Most air source heat pump systems will comprise only two indoor elements; a hot water tank and a buffer tank (which improves the efficiency of the air source heat pump by evening out peak heat demands.) The size of the tanks will depend on the size of the property and there are single tanks available that combine both the hot water tank and buffer tank.
Some air source heat pumps are a “split” system whereby the “heat pump” element is separate to the outdoor fan unit and located in the property being the size of a small wall cupboard.
Typically, the tanks will be in a plant room, utility room, garage or airing cupboard. If planning a new build property, it is always advisable to consider where you can accommodate these at an early stage of the design and Fervo would be pleased to discuss this with you.