SENVILLE R454B 2-Zone Heat Pump | 27000 BTU

Two zones, one outdoor unit: why this SENVILLE is particularly interesting for Quebec homes that are difficult to cool with a single head

A multistory house, a condo with a living area separate from the bedrooms, or a bungalow whose living room and basement require different temperatures presents a problem we regularly encounter at AirGreen: a single wall-mounted heat pump may have enough BTUs but be unable to distribute the air properly everywhere comfort is needed.

This is precisely where a SENVILLE R454B two-zone heat pump, based on the SENA-28HF-MOA outdoor unit, becomes relevant. Rather than installing two independent compressors on the exterior wall, we can connect several indoor units to a single outdoor unit and create two distinct comfort zones.

The AirGreen product sheet presents this configuration as a 27,000-BTU two-zone heat pump, while Senville documentation identifies the SENA-28HF-MOA outdoor unit as a nominal 28,000-BTU platform that can serve two to four zones, depending on the selected combination. The brochure confirms a nominal cooling capacity of 28,000 BTUs and a modulation range of approximately 9,838 to 30,438 BTU/h.

For the homeowner, this small nomenclature discrepancy does not change the essentials: before purchasing, what must be verified is the exact combination of indoor units, the corresponding AHRI reference, and the certified capacity of that combination, not just the commercial name shown on the box.

For the configuration published by AirGreen, the important data includes:

• Outdoor unit: SENA-28HF-MOA
• AHRI reference: 215735314
• Published cooling capacity: 27,000 BTU
• Refrigerant: R-454B
• ENERGY STAR: yes
• Cold-climate certification: yes
• ENERGY STAR number: 3630061
• SEER: 23.0
• EER: 12.5
• HSPF: 10.5
• Heating down to: -30 °C
• WiFi: included
• MCA: 30 A
• MOP: 35 A
• Outdoor sound level: 61 dB(A)
• Maximum outdoor airflow: approximately 2,130 CFM
• Outdoor dimensions: 37.24 × 16.14 × 31.89 in
• Piping: 1/4 in – 3/8 in for applicable connections
• Provincial rebate indicated on the AirGreen product sheet: $3,600

Two zones do not simply mean “two times 13,500 BTUs”

This is probably the most important point to understand about a multi-zone heat pump.

A two-zone heat pump does not necessarily divide its 27,000 or 28,000 BTUs into two fixed and equal portions.

The inverter compressor adjusts its output according to the simultaneous demand from the indoor units. If one zone has a high heating demand while the second is nearly satisfied, a larger portion of the available capacity can be directed to the active zone, within the limits of the operating conditions and the installed combination.

The Senville brochure confirms a heating range of 8,218 to 31,000 BTU/h, with an advertised nominal capacity of 28,000 BTU.

This modulation explains why a multi-zone system must be designed according to the room loads, rather than simply adding the numbers listed on the indoor units.

A combination including, for example, two 12,000 BTU units does not necessarily mean that the compressor will constantly provide 12,000 BTU to each one. Demand varies continuously.

A practical advantage for a two-story home

Let’s consider a scenario we frequently encounter in Greater Montreal.

The ground floor of a South Shore home is open, with a living room, dining room, and kitchen. The upper floor contains three bedrooms connected by a hallway.

Installing a single very high-capacity unit in the living room could cool the ground floor effectively, but the cool air would not naturally rise to the bedrooms evenly. In heating mode, the behavior will be different again, since warm air tends to rise, sometimes at the expense of comfort on the ground floor.

With two zones, we can instead position:

• an indoor unit in the main living area;
• a second unit in a strategic area upstairs.

The result is not simply an increase in capacity. Above all, it is better distribution of heating and cooling.

Two thermostats, two truly independent temperatures

Each indoor unit has its own control.

This means that a homeowner could request, for example:

21 °C on the ground floor
19 °C in the bedrooms

At night, the needs may be reversed. The living room zone may require very little heating while the bedroom zone remains active.

This independence is one of the main advantages of a multi-zone heat pump compared with a single large wall-mounted unit.

