All-electric homes: what happens when the power goes out?

If everything in your home is powered by electricity, nothing will work during a blackout unless you have backup measures in place. That’s one advantage that some gas appliances have. For example, a gas cooktop can still work when the power is out, and gas hot water heaters typically use a piezoelectric igniter that works by simply pressing a button.

For some homeowners, blackouts aren’t a major concern. For example, in the 12 years I’ve lived in my current home, I’ve experienced two blackouts, neither of which lasted more than a day. While I could spend thousands of dollars to ensure that I always have power, the investment wouldn’t be worth it to me.

However, not everybody has the benefit of stable utility power. Some homeowners experience much more frequent power outages, making the issue more than just an occasional annoyance. And while this is not strictly an issue related to switching from gas to electric appliances, if you have critical medical equipment at home, having a backup system in place can literally be a life-or-death matter.

If you’re planning to electrify your home but power outages are a concern, this article will help you decide if you should consider backup options, stay with gas for certain appliances, or simply not worry about it at all.

How frequent are blackouts in the United States?

The United States power grid is the world’s largest machine ¹, consisting of more than 7,300 power plants, 7 million miles of transmission lines, and countless transformers and substations. For the most part, it’s something we never think about - a testament to the remarkable reliability of such a complex and interconnected piece of machinery.

Perhaps that’s one reason why power outages feel so jarring: we’re accustomed to everything just working, leaving us unprepared for moments when it doesn’t.

For most people, power outages are rare, but there have been some notable major events in the past few years, such as the California wildfires and resulting blackouts that were the result of under-maintained transmission lines owned by Pacific Gas and Electric, and frozen natural gas infrastructure that caused major winter power outages in Texas ².

The US Energy Information Administration tracks what it calls “major disturbances and unusual occurrences” that affect the power grid and produces an annual report ³. This data only covers “major” events, so local blackouts that might effect a few hundred utility customers or fewer generally won’t be included. Even so, this report gives a good insight into the frequency and severity of power outages in the country.

The table below lists the number of major power outages in the United States in 2022 by the duration of the outage.

As you can see, counting grid disruptions for which duration data is available, the majority lasted less than 12 hours, with a significant number lasting only a few minutes (and many lasted only 1 minute). Relatively few lasted a day or more.

The difference between blackouts that are a mild inconvenience and ones that are major life disruptions that can result in property damage (think failed sump pumps) or health risks (such as having very young or elderly trapped in the cold) is important when it comes to deciding whether you need to plan for backup power, rethink electrification, or simply deal with the occasional blackout.

Again, it should be emphasized that the EIA data above only covers major grid events. You might experience local outages that are too small to be noted by the EIA but are nonetheless major inconveniences to your life.

Heating and cooling your home during a blackout

The loss of heating and cooling during a blackout is perhaps the top concern when it comes to deciding between gas and electric systems.

Unless you’re experiencing a major heat wave or have elderly residents to be concerned about, not having air conditioning tends to be a less serious issue than the loss of heating. There are passive measures you can take to cool a home, such as closing blinds during the day, opening windows at night, or spending time in a cooler basement or ground floor. Box fans also draw little electricity and can be powered by a small battery system (more about those later).

Losing heating, on the other hand, is usually a more serious issue. The difference between room temperature and an extremely hot day - let’s say 110°F - is about 40 degrees. However, a 40 degree difference in winter means an outdoor temperature of only about 30°F, which is just below freezing, and not considered particularly cold by anyone who lives in a northern climate. A very cold day would be more like 10°F - a 60 degree difference.

Because winter tends to result in larger temperature differences, a house will get cold much faster than a home will get hot in the summer. Winter also has the disadvantage is that there are no passive measures to make your home a more comfortable temperature.

You might think that you’re in a better situation with a gas furnace than a heat pump during a blackout, but that’s only true if you’ve planned for backup power. While a natural gas furnace doesn’t use electricity to generate heat, it does require electricity to power the blower motor. If you don’t have power, your gas furnace won’t turn on. This leaves you in a no better position than if you heat your home purely with electricity.

