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Air Conditioning probably has decreased vitamin D

Domestic air conditioning is most prevalent and ubiquitous in developed Asian and Middle Eastern nations and territories, such as Japan, Taiwan, South Korea, Singapore, Hong Kong, Israel, China and the Persian Gulf States such as Bahrain, Kuwait, and the United Arab Emirates. This especially applies to Singapore and Hong Kong due to most of the population living in small high-rise flats. In these areas, with high summer temperatures and a high standard of living, air conditioning is considered a necessity and not a luxury. Japanese-made domestic air conditioners are usually window or split types, the latter being more modern and expensive. In Israel, virtually all residential systems are split types. Air conditioning is also increasing in popularity with the rising standard of living in tropical Asian nations such as Thailand, India, Pakistan, Malaysia, and the Philippines.

In the United States, home air conditioning is most prevalent in the South/Southwest and on the East Coast, areas in which it has reached the ubiquity it enjoys in East Asia.[citation needed] Central air systems are most common in the United States, and are virtually standard in all new dwellings in most states.

Air conditioning has allowed people around the world to get out of the heat
But getting out of the heat has also resulted in decreased vitamin D during the past 40+ years
Less Sun Less D Less Health

Even Arabs and Indians are getting out of the heat and are becoming vitamin D deficient. - many articles in VitaminDwiki

Until recently people in the US were much more likely to get MS and some other diseases if they lived in the North
US military has also noticed the MS latitude effect decreasing during the 20th century file

However, now that people in the Southern portion of the US are staying indoors more the health benefits of living in the South is disappearing.

May 2010 book: Losing Our Cool

Book review in LA Times In 1960, A/C in 12% of U.S. homes, now 85%.
Chapter 7. India: Where “A/C” Means “VIP” The new frontiers of climate control in one of the planet's hottest regions.
Canadian magazine article on the book mentioned that 52% of Canadians have A/C, and 80% of those in Ontario
Also mentions: a Danish study found, individuals eat more in cool environments.

From the same magazine interview
Whereas homes used to feature big awnings and porches, and many windows for cross-drafts, now they’re built around air conditioners—and windows are sealed shut. Inadequate ventilation is linked to asthma and allergies. The suspected culprits, writes Cox, include “volatile organic compounds, moulds, and allergens in floor dust,” and bacteria, which air conditioners harness inside their coils and drip pans, and disperse.
This ignores the possibility that decreased sunlight -> decreased vitamin D -> decreased ability to fend off asthma and allergies

Air-conditioning now accounts for almost 20 percent of year-round electricity consumption by American homes.
Residential air-conditioning units in service in 2005 were an impressive 28 percent more energy-efficient on average than they were in 1993.
New federal standards will result in another 30 percent more efficiency.
In addition to lower operational cost, they also cost less to purchase.

Snips from the book

  • pg 123 Twenty researchers published 10 "equally compelling" reasons for obesity: sleep loss, endocine disruption, decreased smoking, aging of the population, increases in age at childbearing, effects of fetal development, pharmaceutical use, natural selection, and mating preferences. They listed "reduction in variability of ambient temperature" as a potential villain.
  • pg 124 one researcher wrote in the 1970's 'Cattle, swine, rate, goats, and the US Army men all eat more when the temperature is low than when it is high"
  • pg 125 Japan air conditioners 5.7% of homes in 1970, 87.1% in 2004 - with 99% in Tokyo
  • pg 129 Before 1930 there was a strong seasonality of births, with temperature having a secondary influence

Hours of use of air conditioner in US - probably 2010

from web - probably for 2010

Increased US air conditioning ownership

According to the Census Bureau
10% in 1960.
49% in 1973,
89% in 2013 (?)

Everyone in US getting air conditioning - even the poor


See also VitaminDWiki

See also web


In 50 years more power will be used for Air Conditioning than for heating


By 2050 2/3 of all households on Earth will have air conditioning

There’s a simple way to ditch air-conditioning when it’s scorching hot. But we’re ignoring it Fast Company July 2019]

  • " It’s predicted that around two-thirds of the world’s households could have an air conditioner by 2050, and the demand for energy to cool buildings will triple."
    • Thus we can expect Vitamin D levels around the world to continue to drop for many decades

AC unit growth from 2016-2050


This page has been evolving since early 2010

Attached files

ID Name Comment Uploaded Size Downloads
12400 AC unit growth.jpg admin 29 Jul, 2019 19.13 Kb 2006
4069 Everyone in US getting air conditioning.jpg admin 26 Jun, 2014 24.23 Kb 5603
1413 AC in India.jpg admin 22 Jun, 2012 35.66 Kb 3724