Pierre-Louis Guhur

On a job site, a few degrees of difference in orientation or tilt can quickly change output. With simple coefficients and clear tables, you can check in two minutes whether the planned surface holds up, or whether an adjustment is worth it — protecting your pricing and avoiding bad surprises at handover.

5 min read

On a job site, the structure carries a lot of weight in the carbon footprint. Yet you can make real gains without upending your habits, by working the mix design, the additions and the right execution choices. The right reflex is to think it through as early as the pricing stage: what volume, what performance, and where it really counts.

5 min read

On a solar job, a few degrees can change everything. By fine-tuning panel orientation and tilt right at installation, you secure year-round production with no extra material cost, and the client sees the difference on their bill. And when the roof imposes constraints, you have simple levers to limit losses.

5 min read

When you insulate roof spaces by blowing in insulation, the real challenge is getting a layer that's even, dry, and well protected over time. Both mineral wool and cellulose wadding can do the job, provided the choice is adapted to the site, access, moisture, and fire requirements. Here we help you decide quickly, and install cleanly the first time.

6 min read

Sarking has no dedicated national standard of its own: it is a proprietary system covered by a technical approval, while the covering above stays governed by the roofing standards. And re-covering a roof triggers the insulation duty of the French decree of 30 May 2016, with a roof pitched below 60° to be brought up to 5.2 m²·K/W in the coldest climate zone.

5 min read

In winter, you're looking for simple ways to gain a few degrees without adding to the bill or complicating the job. A well-designed glazed space, built against the facade, can capture the sun, store some thermal mass and take the load off heating when everything is properly set. It's up to you to turn that space into a real asset, with the right choices for orientation, ventilation and shading.

5 min read

Stratification is not a comfort question, it is what sets the temperature the generator sees at its heat exchanger inlet. The French EPC calculation method puts a number on the effect of cylinder geometry: a loss coefficient of 0.33 for a horizontal unit against 0.20 for a class C vertical, which is 419 kWh a year apart at 200 litres. Here is the physics, the on-site measurement protocol and the settings that destroy the layers.

6 min read

On an external wall insulation job, the real headaches rarely start on the large façade surfaces. They happen at window reveals, sills, parapets, and all those small junctions that decide whether the finish is clean or whether rework keeps piling up. By mastering these singular points, you save time, secure the sealing, and deliver a clean result, without last-minute improvisation.

5 min read

In an apartment building, hot water is not a detail. It is a line item that weighs on the bill and quickly triggers calls when it runs short. In centralised collective systems, production backed by solar energy can really make a difference, provided you size it correctly, connect it properly, and plan operation from the start.

5 min read

On site, bonded and mechanically fixed EPS remains a safe bet when you need an exterior system that's fast to install, well mastered by crews, and easy to price. If you secure the substrate, flatness, and layout from the start, you save time on rework and avoid disorders that get expensive in callbacks. Here's a rundown of the right installation habits, the ones that make the difference between a façade that's just "put up" and one that lasts.

5 min read

In an apartment building, measuring heat "as fairly as possible" on paper is tempting. On the ground, these small devices can quickly become a source of disputes, between poorly balanced radiators, airing habits, and insulation work that varies unevenly from one home to another. It is well worth knowing their limits so you can explain things simply, make the right diagnosis, and avoid bad surprises at the end of the heating season.

5 min read

When the load-bearing wall also acts as insulation, you save space, simplify site details, and limit thermal bridges from the design stage onward. On the ground, everything comes down to your material choices, moisture management, and envelope continuity, especially around floors and window openings. Well designed, this approach gives you a solid, high-performing "all-in-one" wall that is easier to explain to your client.

5 min read

On a job site, the right domestic hot water system often comes down to three points. Flow rate at the outlets, available space, and the home's usage profile. Instant or tank, you save time by settling these criteria first, before talking about power, volume and connections.

5 min read

On site, the most common way to insulate from the inside is to pair an insulation material with a plasterboard facing — clean, fast, and compatible with most rooms. For you, the tradesperson, everything comes down to the details: a sound substrate, flatness, continuity of the insulation, and careful treatment of sensitive points around cables and window frames. Done well, this installation saves you time while avoiding callbacks linked to moisture and thermal bridges.

5 min read

On site, choosing modules is never 'just a question of price.' Monocrystalline or polycrystalline, you're trading off power per m², visual appearance, and flexibility when roof space is tight. By setting the right benchmarks from the quote stage, you avoid production disappointments and secure an installation that's consistent with the roof, orientation and the client's budget.

