16 kw Heat Pump
Custom Colors
The 16 kW heat pump is the high-capacity model in the Legom Monoblock DC Inverter range, built for large homes and light commercial buildings where heat demand exceeds what the residential platform can cover. It is also, notably, the most efficient unit in the range, reaching a COP of 4.53 in heating and an EER of 3.14 in cooling. Running on R32 refrigerant with a full DC inverter twin rotary Panasonic compressor and a twin-fan configuration, it delivers heating, cooling, and domestic hot water from a single outdoor unit and operates down to -35°C ambient.
16 kW Heat Pump Specifications
Full published parameters for the 16 kW model, Legom Monoblock Series DC Inverter Heat Pump.
| Parameter | 16 kW — QB KFXFC-016SRI |
|---|---|
| Heating capacity range | 6.5 to 18.0 kW |
| Domestic hot water heating | |
| Heating capacity | 18 kW |
| Water yield | 387 L/h |
| Input power | 4.14 kW |
| COP | 4.35 |
| Operating current | 18.5 A |
| Heating A7/W35 | |
| Heating capacity | 16 kW |
| Input power | 3.53 kW |
| COP | 4.53 |
| Operating current | 15.8 A |
| Heating A7/W45 | |
| Heating capacity | 16 kW |
| Input power | 4.38 kW |
| COP | 3.65 |
| Operating current | 19.6 A |
| Cooling A35/W7 | |
| Cooling capacity | 14 kW |
| Input power | 4.46 kW |
| EER | 3.14 |
| Operating current | 20.0 A |
| ERP energy label | |
| ERP at 35°C | A+++ |
| ERP at 55°C | A++ |
| Compressor | |
| Type | DC inverter twin rotary |
| Brand | Panasonic |
| Capacity modulation | Stepless, 20% to 120% |
| Other components | |
| Expansion valve | Electronic expansion valve |
| Air side heat exchanger | Hydrophilic aluminium fin heat exchanger |
| Water side heat exchanger | Plate heat exchanger |
| Fan system | |
| Fan type | Low noise axial fan |
| Motor type | Brushless DC motor |
| Motor brand | NIDEC / SiGe |
| Fan quantity | 2 |
| Water side | |
| Water port size | G1.0 DN25 |
| Water yield | 3.10 m³/h |
| Water pressure loss | 35 kPa |
| Expansion tank | 5 L, included |
| Noise, dimensions and weight | |
| Noise level | ≤56 dB(A) |
| Unit dimensions (W×D×H) | 1040 × 445 × 1350 mm |
| Packing dimensions | 1130 × 495 × 1470 mm |
| Net weight | 120 kg |
| General | |
| Refrigerant | R32 (GWP 675) |
| Power supply | Single or three phase, confirm with the technical team |
| Minimum ambient operating temperature | Down to -35°C |
| Cabinet colours | 11 finishes available |
| Certification | CE, RoHS |
| OEM / ODM | Available |
The Most Efficient Unit in the Range
This is the finding that surprises most buyers, because the usual assumption is that a smaller unit is inherently more efficient. Across this range the opposite holds.
The 16 kW model achieves a COP of 4.53 at A7/W35, the highest of the four capacities, ahead of 4.5 on the 5 kW, 4.46 on the 9 kW, and 4.42 on the 6 kW. It also holds the highest COP at the more demanding A7/W45 condition, at 3.65 against 3.6, 3.45, and 3.43 respectively.
The gap is wider still in cooling. This unit delivers an EER of 3.14, while all three smaller models sit at 2.85. That is roughly a 10% efficiency advantage, achieved because the larger heat exchanger surface and twin-fan airflow reject heat more effectively than a single-fan cabinet can.
| Efficiency measure | 5 kW | 6 kW | 9 kW | 16 kW |
|---|---|---|---|---|
| COP at A7/W35 | 4.5 | 4.42 | 4.46 | 4.53 |
| COP at A7/W45 | 3.6 | 3.43 | 3.45 | 3.65 |
| EER cooling A35/W7 | 2.85 | 2.85 | 2.85 | 3.14 |
The practical consequence is worth stating plainly: on a project whose load genuinely calls for 16 kW, there is no efficiency penalty for the capacity. The unit is not merely adequate at scale, it is the best performer in the range on both heating and cooling.
Vertical Cabinet: Taller but Narrower
The 16 kW unit uses a different cabinet format from the three residential models, and this changes installation planning in a way the capacity figure alone does not convey.
