SENVILLE R454B 2-Zone Heat Pump | 18000 BTU

Two zones, two 9,000 BTU indoor units, and a single condenser: a particularly interesting configuration for Quebec's climate

The SENVILLE R454B 2-Zone Heat Pump | 18,000 BTU addresses a need we regularly encounter at AirGreen: heating and cooling two separate spaces without installing two condensers on the façade, balcony, or side of the house. For properties in Montreal, Laval, Longueuil, the South Shore, the North Shore, and Montérégie, this configuration can be particularly relevant when a single wall-mounted unit cannot properly distribute air to two bedrooms, two floors, or two separate zones.

The configuration presented here is based on the SENA-18HF-MOA condenser, paired in the dual-zone product with two indoor units of 9,000 BTU each. The Senville brochure confirms the 9,000 + 9,000 BTU combination, as well as the inclusion of two 16 ft. installation kits in the configuration shown.

The technical reference to remember is AHRI 215735311. This heat pump operates with R454B, is designed for heating down to -30 °C, offers 25 SEER2 efficiency, is ENERGY STAR certified, and belongs to the category of systems suited to cold climates.

On paper, these figures are already impressive. In practice, it is primarily the distribution of capacity between the two zones, the length of the lines, the positioning of the indoor units, and the heat load of each room that determine whether the system will actually be comfortable.

What the 2-zone configuration actually includes

Page 4 of the brochure specifies that the package includes:

• 2 indoor units of 9,000 BTU each;
• 1 outdoor unit;
• the wireless remote controls;
• a USB Wi-Fi kit;
• 2 16 ft. installation kits;
• the wiring between the units;
• the installation manual.

This is therefore indeed a Dual-Zone 9,000 + 9,000 BTU system, even though the SENA-18HF-MOA outdoor platform is listed in the technical documentation as compatible with 2 to 3 zones.

This distinction is important when comparing products online. The fact that a condenser can accommodate different configurations does not mean that the product sold here includes three indoor units. The configuration we are interested in consists of two wall-mounted units.

18,000 BTU in the name, but 19,000 BTU of cooling capacity in the technical specifications

The commercial nomenclature refers to an 18,000 BTU system, but Senville states in its technical documentation:

• rated cooling capacity: 19,000 BTU/h;
• cooling range: 5,400 to 28,000 BTU/h;
• nominal heating capacity: 20,000 BTU/h;
• heating range: 5,700 to 27,000 BTU/h.

This detail is particularly revealing of Inverter technology.

A multizone system does not constantly produce exactly 9,000 BTU at each head. The condenser modulates its capacity and distributes it according to the zones’ active demands.

If one room requires substantial heating while the other is already at temperature, the compressor load is not necessarily divided into exactly two equal shares.

This is precisely what makes the design of a 2-zone heat pump more interesting than a simple “9,000 + 9,000 = 18,000” calculation.

A very wide modulation range for two rooms with different needs

The published heating range, from 5,700 to 27,000 BTU/h, gives the compressor considerable leeway to adjust its output.

Let’s take a typical example in a duplex in Montreal.

A 9,000 BTU head is installed in the ground-floor living room, which has several windows and an exterior door. The second is installed in a large bedroom upstairs.

On an autumn day, the bedroom may require very little heat while the living room receives more cold air when the door is opened. The Inverter system can adjust its operation instead of constantly producing its maximum capacity.

This modulation generally makes it possible:

• to limit unnecessary on-off cycles;
• to maintain more stable temperatures;
• to operate longer at low capacity;
• to reduce noise fluctuations;
• to better match output to two different thermal loads.

Nevertheless, it is important to keep in mind that the two indoor units share the same condenser. A multizone heat pump should therefore not be considered two completely independent systems capable of simultaneously handling any conflicting heating and cooling demand.

Each zone can have its own setpoint temperature and airflow, but the system remains a shared system overall.

25 SEER2 and 15 EER2: particularly high efficiency for a multi-split system

SENVILLE lists:

• SEER2: 25.0
• EER2: 15.0
• HSPF2 Region IV: 10.4
• HSPF2 Region V: 8.5
• Nominal COP: 4.0.

The figure of 25 should be interpreted as a SEER2, which is the value published in the current brochure.

