Dehumidifier Costs

How much a dehumidifier costs is an important factor in any buyer's mind when making a decision about which brand and model to purchase. We all want to save money. So what are the points to be weighed before we make our way to the "check-out", in-store or on-line?

The most critical issue is what we want the appliance for. If it is not up to the job, however little it costs to buy, it will be a waste of money. What are the key factors to consider?

1: Size of Area

Dehumidifiers come with different capacities, usually expressed in terms of pints or litres of water extracted over a 24 hour period. The capacity of the unit determines how large a space it is suitable for so, if you know the capacity and the size of the area, you can tell which models will do the job, right?

Unfortunately, like most things in life, it is not quite that simple.

Water extraction rates vary according to two factors; how warm it is and how much moisture is in the air. The lower the temperature and/or the relative humidity the lower the water extraction rate.

In the USA many manufacturers subscribe to test conditions laid down by the Association of Home Appliance Manufacturers (AHAM) which are 60°F and 80% relative humidity. Other manufacturers use higher temperature and relative humidity levels of around 90°F and 80% relative humidity, a standard typically applied in Europe.

The difference in water extraction rate is not insignificant. Let's take the example of one 50 pint dehumidifier, I won't name it, currently sold in the US market. Its 50 pint extraction capacity was measured at 90°F/80% RH. Under the AHAM testing conditions of 60°F/80% RH the water extraction rate falls to 25 pints.

The importance of this is that it is necessary to know the test conditions in order to be able to compare one model with another. I suggest that the AHAM conditions provide a good benchmark.

If retailers cannot, or will not tell you the conditions under which a particular appliance was tested I suggest you halve its stated extraction rate and use that rate to compare it with competing brands.

Now we have a reasonable basis for judging what floor area a given dehumidifier is suitable for as given by its water extraction capability.

(NB If you are visiting us from a country where fluid is measured in litres please note that one US Pint is approximately 0.473 litres. A US Pint is not the same as an Imperial Pint which is approximately 0.568 litres.)

2: Condition of Area

The capacity a dehumidifier must have to control moisture in a given area depends not only on the size of that area but also its condition, how wet it is. AHAM define four degrees of "wetness".

1. Moderately Damp (space feels damp and has musty odor only in humid weather)

2. Very Damp (space always feels damp and has musty odor. Damp spots show on walls and floor.)

3. Wet (space feels and smells wet. Walls or floor sweat, or seepage is present.)

4. Extremely Wet (laundry drying, wet floor, high load conditions.)

A "moderately damp" area of 1000 sq ft requires, in their estimation, a unit with at least a 14 pints per day capacity. The same 1000 sq ft area, if "extremely wet" requires one with a capacity of at least 23 pints per day.

A table published by AHAM shows floor areas of 500 to 2500 sq ft in increments of 500, divided by the four degrees of wetness, and recommends minimum water extraction rates to deal with each of the 20 possibilities.

The table is reproduced on the Energy Star Web Site (opens in new window).

We recommend this table because it originates from AHAM, which sets the 60/80 standard, and is a credible guide as it is reproduced by Energy Star.

The information is now available for a reasonable judgment to be made about the water extraction needed for an area of a given size under all degrees of dampness.

(Please note that in the even more extreme condition of standing water in a given area a dehumidifier is not the solution.)

3: Ambient Temperature of Area

If the ambient temperature of the area in question is above or around 65°F (18°C) a standard portable, designed for use in living areas of the house will be adequate.

Below this temperature refrigerant units will struggle due to formation of ice on the cold coils and will be markedly less effective. If the typical temperature of the area is significantly below this level, for all or part of the year, an effective defrost system is essential.

Defrost systems may use the "hot gas defrost" technique of passing warm air across the coils to thaw them, or electrically heat the coils to achieve the same effect.

Some dehumidifiers have a sensor to detect freezing coils and will simply shut the compressor down until the ice has melted. This is a partial solution but does not make the appliance ideally suitable for cold conditions.

This issue may be particularly relevant in some basements and crawl spaces. These areas can be particularly challenging for dehumidifiers and may require a purpose designed basement/crawlspace model which is optimized for low temperature operation and with components made to commercial rather than domestic standards.

It may also apply where dehumidifiers are used in garages and outside the home, in RV's and boats for example.

4: Number of Sub-Areas

A 2000 sq ft basement without dividing walls does not present the same problems as one of the same total floor area that is sub-divided into separate and fully enclosed individual rooms.

A free flow or air is required for a single unit to control the moisture level of any given area. Opening doors to individual rooms will help but the area that can be effectively dried is likely to be less than if there were no partitions.

This applies with even greater force if the target area for humidity control is the whole house. Serious thought should be given to the installation of a unit suitable for ducting to the individual areas of a sub-divided basement and to a whole-house model integrated with the existing HVAC system if an entire home of any size is to be protected from moisture.

