SENVILLE LETO Mini-Split | 18000 BTU | Montréal, Laval, South Shore

An 18,000 BTU mini split designed for summer comfort, supplemental heating, and medium- to large-sized spaces

The SENVILLE LETO 18,000 BTU occupies an interesting position in the ductless wall-mounted heat pump category. With a nominal capacity of 18,000 BTU in cooling mode, inverter technology, WiFi, relatively quiet operation, and R-454B refrigerant, it is aimed at homeowners who want a simple solution for efficiently cooling a large space while also obtaining usable heating capacity down to -15 °C.

At AirGreen, we often encounter this type of need in Montreal, Laval, Longueuil, and the South Shore: an open-plan ground floor becomes difficult to cool in July, a large basement remains uncomfortable, or a living area on the second floor accumulates a great deal of heat in the afternoon. In this kind of situation, a 9,000 or 12,000 BTU unit may be too limited, whereas a properly sized 18,000 BTU unit offers more capacity without necessarily requiring a very large unit.

The model presented here combines the SENL/18CD/OY outdoor unit with the SENL/18CD/IY indoor unit. The AirGreen specification sheet lists AHRI 207613967 and a 220 V power supply.

Senville’s official documentation classifies the SENL-18CD as an 18,000 BTU mini split heat pump designed for residential or commercial heating and cooling. The manufacturer indicates that it is ideally suited to spaces of approximately 700 to 1,000 sq. ft., with heating operation down to -15 °C.

18,000 BTU does not mean continuous operation at full capacity

An essential feature of this SENVILLE LETO is its modulation capacity.

According to the official technical table, the unit offers:

• 18,000 BTU/h of nominal cooling capacity
• cooling modulation of approximately 4,100 to 19,000 BTU/h
• 18,800 BTU/h of nominal heating capacity
• heating modulation of approximately 6,200 to 20,200 BTU/h

Power consumption also varies according to demand: approximately 365 to 1,720 W in cooling mode and 380 to 1,850 W in heating mode.

This modulation is one of the major advantages of DC Inverter technology.

As the room temperature approaches the setpoint, the compressor does not need to run continuously at maximum capacity. It can slow down to maintain comfort more precisely. Senville also indicates that its inverter technology can reduce energy consumption by up to 48% under certain conditions compared with the benchmarks used by the manufacturer.

However, we prefer to consider this percentage an estimate that depends heavily on the building, the system being replaced, and usage habits. To compare units objectively, SEER2, EER2, and HSPF2 ratings remain much more useful.

SEER2 of 19.2: efficient air conditioning without targeting the cold-climate category

The official table lists the following performance figures:

These values come from the technical table in the official Senville brochure.

An SEER2 of 19.2 places this unit in an interesting category for homeowners who primarily want good air-conditioning performance and supplementary heating.

Here, an important distinction must be made from certain Senville AURA models intended for cold climates. The AirGreen product page clearly indicates that this 18,000 BTU LETO is neither ENERGY STAR nor ENERGY STAR Cold Climate.

This does not mean that the unit does not heat. It does heat, but its design and winter operating range are different.

Down to -15 °C: what this really means in Quebec

The AirGreen product page indicates a heating capacity down to -15 °C, which is also confirmed by the Senville brochure.

The data displayed on the AirGreen product page indicate approximately:

• 11,500 BTU/h at -8 °C
• 10,100 BTU/h at -15 °C

This is an important point.

A heat pump may be able to operate at -15 °C without maintaining its full rated heating capacity. As the outdoor temperature drops, the building's heat loss increases, while the capacity of some heat pumps decreases.

For this reason, we generally consider the SENVILLE LETO 18,000 BTU to be a particularly interesting solution for:

• the primary air conditioning of a large area;
• heating during the fall and spring;
• heating during mild winter days;
• reducing the use of electric baseboard heaters when conditions permit;
• supplementary heating in a property equipped with another heat source.

In a climate like Montréal or Laval, we would not automatically select this model as the sole source of heating for an entire property.

700 to 1,000 sq. ft.: a useful indication, but not a sizing rule

Senville recommends this model for approximately 700 to 1,000 sq. ft.

This information is useful for establishing a preliminary estimate, but it does not replace a building analysis.

Two 900 sq. ft. spaces can require very different capacities.

A newer 900 sq. ft. basement in Boucherville with few windows may require much less cooling than an upper floor of the same size in Montreal with:

• large southwest-facing windows;
• a roof directly exposed to sunlight;
• older insulation;
• high ceilings;
• several occupants;
• cooking appliances or electronic devices that generate heat.

We also encounter another common situation: the owner wants to cool 900 sq. ft., but this area is divided among three bedrooms, a hallway, and a living room.

The BTU calculation may be correct even though the air distribution is not.

