'Why save energy?' - through the medium of public information films over the years - 🇬🇧 only in this thread. Hope to do other countries, and commercials, some other time. In the meantime, enjoy - and please send me any films you come across (respond to the thread or DM me).
Why save energy in 1942?
Because WAR - just 5 inches of bathwater will do!
Why save energy in 1944?
Because WAR - energy profligacy is defeat!
Why save energy in 1945?
Because SAVE COAL – there might not be enough!
Why save energy in 1947?
Because RATIONING – ‘Watch your meters!’
Why save energy in 1973?
Because INDUSTRIAL ACTION - 'Switch off some power. Now!'
Why save energy in 1973?
Because MINERS - 'Switch off some power. Others really need it!'
Why save energy in the 1980s?
Because COMMON SENSE – Delia Smith cooks an insane amount of food in one go http://www.dailymotion.com/video/x26tdzp 
Why save energy in the 1980s?
Because MORE COMMON SENSE – Barry Bucknell is dull but trustworthy http://www.dailymotion.com/video/x26tdvc 
Why save energy in 1986?
Because THATCHER - 'Monergy'. [Set of 3 films]
Why save energy in 1995?
Because CLAYMATION – proto energy company obligations
Why save energy in 2008?
2008: because MONEY & ENERGY & CARBON – ‘Act on CO2’
Why save energy in 2011?
Because LISTEN TO THE ENERGY SAVING TRUST – they know everything!
That's it for now - can't find anything for the UK in the 1950s and 60s, but there must be something somewhere. Let me know if you know.
You can follow @enfinnEU.
Tip: mention @twtextapp on a Twitter thread with the keyword “unroll” to get a link to it.

Latest Threads Unrolled: