How to choose windows for a renovation
Start a renovation window choice with the building and project priorities, not the material. Assess window condition, facade, moisture, noise, dimensions, solar protection and ventilation. Then compare equivalent solutions with documented Uw and an installation-junction concept suited to the existing building.
1. Diagnose before replacing
Determine whether the problem lies in the glazing, seals, hardware, frame or wall junction. When the frame condition permits, also consider targeted refurbishment. Full replacement is not always the only response.
2. Define project priorities
Rank heat loss, draughts, noise, security, maintenance, daylight, appearance and summer comfort.
| Need | Request | Watch |
|---|---|---|
| Thermal | Uw, Ug, Uf, g | Dimensions and orientation |
| Acoustic | Whole-window rating | Joints, boxes and air inlets |
| Summer | g and shading | Large glazed areas |
| Maintenance | Finish and access | Seals, hardware and drainage |
3. Coordinate facade, ventilation and installation
Renewing windows and facade insulation together makes junctions and thermal bridges easier to resolve. If work is phased, allow for the future insulation plane. Increased airtightness also requires a ventilation strategy.
4. Compare genuinely equivalent quotations
Use the same sizes, openings, glazing, colour, accessories, removal and finishes for every option.
- Clearly identified drawings or measurements
- Calculated values for the configuration
- Included and excluded work
- Junction and sealing principle
- Shading and sill treatment
- Handover and final adjustment
Related guidance
Need personalised advice?
BO Fenster answers all your technical questions and prepares a free quote for you within 24h.
Request a free quoteFrequently asked questions
Quick answers
Should existing windows be repaired or replaced?
It depends on the frame, glazing, hardware, seals and project goals. Inspection avoids unnecessary replacement or inadequate repair.
PVC or aluminium for renovation?
Dimensions, design, performance, maintenance and budget decide. Compare complete windows with equivalent specifications.
Should facade insulation be done at the same time?
Coordination improves junction and thermal-bridge design. If work is phased, plan now for the future insulation layer.
Why check ventilation?
New windows often reduce air leakage. Air renewal must remain sufficient for indoor air quality and moisture control.