1-Way Ceiling Cassette SENVILLE SENA R454B | 18000 BTU

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• Federal Rebate:
• Provincial Rebate: 1740$
• Energy Star®: Oui
• WiFi: En Option
• AHRI: 216623595
• Efficiency: 20.6 SEER
• Warranty (Compressor - Parts - Labor): 10-10-0
• Additional Warranty (10-10-10): Possible
• Voltage: 220V
• Sound Pressure Level (Outdoor): dB(A)
• Gas (Freon): R-454B

A long, discreet ceiling heat pump designed to send air in a precise direction rather than in four directions

The SENVILLE SENA R454B 1-Way Ceiling Cassette | 18,000 BTU occupies a very specific category among ductless heating and cooling solutions. It does not seek to systematically replace a wall-mounted heat pump or a square four-way cassette. Its strength lies elsewhere: its indoor unit is recessed into the ceiling and directs air primarily in a specific direction, which can be much more suitable in a long room, corridor, office, business, meeting room, or area where airflow must follow the geometry of the space.

For our HVAC projects in Montreal, Laval, Longueuil, the South Shore, and the North Shore, this distinction matters enormously. In some buildings, a wall-mounted heat pump has an excellent location. In others, the walls are occupied by windows, cabinets, doors, artwork, shelving, or architectural elements that make a wall-mounted unit impractical. The one-way cassette then makes it possible to move the airflow challenge to the ceiling.

The configuration presented here pairs the SENA-18HF-OG outdoor unit with the SENA-18HF-1WCG indoor unit, under reference AHRI 216623595. This combination is ENERGY STAR certified, rated for cold climates, operates with R454B, and has a SEER2 of 20.6, an EER2 of 12.5, and an HSPF2 Region IV of 12.2.

Senville also specifically presents the SENA-18HF-1WCG as a ceiling cassette with one-way airflow, designed for corridors, narrow rooms, and commercial installations where available space is limited.

18,000 BTU in the name, but 16,700 BTU of certified cooling capacity

The first detail we explain to our customers is the difference between the 18,000 BTU commercial class and the certified capacity of the exact match.

The Senville brochure's technical table indicates the following for the SENA-18HF-1WC:

• power supply 208/230 V, single-phase, 60 Hz;
• cooling capacity of 16,700 BTU/h;
• SEER2 of 20.6;
• EER2 of 12.5;
• nominal heating capacity of 20,000 BTU/h;
• HSPF2-4 of 12.2;
• nominal COP of 3,01;
• liquid line of 1/4 po;
• gas line of 1/2 po.

The AHRI 216623595 certification also confirms 16,700 BTU/h of cooling, 20,000 BTU/h of heating, 20.6 SEER2, and 12.2 HSPF2.

This is therefore not a contradiction: “18,000 BTU” identifies the product category, while the certified values describe the actual performance of this specific combination.

At AirGreen, we use certified values when properly sizing a system or comparing two units.

Why a 1-way cassette is not simply a narrower square cassette

The traditional four-way ceiling cassette distributes air in several directions around its perimeter. This works very well when it is positioned relatively centrally in an open area.

The SENVILLE 1-way cassette follows a different approach.

It is long and narrow and directs its airflow primarily toward a specific area. Senville specifically highlights this directional airflow as one of its main advantages.

This can be particularly useful in:

• an elongated living room;
• a residential hallway;
• a rectangular office;
• a narrow commercial space;
• a room with a large glass façade;
• a room where we want to project the air parallel to the length of the space;
• a renovation where a wall cannot accommodate a wall-mounted unit.

The choice between a 1-way cassette, 4-way cassette, and wall-mounted heat pump should therefore not be based solely on appearance. You need to consider the room’s actual geometry and the direction in which the air needs to circulate.

An indoor unit more than 50 inches wide but less than 9 inches high

The geometry of this cassette is one of its most interesting features.

Senville indicates the following for the indoor unit:

50.31 in wide × 13.19 in deep × 8.98 in high.

The outdoor unit, meanwhile, measures:

35.04 in × 13.46 in × 26.50 in.

The indoor unit’s format is therefore very different from that of a square cassette.

