The choice of equipment for a modern home is no longer reasoned product by product. Since September 2026, the refocusing of public aid on large-scale renovations requires thinking of each technical component as part of a global system. Ignoring this logic means losing access to funding and degrading the actual performance of the building.
Thermal compatibility of equipment: the trap of isolated sizing
We regularly observe projects where the choice of an air-water heat pump precedes the study of heat losses. The result: an oversized device that cycles continuously, premature wear of the compressor, and a real COP much lower than catalog data.
Thermal sizing conditions every equipment decision. Before selecting a generator, one must know the target thermal resistance of the walls, the air renewal rate, and the need for hot water. These three parameters determine the necessary power, the type of emitter (low-temperature underfloor heating, radiators, ducted systems), and the associated water regime.
An underfloor heating system operates at a regime of 35 °C, whereas conventional radiators often require 55 °C or more. Choosing emitters before insulation means fixing a temperature regime that subsequently limits generator options. We recommend locking in the insulation and ventilation package before making any decisions on heating.
To compare technical characteristics post by post, the equipment on Maison Info details specifications by product category and facilitates the coherence of the different packages.
Large-scale renovation and MaPrimeRénov’ 2026: what it changes for equipment choices
Since the start of the 2026 school year, occasional insulation work (walls, attics, roofs, windows), ventilation (VMC), certain water heaters, and wood stoves are no longer part of the “gesture” pathway of MaPrimeRénov’. They are only funded within the framework of a large-scale renovation aimed at achieving a gain of several energy performance certificate (DPE) classes.
In practical terms, installing a dual-flow VMC alone or replacing windows without addressing the rest of the envelope no longer qualifies for aid. The project must simultaneously include insulation, ventilation, and a decarbonized generator to remain eligible.
Exclusion of fossil fuels in funded pathways
The latest regulatory developments tighten the place of gas and oil. In supported large-scale renovations, any equipment installing or maintaining fossil heating is excluded from funding. This mechanically directs towards heat pumps, solar thermal, or certified biomass.
For a homeowner who hesitates between keeping their recent gas boiler and switching to a hybrid heat pump, the answer depends on the planned work package. If the project aims for a jump of two DPE classes, maintaining gas compromises eligibility. The decision is no longer just technical; it is financial.
Ventilation and air tightness: the underestimated component in modern homes
A highly insulated envelope without appropriate ventilation generates rapid pathologies: condensation in the walls, mold, degradation of indoor air quality. Ventilation is not a comfort accessory; it is the structural complement to insulation.
A dual-flow VMC with a high-efficiency heat exchanger recovers the majority of the heat from the extracted air. The additional cost at installation compared to a simple hygroscopic flow pays off more quickly as the envelope performs well, since losses through air renewal become the dominant factor.
Some discriminating criteria for choosing a dual-flow VMC:
- The efficiency of the heat exchanger: aim for a certified exchanger with a recovery rate above 85% according to the Eurovent protocol
- The noise level of the unit: below 30 dB(A) at nominal flow for an installation in a habitable space, otherwise plan for a dedicated technical room
- The filtration class: F7 minimum on the fresh air to filter fine particles, with easy access for filter changes
- The management of condensates: in cold climates, the exchanger produces water that must be evacuated without risk of freezing in the network
Hot water and energy management: coupling the components
The thermodynamic balloon is emerging as the standard solution in modern homes. It captures heat from the ambient air (or air extracted from the VMC) to heat water, with a performance coefficient significantly higher than that of an electric resistance water heater.
Coupling the thermodynamic balloon with the air extracted from the dual-flow VMC presents a dual advantage: it improves the balloon’s efficiency (air at a stable temperature) and avoids the need to install an additional air intake.
Management and load control
An energy manager capable of shifting hot water production to off-peak hours or during peaks of photovoltaic production significantly reduces operating costs. We recommend checking the compatibility of the balloon with common control protocols (dry contact, EDF signal, open home automation gateway).
Proprietary closed systems limit evolution possibilities. Prioritizing equipment compatible with open protocols ensures the ability to integrate a future hybrid inverter or a storage system without replacing the manager.
Balancing comfort, performance, and operating budget
The cost of equipment is not reflected on the price tag. A low-temperature underfloor heating system costs more to install than radiators, but it allows for the optimal performance of a heat pump, which reduces the annual bill over the entire lifespan of the system.
The decision grid we use is based on three axes:
- The total cost over fifteen years (investment + maintenance + energy), not just the purchase price
- Eligibility for aid within the framework of a large-scale renovation, which can absorb a significant part of the initial extra cost
- Technical reversibility: equipment that can be evolved without breaking the existing system (adding solar panels, replacing the generator, home automation extension)
A well-designed project balances these three axes simultaneously. Choosing the cheapest equipment for each component often results in an incoherent set whose total cost exceeds that of an integrated solution from the start.