For an 18,000 BTU multizone heat pump, this efficiency level is one of the model’s main selling points. Senville also presents the system as ENERGY STAR certified and claims reduced consumption compared with less efficient systems.

At AirGreen, however, we avoid directly converting a SEER2 rating into a dollar amount saved.

A highly efficient heat pump installed in a poorly insulated building may consume more than a less efficient heat pump installed in a property with a low heat load.

Actual performance also depends on:

• the requested temperature;
• the level of insulation;
• windows;
• sun exposure;
• the number of operating hours;
• the load of each of the two zones;
• sizing;
• and the quality of the refrigeration installation.

A true cold-climate heat pump down to -30 °C

The brochure indicates a minimum outdoor heating temperature of -30 °C, or -22 °F.

The AirGreen product sheet associated with pairing AHRI 215735311 provides particularly useful capacities for understanding what this represents during a Montreal winter:

• 20,000 BTU/h at -8 °C;
• 19,000 BTU/h at -15 °C;
• approximately 10,000 BTU/h at -30 °C under the maximum published condition;
• COP of approximately 2.53 at -8 °C;
• COP of approximately 1.3 at -30 °C.

These values show why the simple statement “operates at -30 °C” is insufficient for comparing heat pumps.

At -30 °C, the unit can still operate, but its available capacity is lower than at -8 °C.

To determine whether electric baseboard heaters or another supplemental heat source will be necessary, we must compare this capacity with the building’s heat loss.

In a very well-insulated condo in Laval, 10,000 BTU/h at very low temperatures can represent a significant contribution. In an old Montreal duplex with substantial air leaks, the requirements may be much higher.

Capacity almost maintained at -15 °C

The drop from 20,000 BTU/h at -8 °C to approximately 19,000 BTU/h at -15 °C deserves particular attention.

This means that the heat pump maintains substantial heating capacity across a temperature range that is very common in Quebec.

For a homeowner who wants to reduce the use of electric baseboard heaters, capacity at moderate winter temperatures is often more important than performance at an extreme temperature reached only during certain periods.

This is exactly the type of data we use at AirGreen to compare two models that both display “-30 °C” on their marketing specifications.

Why two 9,000 BTU heads can be more effective than a single large unit

One of the most common scenarios involves two physically separate spaces.

Imagine a floor consisting of:

• a large primary bedroom;
• an office or a second bedroom on the other side of the corridor.

A single 18,000 BTU heat pump in the hallway might have sufficient total capacity, but that does not guarantee that the air will reach both rooms properly, especially when the doors are closed.

With two 9,000 BTU units, each space receives its own direct airflow.

This allows us to distribute air more precisely without needing two outdoor condensers.

One condenser: a concrete advantage in dense neighborhoods

In Montreal, the number of outdoor units is not just an aesthetic issue.

In plexes and closely spaced homes, we often have to work around:

• narrow side passages;
• balconies;
• brick walls;
• closely spaced windows;
• property-line limitations;
• municipal restrictions;
• areas where noise must be controlled;
• very little space for the piping.

We recently completed a DoubleZone installation in Villeray–Saint-Michel–Parc-Extension on a brick Montreal building where the available space, windows, and piping route required particularly precise planning. Although this project involved another brand, the design logic is exactly what we apply to Senville systems: two indoor zones while limiting the outdoor installation to a single condenser.

This is often what makes a Dual Zone heat pump more appealing in an urban environment.

What we check at AirGreen before installing an SENVILLE 2-Zone 18,000 BTU

Two 9,000 BTU units do not mean that every room is suitable for 9,000 BTU

We assess each zone separately.

A 250 sq. ft. room with full southern exposure and a large picture window may have a greater load than a 400 sq. ft. room facing north and surrounded by heated rooms.

We specifically check:

1. floor area;
2. ceiling height;
3. insulation;
4. windows;
5. sun exposure;
6. exterior-facing walls;
7. air infiltration;
8. how the room is used;
9. communication with the other spaces.

The brochure suggests this range for applications covering approximately 750 to 1,250 sq. ft., but this figure refers to a general scenario, not a guarantee for every property.

