Compare footprints by marking each shortlisted tree's complete assembled outline on the floor, including any platforms or beds that extend beyond its base. Use removable floor markers only where suitable for the surface, or make a paper plan to scale. Leave additional room for the cat to approach, turn and descend, and for people to move normally through the room. Check door swings, drawers, curtains and nearby chairs in their everyday positions.
A base measurement alone can understate the space a tower occupies. Height also matters near sloping ceilings or shelves, although a tall model is not automatically the most intrusive visually. Keep the marked outline in place during ordinary household activity if practical. If the room only works when furniture is repeatedly shifted, reconsider the position or model. A realistic footprint comparison makes the purchase easier to live with after the initial assembly photograph is taken.
Cat-Cave lists a 60 × 50 cm base but a 110 × 75 cm full footprint. Comparing only the base would omit 50 cm of overall width and 25 cm of depth; use the full outline to plan the space it occupies.
For product comparisons alongside this advice, see Ultimate PawHouse and Taj-MeowHall. The details below explain their sizes and uses.
Further reading: giantpaws.co.uk.
Ultimate PawHouse
Taj-MeowHall
Cat-Cave