Dehumidifiers: Why bigger is better

Nobody likes humidity. In addition to just being downright uncomfortable, high levels of humidity in your home or workplace can cause horrible smells, mold and can even increase your chances of respiratory illness. Fortunately, buying a dehumidifier can easily sort out the humidity around you. They are small, cheap and easy to use, and they can save you a lot of discomfort as a result. So if you have a humidity problem in your everyday life, consult this buying guide to help find the best dehumidifier for your needs.

What is a dehumidifier?

A dehumidifier is a household appliance that, as the name suggests, reduces the level of humidity in the air. Usually used for health and comfort purposes, dehumidifiers extract water from the conditioned air.  They are a bit like a vacuum cleaner, in that they suck out air from the room at one end and blow it back out again after sucking the moisture out of it.

In addition to their common household use, dehumidifiers can also be used for both office and industrial purposes. This buying guide, however, will only focus on home dehumidifiers, as they are the ones you’ll likely be considering. We’ll get started with how they work.

guide to dehumidifiersHow do dehumidifiers work?

Dehumidifiers work in two ways – refrigeration and absorption. This section will go into detail on both of these methods. Both types of dehumidifiers work better in different environments.

Refrigeration

Refrigeration (or compressor) dehumidifiers draw in air through a filter and over cold coils. Most home dehumidifiers use this method and the full process is as follows:

  1. Moist air is sucked in through a grille
  2. The warm air passes over cold pipes through a coolant.
  3. As the air cools, the moisture turns back into a liquid and drips off the pipes
  4. The now moisture-free air passes over a heating element and returns to its original temperature
  5. The dry air passes back into the room through another grille
  6. The moisture that was in the air drips into a tray which needs to be emptied from time to time.

These are the most common types of dehumidifiers. It is claimed that they work better in higher temperatures and humidities, so they are perhaps the most suitable type for Australian households.

Absorption

Also known as desiccant dehumidifiers, they use absorbent material to extract water from the air and heat it internally.  Their process can be simplified to the following steps:

  1. Moist air is drawn in through a duct
  2. This moist air moves past a rotating wheel made of water-absorbing material
  3. The air is drawn by an electric fan and blown back into the room
  4. An air duct is heated, and a moisture absorbing wheel rotates through this heated air space and has hot air blown past it
  5. The hot, wet air is blown out through and exhaust duct

As you might be able to tell, absorption models are more complicated in their design and are believed to be less energy efficient, according to www.which.co.uk. Absorption dehumidifiers work better in lower temperatures as well, so they are perhaps not as appropriate for the Australian climate as refrigeration models. However, this isn’t to say that you shouldn’t buy an absorption model. They can still do a job in hot temperatures, it’s just that studies have shown refrigeration models to perform better in these conditions. Speak to an expert about your living conditions before you buy to find out which of the two are more suitable for you.

Absorption Refrigeration
·         Maintains high performance even in low temperatures (1-15°C)

·         Portable and lightweight (5-9kg)

·         Minimal noise

·         May include heater. Higher wattage

·         Increases room temperature by 3-5°C

·         Only works well in higher temperatures

·         Bulkier and heavier (over 10kg)

·         Noisier

·         Less power consumption

·         Increases room temperature by 1-2°C

dehumidifier buying guideWhat size is best for you?

Now you know the differences between the two types of dehumidifiers, you also need to understand the different size classes. As with any device, you should measure the space you plan on putting your dehumidifier in, but this isn’t crucial, as many household dehumidifiers are portable and can be placed anywhere in a room. However, if you want to buy the largest one you can afford, measuring the space in your home is a good idea. There are generally three standard sizes of dehumidifiers.

  • 70 pints – Large capacity
  • 50 pints – Medium capacity
  • 30 pints – Small capacity

Dehumidifiers vary according to how many pints of moisture they can remove in 24 hours.

Large capacity dehumidifiers

Large capacity dehumidifiers (like the Dimplex model pictured) can remove up to 70-75 pints of moisture in any 24 hour period, and can handle a wider range of humidity levels with little additional noise. They are obviously best-suited for large wet spaces, but as we said before, buy a large capacity model if you can afford it, as the difference in cost between large and medium capacity models is modest to say the least.

Medium capacity dehumidifiers

Medium capacity models are ideal for spaces that aren’t quite as damp, as they remove about 50 pints day. They weigh about the same as large capacity models (17-20 kgs) and cost about the same upfront, but are quite often slightly cheaper.

Small capacity dehumidifiers

Finally, small capacity models can remove anywhere between 25-40 pints per day, with the average being around 30. They are commonly used to dehumidify small spaces that are damp rather than wet, and cost the least overall. Despite the low cost, there are a number of reasons why you should look for a large capacity model over a small one.

