Dehumidifier reviews and testing
If you have read or seen my articles or videos on either how to cure condensation, my best dehumidifiers page or any of my dehumidifier video reviews, you may already know that sometimes my work involves helping tenants and private home owners to solve damp and mould. This regularly brings me into contact with lots of real world feedback from people who own and use dehumidifiers day to day.
Occasionally I video review dehumidifiers loaned to me, usually by landlords, so people can have a look at them, read the manual online, and basically have some idea of not only how they work, but how well they work. If you are interested this page informs you how I test them.
First lets talk about the test environment. My house is a typical mid 1930’s semi detached house, built from two skins of bricks to form a early cavity wall construction. This has been insulated by the injection of chopped fibreglass insulation, and the loft space is insulated with 300mm (12″) of standard fibreglass wool. This is similar to literally millions of homes in the UK.
The timber ground floor of my house is suspended on wooden joists over a 600mm or 2ft crawl space, beneath which is basically a compacted substance like clinker from fireplaces, colliery shale from mining, or Power Station waste. This was often called ‘blinding’ or referred to as ‘small granular material’ in the building manuals of the time. Mine has a fine coating of sand on the very top for good measure.
Suspended floor – This is a cutaway section to explain the basic principle of early suspended floors.
Unfortunately for me, this often means after heavy rain or repeated light rain the indoor humidity <(dampness) rises as a direct result, for a few days - or weeks - the ventilation bricks built into the house below floor level slowly ventilate away any build up of ground moisture. (by the way this is why you should not block these low vents off) As you can imagine it's a pain in the butt. However it does offer me probably an ideal and remarkably stable testing environment for Dehumidifiers, PIV systems or anything else related to condensation and damp for that matter. Err... brilliant.
Room size for testing
All of my tests are conducted in the downstairs lounge with the suspended floor as described above. The size of that room is 10.4 metres long by 3.5m wide, or 34ft x 11ft 6″ in old money.
Testing environment – That’s a total floor space of 36.4 square metres or 391 square feet. I always lock off the room from the rest of the house during any tests by closing the doors to stop interference from anywhere else in the house.
Setting the humidity
I raise the humidity in the lounge by a combination of factors, i.e. drying laundry indoors or on the radiators, cooking with no ventilation or by operating a steam wallpaper stripper in the room until a nice stable high humidity is reached. I aim for approximately 60% RH (relative humidity) because this percentage and above in my experience, is a common problem level for most people.
Typically I then test the dehumidifier on its standard every day low power setting, and a high power mode to check the reduction in humidity before measuring the water removed for each setting.
Testing exhaust speed and temperature
Often you will see me measure the exhaust speed and temperature, and it’s really an indication of how effective it will be when drying items like laundry, or any damp surface in close proximity. The temperature of the room is also often taken to show any increase in room temperature during operation, and is a visual indicator of how operating a dehumidifier will contribute to home heating during it’s operation. This obviously helps offset the low cost of running a dehumidifier further.
Testing power consumption
In my early tests I used to test the electric consumption or wattage, and initially this was great. However on some units, especially those with complicated energy saving algorithms or fuzzy logic, test data began to vary. This as it turns out can be due to the computer control of the dehumidifiers power and heat, as well as complicated environmental conditions which change as the unit works. So in short I could no longer achieve a fair or balanced reading, and as a result I now only quote the manufacturers power consumption figure. Which to be fair they will have had tested under laboratory conditions.
If you have seen any of my video reviews on dehumidifiers you will notice I do not use a decibel meter to measure the sound levels of any dehumidifiers I test, and the reason is simple. Mobile phone apps, or cheap uncalibrated decibel meters are unreliable, and my test environment will differ from the lab conditions that manufacturers test in, and in turn your home. Not to mention the average person will not have a meter to hand, or be able to imagine what it actually sounds like.
My method is to record the audio from 5 feet away and adjust the volume in the video, so that if you can hear my voice at a normal volume, the recorded sound should be representative of what you would hear in real life. It may not be perfect, but is the best solution I have devised so far. And of course I state the manufacturer’s dB rating as well.
Moisture extraction rate
This could not be easier and is normally just a matter of measuring the water removed from the air in the living room over a set period of time, usually a two hour test. Often you will find the results to be quite similar to that of other dehumidifiers I have tested – simply because I only go to the trouble of reviewing, recommending, or testing what I would consider to be a good dehumidifier in the first place.