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APOLLO Air-to-Water Heat Pump - 3.5 Ton - 42K BTU

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APOLLO Series — Standard

APOLLO Air-to-Water Heat Pump - 3.5 Ton - 42K BTU

Heating Capacity: Up to 2,500 ft²

Cold-climate hydronic heating, cooling, domestic hot water, and optional pool heating with leaving water up to 131°F.

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  • Apollo 6 ton air to water heat pump installed outdoors beside a brick home.
  • Apollo 5 ton air to water heat pump installed outdoors on a concrete pad in winter conditions.
  • Apollo 3.5 ton air to water heat pump mounted outdoors on a wood stand beside a workshop.
  • Apollo 3.5 ton air to water heat pump with insulated hydronic lines mounted beside a metal building.
  • Square crop of an Apollo 6 ton air to water heat pump installed outdoors with insulated piping.
  • Apollo 6 ton air to water heat pump installed on a raised wood stand beside a blue-sided home in snow.
  • Apollo 5 ton air to water heat pump with a tablet positioned on the outdoor unit during commissioning.
  • Apollo 5 ton air to water heat pump connected to copper piping and hydronic lines in a utility room.
  • Apollo air to water heat pump installed outdoors on raised concrete blocks beside a metal-sided building.
  • Dual-fan air-to-water heat pump installed beside a lakeside home on a concrete pad.

Installed in real homes and workshops

Customer Success Stories

The Apollo heat pump system is very efficient, quiet, and easy to install. It stands out for its clear design, well-organized components, and advanced features like a touchscreen and remote monitoring through an app. It also allows precise temperature control and includes an electric backup for very cold conditions. Overall, it's a reliable and practical system.

Maximizing Efficiency with Apollo Heat Pump

Economical performance that isn't affected by low temperatures.

Product details

  • Four-season hydronics
  • Cold-climate operation
  • EVI inverter control
  • Up to 131°F water

APOLLO Central Heat Pump – 42k BTU / 3.5 Ton (Air-to-Water EVI Inverter)

High-performance air-to-water heat pump designed as a complete boiler replacement solution, combining heating, cooling, hot water, and high energy efficiency in one compact and ultra-quiet system.

Key Benefits

  • All-in-one solution for heating, cooling, domestic hot water, and pool heating
  • Up to COP 5.65 efficiency for maximum energy savings
  • Operates in extreme temperatures (-31°F to 110°F)
  • EVI full inverter technology for stable performance and lower consumption
  • Virtually silent operation (up to 12dB quieter than standard heat pumps)
  • Built with premium components (Panasonic compressor, Siemens motor)

Specifications

  • Heating Capacity: 42,000 BTU (3.5 Ton)
  • Recommended Area: 1,000 to 2,500 ft²
  • Applications: Radiant floor, fan coil (FCU), air handler (AHU), hot water (DHW), pool heating
  • Technology: Air-to-water EVI DC inverter
  • Efficiency: COP up to 5.65
  • Operating Range: -31°F to 110°F
  • Refrigerant: R-32 (low GWP)
  • Control: Wi-Fi smart controller
Rated heating / cooling
35.8 / 27.4 KBTU
Ambient operating range
-31°F to 110°F
Power supply
220–240V / 1 / 60Hz
Water flow / connection
8.2 GPM / 1 in
Refrigerant / charge
R-32 / 49.3 oz
Dimensions / weight
43.4 × 18.5 × 33.1 in / 275.6 lb
Heating at 41°F
42 KBTU; 9.2 kW; COP 4.6
Heating at 10°F
22.2 KBTU; 10.5 kW; COP 2.11
Cooling at 95°F
27.3 KBTU; 6.8 kW; COP 4.6

For US customers

Incentives and rebates may be available

Federal, state, utility, and local programs can depend on location, equipment eligibility, installer requirements, and system configuration.

Published air-to-water heat pump programs found for:

Compare all 4 state rebate guides

Check locally

  • State, ZIP code, and utility provider
  • Licensed-installation requirements
  • Model-specific efficiency and certification rules
  • Whether savings are rebates, tax credits, or utility incentives

MBTEK can provide

  • Purchased equipment model details
  • Manuals, specifications, and certification documents
  • Product information needed during program research

Confirm eligibility with your installer, utility, and program administrator before purchase. MBTEK cannot guarantee eligibility, approval, or claim administration.

