8 Steps to Installing a Whole House Standby Generator

We finally did it! We declared independence from our local electrical utility! We installed a whole house standby generator. When the utility shuts down because of bad weather — not just winter, but for us this year, summer too — we can now flick a switch and generate our own electricity to run our whole house! What a blessing and mental comfort! Okay, it is like insurance — you hope you never have to use it — but every time we have had an outage, we have thumped ourselves on our foreheads, and asked why we didn’t take action to be able to live comfortably and have electricity for the multiple hours, days, or even weeks without power.

A standby generator may seem like a luxury unless you live on a well like us. Then it is a necessity. Without water, you can’t flush, you can’t bathe, and you can’t even brush your teeth. Also, this summer’s power outage was during record-breaking heat. and without air conditioning, we needed daily (or more frequent) baths.

So this post is about the steps we took to research what we needed, to purchase equipment, and to have it installed and up and running. Please comment with any questions you might have about the process, and we will attempt to answer all inquiries and comments. I have other posts about why we bought a generator, and the particular decisions we made to select and install the one we now have, so read those too if you have questions about what we did and why.

But first, an overview of what is involved

You will need to buy, obviously, a generator and engine to power it.  This is sometimes referred to as a “GENSET.” Here, I’ll just refer to the unit as a generator.  You will need to determine how much power you will need, expressed in Kilowatts (Kw) to run whatever it is you want to supply power to when your utility power is down.  This will be the most expensive part of what is needed to supply auxiliary power to your house.  Next you will need a concrete pad on which to place the generator.  A 6” thick reinforced pad should be

able to support all but the largest generators.  We have seen thicker and taller pads in Florida where they get a lot of water. Your supplier and contractor can best advise you on this.  Then you will need to buy, and have a licensed electrician install, a transfer switch.  This is the part that takes this job out of the DIY realm.  The transfer switch must be installed between your electric meter and circuit breaker box.  For this part of the installation, power must be cut before it enters the house.

This might require pulling the electric meter.  Your electrician will know what must be done and how to do it without getting electrocuted – or find another electrician!  The purpose of the transfer switch is to switch the source of power from the utility to the generator in a manner such that your generated power does not go out through the utility line.  This is called “back feed, ” another term you might run into.  Back feed can electrocute linemen or -women working on what are supposed to be uncharged lines.

system 8 Steps to Installing a Whole House Standby Generator

When you look for a transfer switch you want to search for those that are “SUSE rated.” “SUSE” just means that the switch is “Suitable for Use as Service Entrance” – in other words, it can handle the high voltages carried by utility and generator lines.  Finally, you will need to decide whether you want to generator to start automatically when power is lost, or if you want to start the generator manually.  I discuss this in more detail further on.  Your decision here will determine whether you buy an automatic or manual transfer switch, and whether you also need to purchase an “auto start panel” for the generator. Some generator manufacturers split the auto start panel components between the generator and their own (proprietary) automatic transfer switch. This might limit your selection of transfer switches, and other options.  Finally, in regard to major expenses (other than the labor to get all of this done!) will be the wire that carries power from the generator to the transfer switch.

Steps to Install Whole House Generator:

1. This is not a DIY project. Select your installer carefully!

This is probably the most important step in the process you will take. Get references, and make sure the installer has installed your generator before. You don’t want the installer to be learning on your installation. However, be aware that every installation has some customization associated with it, because it is being adding to an existing structure, so there might be some issues that will come up as installation proceeds, so factor that into installation time. Much of the installation is electrical and most jurisdictions require a licensed electrician to do the installation.  Gas (natural or propane) powered generators also require specialized installation. Some installers will take care of all the other steps listed below, making the installation transparent for you. Even in this case, you will still want to know the steps below so that you are aware of what is involved, what questions your installer will want you to decide, and why an installation costs what it costs. We selected an installer who had previous experience, and allowed us the options we wanted, because he also is a general contractor, and could work through the issues we wanted to address in an even more customized way than might suit the average homeowner.  Also, make certain that the supplier of your equipment has a technical support number not only for you to consult, but also, just as important, for your contractor to consult.

2. Determine what type of engine will power your generator

There are many types of standby generator engines:

  • gasoline engine (generally only small ones generators, rarely large enough to run a whole house);
  • natural gas or propane engine (very convenient if you already have gas heat or access to natural gas or propane); and
  • diesel engine.

For those of you interested in a propane-powered engine, there is a great blog on a residential installation here.

3. Determine what size of engine you need

The size of engine you will need depends upon how much of your house you want to power simultaneously. We used Kohler’s web site to calculate what we needed in power. There are other websites that will help you in your calculations, and remember that not every appliance needs to be powered in an emergency. Be sure to figure in your heat in the winter, AC in the summer, and refrigerator, freezer and water heater (if electric) year round. If you have a well and sump or extractor pumps, these will be necessities that you will have to have powered. You will want to be able to see at night, so lighting will be a must, but you might not need the washer/dryer, dishwasher, or even oven, if you have a counter top toaster oven and microwave with which to heat food. Don’t forget other motors that you might need (garage door openers?), or that might come on automatically and that you might not think about. The amount of power they need to start is much higher than what they use while running.

