Question: Paddletail newts

[Mike mawp]

I've just been given two adult females. I've read the care sheet, and it recommends that the water temperature should ideally not exceed 18 degrees. What is the minimum recommended temperature? Will they stand the winter in frost-free greenhouse?

 

[Otterwoman]

Here is the caresheet.

 

[Mike mawp]

Thank you for the link, but I had read that. My quandary is should I keep these indoors at close to 65 degrees, or will they stand overwintering in a frost free greenhouse, where the temperature could drop to 40 degrees. I have much more space available outside for a larger tank.
Someone on another site has answered my query, so no more replies are necessary thank you.