However, it is important to understand a fundamental limitation of multi-zone systems: indoor units connected to the same outdoor unit must normally operate in compatible modes. With a conventional reversible compressor, you cannot continuously request cooling in one zone and heating in another.

This is a detail we always explain before installation, particularly in buildings where some rooms receive a great deal of sunlight while others remain cold.

-30 °C: the SENVILLE continues to heat, but the available capacity changes

The AirGreen specifications indicate heating operation down to -30 °C, and the Senville brochure also confirms a minimum outdoor operating temperature of -22 °F / -30 °C.

The “-30 °C” designation must nevertheless be interpreted correctly.

It does not mean that the system produces its full nominal capacity of 27,000 or 28,000 BTU at that temperature.

The data published by AirGreen notably indicates:

The stated COP is approximately 2.36 at -8 °C and 1.26 at -30 °C.

This information is extremely useful for a Quebec home.

At -8 °C, the published heating capacity is even higher than the machine's nominal capacity. At -15 °C, it remains substantial. But when we reach -30 °C, the maximum capacity drops to approximately 14,000 BTU/h.

This heat pump can therefore continue heating during a period of intense cold, but it may need the support of supplemental heating if the property's heat loss exceeds the heat it can produce at that point.

Why the COP at -30 °C must be understood before evaluating savings

A COP of 1.26 means approximately that for each unit of electrical energy consumed, the heat pump transfers 1.26 units of heat.

At more moderate temperatures, a COP of 2.36 at -8 °C is considerably more advantageous.

That is why the annual savings from a heat pump should never be judged solely by its performance on the coldest day in January.

In Montreal, Laval, Longueuil, on the North Shore or South Shore, much of the heating season takes place at temperatures far milder than -30 °C. During these hundreds of operating hours, the heat pump can significantly reduce the use of electric baseboard heaters or another backup heating system.

Cold-climate and ENERGY STAR certification

For this AirGreen configuration, the SENVILLE is identified as:

ENERGY STAR: yes
Cold Climate: yes

Senville documentation also confirms that the SENA-28HF-MOA is marketed as an ENERGY STAR system and as a cold-climate heat pump capable of operating down to -30 °C.

This distinction is important in Quebec, particularly when the heat pump is selected as part of a financial assistance application.

The AirGreen product sheet indicates a $3,600 provincial rebate for the combination in question. As with any financial assistance, we recommend confirming the eligibility of the exact combination installed and the applicable conditions at the time of the project.

With a multi-zone system, this verification is all the more important because the same outdoor unit can support different combinations of indoor units.

The AHRI number matters more than the series name

The SENA-28HF-MOA unit is a multi-zone platform. The brochure states that it can be configured for 2 to 4 zones.

The product sheet shown in the brochure presents, for example, a combination with two 12,000 BTU indoor units each and two 16 ft installation kits.

This does not mean that all possible combinations have exactly the same certified performance.

For AirGreen, the AHRI 215735314 reference associated with the product is therefore essential. When a homeowner compares quotes, they should always verify:

• the outdoor unit model number;
• the indoor unit models;
• the AHRI combination;
• low-temperature heating capacity;
• ENERGY STAR status;
• eligibility for the subsidy.

Simply comparing “Senville 28,000 BTU” with another 28,000 BTU heat pump is not enough.

Installation, energy consumption, and technical details: what we verify before recommending this SENVILLE 2-zone system

23 SEER2: high cooling efficiency

The Senville brochure displays 23 SEER2 ENERGY STAR for the system, and its technical table indicates a SEER of 23.8 and an EER of 12.5.

The AirGreen data sheet lists SEER 23.0 and EER 12.5.

These differences may result from the type of data displayed, the combination of indoor units, or the certification method. We therefore avoid using a single figure to compare two multi-zone systems without verifying their exact configuration.

In practice, the important point for the homeowner is that this is a high-efficiency multi-zone heat pump designed to modulate rather than operate constantly at maximum capacity.

R-454B: an important consideration for a new installation

This generation uses R-454B refrigerant.

The brochure indicates a charge of 120.61 oz and a precharge allowing up to 100 ft of piping, depending on the configuration specified by the manufacturer.

