A millimeter-precise installation beneath a sloped ceiling with decorative moldings
This ELIOS EMC wall-mounted heat pump in Howick installation presented an immediately visible constraint: the indoor unit had to be integrated beneath a sharply sloped ceiling, just a few centimeters from substantial decorative moldings. In this type of room, an approximate installation would quickly have led to interference with the ceiling, poor airflow, or insufficient access for maintenance.
Our AirGreen team installed an indoor unit bearing reference EWHMA12C2AS1, corresponding to the 12,000 BTU ELIOS EMC system. This capacity is a versatile choice for cooling and heating a moderately sized residential area, provided that sizing has been validated according to the building’s actual configuration.
The photograph shows a compact installation, aligned with the slope and positioned to allow the lower louver to operate freely. The unit is not simply mounted as high as possible: its placement takes into account the ceiling geometry, front panel opening, air circulation, and future HVAC maintenance.
An architectural configuration that leaves very little room for error
The ceiling of this residence in Howick slopes at a pronounced angle above the unit. A molding composed of several horizontal profiles also follows this slope, further reducing the available vertical space.
Several measurements had to be verified before drilling the wall:
- the exact height of the indoor unit;
- the distance between the top of the unit and the moldings;
- the space needed to remove and clean the filters;
- the clearance required to lift the front panel;
- the full opening of the air outlet louver;
- the position of the conduits behind the unit;
- the level of the mounting plate despite the sloped ceiling lines.
This final check is particularly important. In a room with a sloped ceiling, the eye can easily be misled by the architectural lines. A truly level unit may appear tilted when compared with an angled molding. However, the wall plate must be installed correctly, particularly so that condensate flows toward the drain rather than accumulating in the indoor pan.
At AirGreen, we therefore never use the ceiling slope as a reference. We use independent measurements and leveling instruments to maintain a technically correct installation.
A 12,000 BTU unit identified directly on the unit
The nameplate visible on the side of the unit indicates the indoor model EWHMA12C2AS1. According to the EMC series’ technical table, this model is paired with the outdoor unit ESHMA12C2AN1.
The 12,000 BTU version offers the following features:
- nominal cooling capacity of 12,000 BTU/h;
- cooling modulation from 3,600 to 13,500 BTU/h;
- nominal heating capacity of 12,000 BTU/h;
- heating modulation from 3,800 to 16,000 BTU/h;
- TRÉS2 efficiency of 24;
- TRÉ2 efficiency of 13.2;
- CPSC2 of 8.0 in Region V;
- 208 to 230 V power supply;
- maximum 15 A outdoor fuse;
- heating operation down to -30 °C;
- refrigerant R454B;
- ENERGY STAR V6.1 cold-climate certification.
These data place the ELIOS EMC heat pump among the units designed to provide useful heating during Quebec winters while maintaining good cooling efficiency.
Why 12,000 BTU does not automatically correspond to a specific area
It is common to look for a simple rule linking a 12,000 BTU capacity to a given area. However, this method can lead to the wrong choice.
In Howick, as elsewhere in Montérégie, the heat load depends in particular on:
- the level of insulation;
- the age of the building;
- the area and type of windows;
- sun exposure;
- the average ceiling height;
- the number of exterior walls;
- connection to adjacent rooms;
- air infiltration;
- how the room is used;
- heat-producing equipment.
For this project, the sloped ceiling changes the actual volume of the area. A room may have a moderate floor area while containing more or less air than a conventional room, depending on the height of the slope.
Proper sizing therefore does not mean selecting the highest capacity as a precaution. An oversized heat pump can cool too quickly, reduce dehumidification, and create uncomfortable fluctuations. An undersized unit may run continuously without reaching the desired temperature on extreme days.
A compact width well suited to this location
The 12,000 BTU indoor model measures approximately:
- 31.57 inches wide;
- 7.87 inches deep;
- 11.61 inches high.
These dimensions are identical to those of the series’ 9,000 BTU version. They made it possible to install the unit in a wall section limited by the slope without installing an excessively wide enclosure.
For comparison, the 18,000 BTU ELIOS EMC model is more than 42 inches wide. A unit of this size would have taken up considerably more space and could have conflicted with the room's geometry.
This installation illustrates why the evaporator's physical dimensions must be verified before recommending a model. Two heat pumps with different capacities can completely change the feasibility of a location.
Upper clearance: a determining detail
The unit is positioned near the trim, but is not directly wedged against it. Functional space must be maintained so that the unit can draw air through its upper section.
When this clearance is overlooked, several problems can arise:
- restricted airflow;
- more noticeable suction noise;
- reduced capacity;
- difficulty opening the panel;
- filters that are difficult to remove;
- longer and more costly maintenance;
- accelerated dust accumulation.
In a standard room, it is often possible to lower the unit slightly. Here, the installation also had to maintain sufficient height to promote air distribution. Our task was therefore to make smart use of every available centimetre.
