Air quality sensors / air purifiers

Forums › Gadgets, robotics, home automation, electronics (including wearables) › Air quality sensors / air purifiers

mdf

3566 posts

Uber Geek
+1 received by user: 1519

Trusted

#299292 26-Aug-2022 16:13

I get seasonal hayfever, and every now and then have an hour or so where my nose drips and I can't stop sneezing. Separately, Littlest Miss MDF has a very mild case of asthma.

I was cogitating as to whether an air purifier may help one or both these things. I was initially looking for an air quality sensor to see if I had a problem that could be fixed, but they don't appear to be cheap. Just wondering if anyone else has done this, or am I better just going straight for an air purifier?

richms

29097 posts

Uber Geek
+1 received by user: 10205

Trusted

Lifetime subscriber

#2959901 26-Aug-2022 16:29

I bought a kmart air purifier. The number on it only goes down to 12, its always on 12 unless I cook something and then it will go up to 50-60 and the fan speeds up.

I dont think it really does much. I was hoping it would help with the smell from the litter box. It doesnt seem to do anything despite a large charcoal filter in it.

Richard rich.ms

tweake

2641 posts

Uber Geek
+1 received by user: 1137

#2959934 26-Aug-2022 17:25

forget air purifiers. a lot of them are gimmicks and the UV/ozone ones can make more pollutants.

all you really need is filtration and decent ventilation.

full house ventilation with decent filters on it, ie hepa. but they are much bigger and cost more. basically blow most contaminants out of the house with clean pollen free air.

2nd is secondary filtration. there is a few systems around, or you can make your own with filters and a fan. downside is they are big and have big airflow. units that are small probably won't have enough air flow to do much. again hepa filters recommended. downside is they tend to only do the room its in unless you have something like a ducted heat pump circulating the air around the house.

timmmay

20857 posts

Uber Geek
+1 received by user: 5349

Trusted

Lifetime subscriber

#2959936 26-Aug-2022 17:29

I have a positive pressure ventilation system which pulls air in from outside. I put a filter box with two filters in it in the path of the air, HEPA and charcoal, to remove pollen, dust, hydrocarbons and smoke, since we're near a motorway. We turn that on a couple of hours a day in the middle of the day, along with the ducted ventilation system to push that fresh air around. The positive pressure system also goes on after dinner. The timing of it varies summer and winter, winter it's more middle of the day, summer it's start and end of the day. I don't know for sure if it worked, but the place is a bit less dusty, and we don't really smell smoke very often any more.

I've been thinking about an air quality meters, but the better ones can be quite expensive.

tweake

2641 posts

Uber Geek
+1 received by user: 1137

#2959940 26-Aug-2022 17:59

timmmay:

I have a positive pressure ventilation system.........We turn that on a couple of hours a day in the middle of the day,

that method i dislike. its a bit old school way of doing it. vary the time it runs instead of the flow, tho typically its run so many minutes per hour.

imho ventilation should be running constantly (vary the flow instead of the time). we are basically cleaning the air by dilution, which takes a long time and a lot of air changes. letting dirty air build up makes it much harder to get rid of.

keep in mind that air is leaking into your house from outside constantly. so its getting dirty from pollen constantly. only having it clean a few hours a day is poor imho.

timmmay

20857 posts

Uber Geek
+1 received by user: 5349

Trusted

Lifetime subscriber

#2959945 26-Aug-2022 18:12

tweake:

that method i dislike. its a bit old school way of doing it. vary the time it runs instead of the flow, tho typically its run so many minutes per hour.

imho ventilation should be running constantly (vary the flow instead of the time). we are basically cleaning the air by dilution, which takes a long time and a lot of air changes. letting dirty air build up makes it much harder to get rid of.

keep in mind that air is leaking into your house from outside constantly. so its getting dirty from pollen constantly. only having it clean a few hours a day is poor imho.

It's working well for us, I don't have any plans to change it. The house is quiet well sealed, not perfect, but double glazed and rubber sealed windows and doors, no obvious air leaks. I also can't easily vary the flow rate, but it's very easy to put a WiFi timer on a basic system like this.

I don't want it running overnight, because it makes the house cold for no huge gain. In summer I run the system for longer, but in winter I don't see any point paying to warm air we just push out. Filters also get damp when you run damp air through them, which I'm not sure is good for them, so I don't run it too early in the morning.

Zorg2000

73 posts

Master Geek
+1 received by user: 25

Lifetime subscriber

#2960509 28-Aug-2022 17:44

My daughter (9yrs) gets bad hay-fever (lots of sniffing at night) so we got one of these from PB Tech back in April for her bedroom. https://www.pbtech.co.nz/product/HOMMIX33664/Xiaomi-Air-Purifier-4-Pro-Smart-APP-Control-CADR-U

Seems to do the trick for her. Just have it set on auto with the display dimmed and it self adjusts fan speed based on air quality. It has a a low noise sleep mode as well and it is so quiet you have to check it is actually on.

I smoked the house out a bit with some baking the other day and it's the only time I have heard the fan speed really ramp up. Not cheap but managed to get a good discount.