With a nominal height of less than nine inches, it may suit certain ceilings where a deeper unit would be difficult to integrate. However, its width of more than four feet means that the orientation of the joists, beams, and other structural elements must be checked carefully.

This is exactly the kind of product that looks simple in a photo but requires a proper ceiling inspection before the installation is confirmed.

A particularly interesting cassette for long rooms

Let’s take a common example in a condo in Montreal.

The living room and dining room are arranged lengthwise. One side wall is almost entirely occupied by windows, while the other has cabinets and a hallway door. A wall-mounted heat pump could be installed at one end, but its location would be visually dominant, and the airflow would not necessarily be directed ideally.

A ceiling-mounted 1-way cassette can project air along the room’s longitudinal axis.

In an office in Longueuil, we may encounter the opposite situation: a unit installed above a circulation area can send the airflow along the workstations without taking up wall space.

In our own AirGreen documentation on 1-way cassettes, we also noted the value of this type of air distribution in a professional space in Longueuil: directional positioning made it possible to better control drafts toward the occupied area.

Automatic vertical louver and manual horizontal orientation

The AirGreen product sheet for this model indicates automatic vertical louver control and manual horizontal adjustment.

This combination aligns well with the logic of a 1-way cassette: we carefully choose the general direction of the installation, then the automatic louver allows the airflow sweep to be adjusted during operation.

This detail matters from the design stage.

With a wall-mounted unit, a few degrees of orientation can sometimes be compensated for by the motorized louvers. With a directional cassette recessed into the ceiling, we want its axis to align with the area to be conditioned from the outset.

20.6 SEER2: compelling efficiency for a recessed cassette

The certification for the SENA-18HF-OG + SENA-18HF-1WCG combination indicates a SEER2 of 20.6, an EER2 of 12.5, and an HSPF2 of 12.2.

This efficiency must be interpreted in the context of a cassette unit.

We do not compare only the SEER2 rating with that of a wall-mounted heat pump. A cassette is sometimes chosen precisely because a wall-mounted unit cannot distribute air properly throughout the building.

A wall-mounted unit with a higher stated theoretical efficiency is not necessarily the best choice if its location forces the air to hit a nearby wall or remain concentrated in just one part of the room.

The actual efficiency of an HVAC system therefore depends both on the equipment’s performance and on its ability to distribute heating or cooling where the building needs it.

Heating at −8 °C: 14,500 certified BTU/h

The ENERGY STAR certification associated with this cassette indicates a heating capacity of approximately 14,500 BTU/h at 17 °F, or approximately -8 °C. It also indicates 17,500 BTU/h at 5 °F, or approximately -15 °C, with a COP of approximately 1.89 at this temperature.

These values are particularly relevant for Montreal, Laval, Longueuil, the North Shore, and the South Shore.

A unit may be advertised as operating down to -30 °C, but the real question for the homeowner is how much heat it can still produce as the temperature drops.

For this configuration:

• rated heating: approximately 20,000 BTU/h;
• heating at approximately -8 °C: 14,500 BTU/h;
• heating at approximately -15 °C: 17,500 BTU/h according to the available certification;
• maximum capacity indicated by the AirGreen product sheet at -30 °C: approximately 9,500 BTU/h.

Performance is therefore not a simple straight line where capacity decreases exactly the same way with each degree. The certified points correspond to specific test conditions and different operating speeds of the Inverter compressor.

COP at -30 °C: approximately 1.47 according to the AirGreen product sheet

The AirGreen product sheet indicates a maximum COP of approximately 1.47 at -30 °C.

This means that the unit can still transfer more heat than a resistance-electric system directly produces with the same amount of electrical energy consumed by the heat pump, under the conditions corresponding to this figure.

Performance is obviously much lower than at mild temperatures.

For this reason, we never present a “-30 °C” heat pump as a guarantee that it can heat any home on its own at -30 °C.

If the building's heat losses exceed the 9,500 BTU/h available at this temperature, supplemental heating is still required.

R454B: a new generation of refrigerant that changes installation methods

This cassette operates with R454B.

The Senville brochure specifies that the system is precharged for up to 25 ft of piping and that an installation with a 50 ft kit requires the installer to add refrigerant. It also states that professional installation is required to preserve the warranty and performance.