For a multi-zone system, the total piping length is particularly important, because each indoor unit has its own route to the outdoor unit.

In a two-story home in Laval, for example, a ground-floor head may be 15 ft from the compressor, while a head located upstairs may require 35 or 40 ft of piping.

We therefore calculate the piping routes before confirming the location of the outdoor unit.

An installation where the piping unnecessarily runs throughout the entire building increases costs, multiplies the areas that need to be covered, and complicates future maintenance.

Piping: do not extrapolate a single size to every configuration

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

For a multi-zone heat pump, however, the diameters must always be confirmed according to the actual connected indoor units. The requirements of a small-capacity head may differ from those of a larger head.

At AirGreen, we therefore do not order the piping simply based on the total tonnage of the outdoor unit.

MCA 30 A and MOP 35 A

The technical documentation states:

• MCA: 30 A
• MOP: 35 A
• power supply: 208/230 V, single-phase, 60 Hz
• voltage range: 187 to 253 V

The MCA represents the minimum circuit ampacity required based on the equipment specifications, while the MOP indicates the maximum overcurrent protection permitted for the unit.

These are essential data for planning the electrical circuit correctly.

A common mistake is choosing the circuit breaker solely based on the nominal BTU capacity. Instead, the electrical specifications listed in the documentation and on the nameplate should guide the installation.

A 168 lb outdoor unit: the support deserves serious consideration

The outdoor unit measures 37.24 in. wide × 16.14 in. deep × 31.89 in. high and weighs approximately 168.43 lb.

This is not a small 9,000 BTU unit.

We must provide a support suited to its weight, height, and winter conditions.

In Montreal and on the South Shore, we regularly see older installations where an outdoor unit is almost at ground level. After a heavy snowfall, the lower heat exchanger may be partially blocked.

For a heat pump designed to operate down to -30 °C, this mistake is particularly counterproductive.

We look for a location where:

• snow does not block the heat exchanger;
• defrost water can drain away;
• air circulates freely;
• the unit remains accessible for maintenance;
• vibrations are not unnecessarily transmitted to the building.

Approximately 2,130 CFM through the outdoor unit

The published maximum outdoor airflow is 2,129.41 CFM, or approximately 2,130 CFM.

This figure explains why clearance around the outdoor unit is essential.

A heat pump installed too close to a wall, enclosed under a deck, or surrounded by objects may draw back in some of the air it has just discharged and operate under less favorable conditions.

We therefore plan the location before even determining the pipe route.

61 dB(A) outdoors: choosing the right wall

The stated outdoor sound level is 61 dB(A).

In a detached house with plenty of side space, this value is rarely the only decisive factor.

In a Montreal plex or a Laval condo, or on a property where the houses are close together, placement deserves more attention.

We avoid placing the outdoor unit directly near, whenever possible:

• a bedroom window;
• a patio;
• a frequently used balcony;
• a nearby window;
• a corner formed by several walls that may reflect noise.

An acoustically acceptable system on paper may seem more noticeable when installed in a location that amplifies vibrations or sound reflections.

WiFi included and smart control

SENVILLE enables smart control, and the brochure confirms integration with Alexa as well as control through the app.

In a two-zone installation, WiFi is more useful than it may seem.

The homeowner can manage both zones without walking through the house to adjust each remote control. For a second home or rental property, they can also adjust the temperatures remotely.

We consider this feature a complement to the control system, not a substitute for proper sizing. An app cannot compensate for a poorly placed indoor unit.

Automatic louvers improve air distribution

The AirGreen specifications indicate automatic vertical and automatic horizontal louvers for the units concerned.

In a large room, this movement allows the air to be distributed over a wider area.

Positioning remains much more important than oscillation, however.

A unit installed above a tall cabinet, facing a wall a few feet away, or in an enclosed corridor may remain limited, even with motorized louvers.

How we choose the two indoor locations

For a multi-zone HVAC installation, we want to achieve the best possible airflow with each unit.

