Anyone made their own air filtration unit, the sort of thing with HEPA and or other techniques for keeping down the indoor stuff that typically upsets allergy / asthma suffers please?
Googling about it seems like HEPA based jobbies are the best VFM and as long as they process the air 5+ times an hour are ok.
I'm thinking some sort of sealed box (medium Hifi speaker shape / size?) with suitably quiet (suction) fan at one end (top) and filtration towards the other.
The HEPA filter could be pre-filtered with the cut sheets you can get for domestic suction cleaners and / or some washable foam etc etc.
I've even seen mention of UV in such things. Should be easy to put a UV lamp in there somewhere (couldn't do any harm could it)?
I know you can buy such things for around £100 up but if I could source some nice cheap filters I could build something (for s*1t n giggles) to fit them I might be able to reduce the running costs?
What does the panel think please (as you generally come up with a good range of options). ;-)
- Most work by recirculating air, so progressively filter it down with each pass through the filter.
- A prefilter is usually required to prevent premature clogging.
The cheapest way to buy HEPA filters is as standard cardboard framed panel filters. They can be standard size or just made to size of a roll of material.
The best domestic HEPA filter unit is Honeywell which use a large drum "cartridge" about 10 inches high and over 12 inches in diameter, air is drawn in via the middle with the cartridge sealing top & bottom. Price about =A320-40.
Airflow resistance.
- HEPA filter present very high resistance to airflow, which increases as they clog (as with any filter)
- Airflow resistance rises disproportionately to airflow, so the faster you want to filter the air either bigger the filter or the more power and noisier the fan
Thus you end up needing a big radial fan of 50-150W - either noisy for fast filtering or quiet yet left running for some time.
UV to kill bugs is good, no idea how slow the airflow need be (ie, what time in front of the UV lamp is required).
So the cheapest solution is a Honeywell HEPA unit, they are about =A379-109-199 - sometimes turning up cheaper. The vertical drum version are quieter then the old "drum flat on the floor" basically by using a lower speed setting. If you suffer from hayfever 1) get a decent HEPA vacuum 2) run the HEPA unit at the relevant time of the year. You may find the HEPA vacuum does enough in the house, comes down to whether you have ferns, conifers and so on outside :-)
I think production of artificially super-clean environments is most likely to be the cause of lots of allergies we see nowadays. If you have someone with an identified allergy to something specific, then filtering that seems reasonable. Your immune system needs exposure to bacteria and viruses in order to work. The last thing you want to do is try and remove those from your environment, as that will stop your immune system working properly.
I read somewhere they work in various ways. The stuff being filtered can run straight into the fibre of the filter like a car running into a tree, or getting caught between the fibres (like a fish in a net) or caught up in eddies (like the dirt up the back of a van).
Yup, and part of my plan. ;-)
Cool, that was the sort of thing I was after (especially if they are really cheap). The best I've seen so far I think is from a vacuum cleaner at £2.99 each but I don't supposes they would be very big (so could end up using a few at once to form a bigger panel).
Ok ta.
Understood. There are a few people selling the 3m Filtrete units and the reviews suggest they are quiet and have a high flow rate because they *don't* use a HEPA filter. 3m suggest they get near (or better for some facets) performance than HEPA models? I guess 3m might know a thing about filters?
formatting link
- Airflow resistance rises disproportionately to airflow, so the
Hmmm. That's why I was thinking of getting a large (but cheap) filter panel somehow).
Understood.
I think 'longer the better' but (apparently) even short exposure times can sterilise them so in time ... (and why hanging stuff out in the sun is a good thing).
Ok.
Like this?
formatting link
If you suffer from hayfever 1) get a decent HEPA
The daughter does (19) and I might be allergic to something, possibly house mites, now (at 53). I've never been allergic or reacted to anything, including fibreglass or chemicals etc. I've now had a background cold / blocked - runny nose - sneeze - sore throat thing for about 10 weeks and now on a tablet (not sure its working hence ...). However, we have also been having a bit of a spring clean so it could be a catch 22 (stirring up the dust, cleaning up the dust etc).
I think the Dyson(s) have HEPA filters and the Meile (Big Cat N Dog) has a carbon (but probably a HEPA option). For us it's more the problem of being in the Lea Valley and being surrounded by roads rather than any particular vegetation ... ;-(
You are probably right, however I'm pretty sure that hasn't been the case in our / my case.