It measures 1040 × 445 × 1350 mm against 1075 × 480 × 805 mm on the 6 kW and 9 kW. It is 545 mm taller, but it is also 35 mm narrower and 35 mm shallower. The result is a smaller floor footprint despite substantially greater capacity, achieved by stacking the twin fans vertically rather than widening the cabinet.
Plan for height and weight, not just floor area. At 1350 mm tall and 120 kg net, this unit needs vertical clearance above it for airflow, a stable base capable of carrying the load, and an access route that accommodates the 1470 mm packing height. Confirm all three before delivery. The narrower footprint is genuinely useful where ground space is tight, but the height introduces constraints the smaller models do not have.
Electrical supply needs checking
This unit draws considerably more current than the residential models: 15.8 A in heating at A7/W35, 19.6 A at A7/W45, and 20.0 A in cooling. The power supply can be configured as single or three phase, and the correct option should be confirmed with the technical team at specification stage rather than assumed.
For commercial installations in particular, verify the available supply capacity and whether three-phase is present on site before committing to the capacity. This is a straightforward check that prevents an expensive discovery during commissioning.
Is a 16 kW Heat Pump the Right Size?
This unit modulates from 6.5 to 18.0 kW, and the lower figure is the one that determines suitability more than the upper one.
A 6.5 kW minimum output means the unit cannot serve a building whose mild-weather demand falls below that. In a well-insulated home needing 3 kW on a spring day, this unit would produce more than double what is required, reach the set point, shut off, and restart repeatedly. Cycling of that kind reduces seasonal efficiency and accelerates compressor wear, and it would occur through most of the heating season rather than occasionally.
This is not a unit to specify with margin in mind. Its minimum output alone exceeds the entire design load of many homes. Specify the 16 kW only when the calculated heat load genuinely sits in the 10 to 16 kW region, and have a qualified installer perform a heat loss calculation rather than estimating from floor area.
When the 16 kW is the right choice
- The calculated heat load sits between roughly 10 and 16 kW
- The building is a large house, or a light commercial property such as an office or shop
- Domestic hot water demand is high, with 18 kW capacity at 387 litres per hour
- Cooling demand is substantial and 14 kW of cooling capacity is required
- Ground space is constrained but vertical space is available
- Three-phase supply is available, or single-phase capacity has been verified
- Efficiency is a priority, since this is the highest-performing unit in the range
If your calculated load falls between roughly 6 and 9 kW, the 9 kW model will modulate far better and shares the same DN25 water connections, so the hydraulic design carries across. For loads beyond 16 kW, several units operating in parallel are the usual approach, and the technical team can advise on the configuration.
Inside the Unit
A heat pump does not generate heat, it moves it. Refrigerant evaporates at low temperature while absorbing heat from outdoor air, the compressor raises its pressure and temperature, and that heat transfers into the water circuit through the plate heat exchanger before the electronic expansion valve drops the pressure and the cycle repeats. Because the unit transports existing energy rather than creating it, it delivers several units of heat per unit of electricity, which is what produces a COP above 1.
Integrated 5 litre expansion tank
The 16 kW is the only model in the range supplied with an expansion tank built in. The three residential units require one to be specified separately as part of the system design.
This is a practical convenience rather than a headline feature, but it removes a component from the installation list, reduces the number of connections to be made and later inspected, and eliminates one opportunity for a sizing error. On a commercial installation where the plant space is already busy, that has real value.
Key Technologies
High Efficiency Full DC Inverter Compressor
Integrating cutting-edge technology, our HVAC systems feature a high-performing DC inverter compressor and DC brushless fan motor. This innovative configuration enables seamless 20% to 120% stepless capacity adjustment. By intelligently adapting to the real-time load requirements, the compressor and fan automatically modulate their speeds during operation. This dynamic adjustment minimises energy consumption, allowing the unit to operate at an optimised level, precisely meeting the desired output while significantly reducing energy costs.
The 16 kW model uses a Panasonic twin rotary compressor paired with twin NIDEC or SiGe brushless DC fan motors. The twin-fan arrangement is what allows this unit to reject heat efficiently enough to reach the highest COP and EER in the range, and it means the two fans can modulate together to match airflow to the actual compressor duty rather than running at fixed speed.
Verified Efficiency: COP 4.53 and EER 3.14
The 16 kW unit carries an ERP rating of A+++ at 35°C and A++ at 55°C. At A7/W35 test conditions it achieves a COP of 4.53, delivering 16 kW of heat output from 3.53 kW of electrical input. In cooling it reaches an EER of 3.14, roughly 10% ahead of the three smaller models. For domestic hot water the COP is 4.35.