5 min read

On site, the choice of ventilation unit directly affects comfort, actual airflow and noise once the vents are fitted. Between single-speed and two-speed, everything comes down to how the home is used, the moisture load to manage, and the level of control you want to leave the client. By setting this out clearly at the quote stage, you avoid callbacks and secure a clean installation.

5 min read

In a damaged home, it's often the small defects that trigger the big callbacks. Moisture setting in, odours coming back, occupants complaining and your schedule blowing up. By spotting the signs quickly and setting up a simple diagnosis, you secure your work, reassure the client and turn a complicated renovation into a clean, controlled intervention.

5 min read

When a project goes off the rails, it's often a small decision made early on that ends up costing dearly in time, margin and reputation. As a tradesperson, you can secure the result from the preparation stage, by framing the needs, the interfaces between trades and the checkpoints at the right time. The idea is simple: avoid recurring pitfalls before they turn into rework.

5 min read

When you're looking to improve comfort without pushing up the bill, the ground can become a real ally. By routing fresh air through a buried duct, you temper it before it enters the building, which helps smooth out cold and heat peaks. The result is a solution that's simple to explain to the customer, provided you take care with the layout, drainage and maintenance from the job-site stage.

5 min read

On a job site, every hour saved counts. With a monobloc solution, you cut down on the connections to make and move faster, with fewer sensitive points to watch. From preparation to commissioning, you keep control of a clear process, so you deliver cleanly and without surprises.

5 min read

On the day the client walks the site with you, everything comes down to the details. With a simple method and a few checkpoints, you secure quality, avoid costly rework, and walk away with a clear file. For you, it's the moment to turn the end of a job into a real, clean validation, with no grey areas.

5 min read

On a whole-house retrofit, the difference is often made by day-to-day organisation. When the right trades arrive at the right time, you avoid rework, slipping deadlines and impatient clients. With a simple method for preparation, follow-up and handover, you keep control of quality, schedule and margin.

5 min read

A heating circuit is a bit like a bloodstream. Once sludge and oxidation set in, breakdowns come faster and efficiency drops. As a tradesperson, you can secure the system right from initial fill or after a power flush, with protection that's simple to apply and easy to check over time. The result: fewer callbacks, circulators that last, and client comfort that stays stable season after season.

5 min read

On a facade, external thermal insulation (ITE) changes everything, including fire behaviour. As a tradesperson, you need to secure the job from the design stage onward — material choices, critical junctions, continuity, and how penetrations are treated — to stop a fire from spreading through the building envelope. With the right rules and the right reflexes, you gain in compliance, peace of mind and quality of installation.

5 min read

Solar heat transfer fluid is not a consumable you swap on a calendar: it is a product whose antifreeze concentration is capped at 50 % by the solar thermal reference standard, whose fresh pH sits between 9.0 and 10.5, and which decomposes above 200 °C while a stagnating collector can exceed that figure. Here are the four values to record on a service visit, the thresholds that trigger a drain, and what goes on the service record.

5 min read

Choosing between a solar water heater with an integrated backup and one with a separate backup is not a comfort decision: it decides the declared water heating efficiency of the package, the class required of the solar cylinder, and the number of service points you commit to holding. Here is the comparison of the two architectures and the product requirements that apply either way.

6 min read

The cold wall effect can be measured, not guessed. BS EN ISO 7730 links radiant temperature asymmetry to the percentage of dissatisfied occupants, and that curve explains the “I heat the place and I'm still cold” complaint in a dwelling held at 20 °C. For the trade, the job is to record the right quantity during the technical survey, then derive the measure that corrects it: wall insulation, thermal bridge treatment, or window replacement.

5 min read

As your clients grow older, thermal comfort becomes a health issue as much as a wellbeing one. It's up to you, as a tradesperson, to propose work that's simple to explain and genuinely effective — targeted insulation, well-adjusted ventilation, suitable heating — to avoid rooms that are too cold in winter and stifling in summer. You gain clarity, they gain daily peace of mind.

5 min read

Felt temperature has a calculation definition, the operative temperature, which is the average of the air temperature and the mean surface temperature. It explains why a home at 20 °C of air can feel cold, and above all it supplies the numbers behind an insulation job: every degree gained on the surfaces buys a degree off the air setpoint at equal comfort. Here is the calculation, the regulatory framing, and what to record on a survey.

5 min read

When a client asks you for a quick estimate, you don't have time to redo ten calculations by hand. With automated calculations, you gain consistency, limit oversights, and can move faster from the site survey to a clear proposal. The idea is simple: you keep control of the assumptions, and the tool does the heavy lifting, always the same way. The result is fewer back-and-forths, and technical decisions that are easier to justify to the client.

5 min read