A visible A2L label on the side of the unit
The photograph clearly shows the pictogram A2L on the side plate. This identification is related to the use of the refrigerant R454B, classified as a mildly flammable refrigerant.
R454B is used in this series to comply with the sector's new environmental guidelines. Its installation requires appropriate practices, including:
- using compatible tools;
- professional handling of the refrigeration circuit;
- a rigorous leak test;
- proper evacuation;
- following the manufacturer's procedures;
- verifying the safety measures associated with the refrigerant.
The EMC series also includes a refrigerant leak detection sensor. The documentation states that, if a leak is detected, the unit can stop operating and activate the fan according to its safety sequence.
This device does not replace a sealed installation. It provides additional protection integrated into the equipment.
A system designed to provide heating down to -30 °C
In Howick, winter temperatures can place a significant load on a heating system. The ELIOS EMC heat pump is advertised to operate in heating mode down to -30 °C.
The Heat+ technology is designed to increase available capacity as the outdoor temperature drops. The manufacturer also states that the series can provide 100% of its rated capacity at -15 °C.
This performance is important, but it must be interpreted correctly. A heat pump operating down to -30 °C does not automatically eliminate every source of supplemental heating. Actual needs depend on the building’s heat loss and the heat pump’s precise capacity at different temperatures.
In many residences in Montréal, Laval, Longueuil, the North Shore and the South Shore, a wall-mounted heat pump is used with electric baseboard heaters. The heat pump then handles a large portion of the heating, while the baseboards remain available in certain areas or during periods of peak demand.
The Inverter compressor for more consistent comfort
The ELIOS EMC heat pump uses Inverter Drive technology. Its compressor can modulate its frequency rather than operating only at full capacity.
This modulation is particularly advantageous in a room with a sloped ceiling, where the temperature can vary between the lower and upper parts of the space. A modulating unit can maintain a more consistent airflow and limit sudden fluctuations.
The benefits include:
- more uniform temperature;
- fewer on-off cycles;
- energy consumption better matched to demand;
- better dehumidification when the unit operates at low speed;
- quieter operation;
- reduced mechanical wear compared with repeated starts.
The compressor frequency of the EMC series can be controlled in 1% increments, allowing fine modulation according to the room’s demand.
Unobstructed airflow despite the proximity of the trim
The lower louver is completely unobstructed and can direct airflow toward the usable part of the room. The unit is neither enclosed in a recess nor blocked by a soffit.
This arrangement is essential for making full use of the unit’s capacity.
Recommended cooling setting
In cooling mode, the air should generally be directed forward or slightly upward. Since cooled air naturally descends, this direction allows it to travel farther before reaching the occupied area.
A louver set too low can concentrate cold air in one part of the room and create an uncomfortable draft.
Recommended heating setting
In heating mode, the air can be directed more toward the floor. Since heat tends to rise, this direction helps warm the occupied area rather than allowing warm air to accumulate near the sloped ceiling.
The variable-speed fan in the EMC series also allows airflow to be adjusted according to occupants’ preferences.
Indoor operation as low as 20 dB(A)
For the EWHMA12C2AS1 model, the documentation indicates an indoor sound level as low as 20 dB(A) at the quietest setting. The other stated levels are 22.5 dB(A) at low speed, 35.5 dB(A) at medium speed, 42 dB(A) at high speed, and 44.7 dB(A) in turbo mode.
This low minimum sound pressure level is relevant when the unit serves:
- a bedroom;
- an office;
- a reading area;
- a room used in the evening;
- an area where occupants are sensitive to noise.
The “Do Not Disturb” mode also allows you to disable audible alerts and the display during the night.
However, it is important to distinguish the appliance's noise from noise caused by improper installation. Vibrations, a poorly secured plate, lines contacting the structure, or an incorrectly positioned drain can generate sounds that do not come from the heat pump's normal operation.
The technical details that turn a difficult installation into a durable one
The wall plate must remain perfectly stable
The indoor unit rests on a metal plate secured to the wall. This plate must support the unit, maintain its alignment, and prevent movement while the fan is operating.
Under a sloped ceiling, the installer may have little room to work above the unit. Nevertheless, they must:
- locate the wall structure;
- choose fasteners suitable for the material;
- level the plate;
- check the position of the refrigerant outlet;
- plan for the drain slope;
- confirm that the housing can snap fully into place.
A slightly warped or misaligned plate can prevent the unit from sitting properly against the wall. This can sometimes result in a visible gap, vibrations, or difficulty removing the appliance during servicing.
Drainage must be planned before fastening
The heat pump produces water in cooling mode. This water must leave the condensate pan through a properly sloped drain.
The most common errors include:
- a drain with insufficient slope;
- a pipe crushed behind the unit;
- a line rising after the outlet;
- an improperly sealed connection;
- a drain exposed to freezing temperatures;
- an incorrectly positioned outdoor outlet;
- a pipe inserted too deeply into an existing line.
