TCL APEX XS Central Heat Pump (Black) | 3 Tonnes - 36000 BTU
SEER2 (Seasonal Energy Efficiency Ratio)
HSPF2 (Heating Seasonal Performance Factor)
EER2 (Instant Cooling Efficiency)
COP at -8 °C (Heating energy efficiency)
COP at -15 °C (Heating energy efficiency)
Operating temperature down to -30 °C (MAX)
Performance Airflow (Airflow Rate)
How Do You Determine That a House Needs Three Tons, Not Four?
The most consequential question in a central heat pump project is not the brand. It is the capacity. A one-ton difference in either direction affects comfort, energy costs, and compressor life—and this decision is made before even discussing a model.
Here, we use the 3-ton TCL APEX XS central heat pump in Basalt Grey as a practical example to explain how proper sizing is determined and why the rule of thumb so often fails in Quebec.
Why “One Ton per 500 Square Feet” Does Not Work
This rule has been around for decades. It originated in the southern United States, where the dominant load is air conditioning and the housing stock is relatively uniform. Applied to the Greater Montreal Area housing stock, it produces errors in both directions.
Two 1,800-square-foot homes can have loads that differ by as much as two to one. What separates them includes:
- Year of construction and actual insulation. An unrenovated 1955 cottage and a 2015 construction have nothing in common thermally.
- Window area and orientation. A wall of south-facing windows is a major solar gain in summer and a significant heat loss in winter.
- Air tightness. Infiltration accounts for a considerable share of the load in older buildings, and it cannot be seen on a floor plan.
- Design temperature for the area. It is not the same in Montreal, Saint-Jérôme, or Sainte-Agathe. Using the wrong one throws everything else off.
- Volume, not just floor area. Nine-foot ceilings add 12% more volume to heat than eight-foot ceilings.
- Number of occupants and internal gains. These matter more than people generally assume for air conditioning.
What We Actually Calculate
A proper assessment produces two distinct numbers: the heating load at the winter design temperature and the cooling load at the summer design temperature. These two loads do not occur at the same time and do not necessarily point to the same capacity.
We then determine the balance point: the outdoor temperature at which the heat pump’s capacity exactly matches the building’s load. Below this point, supplemental heat takes over. This is the most useful figure we can provide a client because it concretely predicts how many hours per season the supplemental heating will operate.
With the 3-ton APEX XS, this calculation is clearer than usual for one specific reason: the unit maintains 36,000 BTU/h down to -15°C. Its capacity curve is flat, so the balance point falls low and does not depend on questionable extrapolations.
Certified Data
- 36,000 BTU/h at 8.3°C — COP 3.60
- 36,000 BTU/h at -8°C — COP 2.30
- 36,000 BTU/h at -15°C — COP 1.85
- 18,800 BTU/h at -30°C at maximum capacity — COP 1.20
Values from the NEEP cold-climate heat pump directory, based on AHRI-certified testing. Seasonal efficiency: 18.0 SEER2, 11.0 EER2, 9.5 HSPF2.
What Happens When the Capacity Is Chosen Incorrectly
The two errors have distinct signatures, and we regularly diagnose them in systems installed by others.
An oversized unit reaches the setpoint quickly and then shuts off. In cooling mode, short cycles do not allow enough time to remove humidity: the air becomes cold and clammy, the occupant lowers the setpoint, and energy consumption rises without improving comfort. In heating mode, repeated starts wear out the compressor and create noticeable temperature fluctuations. The paradox is consistent: an oversized system uses more energy and provides less comfort.
An undersized unit causes the electric auxiliary heat to start far too often. Since auxiliary heat has an efficiency of 1.0 compared with 2.30 for the heat pump at -8°C, every hour of auxiliary operation costs more than twice as much. The expected project savings never materialize, and the homeowner wrongly concludes that “heat pumps do not work in Quebec.”
Technical Specifications
- Air handler: H36APH20UDE — Outdoor unit: H36SDH20XQC
- AHRI certificate: 218453817 — ENERGY STAR number: 4622453
- Refrigerant: R-32, 105.8 oz charge
- Airflow: 1,200 CFM — static pressure: 0.58 / 0.8 in.
- Outdoor power supply: 220 V — MCA 30 A, MOP 50 A
- Line set: 3/8 in. liquid, 3/4 in. gas
- Sound level: 52 dB(A) indoors, 54 dB(A) outdoors
- Outdoor unit dimensions: 43.13 x 19.44 x 33.75 in.
- Auxiliary heat kits: 5, 10, or 15 kW — filter 18 x 20
- LogisVert assistance: $4,320 for existing homes
Sizing the Auxiliary Heat: The Other Half of the Decision
Choosing the heat pump is not enough. You must decide what takes over below the balance point, and that choice has a direct impact on electricity use.
The auxiliary heating kits available for this model are 5, 10, or 15 kW. The instinct is to choose the largest one “for safety”—and that is precisely what should be avoided. An unjustified 15 kW element adds a considerable electrical load, may require a panel upgrade, and will never be fully used if the balance point is low.
When an existing furnace is retained in a retrofit, the question does not even arise: it provides the auxiliary heat, and no electric element is required. This is often the most economical configuration in homes already equipped with a gas or dual-energy system.
The Basalt Grey Finish
This version differs from the Zinc White variant in the outdoor unit’s surface finish, with no mechanical or efficiency differences. The dark grey integrates better with a foundation, dark brick, or contemporary siding—a consideration that matters when the unit is visible from the street or an outdoor living area.
Why AirGreen
Rigorous sizing takes time and is not billed separately. Yet it is the step that determines whether a client will be satisfied for fifteen years or call us every winter. At AirGreen, we calculate the loads, establish the balance point, size the auxiliary heat accordingly, and verify the available electrical capacity before providing a quote.
We often recommend a lower capacity than the one requested. It is rarely what the client expects to hear, and it is almost always the right decision.
Contact AirGreen for a proper load calculation and a detailed quote for the 3-ton TCL APEX XS in Basalt Grey in Montreal, Laval, Longueuil, on the North Shore, and on the South Shore.