A whole house or purpose designed basement model costs substantially more than a portable. They are, on the other hand, likely to have a longer service life and generally have longer warranties, up to five years.

Often a large capacity dehumidifier costs less to run than a smaller unit or units because it is more energy efficient, judged by pints/litres extracted per kilowatt hour, and is likely to run for fewer hours to obtain the same result.

If portables are used in these circumstances more than one is likely be needed and the combination of their probable shorter working lives and higher energy costs could make this a more expensive option in the medium to long term.

5: Accessibility of Area

If the drying area is difficult to reach as, for example, a crawlspace, or is a fair distance from your home, such as a boat perhaps, two features are essential.

First continuous drainage. If you rely on the water collection bucket alone it will need to be emptied regularly or the appliance will simply stop working. If it is not possible or convenient to visit a distant location at least once per day the effectiveness of the unit will be very limited.

Second auto-restart. This feature ensures that the appliance will restart at its programmed settings following a power outage.

I have considered five variables which should be assessed when forming a "specification" for the dehumidifier needed for a particular set of circumstances and, I hope, provided the means for each model on the market to be assessed and either included or excluded from a short-list of possibles which are "up to the job".

At the end of the day if the appliance that is purchased can't do what it was bought to do it is all cost and little or no benefit.

By now you should have a good idea of the water extraction capacity, capabilities and particular features of the unit you need. Draw up a list of the models that appear to match your needs, double check that they include the features that are essential to you and take a look at each one in a little more detail.

What You Should Consider

6: Energy Factor

If you live in the USA or Canada you are most likely aware that dehumidifiers are among the appliances which are certified under the Energy Star programme. Energy Star certified models are claimed to be around 15% more energy efficient than non-certified units and this can make a significant difference to dehumidifier costs over the life-time of the appliance.

All models certified by Energy Star have to meet a minimum standard of energy efficiency called the "energy factor". The energy factor is expressed as the volume of water collected, in litres, per kilowatt-hour of energy consumed. The higher the energy factor the more energy efficient the appliance.

The minimum standard is different according to the water extraction capacity of the unit. Larger capacity units are more efficient than smaller capacity models so the standard is applied in bands to which each is assigned according to its capacity.

So, for example, units capable of less than 11.8 litres (25 pints) per day are in the lowest band and have to achieve a minimum energy factor of 1.2 ltr/kwh. The next band covers units capable of 11.9 to 16.6 litres (25 to 35 pints) per day which have to achieve an energy factor of 1.4 ltr/kwh.

The top band is for units over 35.6 litres (75 pints) per day which have to achieve an energy factor of at least 2.5 ltr/kwh.

A copy of the current list (2 October 2010) of Energy Star products can be downloaded (PDF format) from here (opens in new window).

The full list of bands is under the foot of the table.

The more energy efficient the unit the less it will cost to run but please be sure to compare each dehumidifier with others in the same band.

Energy is a critical part of dehumidifier costs as the power used to operate it during its life time can easily be greater than its purchase price.

7: Warranty

Warranties vary greatly between brands and the "devil is in the detail". In other words, read the small print before you purchase.

In general terms the longer the warranty the greater the insurance against premature failure of the appliance. It is important to be aware that should your unit fail and require work under warranty the purchaser will almost certainly have to pay the cost of shipping the unit back to the manufacturer or supplier for attention. A warranty under which repairs can be done locally is obviously preferable.

As a general rule the longer the warranty period the better, as a lengthy and worthwhile warranty is an indication of the confidence a manufacturer has in the product.

8: Supplier

Many people surf the web when they are thinking about buying a particular product. They compare features, prices, appearance, size and a host of other things. They also look at customer reviews.

Product reviews are very helpful, real consumers describing real experiences with the product you are considering. After they have satisfied themselves about the product many people look only for the cheapest price.

Buyers often overlook the differences between the suppliers of that product. How good is their advice and guidance before the purchase is made? Do they accept returns without problems if the product is faulty? Are refunds offered to dissatisfied customers? How good is their after-sales service?

Good quality service prior to the sale can save you money that might otherwise be spent on an appliance that is far bigger or far less than you need. Good quality service after the sale can help you with problems you may have because the product is new to you and you may not be operating it in the best possible way.

Experienced sales professionals with excellent product knowledge and well developed skills for helping customers reach the right decision cost more to hire and retain than staff whose training consisted of twenty minutes learning how to process an item through the check-out.

Successful business people know that getting a repeat purchase from an existing, satisfied customer is easier and more profitable than attracting a new customer. This may well be reflected in a higher ticket price but may also be a price worth paying.

9: Summary

Keeping dehumidifier costs to a minimum is about choosing a model that is fit for purpose, is highly energy efficient and will have a relatively trouble free and long service life-time.

The ticket price is likely to be less than half of dehumidifier costs overall.

We hope this has been helpful and will assist you in making a choice with which you will be happy.

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