An indoor leak located near decorative trim could damage paint, drywall, or wood. That is why the drainage test is an integral part of commissioning.
The 12,000 BTU model's lines
The 12,000 BTU ELIOS EMC system uses, according to the technical specifications:
- a liquid line of 1/4 po;
- a gas line of 3/8 po;
- a maximum piping length of 82 feet;
- a maximum height difference of 49.2 feet.
These values represent technical limits, not targets. A shorter, logical route generally simplifies installation, reduces potential friction points, and facilitates future servicing.
The lines must be insulated, protected, and installed without excessive bending. Flared connections must be prepared precisely and tightened to the appropriate torque.
A moisture removal capacity of 1.4 liters per hour
The 12,000 BTU model has a moisture removal capacity of 1.4 liters per hour under the manufacturer's test conditions.
Dehumidification is particularly important in rural and semi-rural areas of Montérégie, where summer periods can become hot and humid.
To promote better humidity control:
- avoid an excessively low set temperature;
- use an appropriate fan speed;
- keep the doors open when the goal is to serve an adjacent area;
- clean the filters regularly;
- avoid a significantly oversized appliance;
- use dehumidification mode when conditions warrant it.
The two-filter system and active cleaning
The EMC series includes a two-stage filtration system. The first filter is designed to capture dust, pollen, and pet hair. The second uses carbon to help absorb smoke and certain contaminants.
The active cleaning function helps limit the buildup of contaminants on the indoor coil.
These features remain complementary to regular maintenance. They do not relieve the owner of the responsibility to clean the filters.
We generally recommend:
- check the filters every four weeks during periods of heavy use;
- clean them more frequently when pets are present;
- never operate the appliance without a filter;
- keep the air intake clear;
- arrange for professional cleaning when buildup appears on the blower wheel or coil.
Mistakes to avoid in this type of room
Mounting the unit according to the line of the moldings
The moldings are angled. They should not be used as a reference for leveling the unit.
Placing the unit directly against the ceiling
This restricts air intake, prevents the panel from opening, and makes cleaning more difficult.
Underestimating the depth of the appliance
The model is nearly eight inches deep. Under a slope, clearance must be checked across the entire depth of the enclosure, not just at the back.
Forgetting to allow for the opening of the front panel
A unit may seem perfectly fitted when closed, then come into conflict with the ceiling as soon as the front panel is raised.
Installing a larger capacity without checking the dimensions
The 18,000 and 24,000 BTU versions are considerably wider and taller than the 12,000 BTU version.
Neglecting airflow
A technically feasible location is not necessarily comfortable if the louver blows directly onto a bed, desk, or sofa.
The subsidies must be verified according to the complete system.
The ELIOS EMC series is certified ENERGY STAR V6.1 Cold Climate in the five capacities indicated by the manufacturer. This certification is a requirement frequently specified by certain financial assistance programs.
Eligibility for a subsidy cannot, however, be confirmed solely based on the brand or series name. The following must be verified:
- the exact combination of indoor and outdoor units;
- the reference number recognized by the program;
- the heating capacity used in the calculation;
- the type of building;
- the primary heating system;
- the purchase and installation date;
- the terms in effect at the time of the application;
- the required documents and photographs.
At AirGreen, we pay particular attention to model numbers and the documents provided, because a discrepancy between the quotation, invoice, and rating plate can complicate a claim.
An installation representative of our work in Greater Montreal
Although this project was completed in Howick, the constraints observed are comparable to those encountered in many properties in Montreal, Laval, Longueuil, the North Shore, and the South Shore.
We regularly install wall-mounted heat pumps in:
- attic bedrooms;
- century homes;
- extensions;
- basements with low ceilings;
- condos with decorative trim;
- rooms located beneath a roof;
- homes where available wall space is very limited.
In every situation, our approach remains the same: measure before making a recommendation, verify clearances, anticipate maintenance, and never sacrifice performance to save a few minutes during installation.
The final result in Howick
This HVAC installation in Howick stands out for its precise integration into a particularly challenging space. The 12,000 BTU ELIOS EMC unit is installed level beneath the sloped trim, with functional clearance and a completely unobstructed air outlet.
The rating plate remains visible on the side, making it easier to identify the model during maintenance, a warranty claim, or a technical inspection. The A2L pictogram also informs future technicians that R454B refrigerant is present.
The result does not depend on one spectacular element, but on a series of precise decisions:
- choose a unit with compatible dimensions;
- measure the actual slope;
- keep access to the filters;
- ensure condensate drainage;
- ensure that the unit is level;
- protect the refrigeration circuit;
- properly direct the airflow;
- perform a complete commissioning.
It is precisely in these tight installations that the installer’s experience becomes most important. A difference of a few centimetres can determine whether the unit will be easy to maintain and pleasant to use for years.