How often should I get my windows cleaned?
After more than 18 years running a window cleaning company in Calgary, this is one of the most common questions I get from homeowners, property managers, and business owners.
The short answer is simple: windows should be cleaned whenever they become dirty.
That’s not just my opinion. According to Glass Association of North America (GANA) standards, windows should be cleaned regularly to maintain their appearance and prolong the life of the glass.
But in practice, most people want a clearer guideline. So let’s talk about what I typically recommend for Calgary properties, what causes windows to deteriorate, and the warning signs that you’ve waited too long.
The Simple Rule of Thumb
For most properties in Calgary, a practical cleaning schedule looks like this:
Homes
Exterior: Twice per year (spring and fall)
Interior: Once per year
Restaurants
Interior & exterior: Monthly
Retail storefronts, Offices and Customer-facing businesses
Exterior: Monthly
Interior: Quarterly or semi-annually
Industrial properties
Annually
These are general guidelines. The real question should always be:
Is the window dirty? And does it affect our businesses first impression?
If a window becomes dirty the day after it’s cleaned, it will remain dirty until someone cleans it again.
And the longer contamination sits on glass, the more damage it can cause.
Window Cleaning Isn’t Just About Appearance
Many people assume window cleaning is purely cosmetic.
It’s not.
Window cleaning is preventative maintenance that protects one of the most expensive and visible components of a building: the glass itself.
When contaminants sit on glass too long, they can chemically bond to the surface, causing permanent damage.
Common culprits include:
hard water minerals
bird droppings
environmental dirt and dust
construction debris
oxidation from window screens
Once these materials start etching into the glass, the problem becomes far more expensive to fix.
In severe cases, the only solution is replacing the glass entirely.
Calgary’s Biggest Window Problem: Hard Water
In Calgary, the single most damaging issue we see is hard water staining.
This is especially common on buildings with:
metal or stone facades
poorly aimed irrigation systems
sprinklers spraying directly onto glass
When water evaporates, it leaves behind minerals such as calcium. Over time these minerals bond to the glass surface and etch deeper and deeper into it.
If caught early, these stains can often be removed.
If left too long, the damage becomes permanent.
A Real Example
We once cleaned a high-rise building in downtown Calgary that hadn’t had its windows cleaned in 15 years.
The hard water staining had become so severe that the glass had lost its transparency.
Even after we cleaned the windows, the surface of the glass was permanently etched.
The result?
The building had to replace large sections of glass.
Regular cleaning would have prevented that.
Businesses Often Underestimate How Important Clean Windows Are
Two types of properties consistently underestimate how often they should clean their windows:
Storefront Businesses
Gas stations, retail stores, dealerships, and offices that face the public all rely heavily on first impressions.
Your windows are often the first thing customers see.
Psychologically, people associate clean windows with a clean business.
If the windows look dirty, many customers subconsciously assume:
the business is poorly maintained
the staff doesn’t care about details
the inside might be just as dirty
For restaurants especially, clean windows communicate something very important:
Clean windows suggest a clean kitchen.
That’s why many restaurants choose to have their windows cleaned monthly or even more frequently.
Newer Industrial Properties
Industrial buildings often overlook window cleaning because it isn’t seen as essential.
But many modern industrial properties:
host investors
lease space to tenants
receive customers or partners
Clean windows are one of the least expensive ways to improve the perceived value of a property.
When someone drives up to a building, the glass is one of the largest visible surfaces.
If it looks neglected, the whole building feels neglected.
Warning Signs Your Windows Are Overdue for Cleaning
After thousands of jobs over the years, there are a few clear signs that windows have been left too long.
Hard Water / Calcium Stains
One of the most common red flags is white or cloudy spotting that doesn’t wipe off easily.
These usually come from:
sprinkler overspray
mineral dust in rain
runoff from building materials
If these stains sit long enough, they can permanently etch the glass.
Bird Droppings
Bird droppings contain uric acid, which can damage glass surprisingly quickly.
When baked in the sun, they can:
stain the glass
etch the surface
leave permanent halo marks
Spider Webs & Droppings
Spider droppings appear as small black or brown ink-like dots.
They commonly show up:
under soffits
around window frames
near exterior lights
If left long enough, they can stain both glass and frames.
Construction Debris
On newer homes or buildings, we often see materials stuck to the glass such as:
concrete splatter
stucco
paint overspray
silicone
adhesives
If these are not removed properly and early, they can harden and scratch the glass during cleaning.
Screen Oxidation Staining
Older windows sometimes show a hazy grid pattern that matches the screen mesh.
This happens when:
aluminum screens oxidize
rain washes the oxidation onto the glass
Over time this can create a permanent haze.
Screen Burn and Edge Staining
Another common issue is dark staining around the edges of windows where screens sit.
This occurs when:
dirt accumulates between the screen and glass
moisture traps contamination
Over time the debris stains the glass surface.
The Real Answer: Clean Them Before They’re Damaged
People often ask:
“How often should I clean my windows?”
The better question is:
“How long can contamination sit on my glass before it starts damaging it?”
Once minerals, acids, or debris begin bonding to the glass surface, the cost of restoration increases quickly.
Regular cleaning helps:
maintain appearance
protect glass surfaces
avoid expensive replacement
improve the perception of your home or business
And compared to replacing glass, window cleaning is one of the least expensive forms of building maintenance you can do.