Whole-home humidifiers in Round Hill.

Most towns can’t tell you how hard their water is. Round Hill can. The Town’s 2025 water quality report gives hardness at 115 to 317 mg/L on the main system, which works out to about 7 to 18 grains per gallon, and 182 on the Stoneleigh system. That range runs from moderately hard to quite hard. A whole-home humidifier evaporates the water and leaves the minerals behind on its pad, so here the pad is a bigger part of owning one than in a town with soft water.

In practice that means a pad swap at least once a winter, more in the harder end of the range, and checking the line for scale. A humidifier that stopped working in Round Hill is more often a crusted pad than a dead unit, and the $99 visit usually ends with a new pad and a clean valve. Ask whoever installs yours how they’d handle it, and whether the model you’re looking at has a pad that’s easy to reach.

Heating is mostly electric, with a bit more than half of owners on it, and propane at four in ten. Gas is about two in a hundred. So the typical Round Hill humidifier is a fan-powered Aprilaire on a heat pump air handler, or a bypass one on a propane furnace. Nearly nine in ten homes are detached, in the Villages of Round Hill and the farm roads beyond, so most furnaces sit in a basement or closet with room around them.

Over half the owner homes here were built after 2000, so many are tight enough that a humidifier set too high will put water on the glass in a cold week. Older homes on the edge of town run drier. Where you sit on that line is the main thing that changes how much humidifier you need.