Hurricane Sandy put a tree against my house and although my roof has been buttoned up with plywood sheets and tarps, a large section of the ceilings on the first floor are now exposed to my now well ventilated attic . I have an infinity hybrid system with a high efficiency gas fired burner (not sure of the model number but I think it's at least 98% efficient). I'm keeping my thermostat set at 55F, but I'm wondering if I should run the unit on gas alone rather than the hybrid mode since the weather is now in the 30-50F range here in Northern Virginia. I should mention that I have a Carrier Infinity system. I'll post model numbers when I run by my house later today.