Skirting question- vented or solid

[PFM]

I have a community in Minnesota and in case you are interested in also insulating, here is a link to an earlier post of mine:

Insulated Skirting Question

Regarding insulation…our manager at our community in Minnesota “commandeered” some 2" rigid foam scraps and positioned them behind the vinyl skirting, between the underside of the home and the ground all around the inside perimeter and then installed a radio frequency thermostat and monitored the temperature for one winter. The temperature never fell below freezing that winter with the insulation. Slowly, (and usually after a winter freeze-up) our other residents started copying what my manage…