http://www.energystar.gov/index.cfm?
fuseaction=find_a_product.showProductGroup&pgw_cod e=DE

I used the link above to research dehumidifiers. Look under energy factor
to find the spreadsheet of all units sold in the States. There is a wide
range in efficiency of these things.

Mine is a built-in unit - Santa Fe from Therma sTor - going on 4 years and
still working fine.