This dryer exists for people who literally cannot install a vented model, apartment dwellers, closet stackers, anyone without access to an exterior wall. It does dry clothes without a vent, uses half the electricity, and runs quiet, but you pay for that flexibility with 90-minute cycles, bedding that tangles into damp wads, and three separate filters to clean every week. The control board can fail and run the drum nonstop for days until you physically unplug it, and some units develop odors that never go away. Buy it only if your living situation leaves no other option and you accept the maintenance burden as the cost of doing laundry at home.
Miele's heat pump dryers once defined longevity, T1 owners routinely saw 15 years of quiet, 120V plug-and-play service, but the warranty collapse from ten years to two tells you everything about where the engineering went. Recent buyers report F47 and F99 error codes within months, and Miele support has turned glacial when owners need help. The three-hour cycle is heat pump physics, not a flaw, but you're paying £1200, 2500 for a machine the manufacturer itself only trusts for 24 months. Hunt down a used T1 if you find one; otherwise, Bosch delivers five-year coverage at half the cost.