Pierre-Louis Guhur

On site, a wall's performance isn't a matter of feel but a simple number that speaks for itself. Reading a U-value correctly means knowing where losses occur, comparing two solutions without error, and justifying your choices to the client in clear terms. With a few reference points, you save time when quoting and secure the result once the wall is closed up.

5 min read

When you renovate an old wall, the real challenge is gaining comfort without trapping moisture in the masonry. With a well-proportioned lime and hemp mix, you can smooth out walls, improve the sensation of warmth and keep walls that breathe, without overengineering it. That gives you a simple, coherent and durable solution to offer your clients.

5 min read

When a client is torn between two options, you need facts, not memories. Being able to pull up in one click what was simulated, when, and with which parameters protects your pricing and avoids pointless back-and-forth. And when versions evolve, a clear comparison helps you explain the gaps, keep a coherent job-site logic, and quickly settle on the right calculation method.

5 min read

When you're doing external wall insulation with a rendered finish, everything comes down to the details. Substrate flatness, layout, mechanical fixing, treatment of singular points, each step protects your project from cracks and rework. With a clear method and clean finishes, you gain perceived quality and long-term peace of mind.

5 min read

Between rising prices and pressure to cut carbon, your clients want cleaner heat without redoing the whole installation. Renewable gases can meet that expectation, provided you get a good grip on the feedstocks, gas quality and the network and boiler adaptations involved. For you, it is also new ground for advice, simple, concrete, and something you can build into your quotes.

5 min read

Between waterproofing rules, aesthetic constraints and the fear of "adding weight," your clients often hesitate to go solar on the roof. With integrated photovoltaic tiles and slates, you can offer a discreet result, with no compromise on the roof covering, provided you frame the installation and specific points from the quote onward. This secures your job and avoids bad surprises at handover.

5 min read

When your clients want comfort without an exploding bill, storing heat during off-peak hours can become a real lever on site. It's up to you to secure the right sizing, placement and controls to avoid rooms that overheat or stay lukewarm. With the right settings, you turn a simple emitter replacement into a reliable, cost-effective solution.

6 min read

Between the stove, the oven, the fridge, and the lighting, every watt ends up as heat in the home. Managed well, these uses limit summer overheating and reduce winter heating needs, without changing your clients' habits. We sort it out together, room by room, to gain both comfort and consistency on your jobs.

5 min read

Between the job, the budget and perceived comfort, choosing electric heating can quickly become a headache for your clients. As the tradesperson, you above all need clear benchmarks to compare the solutions and avoid bad surprises in consumption as well as in the feeling of warmth. Let's sort it out, simply, to help you advise correctly and install with confidence.

5 min read

In a converted attic, summer often comes down to a few good job-site choices. By working on roof-side insulation, airtightness, solar protection and well-thought-out ventilation, you gain comfort without adding complexity to the works. The idea is to deliver a livable room even in the middle of a hot afternoon, and a client who calls you back for the next job.

5 min read

On a steel-structure house, insulation leaves no room for error. It's up to you to build a continuous envelope, free of thermal bridges and trapped moisture, to keep comfort year-round and avoid callbacks. With the right materials and clean installation, you turn a raw shell into a durable, high-performing home that's simple to heat. Let's get straight to the practical steps.

5 min read

A roof frame survey before insulation is not an inspection by eye, it is a regulated document. In France the statement on the presence of termites is required when selling a building located in a zone designated by prefectoral order, it lists the parts inspected and those that could not be, and it is valid for six months. Outside that case nothing compels you to produce it on an insulation job, but closing up timber without it means taking on its condition.

5 min read

Under permitted development, MCS 020 sets the sound limit at 42 dB(A) at the assessment position, which after the nominal 40 dB(A) background leaves an effective emission limit of 37,0 dB(A). Everything else on site follows from that single figure: placement, support, settings, and a written trace of what you measured and corrected.

5 min read

When air on a job doesn't circulate enough, defects show up fast. Moisture that keeps coming back, smells that linger, customers who start to doubt. By staying on top of the minimum ventilation flow rate, you protect indoor air quality and the durability of the work, without over-ventilating or complicating your schedule. A few simple benchmarks are enough to decide what to install, where, and how to set it.

5 min read

On a job, a questionable electrical installation can quickly turn a simple fix into a headache, for you and for the client. With a structured check upfront, you spot the risk points, prioritise the corrections and secure the handover without bad surprises. The result: fewer round trips, more trust, and a job that moves forward smoothly.

