Armed with your data from considering and documenting your needs, you’re ready to begin the process of implementing a backup power system.

But first… Understand that this approach is designed to help a family achieve off-grid-capable power incrementally, realizing immediate benefits with the smallest investment possible, but also creating a solid foundation for further enhancements as resources permit.

Off-grid-capable power will require some form of electricity production . Though there are many ways to do this, the simplest means to get started doing so is a Generator.

Note: Some may guffaw at this idea, particularly those with no experience with producing off-grid power, or the uneducated idealists who believe that things like solar or wind power eliminate the need for generators. That is simply not the case. Check with nearly any company providing off-grid power solutions, services, and products and you’ll quickly see that generators are usually an assumed part of the system.

Generators are fuel-based engines that use the engine’s rotational crank power to produce  (generate) electricity. They are widely available. Adding a generator can be very simple, or slightly complex. The degree of such should be determined by the group you identified with in the introduction (Basic, intermediate, advanced, premium) for your backup needs.

The remainder of this page will discuss how to meet the needs of those in the basic category (those who want to be prepared to be off-grid for less than 200 hours per year).

Decide on an appropriate generator

The first thing to determine is what generator you intend to purchase. How will you decide? Generators are sold with designations for their peak wattage and their continuous wattage. Sound familiar? It should because those are the numbers you should have captured after reading Part 1.

For this designation of basic power needs (200 hours of use or less per year), it would be simplest to avoid whole-house-backup or standby generators that are permanently wired. Therefore, you’ll want to look at portable generators. These are sold in most big box stores such as Lowes, Home Depot, Sears, and smaller local dealers.

If you need or desire a permanently installed generator, please direct your attention to Part 3 – Intermediate backup power. 

You will want to purchase a generator that has a slightly higher continuous and peak wattage than your needs – but not much higher. To optimize fuel efficiency, stick with generators that are no more than 25% higher than your needs. Generators may have ratings listed in kilowatts vs watts. A kilowatt is just another way of saying one thousand watts. Example, 4 kW is the same as 4000 Watts.

1) If you are considering more than a 10kW generator at this point, you’ve either misunderstood what is truly a critical load or have an exceptionally high number of critical loads. Too-large a generator for your real needs will just use excess fuel and result in higher cost. If you want a whole-house generator that can run every load, see Part 3 – Intermediate backup power. and size your system accordingly.
2) Consider that your generator is a critical piece of your home infrastructure. Get the best you can afford, not the cheapest you can find. Ask yourself…”if a company has produced a generator for sale, and is willing to sell it to me for $500, but still produce a profit, is it likely a good quality?”. This is not an area you want to be stingy!

Fueling your generator

Remember – we’re considering the needs of those who want to support less than 200 hours of run time annually, so we need to consider the fuel needs to do so. Become familiar with the fuel consumption rate (in gallons per hour) of the generators your consider. Use this to determine how much fuel you’d like to have on-hand.

So far, we’re evaluating generators based on their running wattage, peak wattage, gallons of fuel per hour. The next thing to consider if the type of fuel. Most generators available in the wattages likely being considered will run on gasoline. Some may also support propane and/or natural gas. The more fuels that can be utilized, the better, since this offers far more flexibility during any scenario where a given fuel is in limited supply.

Many gasoline generators can be modified to support the addition of propane and natural gas. Here are a number of online vendors who sell aftermarket kits to make many common gasoline generators tri-fuel compatible:


How to hook things up

To utilize generator power, one must connect the output of the generator to their home electrical circuits. There are a few ways to do this. Several are listed here in order of simplicity, from super-simple to more complex, but well-organized.

Dumb simple

The easiest way to utilize a generator with very little investment (a few extension cords) is to simply plug all the critical loads into the generator on an as-needed basis. Of course, this requires that one do so anytime there is a need to, which could be frustrating when off-grid power is needed in short and frequent durations. Nevertheless, this will keep things running. Just be sure that your generator has the right kind of outlets for your needs and in sufficient quantity.

A better approach

A great approach, where allowed by your municipality and the ‘AHD’ (Authority Having Jurisdiction – check with your local power company, or an electrician), is a “Generator interlock” and a  generator input panel. A generator interlock is installed into one of the top breaker panel positions and mechanically prevents a generator running if the main breaker is in the in position.

Why is this necessary? Because a generator attached to your home electrical grid, that is also attached to the utility grid (if your main breaker panel is ON), presents a shock hazard (and substantial liability) to line workers who may be working on wires expecting them to not be energized. Never, ever run a generator connected to your home wiring with your main breaker in the ON position. Doing so is usually illegal, and always foolish.

Essentially, a special generator input box (like this one or this one) is wired into your home electrical panel (assuming there is room) and is attached to an appropriately sized breaker that is mechanically protected by the interlock.

How it works

Under normal, grid-up conditions, this new generator interlock breaker is in the OFF position and your main circuit breaker is in the ON position. When you need to run off-the-grid, your generator retrieved, fueled, started, and plugged into the newly installed generator inlet (like this one or this one). Next, once the generator is running, and ready, you turn off all the circuit breakers in your electric panel (except for the generator interlock!), and turn the main power breaker to the OFF position.

With the main breaker in the OFF position, the interlock will permit the Generator inlet breaker to be turned to the ON position, allowing the power from the generator to flow in becoming the new source of power to your electric panel. You can then turn on critical load breakers (hopefully by this time you’ve labeled your critical loads with those little stickers!) to control how the generator power is used. When you wish to use grid power again, just reverse the process.

Here are some companies that specialize in interlock kits. To order, you will need to know what kind of electric panel your home utilizes.

If you lack the skills necessary to install an interlock kit and generator inlet, do yourself and hire a professional.  Be sure to adhere to your local requirements for inspections and permitting. Most professionals should be able to install such a system in one day or less and the corresponding cost should reflect such.


For basic off-grid-capable power, the above process will meet most requirements. There will be some investment made in a generator, and the hardware (and possibly installation) to use it. In most cases, the total invested should be within $1500-$4000, depending on the generator selected and the cost of professional services.