A 1,000 sq. ft. home with two large open areas can be an excellent candidate. A home of the same size with five enclosed rooms may require a different configuration.

The published 2,131 CFM is not the airflow of the two indoor units

The technical sheet mentions 2,130.7 CFM. It is important to read the table carefully: this value corresponds to the maximum airflow of the outdoor unit, not the airflow delivered into the rooms by the two wall-mounted evaporators.

This is an important detail because an isolated figure of “CFM 2,131” on a commercial specification sheet can easily be misinterpreted.

Comfort in both rooms depends on the airflow of each 9,000 BTU indoor unit, its fan speed, and above all its orientation.

Positioning the two units is more complex than with a single-split system.

On a Dual Zone system, we seek to achieve good air distribution in two different spaces while maintaining a logical outdoor installation.

We therefore need to find a compromise between:

• the best position for the first unit;
• the best position for the second one;
• the total length of the lines;
• ease of drainage;
• the appearance of the line covers;
• access to the condenser;
• the building’s drilling options.

A poor decision at the outset may save a few feet of piping while compromising comfort for the next ten years.

We therefore prioritize air distribution over ease of installation.

1/4 in – 3/8 in piping: each branch must be properly prepared

The AirGreen specification sheet indicates 1/4 in – 3/8 in piping.

The system contains two refrigerant circuits running from the condenser to the indoor units. This means more connections than with a single-zone installation and, consequently, more points where workmanship quality matters.

We pay particular attention to:

• flaring;
• tightening;
• insulation;
• bend radii;
• branch lengths;
• leak tightness;
• vacuum evacuation.

On a multizone system, a problem on a single branch can affect the operation of one zone and complicate troubleshooting.

R454B and a precharge covering up to 75 ft

The brochure specifies a charge of 78.31 oz of R454B and a precharge advertised for up to 75 ft of piping.

This feature is particularly practical on a Dual Zone system because the two indoor units can be located in different areas of the building.

However, the “75 ft” specification does not mean that we can improvise two routes of any length. The total limits, the lengths of each branch, and the height differences must comply with the manufacturer’s requirements.

The configuration sold in the brochure also includes two 16 ft assemblies, meaning an initial physical length well below the system’s maximum precharge capacity.

R454B: professional installation is particularly important

R454B belongs to the A2L refrigerant category.

The brochure specifically highlights a leak detection and diagnostic system.

For our HVAC work, this means using methods and equipment compatible with the refrigerant installed.

A professional installation involves much more than mounting the units:

• line-set preparation;
• leak testing;
• vacuuming;
• electrical connections;
• drain management;
• commissioning;
• testing of both zones;
• verification of communication between the units.

This is also a requirement specified by Senville to maintain the warranty conditions.

Electrical circuit: 17.5 A MCA and 20 A maximum protection

The official brochure states:

• power supply: 208/230 V, single-phase, 60 Hz;
• voltage range: 187 to 253 V;
• minimum circuit ampacity: 17.5 A;
• maximum protection: 20 A.

The AirGreen listing rounds the MCA to 18 A, but the detailed manufacturer data is 17.5 A.

We always check the nameplate and applicable documentation at the time of installation before finalizing the electrical circuit.

A 137 lb condenser: the outdoor support must be designed for winter

The outdoor unit measures approximately:

37.24 in × 16.14 in × 31.89 in

and weighs approximately 137.35 lb.

Its published outdoor sound level is 61.5 dB(A).

In Montreal, Laval, Longueuil, or on the South Shore, we think about winter from the day of installation.

The condenser must be positioned to limit:

• snow accumulation;
• ice from a roof;
• vibrations;
• obstructions;
• defrosting difficulties;
• access problems during a service call.

On a two-zone system where a single condenser serves two rooms, its location deserves even more attention: an outdoor failure or obstruction affects both zones.

Wi-Fi included: convenient when there are two zones

The system includes a USB Wi-Fi kit and remote control through an app.

For a Dual Zone system, this feature is especially useful.

The owner can adjust the temperatures in different rooms, create schedules, and manage the system without having to go find each remote control.

In a residence where one zone serves as an office during the day and the other as a bedroom at night, the schedules allow usage to be adapted to the occupants’ actual routine.

