How much cold can warm growing orchids take?

[caesium]

Hi guys,
My greenhouse heater stopped working last week and I haven't been able to fix it. I'm ordering a new one, but it most likely won't arrive before I go out of town on the 19th. Most of the orchids I have in the greenhouse are intermediates, but I have some warmer growing orchids as well. Temps outside have been in the mid to low forties with occasional dips into the high 30s at night and 60-70 during the day. I'm not sure what the temps inside the greenhouse are, but the roof is double walled polycarbonate, which should provide some insulation. Do you guys think it'll be okay if I leave my orchids in the greenhouse for the next month?

The plants I'm most concerned about are:
Phal hybrids
Vandas (one is a coerulea which should be fine)
Paph lowii, Kolosand, and Maudiae hybrids
Rhynchostylis gigantea
Mokara Salaya Gold
Rhynchorides (Rhynchostylis x Aerides)
Angraecum x veitchii and sesquipedale
Gongora tricolor