We're not Tier 2 because we don't have a UPS/Generator. We do have two ISPs with dual redundancy built into every aspect of the networking. Our power grid is very stable as it's hydroelectric, and power outages are very rare in our area.
Since the equipment is mostly agnostic of it's state (no memory, hardisks) an outage should only affect it as long as it takes, due to no mining during that time slice.
A network server needs recovery time to get puffed up again, somewhat different.
No raised flooring? cold air from above?
Do vents all line the exterior walls? Just judging from the garage door, is the cold air entering from ~15-20 ft.?
are you doing hot aisle/cold aisle?
In an ideal setup just the temperature differences should be enough to drive the airflow. Not even vents needed, and their power costs (low, mostly investment)