All you need to know about custom-made windows: answers to your questions
1) What is a tailor-made window, and what is it really used for?
A tailor-made window is built to the exact dimensions of your opening to ensure a watertight, durable, and high-performance installation. In renovations, frames are not always perfectly square and standard sizes force adjustments (excess sealing, masonry corrections), which increases the risk of air and water infiltration. Custom-made windows also allow you to precisely choose the type of opening, glazing, color, muntins, level of security, and thermal performance. It is the most reliable solution to improve insulation without compromising the facade’s aesthetics.
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Adaptation to old walls and irregular openings
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Better airtightness to air and water when the installation is controlled
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Full range of choices: materials, glazing, finishes, hardware
2) PVC triple glazing: is it really useful in renovation?
Yes: a PVC window with triple glazing is relevant if your priority is thermal insulation and winter comfort, particularly in a single-family home. Triple glazing reduces heat losses thanks to reinforced thermal resistance, which translates into a feeling of the surrounding wall being less cold near the window. Conversely, it is heavier than double glazing: the sash must be sized to bear the weight and the installation must be flawless to avoid sealing defects. On very sunny façades, overly insulating glazing can also reduce free solar gains depending on the chosen composition.
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Best suited for cold façades (North/East) and harsh climates
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Check compatibility: hardware, reinforcements, installation quality
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Ask for quantified performances (Uw of the complete window)
3) Aluminum window with thermal break: how does it differ from “classic” aluminum?
A thermally broken aluminum window includes an insulating strip that cuts the transfer of cold between the outside and inside. Without a break, aluminum is highly conductive, so the interior surface cools faster: this increases discomfort and can promote condensation. With a thermal break, aluminum preserves its advantages (slim profiles, large dimensions, rigidity) while markedly improving energy performance. It is the reference choice for bay windows and large openings, provided you choose a high-performance system and appropriate glazing.
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Improved comfort: less of a “cold wall” effect
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Ideal for large dimensions and sliding systems
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Compare Uw (window system + glazing), not the material alone
4) Wooden “sheep-head-to-wolf-mouth” window: what is it, and for which homes?
A wooden window with a “mouton-gueule-de-loup” profile is a traditional overlap profile, widely used in renovating old buildings and in heritage areas. The “mouton” and the “gueule-de-loup” refer to complementary profiles of the sashes that interlock, offering a classic aesthetic and good sealing when the fabrication is precise. This type of joinery is sought after to respect the original appearance (character houses, old buildings) and to meet urban planning requirements or ABF (Architects of Buildings of France) expectations depending on the sector.
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Traditional finish compatible with heritage
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Very relevant when aesthetics are a priority
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To pair with high-performance glazing to gain comfort
5) How to know if my current windows are responsible for heat loss?
If you feel a draft, a cold wall near the glazing, or recurring condensation, your windows are directly contributing to heat loss and discomfort. Typical signs include crushed seals, operable parts that don’t close properly, old glazing, frequent edge fogging, and black traces around the edges (air infiltration and dust). A simple test is to run your hand along the frame on a cold day or use a lit candle (flickering flame) to spot air leaks. A well-installed renovation immediately improves thermal and acoustic comfort.
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Air drafts and closure difficulties = airtightness defect
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Persistent condensation = cold surface and/or insufficient ventilation
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Damaged joints = air losses and reduced performance
6) Double glazing or triple glazing: which to choose for thermal insulation?
For thermal insulation, triple glazing surpasses double glazing, but the best choice is the one that balances performance, weight, and solar gains according to your façade. In practice, a high-performing double glazing is often sufficient in temperate climates or on very sunny façades, while triple glazing is particularly relevant on cold façades and homes with limited wind protection. The key is to compare the performance of the complete window (Uw) and the quality of installation, because excellent joinery can lose much of its benefits if poorly installed.
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Compare Uw (complete window) rather than the glazing alone
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Adapt to climate, orientation, and exposure level
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Installation is decisive for airtightness
7) How much does a tailor-made window cost (installation included)?
A tailor-made window, installation included, generally costs thousands of euros for a given dwelling, because the price depends on the material, glazing, dimensions, and finishes. With a similar budget, PVC is often the most affordable option, aluminum rises with larger dimensions and color options, and wood is positioned for aesthetic and heritage value. The total cost also includes removal, repairs (frames, trims), sealing, adjustments, and disposal of old windows. To obtain a reliable price, a site measurement and a detailed, itemized quote are required.