A wall-mounted indoor unit installed in the living room cannot effectively push cold air through several closed doors. In this case, increasing the capacity is not necessarily the right solution.

An airflow rate suited to large rooms

The documentation specifies four indoor airflow levels:

• 429.7 CFM in Turbo mode
• 388.5 CFM at high speed
• 259 CFM at medium speed
• 217.8 CFM at low speed

The sound level ranges from approximately 24 dB(A) at low speed to 50.5 dB(A) in Turbo mode.

The minimum level of 24 dB(A) is particularly appealing at night or when the heat load is low.

However, an 18,000 BTU unit must be able to move enough air when a room accumulates a great deal of heat. Turbo mode and the higher fan speeds may therefore be noticeably louder.

The AirGreen product sheet also indicates that the vertical and horizontal louvers are controlled automatically. This helps distribute the airflow throughout a large open area and prevents all the air conditioning from being concentrated along a single axis.

WiFi and Alexa included: useful for scheduling the unit according to your schedule

The SENVILLE LETO is WiFi- and Alexa-compatible.

The brochure specifies that the user can, among other things:

• turn the unit on or off;
• adjust the temperature;
• schedule times;
• control the system remotely through the compatible app.

This feature can be particularly useful in an office, a residence, a cottage, or a property with varying occupancy schedules.

Rather than keeping the system constantly at a fixed temperature, the homeowner can adjust operating periods to the times when the home is actually occupied.

Dehumidification function: up to 2.5 litres per hour

The brochure indicates a moisture-removal capacity of 2.5 L/h.

This is particularly relevant during humid days in July and August in the Greater Montreal Area.

A heat pump does more than reduce the temperature. When operating in cooling mode, it also condenses some of the moisture contained in the air.

This significantly improves the feeling of comfort.

A room at 23°C with high humidity can feel much more uncomfortable than a room at the same temperature with better-controlled humidity.

The dehumidification mode can therefore be useful when it is humid without necessarily being extremely hot.

Unit dimensions: what to plan for on the wall and outdoors

The indoor unit measures approximately:

37.99 in × 8.46 in × 12.56 in

and weighs approximately 24.47 lb.

The outdoor unit measures:

31.69 in × 12.99 in × 21.81 in

with an approximate weight of 72.31 lb.

The stated outdoor sound level is 56 dB(A).

Before a wall-mounted heat pump installation in Montreal, Laval, or the South Shore, we must therefore plan for sufficient space around both units.

The indoor location must allow for:

• adequate clearance for the airflow;
• access to the filters;
• the opening of the front panel;
• a logical route for the piping and drain;
• a position that does not blow directly onto occupants.

Outdoors, we must plan for service access, snow accumulation, and water drainage.

The technical points AirGreen checks before installing the SENVILLE LETO 18,000 BTU

1/4 in – 1/2 in piping and 25-foot precharge

The AirGreen specifications indicate 1/4 in – 1/2 in refrigerant piping.

The brochure specifies that the system is precharged with R-454B for a length of up to 25 feet. A 50-foot set requires refrigerant to be added on-site by the installer.

This information directly affects installation preparation.

The refrigerant line route must be planned before drilling through the wall. A shorter, more direct installation is generally preferable when possible, but the priority remains finding an indoor location that distributes air properly and an outdoor location that is compliant and accessible.

Why R-454B changes installation methods

The SENVILLE LETO uses R-454B.

This refrigerant belongs to the A2L category, with characteristics different from those of R-410A, which was used for many years in residential heat pumps.

For the owner, this primarily means that the installation must not be improvised. Handling procedures, tools used, leak testing, and commissioning must be adapted to the refrigerant.

The quality of a professional HVAC installation remains crucial for achieving the performance specified by the manufacturer.

Proper evacuation protects the refrigeration circuit

One of the most problematic mistakes when installing a mini-split is assuming that the system is ready simply because it has been precharged.

The factory charge refers to the refrigerant already contained in the outdoor unit. The pipes installed between the two units initially contain air and moisture.

Before releasing the refrigerant into the lines, the circuit must be properly prepared and evacuated.

An improperly executed installation can result in:

• reduced performance;
• incorrect pressures;
• higher electricity consumption;
• long-term problems for the compressor;
• service calls that could have been avoided.

That is why the quality of the refrigeration work is just as important as the choice of model.

Condensate drain: a detail that becomes essential during the summer

With moisture removal of up to 2.5 L/h, the drain must be installed correctly.

We favor gravity drainage with a continuous slope whenever the building configuration allows it.

When a condensate pump is required, it must be accessible for maintenance.

An improperly installed drain can cause odors, noise, water leaks, or backflow toward the indoor unit. These are problems that can be avoided by planning the route properly from the start.