That said, it is lower cost to configure a gas furnace to operate during an extended blackout than a heat pump.

How to configure backup power for a gas furnace

If you have a gas furnace, take a look at how it is wired. In most cases they are hardwired, which means that are connected directly into your electrical system without a plug. However, sometimes a furnace will have a conventional 120v plug that is connected to a power socket.

An advantage of having a furnace with a power plug is that it is easy to operate your furnace with a backup generator during a blackout. Simply connect the furnace plug to a heavy-duty outdoor-rated extension cord, then connect the extension cord to a generator. If your furnace is hardwired, you’ll need to work with a qualified electrician on your options for connecting backup power. One option is a transfer switch, which is a switch that will disconnect the furnace from utility power and allow you to connect it to a generator instead.

In either case, if you’re using an internal combustion generator, make sure that the generator is operated outdoors and at least 20 feet away from your home to avoid carbon monoxide poisoning. Some newer generators have carbon monoxide sensors and automatically shut off when high CO concentrations are detected in the ambient air, providing an important safety feature.

Forced air furnaces will generally draw several hundred watts while operating, which is low enough that a small generator will be able to provide it with enough power. Keep in mind that the blower motor of your furnace, like all electric motors, will demand a brief surge of power known as inrush current when starting up. Generators designed for this will list a rating for both startup and running watts, so make sure that your generator has enough startup watts to meet the inrush current that your furnace demands.

Even if you have the wiring to allow your gas furnace to operate from a generator, there are a couple other gotchas to be aware of.

The first is that your furnace may not operate if it detects that the power supply isn’t “clean” – meaning that the waveform of the AC current is spiky rather than a smooth sine wave – which can be a problem with lower quality gas generators. In general, inverter generators will produce power output that is closer to a pure sine wave than traditional portable generators ⁴.

Another potential issue is that portable generators generally aren’t grounded but instead have what is known as a floating neutral. The electronics in your furnace may detect this as a safety issue and not turn on, even if your generator is otherwise correctly connected and has enough power capacity.

One solution to this is to use a bonded neutral plug, which satisfy the electronics in your furnace and cause the generator’s overcurrent protection to safely trip in the event that a ground fault does occur.

Finally, another solution is to use a battery backup, which are sometimes called portable power stations. If they’re capable of being charged by solar panels, you might see them marketed as solar generators. Battery backups have the advantage of safety: there’s no carbon monoxide risk. However, depending on the battery capacity, you might be able to run your furnace only for a few hours before the battery is depleted. External solar panels will help this and can potentially run your furnace indefinitely, but you’ll need enough solar panels and sunny weather for this to work.

As you can see, it is feasible to operate a gas furnace on backup power, but it requires some planning and the help of a qualified electrician.

Operating a heat pump on backup power

The main advantage that gas furnaces have over heat pumps during a power outage is that furnaces require much less electricity to operate. In contrast to a forced gas air furnace that might need several hundred watts of power, a heat pump will need a couple thousand watts or more. While some portable generators can meet this power requirement, you will need to be sure to have a large fuel supply to keep things running. A home standby generator is designed to power an entire house and will have enough power output to operate your heat pump, but the price will start at several thousand dollars. Also, if going all-electric is one of your goals, then relying on a gas generator to keep your home operating might not be something you want to do.

Gas vs. electric stoves in a blackout

Another gas appliance that can have an advantage during a power outage is a gas cooktop. Even if it normally needs electricity to ignite the burners, you will always have the backup option of using a flame to light them. Being able to operate your stove even in a blackout can definitely be reassuring.

However, this comes with the strong caveat that you should have active ventilation whenever you cook with a gas cooktop. Indoor air pollution is a significant concern with gas cooktops, and is one reason why induction cooktops are growing in popularity.

Some people will also attempt to use their gas stove to provide space heating in a blackout. This is a definite no: keeping a gas stove or oven burning for long periods of time without ventilation can lead to dangerous levels of indoor air pollution, including carbon monoxide poisoning. The home insurance company HomeServe also notes that using a gas stove for space heating can be a fire hazard ⁵.

