The Ghost Room
The Thermo and EMF reader are your best friends for this. As long as the breaker is on, the only cold rooms will be the ones the ghost frequents, and any EMF signals you get will tell you that the ghost is nearby, or at least active.
Of course, ghost orbs will tell you the ghost room if you find any. Beyond that though, you don’t need the ghost room in order to figure out the ghost. Evidence collection often happens when the ghost is simply nearby doing stuff.
Sound sensors can help a fair bit too – I wrote them off in prior updates, but in Ascension they actually transmit any sounds they hear to the truck. it doesn’t necessarily help with identifying where the ghost is exactly, but they help by narrowing the search area.
Each sound sensor has a default range of five meters, and can have it be doubled to ten meters in the truck by interacting with the arrows on the sound display… tier 2+ allows the option for the range to be tripled to a massive 15 meters, and tier 3 can have it’s mic arms positioned in different ways before placing, allowing for more focused listening angles.
In the right positions, you can have one tier 2 sound sensor potentially cover an entire floor of a smaller house if set to max range, and the High School can be fully covered if each sensor is positioned in the middle of each hallway, with some overlap.
Their only real drawbacks are that, as stated previously, they do not completely isolate the exact ghost room on their own… additionally, they do pick up the ambient sounds that don’t mean anything, such as floorboards creaking.