Checklists · Construction planning
Ventilation Strategy Questions Checklist
Prepare an owner to question a ventilation strategy properly by observing existing moisture behaviour, tracing where air enters and leaves, and raising duct, noise and appliance issues with qualified professionals rather than resolving them alone.
8 sections · 42 planning prompts · educational owner-side preparation
https://www.builddesignhub.com/checklists/construction-project-planning/ventilation-strategy-questions · Build Design Hub — educational planning resource. Requirements vary by project and location.
Scope
What this checklist covers
The preparation ground these prompts walk through.
- Where moisture is actually produced by the way your household lives
- Reading existing misting, staining and stale air as evidence to hand over
- Extract points, where they discharge and whether they work at all
- How fresh air is meant to reach each room under the proposed strategy
- Duct routes, ceiling voids and the noise that makes people switch off
- Combustion appliances and the upkeep nobody plans for at handover
Audience
Who this checklist is for
- Owners tightening up a building and unsure what happens to the air
- Households already living with condensation and window misting
- Owners being offered a ventilation approach they cannot evaluate
- Anyone with an open fire or stove alongside proposed extract work
Timing
When to use it
- Describing existing moisture and air quality problems precisely
- Tracing where air currently enters and leaves your home
- Questioning duct routes before ceilings and voids are fixed
- Thinking about noise and upkeep before a system is chosen
- Preparing appliance questions for an appropriately qualified person
Limits
When it is not sufficient
This is general planning preparation. These situations need a qualified professional, and often the relevant authority.
- Choosing or sizing a ventilation system for your property
- Deciding whether extract and a combustion appliance can coexist safely
- Diagnosing the cause of mould, damp or persistent condensation
- Establishing what the relevant local ventilation requirements demand
- Judging whether existing extract provision is adequate for this household
The checklist
Work through the sections
Tick the boxes on paper or on screen — nothing is stored, so print the page if you want to keep your marks.
1.Where the moisture in your home actually comes from
Ventilation is a response to how a household lives. Before anyone proposes equipment, describe honestly what is producing moisture and where.
Write down where laundry is dried, including radiators used for airing and any room where clothes are regularly hung overnight with the door shut.
Indoor drying is one of the largest moisture sources in a home and one of the least likely to be mentioned unless somebody asks directly.
Note whether cooking regularly produces steam, and whether the door between kitchen and the rest of the house stays open while it does.
An open door moves kitchen moisture into cooler rooms, which is where it eventually shows up on a window or a wall.
Record how many people are usually in the house and for how much of the day, since occupants are themselves a continuous source of moisture.
Occupancy is a basic input a designer needs, and it changes over the life of a house in ways worth flagging now.
Note any tumble dryer, aquarium, large quantity of indoor plants or unvented appliance, and write down which room each one sits in.
These are localised sources that explain why one room misbehaves while the rest of the house seems fine.
Write down whether bathrooms are used one after another in the morning, since consecutive use leaves surfaces no chance to dry between them.
The pattern matters as much as the total, and back-to-back showering is a common reason an otherwise adequate arrangement struggles.
2.What the windows and walls are already telling you
Your existing house is a working experiment. Record what it shows without trying to explain it, and hand the evidence to someone qualified.
Note which windows mist on the inside, on which mornings and whether the misting sits at the edges of the pane or spreads across the middle.
Where and when condensation forms is a genuinely useful observation, and it is one only somebody living there can gather over a season.
Record where black spotting appears, checking behind furniture, in corners, inside wardrobes on external walls and around window reveals.
Persistent mould growth should be discussed with a qualified professional, since the cause may involve more than ventilation alone.
Write down which rooms smell stale after being closed for a day, and which recover quickly once a window is opened.
Recovery speed tells you something about how connected a room is to the rest of the house, which is useful when zoning is discussed.
Note whether the house feels stuffy in the evening generally, or only when several people are gathered in one closed room.
Distinguishing background stuffiness from occupancy-driven stuffiness points at quite different responses.
Photograph the affected surfaces and record the date on each image, since these patterns move through the year and memory of them is unreliable.
A dated set taken across a winter is the most convincing evidence an owner can hand over, and it needs nothing more than a phone to collect.
3.Extract points and where the air actually goes
Extract is often assumed rather than confirmed. Follow each one from the room it serves to the point where it leaves the building.
Walk to every extract point in the house and note whether you can feel anything happening, using nothing more than the back of your hand held nearby.
A surprising number of extract points do nothing at all, and the owner is the only person likely to check each one.
Write down where each extract is supposed to discharge, then walk outside and try to find that outlet on the wall or roof.
Being unable to find the outside terminal is itself an important finding to raise with a professional.
