Winter in San Francisco area is usually not too cold....
However, sometimes cold air comes and stays for days.

Since many buildings are not insulated well, 
we experience uncomfortable low temperature 
even inside of the buildings.

I love old buildings and want preserve beautiful buildings elsewhere. 

Hopefully we can adopt energy efficient systems to old buildings soon. 



Here is an article about Carbon impacts that buildings are causing...
http://www.yaleclimateconnections.org/2017/02/buildings-a-surprising-source-of-carbon-pollution/

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