Can You Operate A Tankless Gas Water Heater Without Electricity?

Power outages happen all the time. According to an aggregator of utility blackout data, there was a 73% increase in total power outages in 2020.

When the power goes out, you might be wondering if operating a tankless gas water heater without electricity is possible.

No, operating a tankless gas water heater without electricity is NOT possible. If you have a generator, battery, or tank, your water heater will keep working when the power goes out (for varying amounts of time). Tankless gas water heaters have electronic components that require power.

Virtually no one likes cold showers, especially cold showers in the dark when the power has been out for hours. Even worse is when there’s a limited amount of warm water that runs out halfway through your shower, so you’re stuck with freezing cold water and there’s still shampoo in your hair. A candle-lit warm bath, though? A whole different story.

In order to have that warm, satisfying shower in the morning, you need a water heater. Most US homes have the older, traditional water heater design.

It typically looks like a big metal cylinder in a basement, laundry room, or garage. Without naming each individual component, the basics of the system are actually very simple.

Gas water heaters have a gas burner at the bottom of the tank while electric water heaters have a heating element in either the middle or bottom.

The gas heats a metal tube that runs through the middle of the tank. Through a pipe, cold water floods the tank. Cold water warms into hot water by coming into contact with that hot metal tube or heating element, and then hot water is distributed throughout your home through an outlet pipe.

The tube also, of course, carries toxic gas fumes out so that you’re not drinking chemicals all day. For electric water heaters, this isn’t an issue.

In between warm showers, the water sits in the tank waiting to be run through the pipes and into your bathroom.

Tankless water heaters, on the other hand, work a bit differently.

Remember how we said that the hot water stays in the tank until you need it? What about tankless water heaters? Hot water can’t stay in the tank since there isn’t a tank, so where does it come from?

Well, the concept is essentially the same. There’s only one key difference: instead of having the water heat up in the tank, a heating element or gas burner warms water as it travels through the pipes.

Instead of having this big metal cylinder in your basement or laundry room, homes with tankless water heaters have a much smaller box, about the size of a power meter, hooked up to their plumbing.

Other advantages include an almost endless supply of hot water and a reduced energy bill of about 40%. However, they’re up to three times more expensive to install than traditional, tank water heaters. They’re also better for the environment since they use fewer materials overall. When you have to replace them, you’re not throwing away 150+ lbs of metal. Tankless water heaters, on average, weigh only 27lbs.

There’s another drawback, too: their reliance on a constant stream of energy.

If you have a gas range or oven, you’ve almost undoubtedly been able to enjoy a warm, home-cooked meal even with the power out.

Why can’t a gas water heater do the same thing?

Well, in order to turn that range or oven on, you probably needed matches or a lighter. Your range might have a built-in electrical igniter, but without any power, you can’t use the electricity to start up the range.

There are a few reasons why gas water heaters need electricity, and that’s one of them. Even gas-powered tankless water heaters need an electrical current to fire up the ignitor and warm the water.

Tankless water heater systems prevent scathing hot water by using advanced monitoring systems that are powered by electricity. Even if you have a tankless water heater that’s strictly powered by gas, that’s another reason why they won’t work if your power is out.

If you have a tankless water heater, you’ve probably also noticed that there’s a control system on the front of it. Usually, there’s at least a thermostat that allows you to set the maximum temperature of the water. Well, that control system is, you guessed it, powered by electricity.

Even though tankless gas-powered water heaters use much less electricity than traditional water heating alternatives, they still need electricity to function.

However, that doesn’t mean that you can’t find a way for them to work even when your house is out of power.

What’s the best way to keep your water heater running when the power goes out?

Invest in some sort of alternative energy source. Your best option is a backup generator. You’d be able to power all of the essentials, from the fridge to the water heater to the router to the lights.

If you’re only looking to power the water heater, though, another great option is a backup battery system.

There are backup batteries built specifically for tankless water heaters, but the gist is the same for all of them: they work almost like mini backup generators for any appliance that they’re hooked up to.

So, one of the advantages they have over a backup generator is that they don’t need to be individually plugged in. They’ll kick in as soon as the power goes out. If you’re in the middle of that shower, then, the warm water will just keep flowing.

However, they can get pretty expensive if you’re looking to buy one for each individual appliance you’ll need to keep running.

So, to help you make a better decision, let’s look at the pros and cons of home backup generators and batteries.

How often is this a problem for you and how much are you willing to spend on it? Is the power going out all the time or is it something that happens every few months before clicking back on?

Should you get a home generator to power your tankless gas water heater? You should buy a home generator if you live somewhere you need heating and cooling, and if you work from home and absolutely can’t afford to lose power.

However, if you’re just looking to power a simple water heater, you probably don’t need a full-on home generator. There are definitely other, more affordable options. They might not offer the same level of comfort and convenience, but they’ll certainly let you get back to that warm shower.

Still, of the three options, this is one of the best. A whole-home generator only makes sense for a small number of people who are experiencing very regular power outages. The price is exorbitant and you’re probably unlikely to increase your home value by the amount that it costs to install.

A portable generator, on the other hand, gets the job done effectively and relatively cheaply. Yes, running out in the rain to turn it on can be a major pain, but it’ll probably stay on long enough for the power to kick back on, unless you live in the middle of nowhere.

But what about backup battery systems? How do those work?

A backup battery system might be a great idea if you only want to power your water heater with no frills. You’ll probably have to call a plumber to install it, but the total cost will probably be under $700. It’s more environmentally friendly than both the whole-home generator and a portable generator and it offers peace of mind. You won’t have to worry about running out of hot water ever again.

What if you’re not sure what type of water heater you have? We included a section below to help you figure it out, based on what happens when there’s a storm…

A portable generator is a great option. Most people don’t experience power outages that last longer than a few hours, which is about how long a portable generator lasts. Buy an extension cord, some gas, and a portable generator. Plug it into your water heater. Go take that warm shower. It’s that easy. You can also use the portable generator for camping or any other outdoor use you can think of.

Finally, a backup battery is another great option, especially if you like the peace of mind of a whole-home generator without the cost. You’ll probably need some plumbing experience to install it, but once you do, it’ll sense when the power is off and kick on for about 12-18 hours. Probably one of the most environmentally friendly options, too, since it’s electric.

A tankless gas water heater will not run without electricity. You’ll need some sort of power source since the ignition and control panel depends on it. If you’re interested in operating a tankless gas water heater without electricity (or public utility electricity, that is), consider buying a whole-home generator, a portable generator, or a backup battery.

The costliest but most comforting option is the whole-home generator. Depending on where you live, this might also increase the value of your home and offset your insurance bill, but probably not by enough to offset the cost of the system. Most typical buyers don’t expect a generator, so it’s just a nice addition to have to a home. If you live in an area that demands heating or cooling (and you have money to blow), this could be a good option.