Lake country summers bring dew points near 60 degrees and damp basements, while winter brings fogged windows. Here is how to keep bathrooms, lower levels and sills dry and clean year round.
People think of Minnesota as cold and dry, but homes around Lake Minnetonka deal with moisture in every season. Summer air off the lakes is muggy, basements stay cool enough to pull water out of it, and winter humidifiers can overshoot on frigid nights.
This guide covers where mildew tends to start in local homes, the humidity ranges the Minnesota Department of Health suggests, and routine cleaning that keeps surfaces from staying damp. Mold growth and water damage are jobs for a specialist and are not covered here.
Water is everywhere here. Lake Minnetonka covers about 14,528 acres with roughly 125 miles of shoreline, Maple Grove alone has 13 named lakes, and the Minnehaha Creek Watershed District manages 178 square miles of lakes, creeks and wetlands across the western Twin Cities. In summer that landscape adds up to humid air.
The airport numbers confirm it. Average dew points reach about 60 degrees Fahrenheit in July and 58 in August, with average relative humidity near 65 to 68 percent. June is the wettest month at about 4.6 inches of rain, and July's normal high is in the low 80s. Warm, wet air plus cool surfaces equals condensation.
The Minnesota Department of Health advises keeping indoor relative humidity below 60 percent for most of the year and between 20 and 40 percent in winter. The winter range is lower because cold glass and exterior walls make condensation at levels that would be fine in July.
A simple hygrometer, sold at most hardware stores, takes the guesswork out. Put one in the basement and one on the main floor and check them through the seasons. If the basement reads above 60 percent in summer, a dehumidifier is the fix. If windows fog every winter morning, the humidifier is set too high.
University of Minnesota Extension explains a pattern that confuses many homeowners. Warm, humid summer air let in through open basement windows condenses on cool basement walls and floors, and the resulting wet spots are often mistaken for leaks. Opening the windows to air out a musty basement on a muggy day actually makes it wetter.
Keep lower level windows closed on humid days, run a dehumidifier and empty or drain it regularly. Wipe sweating pipes and the floor under them, keep stored boxes off the concrete, and leave a gap between furniture and exterior walls so air can move.
Bathrooms are where routine mildew shows up first: black spotting in grout lines, on caulk at the tub edge, around the base of the toilet and on the ceiling above the shower. Run the exhaust fan during every shower and for a while after, and leave the shower door or curtain open so it dries.
Regular cleaning keeps surface spotting from settling in. Scrub grout and caulk with a bathroom cleaner, rinse, and dry the surfaces. Wash bath mats and towels often in summer, and do not leave wet laundry in the washer. Caulk that stays black after cleaning has mildew under the surface and should be replaced, not scrubbed harder.
When the cold sets in, the moisture problem moves to the windows. The Department of Health lists condensation on windows and ice dams among the places mold appears. With about 147 nights at or below freezing at the airport, cold glass is a constant. Wipe sills and window tracks dry in the morning, open blinds during the day so air reaches the glass, and lower the humidifier if water beads up daily.
Where water damage, a roof leak or spreading mold is involved, call a qualified specialist. Cleaning addresses surfaces; it does not fix the moisture source. The winter cleaning guide covers the rest of the cold season.
The questions Minnetonka homeowners ask most often about this topic, answered plainly.
TotalCare Cleaning will service Minnetonka and surrounding areas with background-checked cleaners and is insured up to $1 million. Re-clean guarantee: if we missed something, tell us by the end of the next day and we come back to fix it. Beyond Clean. TotalCare.
