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Can a Generator Run a Hot Water Heater? (Explained)

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A water heater is a common appliance in our home. Even a water heater is a must in the cold areas and winter season. Generally, we run a water heater in our houses with electricity. Electricity converts energy to heat.

So, you might be confused about whether a generator can run a water heater or not. Well, you have to know the requirements of running a water heater.

If the generator can fulfill those requirements, you can use the generator to run a water heater. That’s why you have to know details about running a water heater.

Can a generator run a hot water heater?

A generator can run a hot water heater if the wattage of the generator is enough to fulfill the requirement of the wattage of the water heater. For example, an electric water heater runs at 4000 to 4500 watts. So, you will need a generator size that can fulfill the demand of 5000 watts.

However, water heaters can be of many types. For example, electric water heater, gas water heater, tank water heater, etc., water heaters might require different generator power. So, let’s see which water heater you can run with a generator.

Gas hot water heater:

You can use a generator to run a gas hot water heater. Generally, a gas hot water heater requires less power than the electric one. For example, you might have to provide only 1500 watts to run a gas hot water heater.

So, you can use a small generator that can run a 1500 watts gas hot water heater. Moreover, the setup of the house also affects the generator and gas hot water heater.

So, you need to see whether the requirements of a gas water heater can be fulfilled with a generator or not.

Electric water heater:

Generally, an electric water heater requires more power than a gas water heater. So, when you want to run an electric water heater, you will also need a larger size generator. Otherwise, the electric water heater will not run.

For example, a 5000 watts generator will be enough and efficient for an electric water heater. Because an electric water heater will need 4000 to 4500 watts to start.

Tank water heater:

You can also use a generator to run a tank water heater. But you need to match the power and wattage demand for the generator and the tank water heater.

Moreover, the connecting elements of the tank water heater should be connected well with the generator.

Generally, a tank water heater will require 4000 watts to run. So, the generator should have this much or more than this limit of wattage.

Tankless water heater:

A tankless water heater is pretty impossible to run with a generator. Because a tankless water heater requires a huge amount of power to run properly. Sometimes, the electric requirements can be up to 30,000 watts.

So, it will be pretty difficult to run a tankless water heater in a power outage or with a generator.

Can these generators run a hot water heater?

Generators can be of different powers and sizes. So, you have to know which size generator is suitable to run which water heater. Let’s see which generator you can use to run a water heater.

2000 watt:

2000 watts is a pretty small amount of wattage for running high-power elements like water heaters. So, you can’t use a 2000 watt generator to run all types of water heaters.

You can only use a gas-powered water heater with this generator since a gas heater needs less amount of wattage.

4000 watt:

A 4000-watt generator is also not suitable to run a water heater. Because most of the types of hot water heaters require more than 5000 watts. So, you might be able to run a gas hot water heater with a 4000-watt generator. 

5000 watt:

You can run several water heaters with a 5000-watt generator. But you have to ensure that the generator and water heater’s power requirements match.

Generally, an electric hot water heater will need 4000 to 4500 watts to start. So, you must ensure more wattage than this range.

5500 watt:

5500 watts is pretty suitable for running water heaters. Because most of the water heaters require more than 5000 watts. So, you can easily run a medium-size water heater with a 5500-watt generator.

6500 watt:

6500 watts is also suitable to run a water heater. You can also run other equipment with this size of generator along with the water heater.

7000 watt:

You can use a 7000-watt generator to run a water heater. Moreover, you can run most of the water heater types with this generator. But the tankless type water heater will not run with this generator.

7500 watt:

A 7500-watt generator will also be suitable to run many types of water heaters. But the tankless type requires a huge amount of wattage. So, a tankless water heater will not run with a 7500-watt generator.

10000 watt:

A 10000-watt generator is a pretty big size generator. You can use many devices along with the electric or gas type water heater with this generator.

How many watts does a hot water heater use?

Generally, different types of water heaters need different watts demands. So, let’s see how many watts a hot water heater uses.

Gas hot water heater:

Gas hot water heaters don’t require too many watts. Generally, a gas hot water heater will need 1500 watts to run. So, you can run a gas water heater with a 2000 watts generator.

Electric water heater:

An electric water heater will need more wattage than a gas-powered water heater. For example, an electric water heater runs at 4000 to 4500 watts and needs 3500 watts to continue.

Tank water heater:

A tank water heater will also need at least 4000 to 5000 watts to run. So, the tank water heater requires more watts than the gas water heater.

Tankless water heater:

A tankless instant hot water heater will need a huge amount of watts to run. Generally, a tankless water heater might take 10000 to 30000 watts to run.

What size generator do I need for hot water heater?

Generally, the size of the generator depends on which type of water heater you are using. Moreover, the house setup is also a factor in choosing the size of the generator.

Different types of water heaters will need different power requirements. So, let’s see what size generator you need for the water heater.

Electrical water heater:

An electrical water heater will need a medium-size generator. For example. A 5000 to 6000 watts generator will be the best for the electrical water heater.

Gas-powered water heater:

If the water heater is gas-powered, it will need a 2000 watt generator. Because a gas hot water heater can run at 1500 watts.

Tank water heater and tankless water heater:

These two types of water heaters need different types of generator sizes. Generally, a 5000-watt generator will be enough for a tank water heater. On the other hand, you need at least a 10,000-watt generator to run a tankless water heater.

How much does it cost to run a hot water heater with your generator?

How much it costs to run a water heater with your generator depends on the generator type and how much time you are using the water heater. On the other hand, if you use a tankless water heater, it will cost more than the gas-powered water heater.

Generally, if you run an electric water heater for 3 hours a day with your generator, it will cost from $750 to $800 per year. That means, it can cost up to $66 per month. But if you use a gas-powered water heater, it will cost less than this amount.

Can an inverter generator run a hot water heater?

Yes, an inverter generator can run a hot water heater. But the power requirements must match. If you use a gas-powered or electrical water heater, you can run it with an inverter generator.

Otherwise, the inverter generator will not be able to run a water heater since it has lower power input.

Can a portable generator run a hot water heater?

Generally, you can connect a water heater to a portable generator. But you can’t run the water heater for a long time. Because the portable generator doesn’t have a high power output.

Sometimes, a high-powered water heater will not run with a portable generator. If the water heater is a gas-powered water heater, you can run it with a portable generator.

Final Thoughts

A generator can run a water heater. But the water heater has to match the wattage demand of the generator. You can use a 5000-watt generator to run a gas-powered or electric water heater. But if you want to run a tankless water heater, it will not run with a 5000-watt generator.