# Cop Vs Efficiency

Now, before we can pit one against the other, let’s first explain exactly what “CoP” means because it sounds like a made-up word.

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## What Does COP Mean?

CoP means The Coefficient of Performance (COP) and is a ratio of the heat output of a heat pump to the energy it consumes.

A higher COP means the heat pump is more efficient.

COP is calculated by dividing the heat output by the power input and is expressed as a number between 1 and 5, or sometimes as a percentage.

Related: European Heat Pump Statistics

## Let’s Compare The Efficiency Difference of a Heat Pump and a Furnace

If you have a Coefficient of Performance (COP) of 4.0, this means your heat pump is 400% efficient. In other words, for every unit of electricity (1 kWh) that you use to power the heat pump, you’ll get 4 units of heat energy out.

Now let’s say you have a furnace with an efficiency rating of 80%. This means that for every 100 units of heat energy that goes into the furnace, only 80 units come out as usable heat. The other 20 units are wasted up the flue or lost through leaks in the system.

So, if we compare these two systems, the heat pump is 5 times more efficient than the furnace. In other words, it takes 5 units of electricity to produce the same amount of heat as the furnace.

Now, let’s look at this from a cost perspective. If we assume that the cost of electricity is \$0.10 per kWh, and the cost of natural gas is \$0.60 per cubic meter, then we can calculate the operating cost of each system.

For the heat pump, we would need to use 5 kWh of electricity to produce the same amount of heat as the furnace. So, the operating cost would be:

5 x \$0.10 = \$0.50

For the furnace, we would need to use 100 units of natural gas to produce the same amount of heat as the heat pump. So, the operating cost would be:

100 x \$0.60 = \$60.00

As you can see, the heat pump is a lot cheaper to operate than the furnace. In fact, it’s 120 times cheaper!

Now, let’s look at this from a carbon dioxide emissions perspective. If we assume that each kWh of electricity produces 0.5 kg of carbon dioxide, and each cubic meter of natural gas produces 0.9 kg of carbon dioxide, then we can calculate the emissions of each system.

For the heat pump, we would need to use 5 kWh of electricity to produce the same amount of heat as the furnace. So, the emissions would be:

5 x 0.5 = 2.5 kg

For the furnace, we would need to use 100 units of natural gas to produce the same amount of heat as the heat pump. So, the emissions would be:

100 x 0.9 = 90 kg

As you can see, the heat pump produces a lot less carbon dioxide than the furnace.

## Cop Of Refrigerator

The coefficient of performance of a refrigerator is the ratio of the heat it removes from the interior to the work input required.

This is typically expressed as a number between 1 and 5, or sometimes as a percentage.

The ratio is COP = Qlow/(-W) = Qlow/(Qhigh – Qlow)

Where:

COP is the coefficient of performance

Qlow is the heat removed from the interior

W is the work input required

Qhigh – Qlow is the heat added to the interior

For a refrigerator, COP must be greater than 1 in order for it to function. If COP = 1, then there would be no net heat transfer and the interior would not be cooled.

## Cop Of Heat Pump

Now let’s look at the COP of a heat pump. The coefficient of performance of a heat pump is the ratio of the heat it produces to the work input required.

This is typically expressed as a number between 1 and 5, or sometimes as a percentage.

The ratio is COP = Qhigh/(-W) = Qhigh/(Qlow – Qhigh)

Where:

COP is the coefficient of performance

Qhigh is the heat produced

W is the work input required

Qlow – Qhigh is the heat removed from the interior

For a heat pump, COP must be greater than 1 in order for it to function. If COP = 1, then there would be no net heat transfer and the interior would not be heated.

The formula for COP can also be rewritten as:

COP = (Qhigh/Qlow) / ((Qhigh/Qlow) – 1)

As you can see, the COP of a heat pump is the inverse of the COP of a refrigerator.

This makes sense because a heat pump is essentially a refrigerator that has been turned upside down.

