Whole-House Filters

The new Whirlpool filter is self-cleaning -- no filter replacements

Whole-house filters don't remove contaminants such as cysts -- you'll have to add a faucet-mount or other secondary filter if you need that level of filtration. In Consumer Reports' recent tests, whole-house filters weren't great at filtering bad tastes, either. But for stopping dirt, sediment, rust and scale at the door, with a fast flow rate and little clogging, whole-house filters are king. They're especially useful if your water has a lot of rust in it, which can discolor your laundry. Some whole-house water filters also reduce chlorine.

We found relatively few reviews of this type, since most consumers are interested in filtering out contaminants from tap water that doesn't have these problems. This type also takes up a lot more space. On the plus side, filters don't need to be changed very often unless your water has a lot of sediment.

Whirlpool seems to have discontinued its inexpensive whole-house filters, replacing them with a new Energy Star model that costs a lot more. The newer Whirlpool WHELJ1 (*est. $430), made by Ecodyne, gets good ratings from more than two dozen owners rating it at Lowes.com, but we found no professional comparison tests of it. The main advantage is that it's self-cleaning and requires no filters -- ever. However, the warranty is for only one year. Its sleek housing is attractive, but it's still big -- about 10 inches long, 14 inches wide and almost 3 feet high.

The more expensive Aquasana Rhino whole-house water filter (*est. $800) takes up about 45 inches of vertical space. You do have to replace the filter about every three years, and the sediment prefilter needs changing every three to six months. However, it filters out contaminants, not just chlorine. This is the whole-house water filter rated best at Allergy Buyers Club, but we didn't find any reviews that rigorously tested it. Before investing this much in a system, experts urge you to have your water tested, then check the specific NSF certifications to be sure the filter meets your needs.