Mt Airy Greening Network - MAGNet
Dehumidifiers for Damp Basements

Dehumidifiers for Damp Basements
– A journey made by the Mt Airy Greening Network

Steve bought a new home, and discovered that the basement was damp and needed a dehumidifier. Which one to buy?

Options - Went to the AEEE web site and the one for Consumer Reports . Saw that many units are Energy Star rated and learned it's best to buy a unit with the largest size water collection bin we can afford. Some of the brands from Consumer Reports are store brands only available at Sears.

Decision - We decided to buy a 65 point unit from Killian's for $229.99, instead of going to a big box like Home Depot or Wal-Mart or to Sears.  Killian's is affiliated with ACE Hardware -- I believe Killian's is locally owned but stocks up on products sourced by ACE.  Killian's ordered an Energy Star unit for me which will come in about a week.  It's a new brand named Comfort Air made by a company called Heat Controller, and we ordered modelBHD-651.  Last summer there were shortages of dehumidifiers so ACE switched brands to this new one.  According to, a site I got to by doing a look up of Comfort Air on the web, the unit is very good and it confirmed that the unit we ordered is Energy Star. Russell of Killian's said the unit can go flush to the wall, takes in air from the top, has a water bin that's removable from the front, can accommodate a hose in back, is designed to not freeze up, can run at temperatures down to 42 degrees and has two speeds.

Cost - not sure how the cost compares with other units but am aware this one may cost slightly more.

Bottom line - without a major difference in the reviews of the various units I opted to go with a unit from a locally owned store even if it meant we might be paying a small premium.

The Energy Factor - We can look at an appliance's "energy factor", or the amount of energy it burns to do a certain amount of work.  For dehumidifiers this is measured in liters of water removed per kilowatt-hour of energy consumed or L/kWh. A higher energy factor means a more efficient dehumidifier.  The brand you are going with has an energy factor of 1.65 L/kWh.  Energy Star models range from 1.21 up to 2.75 L/kWh!!  Of course, the ones at the high efficiency level may not suit your needs -- they may be more industrial size, for  100 pints/day instead of 65 pints/day like yours, and they may be commensurately more expensive.  All the brands, their capacity, and their energy factor are listed in a spreadsheet available on Energy Star’s website.

The Energy Consumed - To get the kWh your unit will consume in a month, divide 709.8 by the energy factor, assuming the unit collects 50 pints / day on average.  (That's 30 days x 23.66 liters/50 pints = 709.8 ).  The best unit consumes 258 kWh/mo, the worst, 587 kWh/mo.  Yours comes in at 430 kWh/mo.  Remember, these are ALL Energy Star rated so they are all "better than average".

The Cost - Next, multiply the kWh/mo by $0.10/kwh * 6 mo, to learn how much the appliance costs to run in a year (assume it is only active half the year).  The best unit costs $155, the worst, $352.  Yours costs $258.

The CO2 emitted - Finally, if you like, convert the kWh to carbon dioxide emission. Using a national “rule of thumb” of 0.3 kg per kWh, we find that the models emit from 465 kg to 1056 kg of CO2 per year.  Yours emits 774 kg.

To put all this in perspective, planting one tree will REMOVE 1000 kg of CO2 per year for the growing life of the tree.

Anyway, these numbers are not meant to suggest anything bad about your choice -- they are all better than average after all -- but it shows how we can start to think economically about the usage costs of appliances, and not just their purchase costs.  ... And that usage costs are not just dollars, but also pollution into the air thru CO2.

Questions? Comments? Forward them to me

This page craetedon 5 June 2004.

page last updated: February 16, 2005.