R454B belongs to the A2L refrigerant category.

We must therefore work with appropriate procedures and tools, particularly for:

• refrigerant connections;
• leak tests;
• vacuuming;
• refrigerant handling;
• commissioning;
• verification of the leak detection system when applicable.

Senville also mentions self-diagnostic and leak detection functions for this generation, as well as a self-cleaning mode.

An AirGreen 1-way cassette installation starts with the ceiling, drainage, and airflow direction

The real challenge: finding 50 inches of length in the right place

An indoor unit 50.31 in. wide requires serious structural planning.

We need to know what is above the ceiling before choosing the location:

• beams;
• joists;
• ductwork;
• plumbing;
• electrical wiring;
• recessed lighting;
• sprinklers;
• existing lines;
• maintenance access.

A ceiling cassette cannot be moved as easily as a wall-mounted unit once we discover a beam in the wrong place.

During a renovation, we prefer to inspect the ceiling before the finishes are completed. This allows us to coordinate the opening, support, refrigerant lines, drainage, and electrical work at the same time.

A height of only 8.98 in. does not eliminate the need for technical clearance

The indoor unit’s low height is an advantage, but it does not mean that nine inches of clearance will automatically be sufficient.

We must also take into account:

• unit support;
• connections;
• insulation;
• drain;
• required clearances;
• access to components;
• ceiling finish.

On a job site, a few inches can determine whether the project remains simple or whether a soffit must be modified.

That is why we measure the available space above the ceiling, not just the visible height in the room.

A commercial project in Longueuil: why airflow direction mattered more than raw capacity

In a commercial space documented by AirGreen in Longueuil, the main problem associated with a 1-way cassette was not insufficient capacity. The challenge was to achieve airflow suited to the work area while limiting the sensation of a direct draft on occupants.

The principle of a one-way cassette is precisely to direct airflow along a chosen axis rather than blow uniformly in all directions.

This type of situation comes up regularly in our commercial projects: good distribution from an 18,000 BTU unit can be more comfortable than a higher capacity that is poorly directed.

Is a 1-way cassette suitable for 500 to 700 sq. ft.?

Senville’s commercial brochure presents the model as being suitable for approximately 500 to 700 sq. ft..

We use this range only as a general guideline.

A 650 sq. ft. room in a recent building in Brossard and a 650 sq. ft. retail space with a full south-facing glass frontage do not have the same heat load.

We specifically consider:

• area;
• ceiling height;
• orientation;
• fenestration;
• insulation;
• number of occupants;
• lighting;
• heat-generating appliances;
• air infiltration;
• the type of use of the space.

The 1-way format can be excellent for a 600 sq. ft. long room, but less suitable for a square space where multidirectional air distribution would be preferable.

Drainage: a critical consideration when a unit is concealed in a ceiling

Every system that provides cooling produces condensation.

When a unit is installed on a wall, a drain problem can sometimes be detected quickly. In a finished ceiling, the consequences of poorly planned drainage can be much more significant.

We therefore check:

1. the possibility of draining the water by gravity;
2. drain route;
3. slope;
4. access for maintenance;
5. protection of finishes;
6. compatibility with Senville’s installation requirements.

The integrated dehumidification function mentioned by the manufacturer is useful for comfort, but all the water removed from the air must then be properly drained.

1/4 in – 1/2 in piping

Senville specifies the following for the 18,000 BTU version:

• liquid line: 1/4 po;
• gas line: 1/2 po.

This information is particularly important when replacing an existing system.

Piping already concealed in a ceiling is not automatically reusable. We must check its diameter, condition, insulation, length, and compatibility with the new R454B system.

Reusing a line simply to avoid opening a ceiling can create a much more costly problem if it does not meet specifications.

Optional Wi-Fi: a difference to clarify from the outset

The AirGreen product sheet indicates optional Wi-Fi.

The official page for the SENA-18HF-1WCG unit instead emphasizes the wireless remote and local control of the unit.

We therefore recommend confirming the smart control accessory when placing the order if app-based management is part of the customer’s needs.

