icon

Want a better deal? Leave your number or call us

APOLLO cold-climate series

3.5 Ton Heat Pump Air-to-Water

42,000 BTU EVI Inverter · Up to 2,500 ft²

A cold-climate 3.5 ton heat pump for hydronic heating, cooling, domestic hot water, and optional pool heating in homes up to 2,500 ft².

Is a 3.5 Ton Heat Pump Right for Your Property?

Buying the heat pump only?

You could get a better price by calling us for a complete system.

$6,042.03 $5,437.82
Shipping $1,027 Free

One outdoor unit, many applications

Heating, Cooling, and Hot Water From One System

The 3.5 Ton Air-to-Water Heat Pump combines EVI full-inverter control, R-32 refrigerant, Wi-Fi control, and premium components in a flexible hydronic platform.

5-year compressor warranty

Long-term coverage on the core component.

Cold-climate rated

Operating range down to -31°F.

Quiet inverter operation

Variable output avoids hard starts.

COP up to 5.65

High efficiency under favorable conditions.

One hydronic platform

Radiant floors, fan coils, air handlers, DHW, and pools.

  • Space heating
  • Cooling
  • Hot water
  • Pool
Complete APOLLO air-to-water heat pump system diagram

More than an outdoor unit

Build a Complete Hydronic System

The heat pump is one part of the job. MBTEK can help match the Hydro Station, tanks, controls, pumps, radiant-floor components, fan coils, air handlers, and system schematic.

  • Review loads, temperatures, zones, and application goals
  • Build a compatible bill of materials
  • Provide a practical hydronic schematic for the project

Installed in real homes and workshops

Customer Heat Pump Stories

Hear how owners use APOLLO heat pumps in cold weather, radiant floors, shops, and full-home hydronic systems.

Independent feedback

APOLLO Heat Pump Reviews

Company trust comes first, followed by detailed reviews for this heat pump.

Verified company reviews

Reviews for 3.5 Ton Air-to-Water Heat Pump

Convinced by the results?

Ready to order your 3.5 Ton heat pump?

Jump back to pricing, pick your property size, and add it to your cart.

Product FAQ

3.5 Ton Heat Pump Frequently Asked Questions

Direct answers about 3.5 ton heat pump capacity, sizing, cold-weather performance, hydronic applications, efficiency, and installation planning.

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 design heating and cooling loads with the 3.5 ton heat pump output at the local design temperature and required leaving-water temperature. The system design should also account for radiant floors, fan coils, air handlers, zones, domestic hot water, pool heating, and any backup or staged heat source.

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 hydronic system may include a Hydro Station, indirect domestic-hot-water tank, buffer tank, circulators, controls, expansion equipment, air and dirt separation, electrical protection, and radiant, fan-coil, or air-handler distribution. The exact bill of materials depends on the application and piping layout.

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.

Current model

3.5 Ton Heat Pump Specifications

42,000 BTU / 3.5 Ton · Up to 2,500 ft². Homes up to 2,500 ft², smaller new builds, and focused hydronic zones.

Manual rated heating 35.8 KBTU
Manual rated cooling 27.4 KBTU
Ambient range -31°F to 110°F
Leaving water Up to 131°F
Power supply 220–240V / 1 / 60Hz
Sound level 52 dB(A)
Rated water flow 8.2 GPM
Water connection 1 in
Refrigerant / charge R-32 / 49.3 oz
Dimensions L × W × H 43.4 × 18.5 × 33.1 in
Unit weight 275.6 lb
Applications Radiant, FCU, AHU, DHW, pool

Property-size ranges are planning guides only. Final model selection requires a heat-loss or load calculation that accounts for climate, insulation, air leakage, windows, water temperature, and system application. Actual output changes with outdoor air and leaving-water temperature.

Full 3.5 Ton specifications
Specification 3.5 Ton
Property-size guideUp to 2,500 ft²
Rated heating capacity35.8 KBTU
Rated cooling capacity27.4 KBTU
Ambient operating range-31°F to 110°F
Maximum leaving-water temperatureUp to 131°F
Power supply220–240V / 1 / 60Hz
Sound level52 dB(A)
Rated water flow8.2 GPM
Water connection1 in
Refrigerant / chargeR-32 / 49.3 oz
Dimensions L × W × H43.4 × 18.5 × 33.1 in
Weight275.6 lb

Performance in Cold Weather

Performance ratings by test condition

Heating: 41°F outdoor / 59°F wet bulb / 95°F to 131°F water

Measurement3.5 Ton
Capacity42 KBTU
Input power9.2 kW
Current12.2 A
COP4.6

Heating: 44°F outdoor / 42°F wet bulb / 114°F to 113°F water

Measurement3.5 Ton
Capacity35.8 KBTU
Input power11 kW
Current14.8 A
COP3.23

Heating: 10°F outdoor / 7°F wet bulb / 97°F to 106°F water

Measurement3.5 Ton
Capacity22.2 KBTU
Input power10.5 kW
Current14 A
COP2.11

Cooling: 95°F outdoor / 54°F to 44°F water

Measurement3.5 Ton
Capacity27.3 KBTU
Input power6.8 kW
Current13.6 A
COP4.6
Electrical data
Electrical measurement3.5 Ton
Fan motor load0.29 A
Compressor rotor load15.94 A
Total load16.23 A
Minimum circuit ampacity29.41 A
Maximum overcurrent protection39.56 A

Electrical design and overcurrent protection must be confirmed by a qualified professional against the current manual and local code.

Plan with the right documents

Heat Pump Manuals and Certifications

Keep the technical source documents visible before equipment selection and installation.

Installation and service

APOLLO Heat Pump Installation & Maintenance Manual

Installation, startup, servicing, performance, electrical, and maintenance guidance for the standard APOLLO air-to-water range.

Open manual PDF
Compliance

APOLLO Heat Pump Certifications

Compliance and certification documentation for the APOLLO air-to-water heat pump family.

Open certification PDF

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.

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.

Need a complete answer?

Plan Your Heat Pump System With MBTEK

A short call can prevent mismatched temperatures, missing components, and incorrect capacity assumptions.

Sunday,Monday,Tuesday,Wednesday,Thursday,Friday,Saturday
January,February,March,April,May,June,July,August,September,October,November,December
Not enough items available. Only [max] left.
Promotion
Call now 1-888-301-0737