docflabby

It's also used as a strong rat poison so overdose risk is a serious concern.

Best thing would be blood testing (it can be done cheaply with a fingerprick) to see if the persons actually need supplementation...

Hypothesis I would like to test one day - does the increase in calories (and therefore additional energy used to produce food) to heat your body offset the energy saved by reduced heating. Start by assuming person living alone.

Then could take it a step further increase number of people and take into account the body heat of each person (people produce alot of heat + water)

I think stack overflow peaked a few years ago - its grown more and more useless over the last few years - the last questions I wrote 10 or so years ago have long been modded off topic and locked, despite being within the rules at the time - the culture of the site has got hostile - and no one answers any difficult questions any more and it's full of incorrect misleading out of date information. I find the most useful information in github issues nowadays....

Thank you for all the comments and advise, I think I can see a way forward now, its been an eye-opener, I really didn't expect this many responses.