The RIBO system, now marketed under the T.One range by Aldes, is based on a centralized air-to-air heat pump. The treated air circulates through insulated ducts to supply outlets distributed throughout each room. The sizing of this installation directly affects its efficiency, consumption, and the lifespan of the components. An undersized system will run at a constant overload, while an oversized system will cause short cycles that wear out the compressor and degrade thermal regulation.
Room-by-room thermal assessment: the basis for RIBO sizing
Before choosing a heat pump power, calculating the thermal losses of each room remains the starting point. This assessment takes into account the insulation of the walls, the type of glazing, orientation, floor area, and ceiling height. For a ducted system like the T.One, this calculation must also include pressure losses in the duct network, a parameter that traditional thermal assessments for radiators do not include.
The total length of the ducts, the number of bends, and the chosen diameter directly influence the necessary static pressure. A duct that is too long or undersized in section reduces the airflow at the supply point, creating temperature differences between rooms. Field reports vary on this point: some installers prefer larger diameter ducts to limit losses, while others opt for smaller sections with variable flow motorized outlets.
As the opinion of lemagazinedubricoleur.fr on painting reminds us, technical choices in renovation often depend on practical constraints that can only be assessed through an on-site visit.
Air-to-air heat pump power: common calculation mistakes
Oversizing is the most common mistake when installing a RIBO system. A compressor that is too powerful reaches the set temperature in a few minutes, stops, and then restarts shortly after. These short cycles accelerate compressor wear and prevent proper dehumidification of the air in cooling mode.
Undersizing presents the opposite problem. The machine runs continuously without ever reaching the set point, which increases consumption and reduces comfort in the rooms farthest from the indoor unit.
Several factors complicate the calculation of the appropriate power:
- Free solar gains on south and west facades, which vary significantly by season and can represent a significant thermal load in summer
- The airtightness of the building, often better in recent constructions compliant with thermal regulations, which reduces heating needs but increases the risk of summer overheating
- The number of occupants and household appliances, which generate internal gains that are sometimes underestimated in compact housing
A certified installer typically conducts a complete thermal study before proposing a model. A quote without a prior thermal study is a warning sign regarding the quality of the service.
Duct network and number of outlets: often neglected sizing
The power of the heat pump is not everything. The air distribution network determines the actual quality of comfort in each room. A T.One correctly sized in power but connected to a poorly designed duct network will produce disappointing results.
Each supply outlet must deliver a calibrated airflow based on the volume of the room and its specific thermal losses. One outlet per living space is the minimum, but large living rooms or L-shaped rooms sometimes require two supply points to avoid cold zones.
Air return is another critical aspect. Air must be able to circulate freely from the supply rooms to the return outlet, usually located in a hallway or a passage. Closed doors without sufficient undercut block this circuit and unbalance the entire system.
Installation constraints in existing structures
In renovation, the available space for duct passage often limits options. False ceilings must provide sufficient height to accommodate insulated ducts without excessive compression. Compressing a duct reduces its airflow and increases noise, a defect that several users report after installation.
The positioning of the indoor unit also deserves special attention. The more central it is to the serviced rooms, the shorter the duct lengths remain and the pressure losses are limited. A technical closet at the end of the house forces ducts to run the entire length of the building, with direct consequences on the balance of airflows.
Budget for a ducted RIBO system: guidelines for evaluating a quote
For a house of about 100 m², the material cost of a reversible multi-zone ducted system generally ranges between 2,000 and 4,000 euros excluding installation. High-end units rated A+++ and with a power greater than 10 kW can exceed 5,000 euros.
Installation by a certified professional often represents an additional 2,000 to 4,000 euros depending on the complexity of the project: number of outlets, duct lengths, false ceiling constraints. A quote significantly lower than these ranges may indicate a shortcut on the thermal study or on the quality of duct materials.
The available data does not allow for a reliable conclusion on a national average price, as regional disparities and the specifics of each project weigh heavily. Requesting several detailed quotes, with sizing justified by a thermal study, remains the safest method to avoid costly oversizing or a subpar installation.
Choosing an experienced installer on ducted systems, and not just on classic splits, is an integral part of sizing. The quality of the commissioning, the adjustment of flows outlet by outlet, and the verification of the airtightness of the duct network determine the final result as much as the choice of equipment.