Earth Notes: On the HTC-1 Desktop Humidity and Temperature Meter: ReviewUpdated 2021-04-05 20:59 GMT.
By Damon Hart-Davis.
- Reviewed by: Damon Hart-Davis on 2012-11-13.
- Clear display, accurate, cheap.
- This desktop humidity and temperature meter works well. It can be read across a room. It is good value for money.
- Rating: 5 out of 5.
Building regulations are clear that heating energy efficiency must be good. And ventilation must be improved to keep air 'fresh'. That includes keeping relative humidity down. (Above 70% invites mould and mites to grow.)
Thermometers are easy to come by and cheap. Most of us have thermostats. Humidity meters are more rare!
The MHRV (Mechanical Heat-Recovery Ventilation) in our bathroom increases ventilation while retaining heat. It has a humidity sensor. The fan automatically goes into boost mode when humidity is high. This happens during a shower or bath. So I have one device to help crudely manage humidity. It is not enough on its own.
My only humidity sensor with a readout was a piece of test gear. It was a Maplin N09AQ 4-in-1 Multi-Function Environment Meter. It was expensive at ~£70. It does not have a continuous display. Also, humidity sensors seem to work best if allowed to 'settle' for as much as an hour. Making measurements all around the house at the same time is difficult with one meter!
The cheap-n-cheerful Neewer HTC-1 is amazing value at about £4. (Spotted on Amazon by my friend Martin F.) The HTC-1 gives readings within 1°C and 1%RH of my test meter. It is easy for even my small children to read. It is big enough to read from across the room. At that price, having a couple left in important places is fine. (The kitchen, and the living room or a bedroom.)
The HTC-1 seems well built. It also looks good.
I aim to keep relative humidity below 70%. If a meter shows more, I try raising ventilation where practical. (For example, I open a window when it's not too cold out.) Or I can wheel out our portable dehumdifier. That is useful in the kitchen when drying clothes. This meter helps us spot issues and fix them easily. We don't have to guess!
We've seen persistent high readings. We know that we probably need more ventilation. Maybe another fan of similar size per person, in fact. So we're adding another MHRV in the kitchen. Moisture in the house should then be removed quickly.
IMO: The most important things to do to ensure reasonable humidity and fresh air in a house:
- Ventilate (and check the fans every now and again, at least whether they'll hold a square of toilet paper on boost)
- Heat: both to evaporate moisture and increase the capacity of the air to hold moisture. This means that the cold air outside (wintertime) usually holds less absolute moisture than the warm air in your house so when it's brought inside and it mixes with the warm house air, it warms and the relative humidity inside falls. There's a common mistake made when people open the windows and turn the heating off and expect it to dry out.
- Find and remediate particularly cold surfaces, thermal bridges, poor insulation, blown windows etc. Radiators under Windows in older properties (and on) are usually a good idea to ensure there's not a particularly cold surface that warm moist air will find & condensate on. Plus it aids in mixing air and preventing drafts. On modern or well renovated properties such as Damons this isn't as critical.
- Locate and remediate any sources of water ingress such as damaged waterproofing, dodgy gutters etc.