Electrical requirements: 208/230 V, MCA 15 A, and MOP 20 A

The official brochure states:

• power supply 208/230 V
• single-phase, 60 Hz
• voltage range of 187 to 253 V
• MCA of 15 A
• maximum protection of 20 A

The AirGreen datasheet also lists an MCA of 15 A and an MOP of 20 A.

The interconnection wiring specified in the documentation is 14/4 AWG.

As always, these data must be interpreted in accordance with the electrical requirements applicable to the actual installation. The power circuit, circuit breaker, and disconnect switch must match the nameplate data and applicable standards.

A common example in our assessments: a large ground-floor unit or a small multifunctional unit

A typical configuration we encounter at AirGreen is a house or condo ground floor of approximately 800 to 1,000 sq. ft. with a largely open living room, kitchen, and dining room.

In this type of layout, an 18,000 BTU mini-split can benefit from favourable air circulation.

Conversely, if this same area consists of several completely separate bedrooms, we consider other options before recommending a single wall-mounted head.

This distinction helps avoid a common mistake: purchasing enough BTUs on paper while completely overlooking how the air will actually circulate throughout the building.

LETO or cold-climate heat pump: choose according to your objective

The 18,000 BTU SENVILLE LETO should not be confused with a heat pump designed primarily to maintain high heating capacity during severe Quebec cold.

The AirGreen listing indicates:

• ENERGY STAR: no
• ENERGY STAR Cold Climate: no
• heating down to -15 °C

LETO is therefore particularly suitable for customers whose priority is air conditioning, with the added benefit of efficient heating during a large part of the year.

If the main priority is instead to maximize heating at -20 °C, -25 °C, or -30 °C, we generally examine models specifically designed for these conditions.

This distinction is essential for properly comparing the prices of different heat pumps. Two 18,000 BTU units may have very different winter performance.

Warranty: an important difference between the AirGreen listing and the brochure

The AirGreen product listing provided for this combination indicates a warranty of:

10 years on the compressor – 10 years on parts – 0 years on labour.

However, the attached Senville documentation indicates a standard warranty of 5 years on the compressor and 5 years on parts. This information appears both in the product presentation and in the technical table.

This difference must be confirmed at the time of purchase.

An extended warranty may depend on the sales channel, registration, a specific program, or the retailer’s terms. We therefore recommend verifying the exact coverage applicable to the equipment delivered and installed by AirGreen rather than automatically assuming that a generic warranty applies.

Subsidy: do not confuse an efficient mini-split with an eligible unit

The AirGreen listing currently does not show any confirmed LogisVert subsidy amount for this model.

Cela correspond au fait que le produit est affiché comme non ENERGY STAR Cold Climate.

This reflects the fact that the product is listed as not ENERGY STAR Cold Climate.

For a homeowner comparing several heat pumps solely based on purchase price, this point can completely change the project’s net cost. A more expensive unit that qualifies for financial assistance can sometimes cost less after the rebate.

Eligibility must always be verified using the exact model combination, the AHRI number, and the rules in effect at the time of installation.

For which homeowner does this SENVILLE LETO make the most sense?

• We consider this model particularly relevant for a customer looking for:
• a 18,000 BTU wall-mounted heat pump primarily for cooling;
• supplementary heating capacity down to approximately -15 °C;
• installation in an area of 700 to 1,000 sq. ft., depending on the layout;
• a unit with WiFi and Alexa;
• indoor operation reaching approximately 24 dB(A);
• an inverter system;
• a 208/230 V power supply;

a solution using the new R-454B refrigerant.

It is less suitable when the main objective is to completely replace the primary heating system during the coldest periods of Quebec winters.

Why AirGreen installation makes a difference

At AirGreen, we do not limit our work to choosing the nominal capacity.

• For a mini-split installation in Montréal, Laval, Longueuil, Boucherville, on the South Shore, or on the North Shore, we check, among other things:
• the space’s thermal load;
• natural air circulation;
• the location of the indoor head;
• the piping route;
• the drain slope;
• the electrical supply;
• access to the outdoor unit;
• the potential snow depth;
• the expected noise level;
• the heating performance actually required.

The SENVILLE LETO 18,000 BTU can be an excellent choice when these parameters match the building. Its SEER2 of 19.2, inverter modulation, WiFi, nominal capacity of 18,000 BTU, and operation down to -15 °C provide a consistent combination for homeowners who primarily want to improve their cooling comfort while also benefiting from a heat pump for a good part of the heating season.

Are you considering the SENVILLE LETO 18,000 BTU for your house, condo, office, or business? Contact AirGreen for a quote and to determine whether this capacity is truly suitable for your space. We serve Montréal, Laval, Longueuil, the South Shore, and the North Shore for the sale, installation, maintenance, and servicing of wall-mounted heat pumps.