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Single Phase Vs. Three-Phase Heat Pumps

Views: 1262     Author: Site Editor     Publish Time: 2023-05-04      Origin: Site


There are many types of heat pumps out there, including dust and ductless heat pumps. However, when it comes to the electricity they consume, heat pumps are categorized into:

Single-phase heat pumps

Three-phase heat pumps 

As the names suggest, single-phase units rely on single-phase electricity, while three-phase devices utilize three phase electricity supply. Generally, single-phase heat pumps are compact and meant for home use, while their three-phase counterparts are mainly used commercially. Nonetheless, with technological advancements, three-phase units are becoming more popular for home use. 

Some manufacturers have opted to dip their toes in the single-phase heat pumps, manufacturing larger units, which is a great niche. Then again, running massive heat pumps on single-phase electricity presents several problems. For instance, compressor motors usually have surged starting currents, which could lead to the flickering of lights or the malfunctioning of electrical appliances sharing a power outlet with the heat pump. 

You have two options to solve the issue of flickering lights and malfunctioning electric appliances. First, you can install a three-phase compressor and an inverter, which turns the single-phase supply into 3-phase power. This solution solves the problem adequately but regrettably gives rise to two issues:

Harmonics – This is interference which goes back through the electric wires and can damage other electrical appliances.

Reduced efficiency – The invertors aren't as efficient as you'd hope, hence might end up wasting electricity. This is one of the reasons why air-source heat pumps are slightly less efficient than ground-source units. 

The other solution is to install a single-phase motor coupled with an electronic limiter that decreases the starting current to a manageable level. However, this current won’t be as manageable as when utilizing an inventor because the electronic limiter is not linked to the circuit when the compressor starts. 

All the same, the loss of efficiency and harmonics problem won’t be an issue with this system. 

With that in mind, here is a single-phase vs three-phase heat pump guide:

Three-Phase Heat Pump

So, what is a three-phase heat pump? With this unit, you will get a three-phase electricity supply. So, if you have such a unit at home, the property has three electrical lines connected to this machine and the load is equally distributed between all three power lines. 

On the other hand, for a single-phase unit, these three lines created by the power station’s turbine aren’t run in every home. Alternatively, different homes are supplied by a single line. Prevalently, this means a cheaper system, less installation costs and less wiring. On the other hand, the power supply may be unbalanced. 

For this reason, most countries need you to inform a network operator before installing a heat pump to give them time to assess the power supply and demand in your region. 

Advantages of Three-Phase Heat Pumps 

Three-phase heat pumps have many advantages, including;

Swift Response to the Ever-Changing Weather

These units can rapidly respond to the changing weather because the changeable speed driver speeds up the heating or cooling when the thermostat perceives a massive temperature change. Additionally, it involves the auxiliary or backup heating system, when necessary, which guarantees unnecessary energy consumption. 

Often Functions at Low Speeds

Most of the time, a three-phase unit’s blower and compressor run at low speeds to attain and maintain your desired room temperature. This lessens the electricity used by the unit by two or three times. 

Moreover, running at lower speeds reduces wear; therefore, your machine will last longer and have less breakdown and malfunction issues from worn-out components. 

Less Power Consumption when Starting It

One of the common issues with single-phase units is their significant electricity uptake when you switch them on. In some houses, the unit demands over 20% of the electrical panel's capacity. 

However, this won't be an issue with the three-phase heat pumps since they don't need much power to start a conditioning or heating cycle, reducing your utility bills. 

Other Benefits 

They work to enhance efficiency, even in the most challenging phases of commercial surroundings and offer unmatched execution in terms of energy efficiency. 

Three-phase heat pumps are somewhat easy to install. When done by professionals, it takes little time. 

Commercial three-phase heat pumps deliver reliable energy and require minimal maintenance. 

Compared to outdated versions, these machines offer excellent safety since they have the latest safety features. 