We look at, among other things:

• the shape of the rooms;
• doors that generally remain open or closed;
• stairs;
• ceiling height;
• exterior walls;
• window placement;
• major heat sources;
• the possible drain route;
• the refrigerant line route;
• future access for HVAC maintenance.

In a bedroom, we also avoid directing the airflow straight toward the bed when the layout allows for a better location.

Why two smaller zones can be better than a single large head

We often have homeowners who think only in terms of total capacity: “If I need 24,000 BTU, why not install a single 24,000 BTU unit?”

Because a heat pump heats and cools with air, and air does not travel effectively through several closed walls.

A 24,000 BTU unit in the living room will not necessarily provide better comfort in a bedroom at the other end of the building than a much smaller unit installed directly in that zone.

In this type of situation, distribution may be more important than raw capacity.

This is one of the key advantages of the SENVILLE 2-zone system.

Beware of oversizing indoor units

The opposite mistake also exists.

Since two heads are available, it may be tempting to choose the largest possible capacity for each one.

We prefer to match each head to the load of its zone. A well-insulated bedroom or small floor does not necessarily need 12,000 BTU simply because the outdoor unit can accommodate it.

An indoor unit that is too large can quickly reach its setpoint and provide less favorable modulation in a small room.

Leak detection and self-diagnosis

Senville also highlights self-diagnosis and leak detection functions, designed to facilitate the identification of certain operating problems.

These functions can assist with diagnosis, but they obviously do not replace a professional inspection when a system loses capacity, makes noise, produces abnormal ice buildup, or displays an error code.

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.

Maintaining a multi-zone heat pump: two indoor units to monitor

A 2-zone system also means two filters, two indoor heat exchangers, two fans, and two drains.

Both zones therefore need to be maintained.

Among the signs that warrant an inspection or cleaning:

• reduced airflow;
• odor at startup;
• visible dust on the fan wheel;
• water flowing inside;
• significant difference in output between zones;
• unusual noise;
• abnormal frost or ice;
• unusual increase in consumption.

A head that operates very frequently in a busy living room can become dirty more quickly than a unit installed in a bedroom used only at night.

Who do we recommend this SENVILLE R454B 2-zone system for?

This solution is particularly well suited for:

• a two-story home;
• a ground floor and basement requiring independent controls;
• two large separate rooms;
• a condo with a main living area and a separate bedroom zone;
• a property where avoiding two outdoor units is desired;
• a project seeking a cold-climate ENERGY STAR heat pump;
• a residence where low-temperature heating is a priority;
• a homeowner seeking built-in WiFi.

It is less advantageous when two zones have completely opposite needs for extended periods, or when the indoor units would be installed in rooms that are too small for their minimum capacity.

A strong technical specification sheet is not enough: the result depends on the installation

The SENVILLE SENA-28HF-MOA combines several features that are particularly relevant in Québec: R-454B, operation down to -30 °C, cold-climate certification, ENERGY STAR, high seasonal efficiency, and multi-zone management.

But the numbers do not replace design work.

At AirGreen Heat Pumps, Air Conditioning & Heating, we assess the building, the loads of the different rooms, the locations of the two heads, piping routes, drainage, electrical installation, and outdoor unit placement before confirming the configuration.

This approach is particularly important with a multi-zone heat pump because the outdoor unit, indoor units, and line lengths must operate as a single system.

SENVILLE 2-zone installation in Montréal, Laval, Longueuil, the North Shore, and the South Shore

For a property in Montréal, Laval, Longueuil, Boucherville, Terrebonne, Blainville, or elsewhere on the North Shore and South Shore, we can verify whether a SENVILLE 2-zone 27,000 BTU configuration with a SENA-28HF-MOA outdoor unit truly meets the building’s needs.

We can also validate the AHRI combination, low-temperature capacities, electrical requirements, indoor and outdoor locations, as well as the subsidy applicable to the project.

Contact AirGreen for a quote and to have your SENVILLE 2-zone heat pump properly sized. Proper configuration is not simply a matter of BTU count: it starts with choosing the right two zones and ends with an HVAC installation designed to operate efficiently during Montréal’s humid summers and winters.

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