Europe · Window Manufacturer
Internorm — Window Cleaning Guide
🇦🇹 Austria · Last reviewed by Justin Orloff
Quick Facts
founded
1931
hq
Traun, Austria
primaryMaterials
uPVC, uPVC/aluminium, timber/aluminium
glazingPartner
In-house, triple-glazing pioneer
marketTier
Premium
Brand at a Glance
- Founded: 1931
- HQ: Austria
- Market position: Europe's largest window manufacturer
- Frame materials: uPVC, uPVC/aluminium, timber/aluminium
- Glazing: In-house sealed units - triple glazing standard, Passivhaus-certified U-values, Low-E coatings; acoustic and safety glass options
- Key products: KF 410 (uPVC), KF 510 (uPVC/alu with I-tec Secure), Timber/alu series
- Certifications: Passivhaus, triple glazing pioneer
- Where they sell: Europe-wide via distribution partner network
- Warranty: 30-year serviceability assurance (maintenance-conditional)
- Official documentation: Internorm Fibel / Gebrauchsanweisung
- Care page: internorm.com
Product Range
- KF 410 (uPVC)
- KF 510 (uPVC/alu)
- Timber/aluminium series
Why This System
Three completely different frame systems live under one brand. Identify the material before you pick a cleaner. I-tec Secure conceals all hardware inside the frame and sash - no visible screws, hinges, or dirt grooves in the rebate. Rounded sash edges make the closing area faster to wipe than older tilt-turn designs. uPVC frames will permanently 'burn in' cleaning product residue if it dries on the surface - always rinse with clear water.
Step 1 of 2: Manufacturer Recommendations
Official Care Guidance
Step 2 of 2: The Orloffs Protocol
The Orloffs Protocol
This is how I clean Internorm windows. The tools and technique below come from 25 years of daily professional work on the glass. Every step has been tested on real installations and adapted specifically for Internorm systems.
Follow these steps in order. Each one builds on the last. This is the same sequence I use on every Internorm installation.
- 1
Preparation -- before any water touches the glass
Fill the bucket with at least 10 litres of water. Add soap for cleaning power -- enough to cut through environmental deposits, not so much you are fighting foam.
Before touching the glass, brush down the surface to remove loose dust, spiderwebs, and debris. Any grit left on the glass during the wash phase risks scratching during agitation.
Check the composite frame condition before you start. Confirm which cleaning product is safe for that surface before opening any bottle.
Cover anything below the windows that cannot be moved.
- 2
Agitation -- apply and work the solution
Dip the microfiber T-bar completely into the soap water, both sides. Remove excess water with your hand so it does not drip. Apply the solution across the entire glass surface with overlapping passes.
The goal is to fully dissolve and release every deposit from the glass surface. Anything not released during agitation gets transported across the glass by the squeegee as a smear.
For stubborn spots -- insect marks, salt residue, environmental deposits -- re-apply soap water and allow it to soak for a full minute before agitating again. Use more soap water, not more pressure.
For panels above arm reach: attach the T-bar to an extension pole. Work in sections -- top first, then middle, then bottom -- keeping each section wet until you squeegee it.
Rinse the T-bar cover regularly during the job. A dirty applicator causes microscopic scratches that accumulate over time.
- 3
Detail the frame edge before squeegeeing
Use your 100% cotton towelling rag, finger pressed into the fabric, to work into every junction and remove pooled soap water before the squeegee pass.
This prevents drips running down onto already-cleaned areas during squeegeeing and keeps soap water out of drainage channels.
On Internorm composite frames, pay particular attention to the bottom edge where glass meets the frame sill -- water pooled here runs into drainage openings and leaves residue over time.
- 4
The squeegee
Tilt the squeegee at a slight angle so soap water spills from one side of the channel only -- not both. If the rubber is jumping or squeaking, either the rubber is not lubricated enough or the glass surface has warmed.
Cutting in: start with the rubber blade making first contact on a dry edge of the glass.
Side to side: horizontal passes across the panel. Works well on wide sections. Top to bottom: vertical passes down the panel. Works well on tall narrow sections.
The J tune: one smooth unbroken motion top to bottom, wrist rotating at each end to reverse without lifting the rubber. The most efficient method on larger panels -- but it requires training before applying it to premium glass.
Wipe the rubber dry after every pass. Overlap each stroke by 2-3 cm.
- 5
Final edge detailing
After squeegeeing, there is always a residual line of water along the bottom edge and at the panel sides. Take a dry cotton rag, fold to a clean corner, and detail these edges in one smooth pass.
On Internorm frames, the bottom edge where glass meets the sill requires the most careful attention. Water left here runs into drainage and leaves residue that affects the next clean.
Rotate the rag to a clean section after every pass. If the rag picks up grit at any point, replace it immediately.
- 6
Frame wipe and hardware check
On Internorm frames, apply the appropriate product for each surface: pH-neutral for aluminium and glass, solvent-free for uPVC, barely damp cloth for timber. Never cross-contaminate products between surfaces.
Check that all drainage openings are clear and unobstructed. Water must be able to flow freely -- a blocked channel leads to accumulation that affects seal performance over time.
Operate every opening window through its full range. Stiff handles or resistance at locking points indicate hardware that needs lubrication. Flag it to the owner rather than forcing it.
What NOT To Do
- No razor blades or steel wool on glass.
- No alkaline solutions, acids, or fluoride-containing cleaners on glass.
- No nitro thinner, petrol, acetic acid, nail polish remover, alcohol, ammonia, or sulphur-containing products on uPVC.
- No orange or lemon-scented cleaning products on uPVC.
- No cleaning aluminium in direct sunlight or above 25 °C surface temperature.
- No abrasive or solvent-containing products on lacquered timber.
- Never let cleaning product residue dry on uPVC - always rinse with clear water.
- No steam cleaners on aluminium.
- No products that impair corrosion protection on hardware.
- Do not skip annual hardware lubrication - Internorm warns this can lead to sash failure.
Bundle Kits and Tool Recommendations
Bundle Kit
Cleaning Frequency
Clean every 4–8 weeks depending on environment.
Frequently Asked Questions
Field Notes
“Use the cleaning stay-arm (Putzschere). Internorm tilt-turn windows have a stay-arm that lets you tilt the sash beyond the standard tilt position, giving access to the outer glass surface from inside. Use it on upper floors. Glass and frames: minimum twice per year. Near industrial areas, railways, or busy roads, increase frequency. Contaminants left on uPVC can cause permanent staining. Internorm recommends annual servicing through their distribution partner network - hardware checks, gasket inspections, seal adjustments, functional testing. If someone else cleans your windows - a housekeeper, a regular cleaner, a property manager - they almost certainly have no specialist knowledge of Internorm's coatings. Pass this guide on to them.”
Justin Orloff
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