Vindsol > About Heat Pump > DC Inverter A.S.H.P (vs) On/Off A.S.H.P

DC Inverter A.S.H.P (vs) On/Off A.S.H.P

Under different temperatures, people’s demand for hot water and house heating will naturally be different. Non-inverter heat pump is also commonly known as the “ordinary” on/off heat pump. The compressor of this type of heat pump cannot adjust the frequency, but only operates at a single frequency, which is not flexible enough. DC inverter air source heat pumps can change the frequency of the compressor because of the addition of a frequency inverter in the equipment to transform the compressor. It is more adaptable to the complex environment.

Take cold areas for example, house heating at -10℃ ambient temperature may require 50℃ hot water, so the heat pump compressor will need to run at full load, and if the temperature is only 0℃, the heating may only need 35℃ hot water. According to the data, in some places, the cold weather with ambient temperature lower than -10℃ lasts for less than 10% of days in a year. That is to say, most of the time, ASHP does not need to be fully operated. On/off heat pump units are unable to change the operating frequency of their compressors, so they cost more electricity.

If choosing a DC inverter air to water heat pump, we can solve this problem completely. There are two built-in modes inside the heat pump unit: the energy-saving mode and the fast heating mode. Under the energy-saving mode, the compressor operates at a lower frequency, which can achieve the maximum power-saving effect. Under the fast heating mode, the heat pump runs at a high frequency, and hot water production can be fulfilled in a short time.

Now let’s get to know the comparison between inverter heat pumps and on/off heat pumps.


During the operation of non-inverter air source heat pump, no matter how heavy the load is, the heat pump unit can only operate at one frequency. When the temperature reaches the set temperature, the unit will stop. It does not restart until the temperature drops to the range. Such frequent shutdown and restart will not only consume electricity, but also affect the life of the compressor. DC inverter air source heat pump can automatically adjust the compressor’s speed according to the change of ambient temperature, and at the same time, the temperature keeps more stable. Even if it reaches the set temperature, the unit will not stop but maintain operation with low energy consumption. Therefore, in terms of service life, energy consumption and service life, DC inverter air source heat pump is better than on/off heat pump.

Heating Efficiency

At room temperature, the heating efficiency of on/off air source heat pump and DC inverter heat pump is similar, but the lower the temperature is, the more obvious the difference will become. Take DC inverter heat pump air conditioner as an example. At 15℃- 20℃, the heating capacity difference between on/off heat pump and DC inverter heat pump is less than 10%. At minus 15℃, the heating capacity of inverter heat pump is about 60% higher than that of non-inverter heat pump, and at minus 25℃, the gap is increased to 80%. Thus, it can be concluded that the best heating choice for low ambient temperature areas is DC inverter heat pump.

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