Why air fresheners and ozone machines do not remove the smell

Almost everybody tries this first, and it is a reasonable thing to try. It is also the reason a lot of people end up calling somebody weeks later than they needed to.

Fragrance does not remove anything

A plug-in, a spray or a scented candle adds a smell on top of a smell. For a short while the new one is louder, so the room reads as improved.

Nothing has left the home. The source is still there, still releasing, and as soon as the fragrance fades you are back where you started, usually with the added problem that the two smells together are worse than the original.

Ozone is a real tool, used wrongly

Ozone generators are sold as the answer and they are genuinely used in this trade, but as one step and never as the step.

• It works on what it can reach. Gas in the air does not travel into the middle of a mattress, under a floorboard or behind a skirting board, which is where the source usually is.
• It does not remove material. If something absorbent has taken fluid in, that material is still in the room afterwards.
• The result fades. Once the source begins releasing again, so does the smell, which is why it seems to work and then stops working.
• It is not harmless. Ozone is used in an unoccupied space for a reason, and a hired unit run in a lived-in flat is a different proposition from one used as part of a controlled process.

Why the smell keeps returning in warm weather

Heat and humidity bring it out. A room that has seemed fine for weeks can announce itself again on a hot, still afternoon, because temperature drives release from whatever absorbed it.

If a smell comes back when the weather turns, it never left. It was only quiet.

What actually resolves it

Removal, not covering. Anything porous that has absorbed comes out of the home, because there is no product that reaches into foam or into timber. What stays behind is treated and then verified rather than declared finished because it looks finished.

Then the space is cleaned, which is a separate step. Odour work and cleaning are not the same job and doing one does not deliver the other.

Before you spend money on machines

If you have already tried fragrance and it came back, that is useful information rather than a failure. It tells you the source is still in the building, and it tells anybody you call where to start looking.

There is more on where it hides in where the smell hides in a flat, and on why it returns in why the smell comes back after a death in a flat.

Why your own nose stops being reliable

Spend long enough in a room and you stop registering its smell. It is ordinary and it happens to everybody, and it is why the person living with a problem is the worst judge of whether it has gone.

It also cuts the other way. Once you know a room had a problem, you will smell it on days when there is nothing there, because you are looking for it.

So use somebody else. Have a person who has not been in the property walk in cold and tell you what they notice in the first ten seconds, before you say anything to them. That is worth more than a week of your own checking.

Check it in the worst conditions, not the best

Closed up, mid-afternoon, warm and still, with the air-conditioning off. That is when anything left behind releases hardest, and a room that passes that passes properly.

Testing it with the windows open and a fan running tells you very little, which is unfortunately how most people test it.

Where it is hiding is covered in where the smell hides in a home, and the mistake that seals it in is in why painting over it traps the smell.