What Size Generator to Run a Heat Pump

A lot of energy goes into heating and cooling a household. While a heat pump is more energy efficient than a traditional heating system, it will generally consume between 545W and 7500W, depending on the heat pump size, wattage (SEER or HSPF ratings), and BTU. The wattage directly influences the answer to the question of what size generator is needed to run a heat pump. 

For example, a 3-ton heat pump (36,000 BTU) can draw between 2500W and 4500W, depending on the heating or cooling mode. A 5,000-watt generator can efficiently run a 3-ton heat pump. Jackery Solar Generators with large battery capacities can easily power different types of heat pumps. These essential home backup solutions ensure you can keep crucial appliances powered during outages or blackouts.

Key Takeaways

• Heat pumps come in various sizes, typically ranging from 545 to 7500 watts, depending on the model and heating or cooling capacity.
• A heat pump's starting wattage is higher than its running wattage due to the power surge when the compressor kicks in.
• Generators for heat pumps include fuel-powered and solar generators, each with different benefits in terms of efficiency, noise levels, and environmental impact.
• Jackery Solar Generators offer reliable backup power, ensuring your heat pump stays operational during outages without relying on fuel.

How Many Watts Does a Heat Pump Use?

A heat pump typically uses between 545W and 7500W of electricity per hour, depending on the appliance size, efficiency rate, and the temperature difference between indoor and outdoor conditions. Heat pump models with higher Seasonal Energy Efficiency Ratio (SEER/SEER2) and Heating Seasonal Performance Factor (HSPF/HSPF2) ratings are more efficient and use less electricity. 

One of the easiest ways to calculate the number of watts a heat pump uses is to divide the appliance's size (measured in BTU) by its SEER or HSPF ratings. 

Heat Pump Cooling Wattage = BTU / SEER 

Heat Pump Heating Wattage = BTU / HSPF 

In 2023, the HVAC industry shifted to SEER2 and HSPF2, which represent real-world energy consumption. If you have SEER and HSPF ratings, you can multiply the SEER2 by 1.05 and HSPF2 by 1.17. 

Here's a breakdown of how many watts a heat pump uses depending on the heating and cooling mode: 

How Much Energy is Needed to Run a Heat Pump

The heat pump's energy consumption can be easily calculated by multiplying the appliance's wattage and the running time. A 1-ton (12,000 BTU) heat pump with a SEER rating of 20 consumes around 600W. If you run the heat pump for 6 hours per day, the total daily energy consumption is 3600Wh or 3.6kWh. The heat pump's monthly power consumption will be 108kWh.

Types of Generators Suitable for Heat Pumps

Standby generators (like diesel or natural gas) and solar generators are viable options to power heat pumps, each with its own advantages. Depending on the power requirements, frequency of outages in your area, and budget, you can choose the best type of heat pump generator. Let's explain both types of generators suitable for heat pumps:

Standby Generator

Standby generators, powered by diesel, propane, or natural gas, are permanently installed outside the homes and get automatically activated during a power outage. While they offer efficient power output, you need a stable fuel supply to keep the generator running. 

Pros

• Standby generators provide a backup power source during outages.
• They can power entire homes, including heat pumps and other appliances. 

Cons

• Standby generators require fuel storage and maintenance.
• They are noisy and emit a lot of toxic fumes, making them unsuitable indoors.

Solar Generator

Solar-powered generators offer reliable and portable home backup solutions for powering heat pumps and other appliances. They use sunlight to produce electricity and power appliances whenever needed. Jackery Solar Generators are essential home backup solutions that can power heat pumps and other crucial household appliances. 

Pros

• Solar-powered generators utilize renewable energy, reducing reliance on grid electricity and fuel.
• They can be cost-effective in the long run.
• They are quieter than standby generators and do not emit toxic fumes.

Cons

• Solar-powered generators require a high initial investment compared to standby generators.

What Size Generator to Run a Heat Pump

To determine what size generator is needed to run a heat pump, you need to consider the appliance's wattage consumption and how long you would like to run it. Here's how to calculate what size generator is needed to run a 3-ton heat pump (36,000 BTU) with an 18 SEER.

Step 1: Determine the Power Consumption of the Heat Pump

Information about a heat pump's power consumption, including SEER (cooling efficiency) and HSPF (heating efficiency), can be found on the yellow and black Energy Guide sticker on the outdoor unit. It can also be found on the manufacturer's website or by contacting them with the model and serial number. 

The wattage consumption of a 3-ton heat pump (36,000 BTU) with an 18 SEER can be calculated as follows: 

Wattage = 36,000 BTU ÷ 18 SEER = 2000W

Step 2: Calculate Wattage With the Safety Buffer

It is essential to add a 20% safety buffer to the power consumption of the heat pump. 