Three factors determine what efficiency you achieve in service. The flow temperature required has the largest influence, demonstrated by this unit's own figures: 4.53 at 35°C water against 3.65 at 45°C. Outdoor temperature is the second, since colder air holds less extractable heat. Building insulation is the third, because a leaky building forces higher flow temperatures and pushes the unit into its less efficient range.
R32 Refrigerant: Energy Saving and Environmental Protection
R32 contributes greatly to environmental protection, with a low Global Warming Potential of 675, just 32% of R410A's 2088. In the same heat pump system, its lower liquid density means the charge amount of R32 is less than that of R410A, which brings higher economic efficiency.
The heat needed to evaporate R32 is greater than that of R410A, so the required mass flow rate per unit is smaller and the COP is higher. We not only take care of your family but also contribute to protecting the earth.
The commercial dimension matters more at this capacity than at any other. A 16 kW unit carries a larger refrigerant charge than a residential model, so the choice of refrigerant has a proportionally greater effect both environmentally and on future servicing. Under the European F-Gas Regulation and equivalent rules elsewhere, high-GWP refrigerants face progressive restriction, and larger charges are the first to be affected by quota tightening.
Stable Running at -35°C
The 16 kW unit is engineered to keep operating in ambient temperatures as low as -35°C, well beyond the range in which many standard air source units lose usable output. For a light commercial building this matters more than for a house, since occupants cannot simply put on another layer and a heating failure has business consequences.
Two elements make this possible. The full DC inverter compressor can raise its speed to compensate as the heat available in outdoor air falls, sustaining output where a fixed-speed unit simply cannot. The intelligent defrost system then clears frost from the air-side heat exchanger without the frequent, disruptive cycles that undermine cold-weather comfort in simpler designs.
Output does decline as ambient temperature drops, which is unavoidable physics for any air source heat pump rather than a limitation of this model. Cold-climate projects should therefore be sized against the local design temperature rather than the nominal rating.
Automatic Intelligent Defrosting
In cold, humid conditions frost forms on the outdoor coil and must be cleared, but how a heat pump manages that process has a large effect on comfort. Demand-based defrosting initiates a cycle only when frost is actually detected, rather than running on a fixed timer.
The result is concentrated, efficient defrosting completed in around three minutes, followed by extended heating periods of up to 90 minutes. An ordinary defrost curve, by contrast, shows frequent and incompletely effective cycles with short heating periods between them, which prevents the indoor temperature from stabilising and produces the sudden drops in warmth occupants notice and complain about.
An anti-freezing sensor at the base of the unit detects ice accumulation and manages protection automatically at low ambient temperatures.
Applications for the 16 kW Heat Pump
Light commercial buildings
This is the application that distinguishes the 16 kW from the rest of the range. It suits offices, shops, small commercial premises, and similar buildings where a single high-capacity unit can cover the load, or where several units operate together for larger requirements. Commercial projects bring their own considerations: verify the electrical supply given the 20 A cooling draw, confirm whether three-phase is available, and check local noise limits where the outdoor unit sits near neighbouring properties.
Large residential properties
For large houses with a calculated load in the 10 to 16 kW region, this unit provides the capacity along with the highest efficiency in the range. Its narrower footprint compared with the 9 kW is often welcome on residential plots where ground space around the building is limited.
High-volume domestic hot water
At 18 kW of hot water heating capacity and 387 litres per hour with a COP of 4.35, this unit produces roughly 80% more hot water than the 9 kW model and three times the 5 kW. That makes it appropriate for large households, guest houses, small hospitality premises, and commercial buildings with significant sanitary hot water demand.
Underfloor heating at scale
Underfloor heating remains the most efficient application, and at 35°C flow temperature this unit reaches a COP of 4.53 against 3.65 at 45°C. At this capacity the installation typically involves multiple manifolds serving many zones through floor heating pipe loops, each with a thermal actuator and room thermostat. A base station becomes genuinely useful here, coordinating zone demand so the heat pump runs only when a zone actually requires heat rather than responding to each thermostat independently.
Radiator central heating
The unit can replace a gas or oil boiler in a larger radiator system. The usual caveat applies with greater force at this capacity: radiators sized for 70 to 80°C boiler water will demand high flow temperatures, and COP falls from 4.53 to 3.65 between 35°C and 45°C. On a large installation that difference translates into a substantial annual cost, so assessing and where necessary oversizing the emitters is worth the effort before conversion.
