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What Size Generator To Run Heat Pump? | Browns HVAC

Maintaining a comfortable home environment is crucial, especially during power outages. 

Central to this is ensuring your heat pump – a device that helps control your home’s temperature – remains operational.

But what size generator do you need to run a heat pump?

Let’s delve into this question and provide you with some much-needed clarity.

What Size Generator to Run a Heat Pump: An In-depth Look

Understanding the appropriate generator size to run a heat pump is critical.

Typically, a generator ranging from 7,200 to 15,000 watts, or 7.2kW to 15kW, is required to run a standard heat pump.

However, HVAC professionals often recommend slightly larger generators between 7.5kW and 20kW to accommodate other necessary home appliances like lights, refrigerators, or computers.

In comparison, the 7.2kW to 15kW generators are typically suited for small to medium-sized homes with a modest amount of additional electric appliances.

On the other hand, the 7.5kW to 20kW generators are more appropriate for larger homes or homes with a higher electrical demand, providing enough power to ensure a comfortable living environment, even during a blackout.

4 Factors to Consider When Choosing a Generator Size:

Selecting the right size for your generator requires a good understanding of a few key variables. These can be summarized in four main points:

1. Heat Pump Size:

Heat pumps, much like any other appliance, come in various sizes, and each size has a unique power demand.

For instance, a larger heat pump used to heat or cool a sizeable space will need more power than a smaller unit designed for a single room.

The power requirement of your heat pump, often mentioned in the product specifications or its manual, should be the first factor to consider when choosing your generator size.

2. House Size:

Your home size and the total number of appliances you have also significantly impact your choice.

Larger homes, especially those with multiple high-energy appliances like electric ovens, water heaters, or HVAC systems, will need a more powerful generator to keep everything running during a power outage.

It is essential to compile a list of all your appliances and their energy requirements to determine the right generator size for your needs.

3. Climate and Location:

Where you live and the kind of climate you experience also play a key role in determining the right generator size.

If you live in an area with harsh winters or hot summers, your heat pump will need to work harder to maintain the desired temperature inside your home.

This added load will need to be factored into the size of the generator you choose.

4. Total Energy Usage:

It’s crucial to consider the total energy usage of your home. This includes lighting, appliances, electronics, and other devices that rely on electricity.

A thorough energy audit can provide an accurate picture of your overall energy consumption, helping you to size your generator correctly.

How to Calculate the Size of the Generator You Need

The process of calculating the size of the generator you need starts with understanding your heat pump’s power requirement.

This requirement is often detailed on the heat pump’s product label or in the user manual.

It’s essential to understand that heat pumps, like many large appliances, have two different power requirements – continuous and starting.

The starting wattage is the temporary surge in power needed to start the appliance, while the continuous wattage is the power required to keep the appliance running.

Your generator should be capable of providing both.

Other Considerations When Choosing a Generator for a Heat Pump

While wattage requirements are crucial, they are not the only factor to consider when choosing a generator for your heat pump. Here are some other important considerations:

1. Fuel Efficiency:

A fuel-efficient generator can significantly reduce your operational costs over time.

Various models offer different levels of fuel efficiency, so it’s a good idea to compare options and choose a generator that balances power output with fuel consumption.

2. Portability and Installation:

Depending on your specific needs, you may opt for either a portable generator or a stationary, permanently installed one.

Portable generators offer the advantage of mobility and can be used for various purposes beyond just powering your heat pump.

In contrast, stationary generators, while typically more expensive and requiring professional installation, can automatically power your entire home in the event of a power outage.

3. Noise Levels:

Lastly, remember that generators can be quite noisy, which can be a concern, especially in residential areas.

If noise levels are a concern, consider investing in a generator specifically designed for quiet operation or exploring soundproofing solutions to minimize noise pollution.

Providing quality heat pump services since 2016, Browns Heating & Cooling is committed to serving the Chicago area and its surrounding regions. Our EPA-certified and factory-trained technicians offer reliable advice and services at fair prices. Dial (708) 536-8134 or book your appointment with us today.


Ensuring your heat pump has a consistent power supply is integral to maintaining a comfortable home environment, especially during power outages.

Understanding your specific needs, taking into account factors like heat pump size, home size, climate, location, and total energy usage, is vital in choosing the right generator size. 

Beyond just the wattage requirements, considering additional aspects like fuel efficiency, portability, and noise levels can also impact your choice.

Armed with this knowledge, you can make an informed decision that not only powers your heat pump effectively but also caters to your broader home energy needs.


Will a 6500-watt generator run a heat pump?

Yes, a 6500-watt generator can run a heat pump. However, its effectiveness largely depends on the specific power requirements of your heat pump. It’s crucial to check your heat pump’s starting and continuous wattage needs to ensure your generator can handle the load.

What size generator to run a 2.5-ton heat pump?

The size of the generator needed to run a 2.5-ton heat pump can vary depending on the heat pump’s specific energy requirements. Typically, a generator of 10,000 to 15,000 watts should suffice. However, to make a precise determination, check the energy consumption of your specific heat pump model.

What size generator for a 3-ton heat pump?

To power a 3-ton heat pump, a generator with a capacity of approximately 15,000 to 20,000 watts is generally recommended. This allows for the heat pump’s power needs, as well as any additional power requirements from other appliances in your home.

Can a heat pump run efficiently on a generator?

Yes, a heat pump can run efficiently on a generator, provided the generator can meet its power requirements. Remember that a heat pump’s efficiency can be influenced by various factors, including the generator’s power output and the heat pump’s condition and energy rating.

How can I improve the energy efficiency of my heat pump to reduce the generator load?

Improving the energy efficiency of your heat pump can help reduce the load on your generator. Some effective strategies include regular maintenance of the heat pump, ensuring proper insulation in your home, using energy-efficient settings, and upgrading to a heat pump with a higher energy rating if your current one is old and less efficient