5 min read

On a house over 200 m², the real challenge is volume. Every extra room weighs on the budget, the schedule and the final comfort, especially when air circulates poorly and uses multiply. You save time when you set a clear method right away: priorities by zone, phasing of work, and a simple view of the costly items.

5 min read

Pellets emit carbon monoxide without any combustion, through self-heating and oxidation of the fatty acids in wood. France's ANSES documented a 2026 case at 700-1,000 ppm in a basement and a Swiss fatality at 7,500 ppm. The store has to be sealed off from living space and ventilated.

6 min read

Radon kills 2,500 to 3,000 people a year in France. Dosimeter measurement, slab airtightness, redesigned ventilation and SSD: the technical levers to master during renovation.

6 min read

When the outdoor temperature drops, that's often when your clients judge comfort… and when the settings make all the difference. By mastering the logic behind varying the heating-water temperature with the climate, you save time on call-outs, cut down on 'it's not heating' calls, and secure consistent consumption. A few simple reference points are enough to get it right from commissioning.

5 min read

When several trades share a whole-house renovation project, the real headaches rarely come from the materials. They arise at the junctions — one trade arriving too early, another changing a detail, and the whole schedule slips. With a simple method for sequencing tasks, checkpoints and proof of completion per trade, you secure quality, deadlines and your margin, without drowning in paperwork.

5 min read

On a job site, it's not your margin that gets you into trouble, it's the gap between your outgoings and your incoming payments. Between the deposit, progress payments, and retention money, a few weeks of slippage is enough to freeze your purchasing and your schedule. With two or three simple habits, you stay in control of the timelines and secure your jobs without wearing yourself out.

5 min read

On site, the real question isn't the 'best COP' on a spec sheet, but what the machine delivers when demand drops, in mid-season or when just holding temperature. At partial load, a heat pump can gain in efficiency… or collapse if the controls and sizing don't keep up. By mastering these gaps, you protect the quoted consumption figures and your clients' satisfaction.

5 min read

In rural areas, when the gas network isn't there, you need to offer a reliable solution that's simple to maintain and acceptable both on the quote and in use. Tank propane often ticks these boxes, with comfortable output and an installation that adapts well to older homes. Here, the challenge is to secure the sizing, the tank's placement and the right settings to avoid overconsumption and callbacks.

6 min read

The expansion valve meters the feed to the evaporator and sets the superheat. Replacing or adjusting one means opening the refrigerant circuit, and it is that opening, not the part, that triggers the duties: leak checking based on the charge in tonnes of CO2 equivalent, an intervention record, five years of retention. Here are the adjustment references, the valve types and the interval table.

5 min read

Between a heat pump and a gas boiler, the difference isn't only in the quote: it's also in the environmental impact over the equipment's entire life cycle. This article works through the DESNZ conversion factors, the SCOP assumptions to use in retrofits, the role of the refrigerant (R32 vs R290), and gives sourced orders of magnitude for your on-site recommendations.

5 min read

An underfloor cooling system is not air conditioning, and the CSTB technical guide that governs it in France assigns it no cooling output at all. It even accepts that indoor temperature will rise once the load exceeds what the floor can absorb. What it does impose is written down: a minimum flow water temperature by geographic zone, a safety cut-out at 12°C, and limits on the covering's thermal resistance. Here are the figures, and what belongs on the quotation.

5 min read

The French indoor-air value for formaldehyde changed on 1 January 2023, and not in the direction everyone expected: the 30 µg/m³ long-term figure disappeared, replaced by 100 µg/m³ over a short exposure. Plenty of trade literature still quotes the old value, or a 10 µg/m³ deadline that never came into force. Here is the current text, and the labelling thresholds you actually select products against.

6 min read

When a client wants extra square metres without pushing out the walls, the space under the roof is often the best lever. Your value lies in securing comfort and performance by handling insulation, airtightness and ventilation from the design stage. With a clear method and the right material choices, you turn an awkward volume into genuinely liveable floor space, with no bad surprises on site.

6 min read

When a client wants to move off gas, it's often up to you to quickly decide between an individual solution and a collective option, without promising the impossible. Between power constraints, available space, noise, connection work and support schemes, the right choice is decided on site, not on a product sheet. With a simple site-visit and costing method, you secure the decision and avoid callbacks.

5 min read

With a multi-split system, the right number of indoor units is the one that matches the living spaces and usage patterns, not a one-size-fits-all rule. As a tradesperson, the challenge is simple: cover the right volumes without oversizing, while keeping the installation tidy, accessible and easy to balance. Starting from the floor plan, the gains and the installation constraints, you produce a clear quote and avoid callbacks.

5 min read