Small-Space Living and the Condensation Problem

A studio is not a small house. It is a single volume of air doing every job at once, and every one of those jobs adds water — the kettle, the shower, the airer, and the people. The same routine that is invisible in a four-bedroom house is concentrated into one room.

Where it shows up first

Condensation forms on the coldest surface available, not evenly around the room. In a small space that is usually the window reveal, the corner of an exterior wall behind whatever is pushed against it, and the strip of floor under the bed if the bed is on an outside wall.

Which is why a room can read a perfectly reasonable humidity on a meter in the middle of the floor while a wall two metres away is wet. The average is not the problem; the cold spot is.

Rearranging beats renovating

• Pull the bed and any large furniture a few inches off exterior walls.
• Keep the airer away from the bed, and out of the room overnight if you can.
• Lid on the pan; extractor on before you start cooking, not after.
• Open the wardrobe occasionally if it sits on an outside wall.
• Air the room hard and briefly rather than leaving one window ajar all day.

About the houseplants

Small-space guides love a wall of plants for cleaning the air. It is worth knowing what the evidence actually says, because this one has been repeated for decades.

EPA's position: there is currently no evidence that a reasonable number of houseplants remove significant quantities of pollutants in homes and offices — the encouraging results came from laboratory chambers, not living rooms. And specifically for damp homes, EPA adds that indoor houseplants should not be over-watered, because overly damp soil may promote the growth of microorganisms which can affect allergic individuals (Improving Indoor Air Quality).

Keep the plants because you like them. Just do not count them as ventilation, and do not leave twelve saucers of standing water in a room you are trying to dry out.

One more honest limit

A tabletop air purifier is not going to fix a damp corner either. EPA notes that table-top air cleaners in particular may not remove satisfactory amounts of pollutants from strong nearby sources. Source control first, then ventilation, then filtration — in that order, because that is the order of effectiveness.

Read the sources

• EPA — Improving Indoor Air Quality — the houseplant and air-cleaner passages; original at https://www.epa.gov/indoor-air-quality-iaq/improving-indoor-air-quality
• EPA — A Brief Guide to Mold, Moisture and Your Home — reproduced here; original at https://www.epa.gov/mold/brief-guide-mold-moisture-and-your-home