Integrated touch panel

Capacitive-touch buttons on the unit's front cover with a small status display. Direct mode selection and boost/standby control without any separate device. The default operating interface for most installs.

Four programmable fan speeds

15, 25, 40, and 60 m³/h pre-defined. Each speed has an exact heat recovery and humidity recovery figure (90/84% at speed 1, 71/54% at speed 4). Levels are selectable manually or set automatically by sensors.

Boost mode

Timed boost at the highest fan speed for clearing odours, post-cooking, or rapid air change after a gathering. Returns to the previously set speed automatically.

Absent mode

Reduced ventilation while the home is empty — minimal background airflow to maintain humidity and prevent stagnation, without paying full energy cost. Overrides automatically on return.

Optional ComfoSense remote

Wired remote control panel (528 009 050) for installations where the unit's integrated panel is not at a convenient height or location. Same control set, repeated at a wall-mounted touch panel.

Optional sensor boards

Plug-in sensor modules for humidity (rH), CO₂, or combined CO₂ + VOC. Sensors plug into the unit's mainboard and automate fan-speed selection based on real-time room conditions.

Filter change indicator

Status display warns when filters need changing. Six-month interval at standard filter grade; longer with infrequent occupancy. Reset is a single button-press after replacement.

RFZ multi-zone module

Optional radio-frequency zone module (527 010 550) groups multiple ComfoAir 70 units into coordinated ventilation zones. Useful for two-bedroom flats with independent occupancy patterns.

Enthalpy exchanger

The defining component. Cross-counterflow exchanger that transfers both sensible heat and latent moisture between the airflows. Up to 90% heat recovery and 84% humidity recovery. Washable for service. No condensate produced.

DC radial fans

Two energy-efficient brushless DC centrifugal fans — one supply, one extract. Sound power 34–47 dB(A) Lwa across the four speeds. Power 4 W at speed 1, 17 W at speed 4, less than 1 W standby.

EPP-insulated cabinet

Aluminium powder-coated housing with expanded polypropylene interior lining. The EPP provides both thermal insulation (no thermal bridges) and acoustic dampening. Free of moisture-trapping cavities.

External wall panel — choice of three

Standard PVC paintable panel (matches the wall finish), stainless steel grille (architectural look), or window reveal module (almost-invisible install). Panel choice is purely aesthetic; airflow performance is identical.

Wall opening

Single Ø270 mm core hole through the external wall. Suits wall thicknesses from 275 to 900 mm (with optional 300 mm extension set). Wall mounting pipe Ø250 mm, supplied separately in 600 mm or 900 mm length.

G4 / F7 filters

Two G4 filters (ISO Coarse ≥ 70%) installed standard, one supply one extract. Optional F7 pollen filter (ISO ePM10 ≥ 60%) replaces the supply-side G4 for hay-fever sufferers. Both filters change in under five minutes without tools.

Integrated control panel

Capacitive touch interface on the front cover with status LEDs. Optional remote ComfoSense panel for wall-mount control elsewhere in the room.

Twin-room connection (optional)

A second supply or extract connection on the unit allows ducting to an adjacent room (typical: bedroom + study, or living room + adjoining nook). One unit, two rooms — useful in compact apartments.

2-year manufacturer warranty

Zehnder provides 24 months warranty from installation (max 30 months from manufacturing date). Built to ISO 9001 standards, with a global service network for parts and technical support.

Filter change every 6 months

Two filters — one supply, one extract. Zehnder original G4 (or F7) filters. Display warns when change is due. Lift the front cover, slide out the cartridge, slot in the new one — under five minutes per pair.

Washable enthalpy exchanger

The cross-counterflow enthalpy exchanger lifts out for cleaning after the upper insulation element is removed. Wash with water periodically (or sooner if filters were neglected). Per Zehnder's maintenance guidance, this is straightforward homeowner-level maintenance.

No condensate drain

Unlike conventional balanced MVHR, the enthalpy exchanger reabsorbs moisture. There is no condensate drain to maintain, no hose down the facade, and no risk of frozen drain in winter.

Optional Zehnder Care contract

Annual professional service contract available through Zehnder UK for owners who prefer to outsource. CleverBloom can also provide post-installation maintenance visits on request.