The Difference Between a Heat Pump And an Air Conditioner

Most modern air conditioners have a heating function. This is directly indicated in their characteristics. The generated heat is indicated as power W/h. Among the common indicators, values ​​​​from 0.7 to 2.5 kW/h. At the same time, 1 kW is enough to heat 10 square meters of room area. Many users are interested in how much difference there is between using a heat pump and an air conditioner for heating a house. In this article, we will consider the features of using each equipment. If you are looking for a reliable company for heating repair in Sacramento, CA, we recommend paying attention to Alpha Mechanical.

How Do Air Conditioners And Heat Pumps Work?

First, let’s briefly consider the operating principle of heat pumps and air conditioners. It is worth noting that monoblock air conditioners cannot be compared with heat pumps since they require placement strictly on the window, which partially closes the view, spoils the appearance of the facade, and creates additional noise inside the room. If we compare split systems with separate outdoor and indoor units, then air conditioners are externally similar to heat pumps.

The operating principle of an air conditioner in the summer is to compress the refrigerant using a compressor:

1. Freon changes from a liquid to a gaseous state, due to which it heats up.
2. A heated freon enters the condenser located outside.
3. Under the action of the fan, the accumulated heat is released into the external environment. Freon cools down, turning into a liquid.
4. The temperature of the refrigerant becomes about 15-20 degrees. Passing through the thermostatic valve, the pressure increases, and the temperature becomes even lower.
5. Cooled freon enters the internal evaporator. The radiator is blown by a fan, driving the cold into the room.
6. At the same time, the refrigerant heats up, taking heat from the room and removing it to the external unit. The cycle is repeated.

When hot air in the room comes into contact with the cooled evaporator, condensation is formed. The liquid collects in a tray under the radiator and is discharged outside through a tube. To operate for heating, the air conditioner starts the circulation of the refrigerant in the reverse order. Heat is taken from the street and given to the room. Everything is similar to a heat pump. 

If you are in the Sacramento, CA area and need help with a heat pump or air conditioner replacement or repair, we recommend turning to Alpha Mechanical.

Differences in Performance Characteristics

If the operating principle of an air conditioner and a heat pump for heating is the same, let’s consider what the difference is between the equipment. Let’s consider models from the middle price category.

When the characteristics of an air conditioner indicate that it can allocate, for example, 1.5 kW/h, which is enough to heat a room of 15 m², it means that the outside air temperature is about +7 degrees. Therefore, when it is 0 °C or -5 °C outside, the air conditioner’s performance decreases. In light frosts, the indoor unit of the split system produces air at room temperature (+19 or +20 °C). This is enough not to freeze, but it will not be possible to warm up either.

When the outside temperature is from -15 to -20 °C, the efficiency of the air conditioner for heating approaches zero. Moreover, the operation of the equipment in such extreme conditions will lead to a reduction in its service life. Although there are air conditioners that claim to operate at -15°C for heating, in practice this may be just a marketing ploy, because the main task of a split system is to cool a room in the summer. So, an air conditioner with characteristics from -7 to +42°C cannot replace a full-fledged heating system.

Heat pumps operate from -30 to +52°C. At the same time, they actually heat the room and do not just provide air at room temperature. As the name suggests, heat pumps are specially designed primarily for heating, so the specified characteristics correspond to the actual ones. As a bonus, in the summer, a heat pump, like an air conditioner, can be run in the opposite direction of the refrigerant flow to cool the room.

Differences in Internal Design

Split systems and heat pumps differ in their internal design, despite the similar operating principle. The main design differences of the latter, providing increased heating efficiency in winter, are:

1. Increased area of ​​the external radiator. The ability to absorb heat from the outside air depends on the size of the external radiator. Heat pumps can have 2-3 rows of capillary tubes, or even two external radiators. Therefore, it works much more efficiently for both heating and cooling.
2. Two-stage compression of the refrigerant. Compressing freon in two stages allows for faster circulation and increased efficiency of the entire system.
3. Improved fan operation. Heat pumps usually use more powerful fans or there may be several of them, which accelerates the release of cold to the outside.
4. Accurate dosing of the refrigerant supply. The amount of incoming freon is determined by an electronic valve. It changes the settings based on the outside air temperature.
5. Crankcase heating. With the help of a small electric heating element, the oil in the compressor located outside is constantly heated. This allows it to remain fluid in severe frosts and protects the compressor from premature wear.
6. Sump heating. Electric heating of the external sump keeps the condensate in liquid form. This prevents the formation of ice, which reduces the area of ​​​​cold transfer to the external evaporator. It also protects the fan blades from damage by ice.
7. Thoughtful defrosting algorithm. Defrosting the external unit is a periodic procedure necessary to remove ice covering the evaporator in winter.

Final Thoughts

A heat pump and an air conditioner are two devices that can perform similar functions, but they still have differences in the way they work and their intended purpose. A heat pump is a more versatile system that can effectively heat and cool a room using renewable energy from the environment. Air conditioners are primarily designed to cool a room, although some models with a heating function can be used for heating in not very cold weather. If you need a reliable company for heat pump or HVAC system replacement or repair in Sacramento CA, we recommend Alpha Mechanical.