Summer cooling at 14 kW
The unit is reversible, delivering 14 kW of cooling capacity at A35/W7 with an EER of 3.14, the best cooling efficiency in the range. For a commercial building or large home in a hot climate, this provides substantial cooling from the same equipment that heats in winter, avoiding a separate cooling installation entirely.
16 kW Compared with the Wider Range
| Parameter | 5 kW | 6 kW | 9 kW | 16 kW |
|---|---|---|---|---|
| Model | QB KFXFC-005SRI | QB KFXFC-006SRI | QB KFXFC-009SRI | QB KFXFC-016SRI |
| Heating range (kW) | 2.0–6.0 | 3.0–8.0 | 3.5–10.0 | 6.5–18.0 |
| COP at A7/W35 | 4.5 | 4.42 | 4.46 | 4.53 |
| EER cooling | 2.85 | 2.85 | 2.85 | 3.14 |
| Hot water capacity (kW) | 6 | 8 | 10 | 18 |
| Water yield (L/h) | 129 | 172 | 215 | 387 |
| Cooling capacity (kW) | 4 | 5 | 6.5 | 14 |
| Fan quantity | 1 | 1 | 1 | 2 |
| Expansion tank | Not included | Not included | Not included | 5 L included |
| Water port | G3/4 DN20 | G3/4 DN20 | G1.0 DN25 | G1.0 DN25 |
| Noise dB(A) | ≤52 | ≤54 | ≤55 | ≤56 |
| Dimensions (mm) | 1065×405×710 | 1075×480×805 | 1075×480×805 | 1040×445×1350 |
| Net weight (kg) | 60 | 70 | 80 | 120 |
| Best suited to | 2–3 bedroom homes | Medium homes | Medium to large homes | Large homes, light commercial |
All four capacities share the same platform: R32 refrigerant, DC inverter twin rotary compressor, reversible heating and cooling, ERP A+++ at 35°C, operation to -35°C, and CE and RoHS certification. The 16 kW unit is the only model with twin fans, an integrated expansion tank, a vertical cabinet, and the option of three-phase supply.
OEM and ODM Customization
Our team offers expert guidance and customization to suit your product needs. Prior to commitment, provide written confirmation of the key parameters: required heating and cooling capacity, power supply configuration, cabinet colour, controller and connectivity requirements, and branding specification. We employ advanced modelling to ensure project confidence, and product development maintains strict confidentiality, safeguarding your project throughout.
Available customization covers cabinet colour across the eleven finishes shown above, logo and nameplate, packaging, and controller and operating parameter configuration for private-label supply. Samples are produced and performance tested against your specification before production commitment, and performance and leak test records are available for production batches. See the full OEM and ODM service for details, or read about our heat pump OEM factory and how the process works.
Frequently Asked Questions
What size building does a 16 kW heat pump heat?
A 16 kW unit suits large homes and light commercial buildings such as offices and shops, with a calculated heat load in roughly the 10 to 16 kW region. The critical figure is not the maximum but the 6.5 kW minimum modulated output: this exceeds the entire design load of many houses, so in a smaller or well-insulated building the unit would cycle rather than modulate through most of the heating season. Specify this capacity only when the calculated load genuinely calls for it, based on a heat loss calculation rather than a floor area estimate.
Is the 16 kW less efficient than the smaller models?
No, it is the most efficient unit in the range, which surprises most buyers. It achieves a COP of 4.53 at A7/W35, ahead of 4.5 on the 5 kW, 4.46 on the 9 kW, and 4.42 on the 6 kW. In cooling the gap is wider: an EER of 3.14 against 2.85 on all three smaller models, roughly a 10% advantage. The reason is the larger heat exchanger surface combined with twin-fan airflow, which rejects heat more effectively than a single-fan cabinet. On a project whose load genuinely calls for this capacity, there is no efficiency penalty.
How much space does it need?
The unit measures 1040 × 445 × 1350 mm and weighs 120 kg net. Note that while it is 545 mm taller than the 6 kW and 9 kW models, it is actually 35 mm narrower and 35 mm shallower, so its floor footprint is smaller despite the greater capacity. That makes it useful where ground space is constrained. What it needs instead is vertical clearance above for airflow, a base capable of carrying 120 kg, and an access route accommodating the 1470 mm packing height. Confirm all three before delivery.
What electrical supply does it require?