## What is “The Energy Efficiency Ratio” (EEF)?

The energy efficiency ratio (EER) is a measure of the efficiency of a heat pump or air conditioner.

It is calculated as the ratio of the heat removed by the unit to the work input required.

The formula for EER is:

EER = Qlow/(-W)

Where:

EER is the energy efficiency ratio

Qlow is the heat removed by the unit

W is the work input required

For a heat pump or air conditioner, EER must be greater than 1 in order for it to function.

If EER = 1, then there would be no net heat transfer and the interior would not be cooled (or heated).

### What is the difference between COP and EER?

The difference between COP and EER is that COP takes into account the heat added to (or removed from) the interior, while EER only takes into account the heat removed by the unit.

This means that COP is a more accurate measure of the efficiency of a heat pump or air conditioner.

## What is Exergy Efficiency?

Exergy efficiency is a measure of the efficiency of a heat pump or air conditioner. It is calculated as the ratio of the exergy output to the exergy input.

The formula for exergy efficiency is:

Exergy Efficiency = (Qhigh x Exoutput)/(Qlow x Exinput)

Where:

Qhigh is the heat removed by the unit

Qlow is the work input required

Exoutput is the exergy output of the unit

Exinput is the exergy input of the unit

For a heat pump or air conditioner, exergy efficiency must be greater than 1 in order for it to function.

If exergy efficiency = 1, then there would be no net heat transfer and the interior would not be cooled (or heated).

## What is Compressor Efficiency?

Compressor efficiency is a measure of the efficiency of a heat pump or air conditioner. It is calculated as the ratio of the work output of the compressor to the work input required.

The formula for compressor efficiency is:

Compressor Efficiency = (Qhigh x Compressor Output)/(Qlow x Compressor Input)

Where:

Qhigh is the heat removed by the unit

Qlow is the work input required

Compressor Output is the work output of the compressor

Compressor Input is the work input of the compressor

For a heat pump or air conditioner, compressor efficiency must be greater than 1 in order for it to function.

If compressor efficiency = 1, then there would be no net heat transfer and the interior would not be cooled (or heated).

## The Bottom Line

The bottom line is that COP and EER are measures of the efficiency of a heat pump or air conditioner.

COP takes into account the heat added to (or removed from) the interior, while EER only takes into account the heat removed by the unit.

This makes COP a more accurate measure of the efficiency of a heat pump or air conditioner.

Exergy efficiency is a measure of the efficiency of a heat pump or air conditioner. It is calculated as the ratio of the exergy output to the exergy input.

Compressor efficiency is a measure of the efficiency of a heat pump or air conditioner.

It is calculated as the ratio of the work output of the compressor to the work input required.

For a heat pump or air conditioner, COP, EER, exergy efficiency, and compressor efficiency must all be greater than 1 in order for it to function.

If any of these measures of efficiency = 1, then there would be no net heat transfer and the interior would not be cooled (or heated).

In conclusion, the most important measure of the efficiency of a heat pump or air conditioner is COP. EER, exergy efficiency, and compressor efficiency are also important measures of the efficiency of a heat pump or air conditioner.

All of these measures of efficiency must be greater than 1 in order for a heat pump or air conditioner to function.

## FAQs

### What is a Carnot cycle?

A Carnot cycle is an idealized thermodynamic cycle in which no heat is lost to the surroundings and all of the work is done by the expansion of a gas.

### Is exergy efficiency higher than energy efficiency?

No, exergy efficiency is not necessarily higher than energy efficiency. Exergy efficiency is a measure of the efficiency of a heat pump or air conditioner. It is calculated as the ratio of the exergy output to the exergy input. Energy efficiency is a measure of the efficiency of a heat pump or air conditioner.

### Do all countries use EER to measure the efficiency of air conditioners?

No, not all countries use EER to measure the efficiency of air conditioners. Some countries use COP instead.