How often does a ventilation system need servicing?
It depends on the type. For balanced heat recovery, BRANZ says a yearly service is ideal, and that manufacturer maintenance may include new air filters every 6 or 12 months and cleaning the heat exchange unit every 12 or 24 months.
Systems that bring air in from the roof space rely on filters to keep ceiling space dust out of your rooms. BRANZ says those filters commonly need replacing every 12 or 24 months.
HRV and DVS are company names, so an 'HRV service' really means a service for whichever system you've got. Follow your own model's manual, or what the company that supplied it recommends, and note when the filters were last changed.
Signs your system needs attention
- Condensation creeping back onto windows that had been staying dry.
- Grey dust marks building up around the ceiling outlets.
- A fan that's louder than it was, rattling, or running when it shouldn't.
- A filter reminder or fault light on the controller.
- Cold air from the outlets on winter nights, which can mean the controller isn't slowing the fan when the roof space is cold.
What a good ventilation service covers
Filters
Old filters out and new ones in, in the grade the system was designed for. Consumer NZ's guide notes F filters trap finer particles than G filters, so nobody should downgrade yours without telling you.
Fan and ducts
A check that the fan runs smoothly and that every duct is still connected, sealed and insulated.
Heat exchanger
On balanced systems, cleaning the core on the maker's schedule.
Controls
The controller, any roof space temperature sensor and the timer settings, so the system slows or stops when it should.
Grilles and vents
Ceiling outlets cleaned, and a balanced system's outside intake and exhaust cleared.
Electrical faults
If the fan or controller needs an electrical repair, that's prescribed electrical work, to be done or supervised by a registered and licensed electrical worker.
Leave the roof space to the technician
Roof spaces have wiring, loose insulation and ceiling linings that won't take your weight. Don't climb up into one to swap a filter or check a fan. Book someone who services ventilation systems every week and knows where to step.
Renting? Who looks after it
Tenancy Services says anything installed to meet the healthy homes standards must be kept in good working order, or replaced within a reasonable time if it can't be. Kitchen and bathroom extractor fans fitted before 1 July 2019 must still vent outside and work, and a failed one has to be repaired or replaced with a fan that meets the current requirements.
Recirculating systems aren't suitable for meeting the ventilation standard, so a roof space system doesn't stand in for those extractor fans. If the house has one and it stops working, let the landlord know in writing.
Yours to do, and the technician's
You can
- Check the controller for filter reminders or fault lights.
- Vacuum ceiling outlet grilles you can reach from the floor with a wand attachment.
- Keep the outdoor grilles on a balanced system clear of plants, from ground level.
- Write down service dates and the filter grade fitted each time.
Leave to a licensed installer
- Anything in the roof space, filter changes included.
- Cleaning a heat exchanger core.
- Fan, duct and sensor repairs.
- Electrical repairs and any new wiring.
What we'd do
How we'd look after it
We'd book a balanced system in every year, and a roof space system at least every second year, timed with the filter schedule in its manual. We'd ask for the filter grade to go on the invoice so you know what's in there. And if condensation is back on the windows, we'd get it looked at before winter, not halfway through it.