Daughter definately has hay-fever but could even manage that when she was working as a tree surgeon. It's me that (at 53) is currently suffering what a doctor (I say 'a' rather than my as I've never seen the same one twice the few times I've been in there) thinks might be an allergic reaction ... and I'm currently on a 'try these and let me know how you are getting on in a month' (Cetirizine Hydrochloride?) type deal. I also got the prescribed 'Nasonex' (and used it a few times) but then read up on steroids and stopped .
I believe there are limits though? ;-)
Understood and not a lot of chance that happening round here for a while. ;-)
- In a house it can be a leak in the loft (damp), chimney damp (unvented, leaking), GCH pipes
- It could be a new plant (a couple of plants whilst seemingly innocuous can cause long lasting skin damage to those unknowingly allergic)
Second, making is not really practical.
- Nearly all are glass fibre by nature of the particulate size (0.3 micron)
- Vacuum cleaner ones rely on the huge static pressure of a 300-1500W motor and only filter that limited airflow
- For multi-hour usage the filter must be much bigger re capacity and static pressure
Basically a HEPA filter is a mesh of spun glass in a corrugated pattern, the surface area of a big Honeywell HEPA "drum" filter is several football fields in size. By being a drum they have the effective area of a 48"x12" panel HEPA filter - very big.
The problem you face is not obtaining the filter, or the enclosure, but the fan to operate it. RS Components do plenty of big radial blowers, but you need 50W minimum (run for an hour), more typically
100W (notice a benefit in 15mins). They are quiet noisy, by the time you have put stuff together you are about 40-60% of a Honeywell HEPA in price.
The smallest Honeywell HEPA is actually very noisy even on the lowest setting - but it does work. The largest Honeywell HEPA is relatively tolerable on the lowest setting - even so it is quite a substantial whine and somewhat intrusive air rushing whitenoise. Louder than a cooker hood on minimum for example. This was the biggest problem with the HEPA units - the ones that really cleaned quickly & effectively were too noisy to sleep with unless you used earplugs (whereupon the whitenoise did eventually get masked by the brain). An example of the "older" HEPA is on Ebay under 280429633400, the 5010E I think is the largest and certainly knocks down hayfever. Realise many HEPA are designed to "leak" and achieve their filtration by "multiple air passes" so if you breathe the air directly you may sneeze, so orient in a room accordingly. The size is about 16" diameter with a central radial blower fan (blows out of top) the huge drum filter fills the entire space - about 3" wall thickness, corrugated, 15" diameter, 6-8" high going by memory. That is not my auction, I would not hell my two HEPA :-)
To anyone who thinks they do not work, try one of the proper ones and you may be surprised at just how fast your nasal passages & frontal sinus are simply opened to free breathing. That not withstanding, vacuuming daily with a proper HEPA filter vacuum will almost negate the requirement for one except in severe High-Pollen (or similar days). The best solution for hayfever is allergy-acclimisation injections (not corticosteroids) and well worth childen having them (many employers do request allergy declaration and will discriminate accordingly re oversupply, particularly in the chemical field although that is not a good area to go near re Indo-China). There is a rest- bite by using such filters for about 30-45min so it can be useful beyond the home environment, HVAC helps in cars re causing the capillaries to contract.
One other note - if the allergy is nasal, try the "red-nose" system. It's a probe you stick up your nose and lights up red, it basically is a drug free anti-allergy system which does in fact work quite well. Check on Amazon and read the reviews. Medinose, =A344. Worth a try if the problem is nasal. Once the allergic reaction is turned off the benefits will last a while.
3M's kit does work very well. If they can achieve pollen filtration without the noise, that would be a huge benefit - the bugbear of the Honeywell systems is they actually DO sound like a library-sized HVAC plant sitting next to you. It's a collosally loud whitenoise with whirrr from a high speed radial fan when set to maximum.
You do not actually need HEPA to trap pollen, if that is the cause.
