Quality Windows, Siding and Doors Since 1976 1-866-4FELDCO® | Customer Support
  • NARI Member - National Association of the Remodeling Industry
  • energy star certified logo
  • all Feldco products are EPA certified to be lead safe
  • osi certified installer
  • window and door magazine dealer of the year
mobile call button

Cleaning Algae Off Windows

Let’s face it: algae and windows don’t mix.  Your windows are a proud investment within your home and should serve the main purpose of being clean and clear, where you can look out of them—without discoloration.  For some homeowners, this is an ugly problem.  Green algae love to grow on the sides of homes, discoloring windows and leaving behind wet, persistent stains.

how to clean algae off windows

Fortunately, there’s a way to rid your windows of algae and get rid of the green or dark colored stain, making your windows look as good as new once again.

You don’t necessarily have to use toxic chemicals to get algae to go away for good, and depending on where the algae is growing on your window, you may not want to.  If you have a greenhouse, your algae may be growing on the inside of your windows, but if you’re like the majority of homeowners, you could be faced with algae growing on the exterior of your home’s windows, especially in areas where the home sees a lot of shade.

Oxygen Bleach & Algae Removal

You won’t want to dump massive amounts of bleach on the algae if you have plants beneath your windows or have kids or pets running around, so instead, use oxygen bleach.  Oxygen bleach is much different than chlorine bleach because it’s non-toxic.

Chlorine bleach will suck the color out of your wood decking, vinyl siding, and even your painted surfaces, just like it does with clothes, and it’s also extremely harmful to plants, humans, and animals.

Oxygen bleach, on the other hand, is just the opposite, which is why it’s the preferred bleach to use on your home’s exterior.  Most oxygen bleach products come in the form of a powder that is to be mixed with water, which then transforms into a concoction of oxygen ions, water, and organic soda ash.

Use warm water to dissolve the oxygen bleach in a spray bottle, then spray the algae spots on your windows, allow it to soak into the surface for 10 minutes or more, and use a scrub brush to remove the algae.  Rinse with a garden hose and say goodbye to that algae.

Using TSP to Remove Algae on Your Windows

Oxygen bleach isn’t your only option in removing algae off of your windows.  You can also use an ingredient called TSP, shorthand for Trisodium Phosphate, which was once ubiquitous in various household items like laundry detergents and dish detergents.

You won’t see TSP in a lot of products these days, as multiple states have enforced regulations on its sale because it was determined that TSP had adverse environmental effects.

You can surmise that using TSP can be potentially harmful to any plants that are located beneath your window if they should catch stray drops from your application and that TSP can discolor painted surfaces, both wood and metal.

However, if you have stubborn algae, you’re going to have to fight it with something tough, and TSP is the solution for that.

The TSP to warm water ratio will depend on the product’s instructions, as they differ from manufacturer to manufacturer.  When removing algae from your windows, test the TSP solution in an inconspicuous, small spot first because it can cause damage on the window’s surface.  Opt to use a rag instead of a sprayer to avoid getting the TSP mixture on nearby plants.  Let the solution sit on the algae spots for a few minutes, then use a hard-bristled brush to scrub the algae off of the windows.

Pressure Washing Away Algae From Your Windows

If you didn’t want to tackle removing the algae from your windows yourself, you can consider pressure washing, a job that can be done with a hired professional.  If you’ve got spots of algae on various areas across your exterior siding as well as your windows, this may be the easiest and quickest solution to your algae problem.

pressure washing algae growth on windows

A professional pressure washer can remove the algae within a day, and the entire job will make your windows and siding look as good as new once again.  The force of the pressure washer will destroy the algae, which is similar to the scrubbing you would be doing with a hard-bristled brush.

You can also pressure wash your home yourself, but you do have to move the pressure washer in a certain pattern where you won’t damage the siding.

Getting Rid of Algae on Your Windowpanes

The downside in utilizing the pressure washer method is that when the algae are covering your windows close to the glass pane, you may not be able to get in as close as possible to remove it.

You don’t want to damage the windowpanes, after all, so this method will depend on where the algae are located on the outside of your windows.

For algae that grow directly on the windowpane either inside or on the outside of your window, your best solution is to grab some spray-on bleach and a good scrub brush to rinse and then scrub it off.  The bleach will kill the algae on contact, and once the life form is dead, it becomes easier to remove with a brush and a rag.

Saying Goodbye to Algae on Your Windows

Keep in mind that algae growth is different than mold, and should be treated as such.  Identifying the discoloration of your windows is essential in resolving it, and once you’ve determined that it’s algae, you can use the proper methods in removing it.  It’s not difficult, but it does require the right products and tools to remove it.

Algae Growth Conditions

Certain conditions must exist in order to notice algae on your windows. Algae growth is a natural process that combines water, natural light and the right temperature conditions. In order to prevent algae growth on your windows, the right approach would be to check your windows for any leaks.

If you have drafty windows then it’s possible that water can leak inside your window panes which can cause algae to grow inside. To counter that, you’ll have to apply window sealants to your windows but the best treatment for your windows is to get replacements.

At Feldco, we have factory trained installers ready to replace your windows with accurate measurements and installation to ensure that your windows are properly sealed from the outside. Speak to a product specialist and get a free quote online today.

Get a Free Quote

It's easy, fast and completely free. Get started below:

Yes, Quote Me! No, I'm Not Ready Yet