Thats a nice idea, but I'm afraid their calculations for cost per litre of water are off: From the specs on that page:

Product Specifications:
* Dimensions (mm/inches): 1215Hx340Wx375D / 42Hx14Wx16.5D
* Weight: 50kg / 110 lbs.
* Refrigerant: R-407C
* Filtration System: Hyflux Proprietary Ultra-filtration
* Electrical Consumption: 600-1000 watts
* Max. Water Storage Capacity: 3.7 US Gallons / 14 liters
* Max. Immediate Dispensing Capacity: 1.32 US Gallons / 5 liters
* Water Production Rate: 0.3 US GPH / 1 liter per hour
* Based on: 77F @ 60%RH / 25C @ 60%RH
* Cooling System: Rating: 658 Watts
* Tank capacity 0.52 USG / 2 liters
* Programmed logic temperature control
* Heating...

Thats a nice idea, but I'm afraid their calculations for cost per litre of water are off: From the specs on that page:

Product Specifications:
* Dimensions (mm/inches): 1215Hx340Wx375D / 42Hx14Wx16.5D
* Weight: 50kg / 110 lbs.
* Refrigerant: R-407C
* Filtration System: Hyflux Proprietary Ultra-filtration
* Electrical Consumption: 600-1000 watts
* Max. Water Storage Capacity: 3.7 US Gallons / 14 liters
* Max. Immediate Dispensing Capacity: 1.32 US Gallons / 5 liters
* Water Production Rate: 0.3 US GPH / 1 liter per hour
* Based on: 77F @ 60%RH / 25C @ 60%RH
* Cooling System: Rating: 658 Watts
* Tank capacity 0.52 USG / 2 liters
* Programmed logic temperature control
* Heating System: Rating: 350 Watts
* Tank capacity 0.4 USG / 1.5 liters
* Programmed logic temperature control
* Air Intake Fan: Blower 390 cubic meters per hr
* Water Filter: Hyflux Filtration Cartidge
* Air Filter: Patented Anti-bacterial Air Filter

This is basically a dehumidifier with a refridge/heating element. 600-1000 watts energy consumption is high as well. That's not cheap. Also the output of this item is based on 60% RH (realative humidity) which is high for indoors. Unless you live in the deep south or near the equator(where humidity is always high).