Note whether any extract appears to discharge into a loft, a ceiling void or a space you cannot identify, and raise it as a question rather than a conclusion.
Where extracted air is discharging must be established by a qualified installer; do not enter a loft or open a duct to check for yourself.
Record where each outlet sits relative to a window, a door, a boundary or a neighbour's opening, based on what you can see from outside.
Where an outlet may terminate is governed by requirements that vary locally; confirm the position with a qualified installer rather than assuming.
Note whether the cooker extract genuinely vents outside or recirculates through a filter, since owners frequently assume the opposite of what is installed.
This is one of the most common misunderstandings in a home, and it changes what the kitchen ventilation conversation is actually about.
Ask what happens to extract performance when the door is closed and there is no gap beneath it or other path for replacement air.
Extract can only remove air that something else replaces, and closed doors on thick carpet quietly defeat an otherwise sensible arrangement.
4.Where the replacement air is meant to come from
Every strategy depends on air arriving somewhere. Establish where that is meant to be, room by room, before construction fixes the answer.
Note whether the windows have opening vents at the head, and whether anybody in the household has closed, blocked or taped them shut.
Closed vents are usually a response to draught or noise, and knowing why they were closed is more useful than knowing that they are.
Write down which windows are genuinely opened during winter and which have not been opened in years, room by room.
A strategy that assumes window opening has to survive contact with a household that does not open windows in January.
Ask where fresh air is intended to enter each room under the proposed strategy, and record the answer separately for each room.
Asking room by room exposes the rooms nobody has thought about, which are usually the ones that later feel stuffy.
Note whether internal doors have a gap beneath them or seal against carpet, a threshold strip or a rug that sits behind them.
Air paths between rooms are made by tiny gaps that flooring choices destroy without anybody connecting the two decisions.
Consider security and outside noise, since any approach relying on open windows behaves differently on a busy road or at a ground floor bedroom.
These constraints are real and permanent, and they should be stated by the owner rather than discovered by the designer later.
5.Duct routes and the space nobody allowed for
Ducts need real physical routes through a building. They are drawn late, discovered on site and resolved by lowering somebody's ceiling.
Ask to be shown the route every duct takes from the room it serves to the outside, drawn on a plan rather than described in conversation.
Routes that exist only in conversation tend to meet a beam somewhere, and the resolution is always at somebody's expense.
Note where a duct would have to cross a joist, a beam or a stairwell, and ask who has confirmed that the crossing is achievable.
Any duct passing through structure raises questions for a qualified engineer; ask who has looked at it rather than assuming a route works.
Write down which ceilings would be lowered or boxed to carry ductwork, and decide room by room whether you find that acceptable.
Boxing is often presented as a minor detail and is one of the most visible permanent consequences of a ventilation decision.
Note whether any duct would run through an unheated loft or other cold space, and ask what is proposed to deal with that.
Ductwork in cold spaces raises condensation questions for a qualified designer; ask what is proposed rather than accepting that it will be fine.
Ask how many bends the longest run contains and where they occur, since the route affects how the arrangement actually performs in use.
A theoretically adequate arrangement routed around three corners can behave quite differently, and the route is worth understanding early.
Record where any central unit would sit, what lies on the other side of that wall and how anybody would reach it once the house is finished.
Units placed in inaccessible voids never get attended to, and their position also determines who hears them working.
6.Noise, draughts and the reasons people turn it off
Ventilation that is switched off provides nothing. Most of the reasons people switch it off are predictable before it is installed.
Ask how audible each part of the system is in the room it serves, and ask to hear something comparable rather than relying on a written description.
Sound is the single most common reason a ventilation system is disabled, and a description on paper conveys almost nothing about it.
Note which rooms are used for sleeping, study or concentration, and where any continuous background noise would be least tolerated.
Identifying these rooms yourself lets the designer treat them differently rather than applying one approach throughout.
Write down whether anyone in the household is particularly sensitive to draughts, since a cool incoming stream is a frequent reason for covering a vent.
This is genuinely useful design information and is exactly the sort of thing owners assume is too trivial to mention.
Ask what happens to the rest of the house when one part of the system is turned down, covered over or switched off entirely.
Understanding the knock-on effects makes it far less likely that somebody will quietly disable part of it one cold evening.
Record who would be able to turn the system down or off, and where those controls would be positioned within the house.
If the building relies on the system for ventilation, ask a qualified professional before disabling any part of it, even temporarily.
7.Open fires, stoves and flues in the same building
Where extract ventilation and fuel-burning appliances share a building, the question belongs entirely with qualified people. Your job is to list what exists.
