Using distilled water to wash exterior windows and avoid hard water spots
Episode #571 of how being a homeowner makes a person stupid and boring…
Our area of Florida is plagued with moderately hard tap water that is packed with dissolved solids. There are professional window washing services that charge about $700 to come over with a hose-fed flow-through reverse osmosis machine (around $4,000) and wash/rinse the windows with pure water that can be allowed to air dry without risk of deposits. The pros don’t like to use squeegees due to the risk of scratching the glass (replacing a hurricane-proof impact window is not simple or cheap!).
Nearly all of the windows and glass doors on our 5,400-square-foot house are readily accessible from the ground or a balcony. A Hungarian au pair across the street wanted to earn some cash for her end-of-year travels. We decided to see how many windows she could wash using distilled water.
The odyssey began at 9 pm in Walmart. Nearly all of the customers were speaking Spanish to each other. A prerecorded announcement in English urged shoppers to buy products from “Black-owned” companies. Distilled water was just $1.26 per gallon in the baby section (and, curiously, $1.34 in the bottled water section). I purchased 8 gallons. Our smaller Walmart doesn’t sell window-cleaning gear, so I stopped next at Home Depot and got a 14″ Unger microfiber scrubber and a dual-compartment Rubbermaid bucket wide enough for the scrubber.
Using a formula that I know is correct because I got it from the Internet (Floridian Bob Vila’s site, actually, so it is also approved by state-sponsored PBS), I mixed a gallon of distilled water with 2 cups of distilled vinegar and one tablespoon of Dawn dishwashing liquid. I filled the other side of the bucket with two gallons of distilled water for rinsing. It takes almost no time to wipe a glass door or big window with the scrubber, first with the cleaning solution and then after the scrubber is dipped in the rinse water (it might be smarter to have two scrubbers, one for each phase). The scrubber holds so much cleaning solution that you can wipe two or three glass doors before dipping into the rinse.
The pros certainly use a lot more water and do a much better job cleaning the dirt around the frames (they also have screen-cleaning brushes), but we were able to get all of the glass acceptably clean using only 6 gallons of distilled water total, without making any serious attempt to conserve (and this is for a 5,400′ house with a lot of glass!). If you don’t feel the need to get every last spot, this can be done in about 3 minutes per window or door.
It’s probably still worth having the professionals come periodically to clean the surrounding frames and screens thoroughly and/or having the “soft wash” people clean the entire house (they don’t use RO water, however, so probably it would make sense to then rinse with distilled water).
(We also cleaned the interior using microfiber cloths and ammonia-free Windex. That actually took longer than the exterior. The Hungarian gal was meticulous and noticed a fair number of places where the windows still had sticker residue left over from their 2021 installation. I removed these with a razor blade and, in some stubborn cases, Goo Gone.)
I’m writing this up because I’m still shocked at how little water was required!
Example machine that the pros use (1.5 gallons per minute):