Wattage (With Safety Buffer) = 2000W + (2000W × 0.2) = 2400W 

In this case, you will need a 3000-watt solar generator or higher to power a 3-ton heat pump.

Step 3: Account for Additional Loads

If you want to power additional loads in addition to the heat pump, add their wattage to calculate the right generator size. 

Let's assume you are powering a refrigerator (400W) and lights (100W) with the heat pump. 

Total Wattage Required = 2400W + 400W + 100W = 2900W 

A 4000-watt generator can safely run a heat pump with additional loads like refrigerators and lights.

How to Calculate the Cost-Per-Hour Usage of a Heat Pump

When calculating the cost per hour usage of a heat pump, you need to know the heat pump's wattage, the electricity rate/fuel costs, and the number of hours it runs. 

In order to make the calculations easier, here are some assumptions: 

• According to the EIA, the electricity rate per kWh is $0.1595.
• EIA also reveals that the 10kW diesel generator operating at 50% load consumes 0.53 gallons per hour.
• Solar-powered generators require only initial investment and do not require any ongoing maintenance costs, which means they cost $0 in the long run. 

Here's a breakdown of the cost per usage of a heat pump when the appliance is powered by grid electricity, a diesel generator, and a solar-powered generator: 

Best Jackery Solar Generators for Heat Pumps

Solar generators provide a cost-effective solution, ensuring your home stays comfortable even when the grid fails. Unlike traditional gas generators, solar generators are quieter, require less maintenance, and offer a renewable energy source. Jackery is a trusted name in manufacturing solar generators, power stations, and solar panels. They can handle the demands of a heat pump while providing clean energy. Below, we explore two of the top solar generators for heat pumps.

Jackery Solar Generator 5000 Plus

The Jackery Solar Generator 5000 Plus is an essential home backup solution that can power most household appliances, including heat pumps. Because of its high battery capacity, it is ideal for running heavy-duty heat pumps. It's a great choice for those who experience frequent power outages or live in areas with harsh winters. The modular and expandable design allows you to expand the battery capacity from 5kWh to 60kWh, ensuring you have reliable energy during prolonged blackouts.

Appliances Running Time

• 1-ton (12,000 BTU) Heat Pump (600W) = 6.6H
• 2-ton (24,000 BTU) Heat Pump (1200W) = 3.4H
• 3-ton (36,000 BTU) Heat Pump (1800W) = 2.3H
• 4-ton (48,000 BTU) Heat Pump (2400W) = 1.7H
• 5-ton (60,000 BTU) Heat Pump (3000W) = 1.4H

Note: For easy calculations, we assume that heat pumps have a SEER rating of 20. 

Customer Review

"I received the Explorer 5000 Plus solar generator to use to run my home if the power goes out. It works great and will run my whole home if the power goes out." — Dennis Carlson.

Jackery Solar Generator 2000 Plus

If portability is your priority, the Jackery Solar Generator 2000 Plus can be an ideal option. It strikes a balance between power and mobility, making it suitable for those who need a reliable backup but also value ease of transportation. Its compact design allows homeowners to move it between rooms where heating is required. The sufficient battery capacity enables the solar generator to deliver enough power and keep a heat pump running during short outages. 

Appliances Running Time

• 1-ton (12,000 BTU) Heat Pump (600W) = 2.8H
• 2-ton (24,000 BTU) Heat Pump (1200W) = 1.4H
• 3-ton (36,000 BTU) Heat Pump (1800W) = 1.0H

Customer Review

"This is the second generator we have bought, and we love it. This one is in our cabin. It's easy to use, and it's nice that it is totally silent. I will recommend this to everyone." — Karon Owen.

FAQs About Generators for Heat Pumps

Can I run a heat pump on a generator?

Yes, you can safely run a heat pump on a generator, but it should be able to handle the appliance's wattage consumption. For example, if a small heat pump consumes around 500W—1500W, you will need a 2000-watt generator. For a larger heat pump consuming 3000W or more, a 5000-watt or 7500-watt generator would be an ideal choice.

What size generator to run a 3-ton heat pump?

A 3-ton heat pump (36,000 BTU) consuming 1500W - 4500W of electricity per hour needs a 5000-watt or 6000-watt generator. It can safely supply running and starting wattage to the heat pumps so you can stay comfortable during the outages.

How to heat a house with a generator?

If you have a gas generator to power heat pumps during an outage, you must always set up the generator outdoors and plug the appliance into the compatible outlet. On the other hand, if you have a solar-powered generator, you can use the power source indoors to keep household appliances like heat pumps powered.

Conclusion

When considering what size generator to run a heat pump, it's essential to choose one that meets your power needs while offering reliability and efficiency. Solar generators provide a clean, quiet, and renewable alternative to traditional fuel-powered options. A reliable Jackery Solar Generator helps prepare you for power outages and reduces your dependence on the grid, ensuring your heat pump keeps running and your home stays comfortable year-round.