List every open fire, stove, flue or fuel-burning appliance in the property, including ones that are blocked off, decorative or no longer used.
Disused appliances and capped flues are routinely forgotten, and they still belong in the list handed to a qualified person.
Ask an appropriately qualified professional how the proposed ventilation strategy and any combustion appliance interact within this particular building.
Interaction between extract ventilation and combustion appliances is a safety matter for appropriately qualified and registered people only.
Note where the air supply to any appliance is understood to come from, and whether other proposed work would affect that route.
Never alter, block or assume anything about an appliance air supply; report what you observe and leave every judgement to a registered person.
Write down whether any chimney has been capped, lined or sealed, along with whatever you know about when that was done and by whom.
Chimney history is rarely documented, and the owner or a previous owner is usually the only source of that information.
Record where carbon monoxide and smoke alarms are currently fitted, and ask a qualified professional what applies to this property.
Alarm provision and positioning must be confirmed with an appropriately qualified person and the relevant local requirements, never assumed.
8.Filters, cleaning and who keeps it working
Ventilation is the part of a project most likely to be neglected once everyone has left. Decide now whether the upkeep is realistic for your household.
Ask what has to be cleaned or replaced, how often, and whether each item can be reached without a ladder or without opening up a ceiling.
Access difficulty is the strongest predictor of whether maintenance actually happens for as long as you live there.
Note who in the household would realistically carry out that work, and whether they are willing to do it repeatedly.
An honest answer here sometimes changes which approach is chosen, which is exactly why the question belongs before installation.
Ask how you would know the arrangement had stopped working properly, since many ventilation faults are entirely silent.
Without an obvious failure signal, a system can sit doing nothing at all while the household carries on assuming it is fine.
Write down what instructions, settings record and documentation you should receive at handover, and where you intend to keep them.
Commissioned settings are easily lost, and reconstructing them later usually means paying somebody to work them out again.
Record where replacement filters or parts would come from, and whether they are the kind of item that stays straightforward to obtain afterwards.
Consumables that are difficult to source tend to go unreplaced, which quietly turns a good system into a poor one.
Preparation
Documents and information to gather
Having these to hand usually makes the first conversation shorter and more useful.
- Dated photographs of window misting, staining and any mould growth
- Notes on which rooms are stale, when, and how quickly they recover
- A list of every fuel-burning appliance and capped flue in the property
- Any drawing showing proposed duct routes and terminal positions
- Paperwork for existing extract fans or ventilation equipment
- Notes on which windows and vents are actually used through winter
Records
Decisions to record before work begins
Write these down in your own words, with the date, so everyone is working from the same version.
- Which ceilings you would accept being lowered or boxed for ductwork
- Which rooms must stay quiet enough for sleep or concentration
- Whether laundry will continue to be dried indoors after the works
- Who in the household is responsible for cleaning and replacements
- Where the central unit may be positioned and how it will be reached
- Where handover documents and commissioning settings will be kept
Professional review
Questions to discuss with qualified professionals
Bring these to the relevant qualified professional, supplier or authority. Requirements vary by project and location.
- Where is fresh air intended to enter each individual room in this strategy?
- Can you show me the route each duct takes from the room to the outside?
- What happens to extract performance when the doors in this house are closed?
- Where does each outlet terminate outside, and what governs that position here?
- How audible will this be in the rooms where people sleep?
- How does this strategy interact with the fire and flue that are staying?
- How would I know if this had stopped working properly long after handover?
- What has to be cleaned or replaced, how often, and how is it reached?
Blind spots
Commonly overlooked items
- An extract fan that has been running into a loft void for years
- A cooker hood everybody believed vented outside but only recirculates
- Trickle vents taped shut because of draughts and never mentioned again
- Door undercuts lost when thicker flooring was fitted afterwards
- A central unit installed where nobody can reach it to change a filter
- The capped chimney that never gets included in the list of appliances
- Commissioning settings recorded nowhere and lost soon after handover
What this checklist does not do
- This page does not select, size or assess ventilation. What your building needs is determined by qualified people and by requirements you must confirm locally.
- Any situation involving extract ventilation alongside a fuel-burning appliance is a safety matter for appropriately qualified and registered people only.
- Persistent mould or damp can have causes unrelated to ventilation; record what you observe and take it to a qualified professional rather than treating it yourself.
- Do not enter lofts, open ductwork or alter appliance air supplies to answer any question on this page. Observe what is visible and ask the rest.
More preparation
Related checklists
Inspiration
Related Ideas Library pages
Design directions to explore once the preparation is done.
Go deeper
Related Build Design Hub guides
Explanatory planning guidance behind the decisions on this page.
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