13 Facts On Heat Pump Air Handler:Wiring,Noise,Cleaning,Leak

We can transfer heat using a mechanical device called a heat pump. Let us discuss heat pump air handler in this article.

Air is distributed to the room with the help of air handlers. These air handlers work in a similar way furnaces work. Although air handlers work with heat pumps only. They will transfer heat from one place to another.

Heat pumps transfer the heat from a reservoir with low temperature to a reservoir with higher temperature.  In this article we shall read about heat pump air handler.

What is heat pump air handler?

Air handlers are used with heat pumps. Let us see what is a heat pump handler.

Air handlers move air throughout the space or room. They are internal part of any air conditioner or heat pump. They are similar to furnaces with the only difference being that air handlers only circulate heat when paired with heat pumps.

Does a heat pump use an air handler?

The heat pumps do not produce heat of their own. Let us discuss whether a heat pump uses an air handler or not.

Heat pumps circulate warm or cool air throughout the room using air handlers. Without an air handler the pump will draw more power in turn reducing its efficiency.

How does heat pump air handler work?

Air handlers are most commonly used for filtration, cooling and heating process depending on the applications. Let us discuss how an air handler works.

The air passes through the air handler before it goes to rest of the parts. Air handler will refine the air and condition it according to our needs, it can cool or heat the air accordingly. The air is heated using the electricity that acts as external work applied on the heat pump.

It has two modes- Heating mode and cooling mode. The heating mode heats up the air and is usually used in winters, the cooling mode similarly is used in summers when the air is meant to be cooled.

Heat pump air handler diagram

Thermostat is a device that controls the temperature of the system. Let us discuss the heat pump air handler diagram.

An air handler’s input is connected to a thermostat which controls the temperature and helps the air handler to set the temperature as required. The connections between air handler and thermostat are shown in the diagram below.

heat pump air handler
Image: Air handler diagram

Heat pump air handler size

The heat pumps use air handler units to condition the air according to our needs. Let us discuss the air handler sizes.

Air handler capacity/typeSize of the room to be covered
1.5 tons600 to 1100 sq ft
2 tons901 to 1400 sq ft
2.5 tons1201 to 1650 sq ft
3 tons1501 to 2100 sq ft
3.5 tons1801 to 2300 sq ft
4 tons 2101 to 2700 sq ft
5 tons2401 to 3300 sq ft
Air handler types and size of the room it covers

Heat pump air handler types and costs

Air handlers are a necessary part of heat pump without which heat pump won’t work properly. Let us discuss heat pump air handler types and its cost.

  • Blow through- The air is blown through the mixing box, cooling oil and gets filtered before entering the ducting network.
  • Draw through- A fan will pull the air through the mixing box, cooling oil and it will also get filtered before entering the ducting network.

Heat pump air handler wiring

The heat pump and air handler cannot work together. Let us discuss the wiring of heat pump air handler.

The wiring are colour coded in air handler so that it becomes easy for the user to understand the connections. In total, five wires are required for the air handler to work. Each wire carries a unique significance.

How to wire a heat pump air handler

Normally a 18-8 or 18-6 gauge wire is used for connecting the thermostat-heat pump air handler. The colour codes for the connections is as follows- Red- 24 V power, white colour is used for heating mode, yellow for cooling mode, green for fan, and blue for auxiliary or common connections.  

How to wire a heat pump air handler with heat strips

The heat strips are installed on the top of the heat pump. These heat strips are used as auxiliary strips that are heated to produce extra heat when the outside temperatures are too low.

How to wire an air handler in low voltage?

The air handlers can work on low voltages like 24 V too. Thermostat and air handler are connected to each other.  An 18 gauge wire is used for the connections.

Why does heat pump leak water inside?

The heat pump is between the indoor fan coil (air handler) unit and the outdoor compressor to transfer the heat . Let us discuss why does a heat pump leak water inside.

The heat pump leaks water due to excess accumulation of dirt inside the drain system. Moisture from air is absorbed by the pump which is expelled through a condensate drain system. When the impurities from air increase overtime and gets clogged inside the drain.

When does heat pump air handler fan does not work?

Heat pump uses an air handler to heat or cool the air by  using some external work. Let us discuss when does heat pump air handler fan does not work.

  • Fan is damaged.
  • Clogging of dust particles.
  • Faulty air filter
  • Defect in thermostat
  • Long time of service

Heat pump air handler noise

Heat pump redistribute heat from the air. Let us discuss heat pump air handler noise.

If we hear noise while the heat pump is operating, then there is a problem in the fan motor. This means that the motor of the compressor/condenser is broken. One of the possible reasons might be that the blower fan of home has broken.

How to reduce heat pump air handler noise?

The heat pump air handler can make noise if their fan is broken. Let us discuss how to reduce heat pump air handler noise.

  • Choose an HVAC equipment which is quieter.
  • Choose appropriate locations and operations of fans.
  • Use sound proofing methods
  • Add sound boots to the system

How to clean heat pump air handler

The machines can get dirty after being used for a long time. Let us see how to clean heat pump air handler.

The heat pump air handler can be cleaned using simple methods like applying detergents and soaps. A mild solution of detergents is sprayed on the air handler unit and kept it for some time. This ensures that the dust particles are loosened up and then can be removed easily.


In this article we studied about heat pump air handlers. Air handlers mostly condition the air as per our requirements. It uses electricity to cool or heat the air and transfers this air further to other parts of heat pump. Sometimes air handlers are used to filter the air coming inside the heat pump as well.

Read more fact on  How Does Heat Pump Use Water, Heat Pump vs. HVAC and Heat Pump Filter Drier