Answers

Frequently asked questions

What is a 3.5 ton heat pump, and how many BTUs is it?

The APOLLO 3.5 ton heat pump is sold in the 42,000 BTU nominal capacity class. Heat pump tonnage describes heating and cooling capacity, not the unit's physical weight. This is an air-to-water hydronic heat pump, not a conventional ducted air conditioner or condenser. Actual output changes with outdoor temperature and leaving-water temperature.

What size home can a 3.5 ton heat pump serve?

The general planning range for this 3.5 ton heat pump is up to 2,500 ft². This is a starting point, not a substitute for load calculations. Climate, insulation, windows, ceiling height, air leakage, required water temperature, and indoor distribution all affect the capacity a building needs.

What is the difference between a 3 ton and 3.5 ton heat pump?

A nominal 3 ton heat pump represents about 36,000 BTU/h, while a 3.5 ton heat pump represents about 42,000 BTU/h. The extra nominal capacity does not automatically make the larger unit a better choice. Select the model by comparing the building load with condition-specific heat pump output.

How do I know whether this 3.5 ton heat pump is right for my home?

Compare the building's heating and cooling needs with the 3.5 ton heat pump output under local winter and summer conditions. Also consider the required system water temperature, indoor equipment, domestic hot water or pool heating, and whether backup heat or additional heat pumps may be needed.

Can this 3.5 ton heat pump heat and cool a home?

Yes. The APOLLO can supply heated water to radiant floors, fan coils, or compatible air handlers. For cooling, it supplies chilled water to fan coils or air handlers designed for cooling and dehumidification. Radiant-floor cooling requires dew-point and condensation controls and should only be used in a properly engineered system.

How does the 3.5 ton heat pump perform in cold weather?

The APOLLO operating range extends from -31°F to 110°F, but operating range does not mean full output remains available at every temperature. At the manual's 10°F heating test condition, this model produces approximately 22.2 KBTU with a COP of 2.11. Compare condition-specific output with the building load to determine whether backup or staged capacity is needed.

Can this 3.5 ton heat pump replace a boiler or work with radiant floor heating?

It can serve as the main hydronic heat source when its condition-specific output and maximum leaving-water temperature of up to 131°F match the building and its emitters. Radiant floors and other low-temperature systems are strong applications. High-temperature radiators or baseboards must be checked carefully before replacing a boiler.

Can this 3.5 ton heat pump provide domestic hot water or heat a pool?

Yes, when paired with the correct indirect domestic-hot-water tank, pool heat exchanger, piping, and controls. The outdoor heat pump does not provide tankless domestic hot water by itself. Tank recovery, system priority, pool load, and simultaneous space-heating demands must be included in the system design.

What equipment is needed besides the APOLLO outdoor heat pump?

A complete system may include the outdoor heat pump, Hydro Station, household hot-water tank, buffer tank, water pumps, controls, expansion tank, components that remove air and debris from the water loop, electrical protection, and indoor heating or cooling equipment. Exact parts depend on the installation.

How efficient is the APOLLO 3.5 ton heat pump?

Published performance reaches a COP of up to 5.65 under favorable test conditions, but that is not a year-round guarantee. COP changes with outdoor temperature, water temperature, load, flow, and system design. Use the condition-specific performance tables when estimating operating efficiency.

How much does a 3.5 ton heat pump system cost?

The product price shown on this page covers the selected equipment configuration, not necessarily a complete installed hydronic system. Total project cost depends on tanks, controls, indoor distribution, electrical work, piping, labor, and project complexity. A system plan is needed for a meaningful installed-cost estimate.

What are the installation requirements for this 3.5 ton heat pump?

This model uses 220–240V / 1 / 60Hz power and has a published sound level of 52 dB(A). Its rated water flow is 8.2 GPM through a 1 in water connection. Electrical protection, piping, clearances, freeze protection, startup, and local-code requirements must be confirmed from the current installation manual by qualified professionals.

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