Why bigger is always better

There are several reasons why you should always look for a larger capacity model if possible. Primarily, large capacity models don’t have to work as hard to dehumidify spaces. A larger capacity model can do in a few hours what a smaller one would take an entire day to do – putting more stress on the smaller unit’s internal parts and harming its longevity. Larger models can also shut themselves off when they’ve reached their goal, so they are also more energy efficient.

In addition to having more features and improved functionality, larger units can remove moisture faster and have a larger water tank. Having a larger tank means you don’t have to empty it as often, which reduces the stress on you and your dehumidifier. A final benefit of larger units is that they tend to be quieter, meaning you can have them be in the same room as you without being a distraction.

All in all, the $30-50 difference in price shouldn’t discourage you from buying a large or medium capacity unit. Ideally, it is recommended that you only buy a small capacity unit if you either can’t afford a larger one, or won’t be able to lift them.

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Special features to look for

If you’ve settled on a higher quality model, then you should also pay attention to some of the most common features that dehumidifiers come equipped with. Some of these can be life savers, saving you both time and money. The following are definitely worth looking for.

  • User-friendly controls: As you might expect, the more expensive models have a higher degree of flexibility when it comes to their controls. These controls should be easy to understand and use, and the two most common examples of features that a dehumidifier might have are a timer and humidistat, which we explain below.
  • Auto-restart: Units with an auto-restart feature will automatically start up again after a power outage. If you want a machine that can run with minimal human intervention, then this feature is a must.
  • Hose connection: If you don’t want to bother emptying the water tray constantly, you might want to consider a continuous drainage option like a hose connection. A hose connection lets you divert the condensed water directly to the drain so you don’t have to do it yourself.
  • Washable air-filter: The better models available have washable air filters similar to those you find on air purifiers. These air filters capture airborne contaminants, and having one that is washable can prolong the lifespan of your unit and maintain its effectiveness.
  • Humidistat: A humidistat allows you to target a relative humidity for the room, and depending on the model you buy, this can either be precise or just basic settings like low to high. The ideal relative humidity for a home is about 50%, although anywhere between 40-60% is good too. If your humidifier comes with this feature, experiment for a bit to see which humidity level feels the most comfortable for you and set it from there.
  • Auto-defrost and low temperature options: If you happen to live in a low-temperature area, an auto-defrost feature could be crucial. Anti-frost sensors turn off the dehumidifier if frost starts to form on the coils, and can be extremely helpful if your climate is regularly below 15 degrees, but most of you are unlikely to need this feature.

dehumidifier buying guideWhat brands should you look for?

The leading brands of dehumidifiers listed on Appliances Online are:

  • Cli-mate
  • DeLonghi
  • Dimplex
  • Dyson
  • Goldair
  • HoMedics
  • Ionmax
  • Omega Altise

Across these eight brands there are 19 different models of dehumidifiers to choose from, so the selection process shouldn’t be too tedious for you. If you want a budget option, then Cli-mate offers a rechargeable option for less than $40 (pictured). But if price is no problem, then the costliest option is Dimplex’s DC17 model (pictured, above), which will set you back more than $800. Dyson also sells a top of the range dehumidifier called the AM10 which is a previous Canstar Blue Innovation Award winner.

Dehumidifiers vs Air conditioners

Air-conditioners and dehumidifiers are extremely similar in both function and appearance. Most people don’t even know the differences between the two. The differences are there, despite the two machines using the same mechanism to produce different results. Indeed, there are two key differences between the two: how they deal with moisture and air movement.

Warm and cool air movement:

To put it simply, air conditioners move warm air and dehumidifiers don’t. Air conditioners have fans that circulate room temperature air over cooling coils that then pumps out cold air. Dehumidifiers also have a fan, but they are used for pulling in moist air and expelling dry air.

Air-conditioners move the warm air outside, whereas dehumidifiers dump the warm air straight back to where it came from. So really, if you want to stay cool, a dehumidifier is not the solution.

Moisture:

Both machines condense moisture onto cooling coils, but they deal with this moisture very differently. Air conditioners pool the moisture into a pan which then drains outside, whereas dehumidifiers are built to pull water from the air. This excess moisture then remains in the unit until it is drained.

Basically, it’s important to remember that while dehumidifiers and air conditioners look and act similar, they perform different functions, and generally aren’t interchangeable. Air conditioners can keep you cool or warm, while dehumidifiers remove the moisture from the air and make everything less sweaty.

This article covers most of the basics you’ll need to know when it comes to buying a dehumidifier. But in the end, it will come down to your personal preferences and budget.

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