In comparison, powering an electric range during a blackout, which requires a 240v service with at least 30 amps, can only be accomplished with a large generator or home storage battery such as the Tesla Powerwall. A smaller portable battery, such as Goal Zero’s Yeti, could power a single-burner electric cooktop for about 3 hours on full power. However, the Yeti starts around $3,000, which is an expensive way to have some limited ability to cook during a power outage. It does, at least, have the advantage of not having indoor air pollution concerns.

The bottom line is that while a gas stove can give you the ability to cook during a blackout, in practice it’s something that you should only do for short periods or in warmer months when you can open windows for ventilation.

Finally, don’t forget about one safer option that many homeowners already have sitting in their backyards: a gas grill.

Gas hot water tanks will generally continue to operate in a power outage

One appliance that should continue to work without interruption in a blackout is a gas hot water heater. In general, gas hot water heaters don’t require an electrical plug. Any small amount of electricity that the heater needs to function will be provided by a thermocouple, which is a small device that generates electricity from temperature differences, or a piezoelectric igniter, which is a button that generates a spark. Most also have a pilot light, which provides the ignition source the heater needs when it cycles on.

As is the case with heating or cooking devices, a heat pump hot water heater requires more electricity than is practical to backup with a small battery, and this is especially true for inefficient electric resistance hot water heaters.

Gas hot water heaters will work well in a blackout, but gas cooking and space heating have disadvantages

In summary, the gas appliance that has the biggest advantage in a power outage is a gas hot water heater. It should continue to operate normally, letting you have hot showers while you wait for the power to come back on.

Gas ranges and furnaces also have theoretical advantages when the power goes out, but the practical reality is that gas ranges can be unsafe to operate if you don’t have good ventilation. They are also sometime misused as space heating devices, which can lead to serious health risks or even be deadly.

Furnaces, which have fairly low electrical requirements, can be practical to operate with gas generators as long as you take the correct safety precautions (by operating them away from your home and being sure to connect them with a suitable heavy duty extension cord). However, in most cases you will need to make modifications to allow the furnace to switch over to generator power, which will require an electrician to install a device such as a transfer switch – a project that may cost several hundred dollars.

The bottom line is that while gas appliances can be advantageous when the power goes out, the measures needed to allow them safely operate mean that, in practice, the advantage of gas over electric is smaller than you might think.

How to survive a zombie apocalypse in an all-electric house

So far we’ve discussed the advantages and limits of gas appliances in power outages. While there are some advantages, if you want to survive what some might call a zombie apocalypse situation, it’s actually the all-electric home that is the superior option – if you’re willing to make an investment.

The reality of gas appliances is that while natural gas will often continue to flow to your home when the electricity goes out, that’s not a certainty. Natural gas can be vulnerable to disruptions, as happened in Texas in 2021 ⁶ when extreme cold shut down gas infrastructure in the state, disabling power generation and leaving many Texans in the cold – with some tragic results. While gas disruptions are less common than electrical blackouts, a homeowner is still at the mercy of a utility company.

If you have an all-electric house, you can become completely self-sufficient and operate your home “off-the-grid” for an indefinite amount of time. That means not having to depend on an external company to provide you with electricity, natural gas, propane deliveries, or any other supplies.

The way to do this is install solar panels and home storage batteries. With solar panels on your roof or in your yard, you can self-produce all of the energy that your home requires. While the electrical consumption of homes will vary wildly, and solar generation depends a lot on local climate, as a ballpark estimate many average sized homes with a sunny roof (meaning one that is roughly south-facing and doesn’t have any shading) will be able to generate 100% of their annual electricity needs with about an 8 kilowatt solar array - give or take a couple kilowatts.

To operate off-the-grid - that is, to be able to have electricity during a blackout - a home solar array also needs a battery system. On a sunny day, the solar panels will generate an excess amount of electricity that the system will store in the batteries. When evening rolls around and the sun goes down, your home will automatically switch over to battery power.