3M products work extremely well, they are just morons when it comes to marketing and an impenetrable website to impenetrable product support. Basically worse than HPQ and far worse than IBM ever were (who had a product range code system larger than the known universe). It's the "Mining" part of MMM that customers are required to do themselves :-)
If the 3M product is quiet, I would give that a try - if Amazon do it they are good with returns (half way to John Lewis, but not the customer service of Amazon USA which is still superior "can do anything, will do anything"... probably hack crazed californians :-)
For anyone considering this device, you may wish to read the report (well, the abstract, the full paper is not accessible to me) for what I would guess is a similar device (the Lloyds pharmacy SN-206):
(This is not meant to praise or to damn - just information.)
And anyone who uses Loratadine (e.g. Clarityn) as their chosen anti-histamine, suggest you buy online. Earlier this year we were paying under 70p for 30 tabs - compared with pounds for 7 tabs in high street pharmacies (e.g. GBP2.99 for 7 Clarityn at Boots).
I'm not 100% sure if you mean desensitization injections. If so its effective but the nhs considers it too risky for most people. It can trigger full-blown allergic response, and deaths do occur as a result.
Has anyone here tried water as a filter? I used it years ago and was happy with the results allergy-wise, and it would seem to be very effective when air is eddied over the water surface. There's also no cost and no need to get or stock filters. And of course requires frequent replacement and sterilisation. How it compares to hepa filtration I don't know, not tried that.
Pretty sure the roof is watertight (but has suffered in a couple of storms and been repaired etc).
Could be damp but all those that are unused are also either partially capped and vented.
We don't have CH.
No plants. However, I did discover some mould behind stuff against an outside wall in a spare room a while back and removed it (wet) and processed little patches that I've found along the way. I've tried to be careful with such things but have never been affected by dust (in general) or 'stuff' in the past (not that that means much now of course). ;-(
Sorry, I meant the enclosure rather than the filter itself. ;-)
Ah, good point.
LOL. We were talking about the sizing of things yesterday ... tall / long as a bus, the area of a football pitch, as heavy as an elephant etc. How heavy is an elephant then, same as a car or a small truck. Would a truck big enough to carry a bus be heavier and taller than an elephant? ;-)
That is. I was thinking of my 'speaker' version having at least 3 sides which were filters but it still wouldn't be a big as that.
I was first thinking if you could use the blower from a fan heater ... or a big PC fan run at the right speed (and possibly inside the enclosure with suitable sound baffle plates) but as you say, you might not get the pressure. I think I was thinking of more a lighter background / general type solution rather than 'this air feels dusty, turn the cleaner on' sort of thing.
Agreed, however part of this was about the d-i-y thing (if there was a chance of creating a d-i-y solution that was practical of course.
Ah, now here's the rub. I suffer from tinnitus so noise levels and types are a tricky thing. ie. For something to be ignorable it has to be loud enough but not too loud. If it's quiet but I can still hear it AND if it's a noise that annoys me then I wouldn't be able to stand it. A noise I can sleep with for example is the ceiling fan but not someone talking loudly 5 houses along or a car ticking over outside, even through the double glazing. White noise is generally ok (in fact desired in some instances). [1]
Never had / heard one but I think I could imagine one.
I couldn't sleep with earplugs because it would amplify my tinnitus (ie, that's all I would hear).
Ok thanks. So would you be able to watch TV in a room with that running on low do you think?
Was this what you called the 'other' design?
formatting link
Realise many HEPA are
Ah, ok. I watched a video on Youtube where a guy was 'dissing' one make because it leaked some air past at the edges of the filters.
That sounds like a lot of filter! I notice some of these Honeywell units mention 'lifetime filters' and that they can be cleaned with a vacuum (with a HEPA filter presumably)?
;-)
Reading some of the reviews you find I have noticed there were people who had replaced their old model with a new model and not had the result they were used to with the old model so returned the new one for a refund or model exchange. This was even though they preferred the new model for other reasons (vent direction / noise levels etc). Suggesting this is a real solution to some people at least.
Ah. We have never vacuumed daily (or we might have done when we had babies and pets but currently have neither), typically doing so when it looked like it needed doing. However I'm (now) aware that it's the unseen stuff that is can cause the problems etc. Having said that we generally also always had windows open giving cross ventilation but as the traffic movement has got worse around us we are seeing more 'dust' on windowsills etc.
