Cow panel greenhouse?

Has anyone made a cow panel greenhouse?
How warm does it have to be during the day to heat up the greenhouse enough to keep the inside temp high enough for seedlings?  
Curious as to how well the cow panel greenhouses work?

I have one for my chickens to hang out in during the winter.  If it's sunny out, they heat right up.  At night they get nearly as cold as outside.  If it's cloudy out in winter they are maybe 10-20 degrees warmer than outside.

Edible Acres on YouTube has a number of videos of his cattle panel greenhouses and he likes them.  

Thanks!  I was wondering for example, if it is spring and it gets up to 65-70 during the day, but drops down to below 38 at night, would it stay above 38 in the greenhouse?  
I know next to nothing about greenhouses and the temps they can maintain.  

I think it depends on how well sealed up the greenhouse is and if you have any thermal mass in there to store the heat.  If you have some barrels of water under your seedlings, they'll gather warmth during the day and lose it at night which will help keep the greenhouse a bit warmer, especially right next to them.

Sealing them up tightly can be an issue during the day if they overheat though.