Made-to-measure uPVC, aluminium and wood windows with high thermal performance, sold without middlemen and installed under a 10-year guarantee. And our team speaks English, from the first call to the final check.
4.8/5 · 328 verified reviews
100% free • No obligation • GDPR-protected data
Our head office is right here in Overijse, at Brusselsesteenweg 321, with direct access to the Ring and the E411. Overijse is a Flemish, Dutch-speaking municipality without language facilities, yet many non-Dutch speakers live here, between the Sonian Forest and the IJse valley. If that’s you and your windows need replacing, we can help in English – and we’re only a few minutes away.
Overijse is known for its hillsides and its table-grape glasshouses, and much of its housing consists of villas and houses surrounded by gardens, in Jezus-Eik, Maleizen, Tombeek or the centre. In this setting, projects are often about light as much as insulation: large aluminium sliding patio doors onto the terrace, wider living-room windows, a front door that matches the rest of the façade. uPVC remains an excellent option for bedrooms and smaller rooms, with very good insulation and little maintenance.
On the edge of the forest or at the bottom of the valleys, some façades stay in shade and damp for long periods. Glazing, double or triple, is then chosen according to the orientation of each room rather than uniformly. A north-facing bedroom and a south-facing living room do not have the same needs, even under the same roof.
Our windows are CE-certified and installed with a 10-year guarantee. We also work in the neighbouring municipalities, from Hoeilaart to Tervuren and Huldenberg, as well as in La Hulpe and Rixensart, on the other side of the language border.
Living in Overijse means grants and the energy performance certificate (EPC) come under the Flemish Region, not Wallonia or Brussels – see the section below. Dealings with the municipality and the Region are in Dutch: we help you understand what’s being asked and gather the technical data sheets for your new windows, without ever promising a grant amount. If you rent, start by getting your landlord’s written agreement, as replacing windows is the owner’s decision.
No middleman margins: you deal directly with the team that designs, adjusts and oversees the installation of your windows and doors, right down to the finishing touches.
Save on your renovation by cutting out the middlemen. A transparent quote, line by line.
No reseller margin
Belgian building rules, listed façades, co-ownership approvals: we explain everything clearly in English, by phone, by email or on site.
English-speaking advisors
High thermal-performance windows, supplied with the technical data you need for your EPB (PEB) energy certificate.
Technical file supplied
HR++ double or triple glazing: instant comfort and lower heating bills from the very first winter.
Double or triple glazing
We look at your needs and point you honestly to the right windows for your budget: uPVC, aluminium or wood.
A careful, free measuring visit at your home, so there are no surprises on installation day.
Respect for your home, protected floors, airtight sealing and a clean site when we leave.
We handle everything, from your first quote to after-sales service.
Describe your project online and receive your priced offer within 24 hours, with no obligation.
A technician comes to your home to take exact measurements, free of charge.
Your windows are manufactured to the exact dimensions taken at your home.
Our qualified fitters install everything precisely and leave your home clean.
We remain available after installation for any question, in English or in French.
Our advisors will guide you by phone, free of charge, in English.
See how our clients in Brussels, Namur and Liège added value to their homes while cutting their energy use.
Brussels
6 uPVC windows + door
“I had 6 uPVC windows and a front door installed. The result is excellent, and the installation was done in a single day, just as André promised. No more draughts at all!”
Mark L.
Homeowner
Namur
Aluminium windows
“A very good company, responsive and professional. The aluminium windows are beautiful and the difference in thermal insulation is impressive.”
Virginie L.
Homeowner
Liège
Full renovation
“I recommend Renov'Châssis to all my clients. The quality of the products and the reliability of the team are faultless. A partner you can trust.”
Kenza B.
Professional client
In Flanders, renovation support comes from the Flemish Region through Mijn VerbouwPremie, reformed on 1 July 2025. For windows, it covers high-efficiency glazing, its conditions depend on your income category, and replacing windows comes with a ventilation requirement. Check your situation on vlaanderen.be (in Dutch) before ordering.
We provide the technical specifications of the windows we install, useful for your application and for the home's energy performance certificate (EPC).
Information checked on 17 October 2026.
No. Overijse is in the Flemish Region, so Flemish support and the Flemish energy performance certificate (EPC) apply. We help you prepare the useful technical documents, but cannot guarantee any amount.
A replacement that does not change the look of the façade is generally simpler than an alteration. If the dimensions change, if the colour is very different or if the property is protected, check with the planning department of the municipality of Overijse before ordering.
Once we've measured up at your home, your free, detailed quote arrives within 24 hours. Take your time to read it, and ask us anything before you decide – we're happy to go through it in English.
Free quote within 24 hours, then a technician comes to measure up at your home, free of charge. We explain everything in English.
Your window quote in 2 minutes
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