like blades to wind turbines).

The production of retrofit parts is necessary in manufacture when the design of a large assembly is changed or revised.