If your intention is to be able to operate all of your electrical appliances normally, including large consumers like a heat pump or central air conditioner, a home would generally need at least two Tesla Powerwall-sized batteries. A single Powerwall has a capacity of 13.5 kilowatt-hours (kWh), so two combined would give you 27 kWh of total storage. There are several other companies that make home storage batteries with capabilities and storage capacities that are similar to the Powerwall, including Enphase, SolarEdge, Generac, and Sonnen, so consumers have many options.

Once you have a solar array that’s been sized to match your home’s power needs and a battery system that has enough capacity to keep your home running between sunset and sunrise, your home can theoretically operate indefinitely without utility power. As long as you have sunny days, the solar panels will recharge the batteries that were drained during the night. Too many cloudy days in a row will leave you with insufficient power, but if you can regulate your electricity usage by only operating your appliances when you need them, a home with this type of solar and storage setup could outlast a blackout of any duration.

Cost is a barrier, of course, but home solar in many markets is less expensive than you might think, especially when the federal incentive is included. The cost varies wildly in different markets due to local pricing and local incentives, but as a very rough starting point, an 8 kW solar array will cost approximately $8,000 after the 30% federal Inflation Reduction Act incentive. According to Tesla’s website, two Powerwalls will cost about $11,000 after incentives.

This means that for roughly twenty grand, you can have a home that can help you survive a zombie apocalypse. If self-sufficiency is a concern, then an all-electric house with solar is actually a superior alternative to a home powered by fossil fuels.

Partial home backups with a critical load panel

Regardless of whether you have gas or electrical appliances, one thing to know about designing a backup system to outlast power outages is that it doesn’t need to back up your entire house. You might only have a few appliances you consider critical, such as your refrigerator, some lights, a circuit in your kitchen, and perhaps a sump pump or garage door opener.

One low-tech solutions is to purchase a portable battery, such as the Goal Zero model mentioned above. In a blackout, you would need to manually plug in your appliances into the battery. For example, you might plug your refrigerator into the battery for an hour or two at a time to prevent it from defrosting, and then move it to a hot plate so that you can cook a meal. That’s not a very convenient approach, but it does have the benefit of being lower cost and not requiring an electrician to do any wiring.

A more comprehensive approach is to have an electrician install a critical load panel and transfer switch into which you can plug a generator. A critical load panel contains only the circuits in your home that you consider to be essential. During a blackout, you would plug your generator into the transfer switch and flip the system from utility to generator power. This will supply electricity from the generator into the critical load panel, leaving the remaining circuits in your home dark.

The advantage of a critical load panel is that it forces you to plan ahead for power outages and allows you to have a smaller backup power supply than you would need to power your entire home. It can be used with either a generator or a battery backup system too, so you don’t have to rely on fossil fuels if you don’t want to.

However, one thing to keep in mind is that the extra cost of a critical load panel and transfer switch could, especially for a smaller home, might not be much less than a full home backup system. It may be the case that for a little extra money you could have a larger whole house backup generator or larger battery system. To help you make a smart decision, you’ll want to reach out to a least a couple electricians to provide options and price quotes tailored to your needs.

Bottom line: if blackouts are a concern, gas and electric appliances both have pros and cons

One of the hypothetical advantages of natural gas over electrical appliances is that they can continue to function in a blackout. While this is true to an extent, there are limits to these advantages because of safety concerns and the fact that gas furnaces require electricity to function. While backup options do exist, the additional cost of a gas generator and installing devices such as transfer switches eliminates some of the advantages that natural gas might have.

The bottom line is that a homeowner who is concerned about the ability to ride out power outages in an all-electric home is to consider how frequent blackouts are, and understanding which appliances really are critical. For example, if your main concern is preventing your freezer from defrosting, a portable battery can provide enough power to run a fridge for a day or two. Because most blackouts in the United States last less than a day, having a portable battery could provide all the peace of mind that you need.

Finally, if you experience frequent power outages, have circumstances (such as medical equipment) that make it critical to always have power, or you simply like the security of a self-sufficient home, installing solar panels and a whole-house battery system can potentially keep your entire home powered though a blackout of any duration. This can be better than a gas-powered generator, because if a power outage is widespread your local gas stations won’t have the power to operate their pumps.

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