Accurate hygrometer / humidity meter for the workshop

Now I have increased the level of insulation for my small workshop, I am curious to note fluctuations in humidity as I vary the temperature, aiming to keep the minimum temperature around 10 deg. The best thing is obviously to buy a decent dehumidifier but anyway I am wondering if any members can recommend a hygrometer for the workshop that is both inexpensive (sub £25) and accurate. I have found online reviews of most cheap hygrometers rather disparaging regarding accuracy.....Thanks

I would guess that most cheapish hygrometers these days will be based on the integrated environmental sensor chips such as the Bosch BME 280. This measures temp, press and rel humidity and communicates them via a serial link to the controller/display. So it's unlikely that there will be much difference between the cheap units in terms of accuracy, and anyway does it really matter? Isn't what you are interested in is looking at how whatever they do measure changes with temperature etc?

But I can recommend getting a dehumidifier - we got one from Machinemart years back and it has been a godsend. They still sell a small one for around £132 which is what we paid, though the unit is smaller.

I have one of those little weather stations from Lidl which have a radio controlled clock, inside and outside temperatures, air pressure and a hygrometer. The temperatures and pressure are accurate as I can verify them against other instruments I have, so the hygrometer is probably quite good as well.

thanks - I believe the Lidl weather station is made by Auriol (German?) who make a variety of temp and humidity meters. The ones on Amazon seem to be all Asian with loads of buyers of brands such as Govee and ThermoPro but each with a very small minority of reviewers saying the humidity component is unreliable. Has anyone tried Bresser or any other Western brands?

What about a Tempo Disc ? We bought one after reading an earlier thread on workshop humidity.

It is a £30 data logger rather than a display, but can be accessed at any time via bluetooth, with the logs showing on an android/IOS app as a graph showing humidity, temperature and dew point over time, Nice and compact, a bit bigger than a 50p coin and runs on a 2032 button cell.

They are made in the UK and if you are serious about wanting a really accurate hygrometer they will test against a standard and issue a calibration certificate for an extra fee. If you want to fix it in place, the silicone hangers were out of stock when we got ours, so I downloaded an STL from Thingiverse and printed one.

Brian G

How about a wet bulb hygrometer, none of this modern electronics stuff. Available on flea bay for ~£10

another thumbs up for the dehumidifier got mine from Machine Mart. drain it daily this time of year. my cheepo hygrometer never moved much but the dampness went and the rust stopped so no idea what it's measuring

you ask for accurate ? what is being used as a standard to check

Very interesting as i was not aware of the wet bulb method - there is a Zeal P2505 for £20 incl postage - only downside is the temperature range is so large as to make the differences around the 10 deg -20 deg range a strain on the eye but a magnifying glass would sort that out. A definite possibility...

Another use ford a humidifier, we've stopped using the tumble drier, just hang washing in smallest room on a clothes horse (winter-hedge if you're from my neck of the woods), switch on the dehumidifier and it dries as is by magic

The dehumidifier is coming but I want to get a good hygrometer first so I can see the difference the heater and dehumdifier settings and run times make .

Tempo Disc £40 from firezy is best price I can find which is double my target price sadly

Takes me back to school days, Duncan has it, the wet buld hygrometer - very simple and almost nothing to go wrong. Noel

Again, wet bulb. You only need to get one old fashioned high quality thermometer from a laboratory supplier and make alternate wet and dry measurements.

Alternatively just go with cheapo because after a while you will probably realise it is only the changes that are interesting and a rough value is enough. Ie when a warm damp front comes in you might be interested to see if he shed is damper even though you haven't opened the door, or if you 6 hour session sweating over hacksawing 500 widgets has made it worse.

I use a Sonoff TH16 which is a thermostatically or humidty controlled switch attached to the wifi network. So you can use it to switch on an off something (a 30w oven lamp under my lathe in this case) and also access it via the internet and it will give you an instantaneous reading of temp and humidty

I have a fully home made insulated garage & workshop made from fridge panels. Video of manufacture on youtube. I also would like one of these devices to see what temp differences i have inner to outer. So will be interested in the answers to this question. My brother in law does have one of the Aldi ones but i'm not sure how accurate it is.

Steve.

Jon that looks very good but how accurate do you think it is?

An accuracy test is to mix 100ml of water with 40g salt in a container and at ambient temperature of 21 deg C you should get a read of 74% humidity in the container

I don't think you're going to find an accurate humidity sensor. It's the nature of the beast, I suspect. I've used two different, but supposedly accurate, sensors and gotten significant difference between them. I would just hope for consistency.

Can't vouch for accuracy but I use a couple of these:-

One to monitor the humidity inside a filament storage box and one outside the box in the workshop. From several suppliers at Amazon and similar for a couple of quid. Different styles and colours some have equal size temperature and humidity readouts. Press-fit into a hole about 45mm x 25mm or just leave them loose. Make useful fridge thermometers as well. More on filament storage box *** HERE ***

John

I have a fairly comprehensive list of humidity standards over saturated solutions of different salts. I expect they are all on the internet, somewhere. Here they are:

**LINK**

One needs to carefully exclude draughts if wanting to compare relative humidity with temperature change. Most youtube idiots tell you how much the humidity falls as their dehumidifier works away - but fail to acknowledge the temperature rise within the room which occurs due to the dehumidifier. Or maybe they are not idiots, just trying to fool the viewers.

Assuming, here, that open fuel burning heaters are not being employed…..