We have a wooden suspended floor in our sitting room in England and some vents in the walls as well. This is the room with a small woodburner à Douvre we get quite a few drafts from them into the room when the wind is in the wrong direction. I imagine that this was part of the decision that we had enough air flow into the room and didn’t need an additional air flow vent. I should have said that the vents are under the level of the floor.
This sounds mad to me. Presumably the reason for lighting the woodstove is to warm the room. A vent to the outside will allow in the cold air and cool the room. I have a stove in my house which has an air intake. Air from the outside is used for the fire in the stove. This means no drafts are created when you light the stove. Warm air from the room isn’t used to burn the wood - cold air from outside is used. This makes the burner much more efficient. I fitted my stove maybe 15 years ago that way. It also has a lined and insulated chimney, which means tar and soot don’t condense inside the chimney pipe. After using it for 7 years, I noticed a chimney sweep working next door - they have it swept twice a year. I asked him to sweep ours, and all he found was about half a cup of dust. Never had the chimney swept since. I must add that all the wood I’ve burned has been really really dry, much of it offcuts from woodworking. Which results in more heat and less condensation.
Vents in the wall to let the outside air in the room sound like a very primitive solution! BTW, I have used an air monitor to check for rising CO2 levels and PM2.5’s. There was no noticeable increase when I lit the stove. But an enormous and fast increase when I lit the gas stove - so we’ve switched to an induction hob.
Check your monitor when you use your vacuum cleaner to clean the house not the stove, love to hear your result and how long it stays at that level?
Never tried using the monitor while running the vacuum cleaner and I no longer have it.
Have you tried that yourself?
The law has changed in the meantime and it’s now mandatory to have your chimney swept once a year by a qualified ramoneur who will issue you with a certificate. It’s necessary for poêle à granules too
Yes and it went off the scale and stayed there most of the day, that was a Henry vac with HEPA bags. Like to see them tell people to stop vacuuming their homes 
Interesting. HEPA should capture most of the particles, so maybe your filters don’t seal well? It would only require the tiniest of gaps to let the PM2.5’s through
The stove I fitted is in my house in the UK. The requirement to have the chimney cleaned every year is one of the reasons I’m not installing a wood burner in the house I’m building, but not the main reason.
HEPA is an absolute filter at PM3 so the damaging PM2.5 and 1 pass through. The more powerful the motor the more filter breakthrough you get and presumably the HEPA test is laboratory based so any tiny leak…
With pool filtration for example, a standard single speed pump is too powerful to really do a good job so particles get abraded in the sand filter only to become smaller and then escape through the sand. (That was from a Swedish research paper on sand filters). Reducing the speed of the pump improves the collection of dirt etc by a factor of 4 due to not forcing dirt through the media. Add to that the energy saving and it’s a win win. Maybe the reduction in motor watts introduced by the EU has actually improved things? My Henry is an older more powerful model. I repeated the test at a friend’s house he uses a Karcher vacuum so not that different. May take a different vacuum with me and repeat the test. Also have friends in the UK with wood burners who are engineers so understand the reasons for experimenting.
It’s required for the chimney to be swept twice a year now, not once. Not a problem.
I really believe a heat pump is the way to go now if possible with the TV running the video of a wood stove flame 
Not from what we have seen of the regs, minimum once per year but if used a lot or the local Maire insists. Old stoves it’s possibly a good idea but the latest burn much clearer (with the right fuel).
Oh, Corona! Fake, fake,fake. Every Christmas in California there was a tv channel which ran a video of a wood fire burning in a grate to appear festive. (Actually looked quite realistic if you could ignore it was on a tv screen)
These days apart from the position of the TV they do look quite similar to modern wood burners 
Some people, particularly in the UK, have giant tvs above the fireplace where normally there would have been a mirror on the chimney breast in days of yore, or still is in my case in the UK. A video of a fire burning above the fireplace sounds wrong to me but each to their own.
Agreed but some modern designer stoves are up off the ground like French inserts
slight drift… but the positioning of the TV is rather important IIRCorrectly to avoid eyestrain (?)… one should be able to watch TV with one’s eyes in the relaxed position straight ahead (or even better, eyes slightly looking downward)
needing to raise one’s eyes upwards for long periods was reckoned a no-no
so the placing of the TV needs to take this into consideration as well as one’s seating arrangements.
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I checked with ChatGPT, and it says HEPA is designed for PM0.3, so 2.5 and 1 get trapped.
‘
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True HEPA filters are rated to remove ≥99.97% of particles ≥0.3 µm (PM0.3) under controlled test conditions (the so-called MPPS — most penetrating particle size).
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That means they’re actually better at trapping both larger and smaller particles than 0.3 µm — because of how the mechanisms (interception, impaction, diffusion) work.
So:
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PM2.5 (2.5 µm) and PM1 (1 µm) are larger than 0.3 µm and are therefore easier for a HEPA filter to capture.
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The really tiny particles below about 0.05 µm may slip through more easily, but those are less relevant to most indoor vacuum dust.’
Could you be a decimal point out?
I’m not Looking for an argument, just trying to sort of the physics. Another reason I’m not installing a wood stove is that where I’m building my house (Argentat, 19400) is one of the least windy places I’ve been (and I’ve sailed through the doldrums!) When there are a series of cold still days and everyone fires up their woodburners, the town (being in the Dordogne valley) just fills with smoke and the air feels worse than downtown Jakarta or Manila. I don’t want to contribute to that.
But I do intend to install heat recovery ventilation, and I was planning on fitting a HEPA filter to the intake to filter out the smoke particles neighbours put out. So I’d like to get this right.
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YouTube to the rescue - this one runs for 8 hours:
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Yes it’s seems I am wrong, probably missed the decimal point in which case it’s bloody shocking that so much PM2.5 and 1 are in the air post vacuuming. As you said previously and I tested ages ago frying a breakfast also goes off the scale but not for as long as vacuuming.
Will definitely be looking at the Henry now, fortunately have it’s twin in the UK so can test here as well.