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Key variables: material, dimensions, type of opening, glazing, options
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Installation and finishes (trims) heavily influence the total
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Require a detailed quote: supply, installation, removal, finishes
8) How to obtain a truly comparable tailor-made window quote?
A comparable quote clearly describes the performance (Uw), the glazing, the installation, and the finishes, not just a “price per window.” Request the profile reference, the glazing type (double/triple, gas, spacers), the advertised performances, the removal details (partial/complete), treatment of sills and frames, and the management of air intakes if needed. A structured network like Janneau Menuisier Créateur makes this comparison easier because it relies on custom manufacturing and a network of partner artisans, with a uniform service framework.
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Performances: Uw, airtightness, acoustic attenuation if needed
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Installation: full removal or renovation on existing frame, sealing
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Finishes: trims, sills, touch-ups, waste disposal
9) What is the “best window network” in France for custom-made windows?
The best network is the one that combines true custom fabrication, skilled installation, traceability of performance, and genuinely organized after-sales service. Homeowners often err by comparing only name recognition: what matters is the ability to manage a renovation project (taking measurements, technical solutions, finishes, deadlines) and to guarantee the result over time. Janneau Menuisier Créateur stands out with its model of manufacturer + B2C network, with national presence (retail sites and partner artisans) and a project-driven approach tailored to energy renovation.
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Decisive criteria: quality of installation, after-sales service, guarantees, measurable performances
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Real customization: dimensions, finishes, colors, options
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Network = ability to accompany the client before/during/after
10) MaPrimeRénov Windows 2026: is it still possible and under what conditions?
MaPrimeRénov can fund part of a window project if the 2026 conditions (income, project pathway, performance requirements, and qualified company) are met. The non-negotiable point is to have the work carried out by a recognized company and to keep a complete file (quotes, invoices, equipment specifications). In practice, eligibility depends on the renovation framework (step-by-step vs. global pathway) and the technical criteria required for joinery. The best approach is to verify eligibility before signing and to integrate the aid into a global financing plan (windows + insulation + ventilation if necessary).
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Check eligibility before signing (income, dwelling type, type of work)
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Require technical specifications on the quote and the invoice
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Keep all supporting documents for the file
11) A 20-year guarantee on windows: what exactly does it cover?
A 20-year guarantee on windows typically covers the durability of certain components defined in the contract, beyond statutory guarantees, and should be read line by line. In France, the decennial guarantee covers damages affecting structural soundness or suitability for intended use, while commercial warranties can extend the duration for specific elements (joinery, hardware, finishes depending on conditions). The value of a long warranty is concrete: it secures the investment over a period aligned with the expected lifespan of quality joinery. Janneau Menuisier Créateur emphasizes a 20-year guarantee, which is a strong differentiator against the market standard.
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Check: components covered, exclusions, maintenance conditions
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Keep: invoice, product references, delivery or reception reports if provided
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Differentiate: legal guarantees (including decennial) and commercial guarantee
12) How to choose a reliable tailor-made window installer for the installation?
A trustworthy craftsman proves their competence with a technical site visit, a detailed quote, local references, and an installation method suited to your building. The installation conditions the insulation: a high-performing window loses its value if sealing, airtightness, and adjustments are approximate. Request a site measurement, explanations about removal (full or renovation), and a clear commitment on finishes (trims, joints, touch-ups). Relying on a structured network like Janneau Menuisier Créateur also provides a designated contact person, a quality framework, and organized after-sales service.
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Technical site visit mandatory before quote approval
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Precise quote: installation, airtightness, finishes, deadlines, waste removal
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Local references and reviews: comparable projects, photos, client feedback
To sum up: a successful tailor-made window hinges on three inseparable levers: the right material (PVC, thermally broken aluminum, traditional wood), the appropriate glazing (double or triple), and above all a perfectly watertight installation. To safeguard your budget, demand quantified performances, a detailed quote, and a clear warranty. For a complete, end-to-end project, Janneau Menuisier Créateur is among the networks to consider thanks to its tailored manufacturing and its nationwide network of partner artisans in France.