For an office or commercial space, this option can be particularly useful for setting schedules based on occupancy hours.

ENERGY STAR and cold climates

The pairing SENA-18HF-OG + SENA-18HF-1WCG, AHRI 216623595 is certified as ENERGY STAR and ENERGY STAR Cold Climate.

The ENERGY STAR registry also indicates a continuously variable compressor, R454B, and a heating capacity of 14,500 BTU/h at around -8 °C.

This combination therefore corresponds to a heat pump designed for year-round use in Quebec rather than simply an air conditioner with an occasional heating function.

Why the AirGreen product sheet indicates a $1,740 rebate

The AirGreen product sheet indicates a $1,740 provincial rebate.

A Hydro-Québec list precisely matching AHRI 216623595, SENA-18HF-OG, and SENA-18HF-1WCG gives a heating capacity of 14,500 BTU/h at -8 °C and an incentive of $1,740 under the corresponding option of the documented program.

The calculation is consistent with a rate of $120 per 1,000 BTU/h:

14.5 × $120 = $1,740

Nevertheless, we always verify eligibility and the amount at the time of the project. The LogisVert rules, building categories, and payment scales may change, and the applicable amount depends on the date and actual circumstances of the installation.

Warranty: a difference between the Senville brochure and the AirGreen product sheet

The Senville documentation provided mentions a 10-year warranty on the compressor and 5 years on parts.

The AirGreen product sheet, for its part, presents 10-10-0, with the possibility of additional coverage.

These two pieces of information must therefore be distinguished.

For every AirGreen installation, the applicable coverage must be confirmed in the final quote and warranty documents. Coverage may depend on the sales program, product registration, and additional protection offered with the installation.

Mistakes we seek to avoid with a one-way cassette

Choosing a cassette because it is more discreet without checking the direction of the airflow

The shape of the room must justify one-way airflow.

Waiting until installation day to inspect the joists

With an indoor unit more than 50 inches wide, this mistake may require relocating the entire appliance.

Underestimating drainage

A leak above a finished ceiling can damage paint, drywall, light fixtures, and furnishings.

Rely only on the “18,000 BTU” rating

The certified cooling capacity of this matched system is 16,700 BTU/h. Sizing must be based on actual data.

Installing the cassette in the easiest location rather than the best location

A shorter refrigerant line is not a saving if the airflow is poorly directed throughout the system’s service life.

Failing to plan for service access

The filters and components must remain accessible. A nearly invisible cassette must not become impossible to service.

Which projects do we particularly recommend this SENVILLE for?

The SENVILLE SENA 18,000 BTU 1-way is particularly suitable for:

• long or rectangular rooms;
• corridors;
• offices;
• retail stores;
• meeting rooms;
• condos with limited available wall space;
• renovations where ceiling integration is possible;
• spaces where directional distribution is preferred over airflow on all four sides.

We would be more cautious in a large square room where a 4-way cassette could distribute air more evenly, or in a property where no technical space is available above the ceiling.

Why choose AirGreen for a 1-way ceiling cassette?

Installing this type of unit requires coordination between refrigeration, structural work, drainage, electrical work, and interior finishing.

At AirGreen, we work throughout Greater Montreal, Montreal, Laval, Longueuil, the South Shore, and the North Shore. In existing buildings, we place as much importance on what is above the ceiling as on the performance figures listed on the AHRI sheet.

We check the required capacity, the optimal airflow direction, the opening dimensions, the 1/4 – 1/2 piping route, drainage, the condenser location, and future access for HVAC maintenance.

This preparation is particularly important with a 1-way cassette: once properly integrated into the ceiling, the installation should look simple. To achieve this result, technical decisions must be made before the finishes are closed up.

Request an AirGreen quote for your SENVILLE SENA 1-Way 18,000 BTU

For a SENVILLE SENA R454B 1-Way Ceiling Cassette | 18,000 BTU in Montreal, Laval, Longueuil, the South Shore, or the North Shore, contact AirGreen.

We can check the heating load, ceiling structure, ideal airflow direction, piping, drainage, electrical supply, Wi-Fi option, and eligibility for the advertised $1,740 rebate according to the rules applicable to your project.