LogisVert subsidy: why the AirGreen listing says $2,400

The heating capacity listed for this Senville is 20,000 BTU/h at -8 °C.

Hydro-Québec currently provides assistance of $120 per 1,000 BTU/h at -8 °C for an ENERGY STAR–certified cold-climate heat pump, subject to compliance with all program conditions.

The calculation is therefore:

20 × $120 = $2,400

This corresponds exactly to the $2,400 LogisVert grant displayed for the model.

Hydro-Québec also specifies that the amount is determined according to the installation date, which means that the assistance must always be verified when the project is carried out.

And in some multi-unit residential buildings?

Since June 15, 2026, certain eligible multi-unit residential buildings may benefit from an enhancement that increases the assistance to $220 per 1,000 BTU/h at -8 °C for an ENERGY STAR cold-climate wall-mounted heat pump, when all program criteria are met.

With a capacity of 20,000 BTU/h at -8 °C, this would theoretically represent:

20 × $220 = $4,400

This enhanced assistance is not automatic. The requirements include, in particular, the type of building and its eligibility for the multi-unit residential component.

At AirGreen, we therefore verify the program applicable to the address rather than presenting an amount as guaranteed.

Warranty

This system is covered for 10 years on the compressor, 10 years on parts and 6 years on labor, straight from the distributor, with the option of additional coverage.

The most common mistakes to avoid with a 2-zone heat pump

Choosing two identical heads simply because the total is 18,000 BTU

Two rooms can have very different needs. The 9,000 + 9,000 combination should match the actual loads.

Positioning the units according to the shortest piping route

An installation can be mechanically very clean while still blowing in the wrong direction. Comfort must remain the priority.

Confusing two zones with two independent systems

The two units share a condenser and a common available capacity.

Neglecting the total length of the lines

A multi-split system requires more rigorous management of line lengths, elevation differences, and refrigerant charge.

Install the condenser too close to the ground

A system advertised for temperatures down to -30 °C must be able to breathe when it snows. The outdoor installation must be adapted to Quebec’s climate.

Comparing price alone

Two quotes for “an 18,000 BTU Dual-Zone heat pump” can conceal significant differences: exact models, efficiency, capacity at -15 °C, warranty, brackets, electrical work, line length, and quality of commissioning.

Who do we primarily recommend this SENVILLE 2-Zone system to?

We consider this configuration particularly suitable for:

• two bedrooms located in different areas;
• a ground floor and an enclosed room that does not receive enough air;
• an office and a bedroom;
• a small duplex or apartment where two zones need to be treated separately;
• a home where the available outdoor space does not allow for two outdoor units;
• a homeowner who wants to benefit from an ENERGY STAR cold-climate system down to -30 °C;
• a property where the LogisVert rebate significantly improves the project’s cost.

We would be more cautious if one of the two zones had a very high heating load or if several other enclosed rooms also needed to be heated and cooled.

Why entrust a Dual-Zone installation to AirGreen?

A multi-split heat pump requires more planning than a single-split system.

At AirGreen, we must consider the two indoor units, their drains, the two piping routes, the shared outdoor unit, the electrical circuit, and how the two zones behave when needs change.

We carry out this type of HVAC installation in Montreal, Laval, Longueuil, on the South Shore, the North Shore, and in Montérégie, in single-family homes as well as in plexes and condos where physical constraints are much tighter.

Our goal is not simply to manage to fit two 9,000 BTU units in the building. We want their location, capacity, and operation to truly match the two spaces the customer wants to control.

Request an AirGreen quote for the SENVILLE 2-Zone 18,000 BTU R454B

For an SENVILLE R454B 18,000 BTU 2-Zone Heat Pump in Montreal, Laval, Longueuil, on the South Shore or the North Shore, contact AirGreen.

We can assess the load of each room, confirm the 9,000 + 9,000 BTU configuration, plan the routing of the two refrigerant lines, validate the electrical installation, and check eligibility for the $2,400 LogisVert rebate under the current conditions.

With a Dual-Zone heat pump, the quality of the result depends just as much on choosing the two locations as on the performance listed on the technical data sheet.

Warranty: 10 years on the compressor, 10 years on parts and 6 years on labor, straight from the distributor.