Power supply can be configured as single or three phase, and the correct option should be confirmed with the technical team at specification stage. The unit draws considerably more current than the residential models: 15.8 A in heating at A7/W35, 19.6 A at A7/W45, and 20.0 A in cooling. For commercial installations in particular, verify the available supply capacity and whether three-phase is present on site before committing to this capacity, since discovering a supply limitation during commissioning is expensive to resolve.
Does it include an expansion tank?
Yes, and it is the only model in the range that does. The 16 kW unit is supplied with a 5 litre expansion tank built in, whereas the 5 kW, 6 kW, and 9 kW models require one to be specified separately as part of the system design. This removes a component from the installation list, reduces the number of connections to be made and later inspected, and eliminates one opportunity for a sizing error. On a commercial installation where plant space is already busy, that has practical value.
How much hot water does it produce?
The 16 kW unit delivers 18 kW of domestic hot water heating capacity at 387 litres per hour, with a COP of 4.35 and an input power of 4.14 kW. That is roughly 80% more than the 9 kW model and three times the 5 kW, making it appropriate for large households, guest houses, small hospitality premises, and commercial buildings with significant sanitary hot water demand. Actual delivery depends on cylinder size, incoming cold water temperature, and target storage temperature, so confirm the full hot water arrangement with your installer.
Can it provide cooling as well as heating?
Yes, and cooling is a particular strength of this model. It delivers 14 kW of cooling capacity at A35/W7 conditions with an EER of 3.14, the highest cooling efficiency in the range. For a commercial building or large home in a hot climate, this provides substantial cooling from the same equipment that heats in winter, avoiding a separate cooling installation. If the system feeds underfloor heating, note that radiant cooling requires attention to condensation risk, since surfaces cooled below the dew point attract moisture.
Should I choose the 9 kW or the 16 kW?
The decision rests almost entirely on calculated load. Choose the 9 kW if your load falls between roughly 6 and 9 kW, because the 16 kW cannot modulate below 6.5 kW and would cycle badly in that range. Choose the 16 kW if the load sits between 10 and 16 kW, or the building is light commercial. Both share G1.0 DN25 water connections, so the hydraulic design carries across between them. The 16 kW additionally offers better efficiency, an integrated expansion tank, and a narrower footprint, but none of that compensates for oversizing.
How noisy is the 16 kW heat pump?
The unit is rated at ≤56 dB(A), only one decibel above the 9 kW model despite delivering nearly twice the output, using twin low-noise axial fans with brushless DC motors. Because twin fans share the airflow duty, each runs at lower speed than a single fan moving the same volume would need to. Placement still matters: for commercial installations check local noise limits where the unit sits near neighbouring properties, and in residential settings position it away from bedroom windows and clear of corners where sound reflects.
Will it work in a cold climate?
The unit is engineered to keep operating down to -35°C ambient, which covers the great majority of populated cold-climate regions. Output does decrease as temperature falls, which applies to every air source heat pump, so cold-climate projects should be sized against the local design temperature rather than the nominal rating. For a light commercial building this reliability matters more than for a house, since a heating failure carries business consequences rather than just discomfort.
What colours is the 16 kW heat pump available in?
Eleven cabinet finishes are available: white, white grey, grey, black, blue, green, red, yellow, gold, brown, and mocca. This range exists for two reasons. For OEM and private-label partners, cabinet colour is part of brand identity. For commercial and residential projects alike, the outdoor unit is often visible, and at 1350 mm tall this unit is more prominent than the residential models, so matching it to the building rather than accepting a default white is a meaningful specification option.
Is the 16 kW model available for OEM supply?
Yes. OEM and ODM customization covers cabinet colour across eleven available finishes, logo and nameplate, packaging, and controller and operating parameter configuration for private-label supply. Power supply configuration should also be confirmed at specification stage. Samples are produced and performance tested against your specification before production commitment, and performance and leak test records are available for production batches. All projects are handled under confidentiality agreement. Contact the technical team with your target market and volumes to discuss terms.
What certification does it carry?
The unit is CE and RoHS certified and carries an ERP energy label rating of A+++ at 35°C and A++ at 55°C. CE confirms compliance with applicable European safety, electromagnetic compatibility, and low voltage requirements, and RoHS confirms restriction of hazardous substances in electronic components. Certification documentation is available on request for regulatory submission and procurement compliance. For commercial projects, confirm any additional market-specific requirements for your destination, since certification obligations depend on where the product is sold rather than where it is manufactured.