Window Heat Pump Information Center

We will look at a few window heat pumps that are available in today's market:

  • Friedrich Kuhl Series
  • Amana AH Series
  • Carrier XQB Series

These reviews will consider the following important features of each model:

  • Cooling Capacity and Efficiency
  • Heating Capacity and Efficiency
  • Dehumidification Capacity
  • Physical Constraints
  • Cooling Area
  • Operation Constraints
  • Warranty

But, first let's clear up a common misconception....

Not all window air conditioners that also heat an area are called heat pumps.

Why is this significant?

All window units cool by means of a refrigeration system, consisting of a compressor, refrigerant, and other components.

But....window units that heat, do so largely by the following two methods:

  • Electric Heat
  • Heat Pump (or, reverse refrigeration cycle)

Why should you care?

Because electric heat is expensive.

Granted, the window unit with electric heat is usually cheaper to purchase.  But the window heat pump is generally less expensive to operate.

Amana AH Series

So, which type of window unit should YOU purchase?

This is not always a simple answer.  However, in general, if you live in a climate with mild winters (30 degrees Fahrenheit or higher), the window heat pump is usually less expensive in the long run.

Most window heat pumps also have backup electric heat for very cold weather.  Heat pumps do not operate well in heating mode during extremely cold periods (less than 30 degrees Fahrenheit).

So if your winters drop below 30 degrees Fahrenheit for weeks (not months), generally the window heat pump is a better long term purchase.

Now, let's address our first review topic:

Cooling Capacity and Efficiency

Usually window heat pumps are purchased based on the cooling capacity required.  Below you will find a summary of the available cooling ranges for each brand:

Cooling Capacity and Efficiency By Model
Friedrich
Amana
Carrier
Model Num. 10N 12N 18N 24N AH09 AH12 AH18 101 123 153 183
Btu/hr 9500 11500 17900 24000 9500 11600 17300 10400 11800 15000 17500
EER 10.4 10.4 10.4 9.8 10 9.5 9.0 10.0 10.0 10.2 9.4
Watts 720 960 1570 2040 960 1220 1920 1040 1180 1470 1860

Note: Btu/hr denotes the cooling capacity.  EER stands for "energy efficiency ratio", which is the cooling efficiency measurement that is used in the heat pump industry.  Watts gives the power consumption at each full operating load.

In review of the above, we see:

  • Each brand has comparably sized units.
  • Friedrich tends to be slightly more energy efficient.
  • Amana is the least efficient of the three brands.

Heating Capacity and Efficiency

While a customer will typically select the window unit based on the cooling capacity, it is also important to pay attention to heating capacity.  

This allows us to select the right size unit for installation in a colder climate and it gives us an efficiency by which to measure the heating side of the heat pump.

Heating Capacity and Efficiency By Model
Friedrich
Amana
Carrier
Model Number 10N 12N 18N 24N AH09 AH12 AH18 101 123 153 183
Btu/hour 8000 9400 15500 22000 8400 10300 16000 9000 9800 12100 14000
COP 2.7 2.4 2.5 2.6 2.9 2.6 2.6 2.9 2.9 2.8 2.6
Heating Watts 870 1139 1824 2391 850 1160 1800 900 1000 1260 1590

Note: Btu/hr denotes the heating capacity.  COP stands for "coefficient of performance", which is the heating efficiency measurement that is used in the heat pump industry.  Watts gives the power consumption at each full operating load.

In review of the above we see:

  • As with the cooling side, each brand has comparable heating capacities.
  • For heating efficiency, Carrier was the most efficient of the three brands.
  • Friedrich was the least efficient.

Dehumidification Capacity

Window heat pumps can also serve as dehumidifiers for treating moist air.  If dehumidification is a major concern for you, consider purchasing the unit with a larger dehumidification capacity.

Dehumidification Capacity By Model
Friedrich
Amana
Carrier
Model Number 10N 12N 18N 24N AH09 AH12 AH18 101 123 153 183
Pints Per Hour 1.9 3 5.4 7 2.2 2.5 4.1 4.2 3.2 4 5

Physical Constraints

Each window heat pump is manufactured within standard constraints due to window sizes being quite universal.  In case your window is not within standard dimensions, here are a few of the sizes available (listed in inches and pounds):

Required Window Dimensions and Unit Weights By Model
Friedrich
Amana
Carrier
Model Number 10N 12N 18N 24N AH09 AH12 AH18 101 123 153 183
Min.Window Height 16.5 16.5 18.5 21 16 16 18 18 18 18 18
Min. Window Width 27.5 27.5 27.5 30 23 23 27 30.5 30.5 30.5 30.5
Max. Window Width 42 42 42 42 * * * 42 42 42 42
Unit Weight 109 115 141 197 91 96 143 104 115 121 123

* Indicates this information is not available

Cooling Area

A very common question in relation to air conditioners of all kinds is:

"How much cooling capacity do I need in order to sufficiently cool my room/house?"

Below is a chart that is a GENERAL guide to cooling capacity required based upon the size of the room being cooled.  This applies toward a room that is sufficiently insulated and does not have significant amounts of outdoor air infiltration.  

Cooling Capacity to Room Size
Cooling Capacity (Btu/hr) Room Size (sq.ft)
6000 150
8000 300
10000 400
12000 450
14000 550
18000 700
20000 1000
24000 1400
30000 2000
36000 2500

Operation Constraints

Depending on it's design, heat pumps can struggle to operate well in frigid temperatures.  So below we have summarized the low temperature operation limit.

Most heat pumps are supplemented with an alternate heat source (usually electric for window heat pumps) for heating operation in very cold weather.  Where you see the acronym "BUH", it stands for "back-up heat".  In this case, there is no minimum temperature operation limit.

Is "BUH" the best window unit to purchase?  Not necessarily. It may be necessary to purchase a BUH unit if you live in climates that can reach frigid temperatures.  

However, if you live in an area that would never drop below the units minimum temperature.....why worry?

It must be noted the when a heat pump starts to use the backup electric heat, it can become very, very expensive.

Low Temperature Operation Limit By Model
Friedrich
Amana
Carrier
Model Number 10N 12N 18N 24N AH09 AH12 AH18 101 123 153 183
Low Temp Limit 40 F 0 F 0 F 0 F BUH BUH BUH BUH BUH BUH BUH

Warranty

When purchasing a heat pump it is very important to be aware of the warranty.  This can be the difference between a very expensive repair or just an inexpensive inconvenience.

Below is are the warranty policies of each manufacturer discussing above.

  • Friedrich offers a one year warranty on the entire unit for any defect in material or workmanship.  This includes the labor required to fix the heat pump.  However, as with all warranties it does come with limitations.  There is also a five year warranty on the sealed refrigeration system.
  • Amana provides a similar warranty as Friedrich, however it also includes a five year parts warranty on specific items such as fan motors, relays, etc.
  • Carrier also has a one year parts and labor warranty and five year sealed refrigeration system warranty.

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