Capacity
Smaller homes may be fine with 7kg or 8kg. Bigger family loads often justify 9kg.
If you are unsure where to start, focus on four things: your weekly laundry size, how often you will use the dryer, the room setup, and whether you care more about lower spend now or stronger efficiency later.

Smaller homes may be fine with 7kg or 8kg. Bigger family loads often justify 9kg.
Heat pump for stronger long-term efficiency. Condenser for lower upfront price.
Think about where the machine will live and how practical that location is.
Decide whether you want the cheapest acceptable option or the stronger all-round option.
Many buyers go straight to price or to a long list of features. In practice, usage pattern and category choice usually make the biggest difference first.
Use the main guide if you are ready to compare real models instead of generic categories.