Secondly, as the last kid is in the process of weaning herself away from us we are going through stuff in general and in so doing, disturbing quite a bit of dust in the process. I'm not sure if it's this burst exposure of high levels dust (we try to be careful even then, catching as much of it in the (HEPA) vac as we can) but it still must be higher than usual etc? However, the Mrs is fine? Does that mean her immunity to such things is higher than mine? I've always been more vulnerable to 'colds' whereas she had a reputation of never catching anything (although we all (daughter and b/f are also here atm) seem to have this current cough / nose thing in varying degrees).
Maybe something 'noisy' but powerful could be used to manage the dust levels while > after we were disturbing stuff?
The Doctor did mention somesuch.
;-(
And I've even seen those little portable ones you wear round your neck. Didn't I see something similar on a SiFi program a while back? ;-)
To be honest I don't know what it (mine) is. It started one day some weeks ago by very very quickly having a blocked / runny nose, sore throat and batches of sneezing (maybe only a few times a day but about
6-10 sneezes in a batch. I rarely sneeze). I used up several boxes of tissues over 4-5 weeks and trying various basic solutions but nothing worked. Booked an appointment at the Doc (earliest appointment, any Doctor, 8 days) and the day I went was the first day I had been ok for all that time (ironically). I was good for about a week and then it came back .. or very similar symptoms anyway (mainly just the blocked / runny nose and not anything like as bad as before).
The only thing I have sensed has changed with me other the years is hearing a slight buzz or click when laying on my left when the breathing is very very shallow. Sometimes a couple of coughs will clear it but it's pretty persistent bit not something I have had for the previous 52 years. Doc did check it out a whole back, said my lungs etc were all ok? I was carrying 1.5st more then but loosing that didn't have any effect (as was suggested at the time).
Thanks very much for all the feedback. Very interesting.
T i m
[1] I was looking into a white noise sleep unit that may have the following settings:
Starting volume Full volume run time Final volume Full to final volume ramp down period
The idea would be that you pressed 'Start' and it produced white noise (or rain recording / whatever) at you preferred volume. Then, hopefully as you were going off to sleep the ramp down timer would start and the volume would gradually fall to the final volume. It wouldn't cut off completely as a) you might hear it do so and b) if you woke up you wouldn't hear it and may have to start the cycle again (unless you had an extra 'Snooze' button that restarted the final volume etc).
I'd be happy if it was pollen and house mite dust etc.
Hmm.
One of the review site for many different makes and models of such machine mentioned that they nearly didn't site the 3M gear as they suggested 'Their system was as good if not better than HEPA for a greater flow rate'. However they did concede that 3M were probably right but for not a wide a spectrum of stuff or reasons that may be covered by 'HEPA'.
Ok, well that's a though. I don't generally buy things with the thought that I could take them back (do sufficient research to minimise the risk etc) but that's worth thought.
I wonder if Argos would be as good if it didn't actually work but wasn't 'broken' as such (as they are at the top of our road)?
Tim I will admit I haven't read this thread all through and it is possible that someone has already come up with this info - apologies if so.
The wood working community is very conscience of dust and the info on the site below may help : the starter posting has links to "this thread" and "page 3" - these lead to the original extractor design.
formatting link
may well be that this is of no use to you, but there may well be others who like me have opened up this thread with the workshop scenario in mind and could find this of help to them.
I think the 3M jobbies use something similar with the non HEPA solution. I have also seem it mentioned on these 10 stage 'intelligent air purifiers you can get now (that often also use ozone but I'm not sure about that as a solution).
Along with the practical ideas and feedback that often come from this group I also like the tangents and 'have you also considered' type stuff.
There are also easy solutions to things, like 'where can I by screws' and then the others questions like 'where can I buy stainless steel left hand thread security head screws' or as with the tumble dryer were there are other technologies that may or may not be cost effective in the long run etc etc.
So, what I believe I would like for the air filtration problem is a £50, automatic, silent, efficient, filterless / lifetime filter compact solution but as it sounds like that doesn't exist it's now a matter of seeing how near I can get. ;-)
Thanks for the thought Rob. As you predicted, I don't think it would be any use for my current project (don't think it would go down fine enough or be quiet / small enough etc) but may be use in the workshop. ;-)
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.