Single Phase Heat pumps 

Single-phase heat pumps use one line of power supply. This restricts the power the unit can generate for hot water for heating purposes. Traditional boilers feature one energy supply channel, like an oil or gas supply running through the property, whose main use is heating. 

They usually utilize electricity for the main circuitry, which symbolizes a small electrical load. The motors need to compete on the circuit with other home appliances, small and large; hence you have to ensure demand is restricted to guarantee it doesn't interrupt the supply to different appliances. Also, it helps prevent blowing up the main fuse. 

Advantages of Single-Phase Heat Pumps 


Single-phase units use one power line instead of three, so you'll save money on the cables required. Additionally, these units are usually cheaper in terms of price and installation. Considering some of them are compact, the installation is much easier. 


While single-phase units might not be as efficient as three-phase heat pumps, they will get the job done. Similarly, they will reduce your utility bills though not as much as a three-phase would. 

Difference Between Single-Phase & Three-Phase Heat Pumps

Evidently, there are several differences between these units, and they are as follows:

Generally, more compact heat pumps usually need a single-phase power supply, while the larger models use a three-phase power supply. The former is available up to approximately 35kW. However, in the future, all heat pumps will be 3-phase units.

Single-phase heat pumps use 220 to 240 volts and utilize a single live and another neutral cable. On the other hand, three-phase units use 380 to 415 volts and include three live cables and a neutral wire occasionally. 

The last difference between these two units is that one is built for the European market and the other for the UK market. 


How Can I Benefit from Buying a Heat Pump?

Since a heat pump only utilizes electricity for power instead of heat generation, it delivers an incredibly high-efficiency rate. For instance, when employing old-fashioned resistive electric heat, the heat produced is comparable to the electricity used; so, one heat unit for every electricity unit is for utmost efficiency. 

When you have a heat pump, this rate increases significantly since the electricity used only works to power the condenser, compressor, evaporator, and pump to concentrate the surrounding heat and carry it to the system right into your home. 

Thanks to this, heat pumps, whether single or three-phase, can offer over three heat units for every electricity unit, hence delivering a 300% efficiency rate. This translates to reducing your utility bills at home. 

Generally, heat pumps are cheap to operate, reducing your electric bill by over $50 monthly per unit that's continuously operational. Further, if you use a heat pump and another heating system like electric, gas or oil, you'll save some more by utilizing the pump to balance the main fuel utilization. 

For instance, one machine can offset approximately 300 oil gallons in a small home, saving funds on pricy fossil fuels. Also, heat pumps will be handy in this way to lessen your carbon footprint. 

How Will a Heat Pump Reduce My Electric & Heating Bills?

Every single unit heat pump utilized daily will surge your electricity bill by up to $100 monthly. Nevertheless, a heat pump will reduce heating fuel expenses. For instance, in an average home that utilizes 800 oil gallons annually, a heat pump can lessen the oil used by about 300 gallons. 

If oil is sold at $2.70 per gallon, the cost would be $28 per million BTU. For a similar amount of heat, one million BTU, from a unit with the regular 14.5 cents per kWh rate, it would cost about 14.70. This means having a heat pump as a source of heat for your household is the same as heating it with oil for $1.40 per gallon, which translates to 48% less. 

What Advantages of Using a Heat Pump with Solar Electricity?

Solar energy is better than relying on the power grid to run your heat pump. When the sun comes up during the day, the solar panels will absorb solar energy and convert it into electricity at home. 

In many households, power produced by a device that's not used in the house is credited to the utility bill and then used to pay off your electricity bill. Since a heat pump relies on electricity, and when you use solar panels as a source of electricity for your heat pump, you will be heating your household at approximately 9 cents per kWh.

This is better than the 14.5 cents per kWh without the solar panels, significantly reducing your heat pump's operating cost by 400 % annually. 

Single-phase and three-phase heat pumps are quite different, each coming with its pros and cons. However, depending on the season, they will reduce your utility bills and help keep your home warm or cool. 

Hopefully, this guide has helped you better differentiate these two types of heat pumps. 

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