Planning ventilation: give the equipment and ducts a place

Describe the job before choosing the box

Start with the activities your home needs to accommodate: showers, cooking, drying washing and the people occupying bedrooms and living spaces. Ask the designer to explain how the proposed approach deals with both moisture extraction and fresh-air supply.

MBIE's active ventilation guidance explains that an extractor removes air but needs a way for replacement air to enter. I would ask for that whole journey to be explained. A fan symbol in a bathroom is only one part of the conversation.

Keep the brief in ordinary language. You might want straightforward controls, access to filters without emptying a cupboard, and an explanation of what runs continuously. The design team can turn those preferences into an appropriate proposal.

Trace a route through the building

If ducted ventilation is proposed, ask to see the routes on a plan and a section through the house. A section shows the vertical space that a floor plan cannot: ceilings, roof construction, beams and any proposed bulkheads.

BRANZ's Build guidance explains why duct layout and installation affect performance, including the value of shorter runs and fewer bends. I would use that as a reason to coordinate the route early, with the ventilation designer confirming the details for the selected system.

Imagine a hypothetical renovation where a bathroom sits beneath an upstairs bedroom. 'Run it above the ceiling' leaves several questions unanswered. Does the route cross a beam? Where does it reach outside? Would a lowered strip of ceiling be visible from the hall? Compare the options while those choices are still open.

• Where are the outside intake and discharge points?
• Which routes need space within walls, ceilings or cupboards?
• Who checks clashes with structure, lighting and other services?

Draw the space needed to look after it

I would ask the supplier to show the access needed to remove a filter or service a unit, as well as the dimensions of the equipment itself. A component fitting into a void does not tell you whether someone can reach it later.

MBIE notes that correct operation and maintenance affect ventilation performance. Ask for the manufacturer's maintenance instructions before agreeing the location, then work through what following them would involve in your finished home.

• What needs cleaning or replacement, and how often for this particular system?
• Where will someone stand or gain safe access?
• Can parts be removed without dismantling permanent joinery?
• Which tasks can the household do, and which need a service technician?

Give the coordination a named owner

Ask who brings the ventilation proposal back into the architectural drawings, and when that happens. If routes or equipment change, agree who checks the consequences before installation.

The published Fraser Hill project account describes ventilation being considered alongside insulation, acoustic requirements and openings. It is a useful example of related decisions being developed together. For your own project, I would want that coordination translated into drawings and clearly allocated responsibilities.

Include the handover in your brief

Before accepting a proposal, ask what installation checks and performance testing it includes, who records the results and who will demonstrate the controls. Request a simple operating guide, maintenance information and a contact for questions.

If you are planning a home or renovation, bring your drawings and the ventilation questions they leave unanswered to a consultation. We can discuss the space to reserve and which specialist input is needed before the design moves further.