Search terms:ventilation device; living space ventilation; living room ventilation system; ventilation system; Efficient living space ventilation; Energy-saving ventilation technology; energy efficient ventilation system; heat recovery; energy recovery; heat return; noise development minimized; noise-optimized; quiet in operation; Frost Guard; antifreeze; protection against frost damage; condensate drainage; condensate drainage; removal of condensate; More hygienic environment; Hygienic conditions; clean environment; minimize energy consumption; energy saving; energy efficient; Excellent recovery; High heat recovery; effective energy return; stainless steel case; Stainless housing; hygienic housing; soundproof insulation; noise insulation; noise-reducing insulation; Permanent spare parts g.