Remember that many of your electronic devices run in the background and use electricity even when switched off.  The amount of electricity used is small, but don’t forget to add that in.You can generally bet that this is the case for TVs, computers, cordless phones, and anything with a remote control. In the summer, you might be able to give up air conditioning and use fans. But if you have any medical equipment or devices that run on electricity, be sure to add them also to what you need. Electric blankets in the winter might be a necessity for one family, and completely optional for another.

4. Determine whether you want an automatic or manual switch to turn on the generator when you lose electricity from your utility, and a manual or automatic transfer switch to switch power over to the generator

There are pros and cons with either decision. If you happen to be gone for a few days, having the generator start automatically when you lose power will be good so that when you come home, you will not have lost food because the refrigerator warmed up or the freezer defrosted. That would require an autostart panel for the engine, and an auto transfer switch for the power. Obviously in the winter, having heat while you are gone will prevent other problems such as frozen plumbing pipes. However, it will be necessary to pick which appliances, circuits, etc. will be powered by the generator and which will not be, so they can be wired correctly for automatic start up., or so that you can turn the circuit breakers off for those things you do not want to run. Below is shown the manual transfer switch in our basement. Whether automatic or manual, the switch can be quite large, so space will be needed to mount it on a wall.  Automatic transfer switches are much larger than manual ones, and much more expensive!

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power panels on left, manual switch on right

Also, you will need to make sure that you have enough fuel to run the generator as long as you might be gone if you have auto-start. This might not be a concern with natural gas, but will be with propane, diesel, or gasoline. With propane, your fuel supplier might be able to refuel during a weather emergency while you are gone. With diesel or gasoline, you might be stuck with refueling yourself, so you need to know what size your fuel tank is for the engine that powers your generator, and how long that fuel will last when the generator is powering your house (or the few devices that you must have powered while you are away). It will burn less fuel when only running a few devices as compared with running everything in the house. You can have your unit modified to have more fuel made available to it, or have someone come to check on the fuel level while you are away, and refuel the engine if necessary.

If you decide to manually switch over to your standby generator, you might need to drain your house’s plumbing if you are going to be away for any length of time, especially in the winter. But you won’t run out of fuel while you are gone!

Either of these switches, whether manual or automatic, are usually located next to the incoming power supply box that houses the fuses or circuit breakers for each room, appliance, etc.

5. Determine where you will locate the generator

Most standby generators are intended to be located out of doors. This is especially important for gasoline or diesel powered generators, because they generate fumes (carbon monoxide that are hazardous to your health. Whole house generators are large and heavy items, best located on reinforced concrete pads. Find out the weight of your selected generator, and plan and prepare its location accordingly. Be aware that some generators are quite noisy, so much so that you and your neighbors may be bothered by the engine noise. Some generators are specifically designed with extra insulation and other design features to be quiet.

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Our generator on its concrete pad

6. If you decide to have a manual switch to turn on the generator, decide where you are willing to turn on the generator

If you have a switch that will turn on your generator automatically when you lose power, you will not have to decide how you are going to turn on the generator, it will turn on automatically, and if you have an auto-transfer switch, it will begin delivering power to your house automatically. If you decide to have a switch that you manually control to turn on the generator, it will be convenient to get a switch installed inside your house or garage to turn on your generator so that you don’t have to go outside during inclement weather to start up the engine that powers the generator. Note that for some generators you might need to purchase and install an auto-start panel to permit remote starting.

DSC17751 1024x871 8 Steps to Installing a Whole House Standby Generator

The switch on the left is in our basement and starts generator outside remotely; note the red safety cover.
The cover is up, but the switch is still in the “Off” position. The switch on the right controls an outlet in
the generator cabinet for an engine block heater and battery float charger.

7. Determine if there are other considerations that will require extra equipment to conveniently run your generator

For example, we decided to install a diesel powered generator, and diesel engines can be hard to start in very low temperatures, so we had a block heater installed that supplies continuous heat to the engine when it is very cold outside. We are looking into adding a thermostatically controlled switch to this line so the block heater will only come on when it is cold and won’t run in warm weather. Additional modifications or additions might be to add a larger fuel tank to the engine or install an auxiliary fuel tank near the generator to provide continuous fuel  delivery for a longer period without manually adding fuel (important for gasoline or diesel engines.)

8. Determine whether there is a maintenance schedule for your generator

Some generator engines require exercise regularly to make sure they will start up when needed (remember, you might not need emergency power for months or even years), and keep internal mechanisms and seals lubricated. This regular exercise might be automatic if you have an auto-start system from electrical utility to generator, or it might be something you have to initiate on a monthly or quarterly basis on your own. Be sure to find out whether you need to do anything on a regular basis, and set an appointment with yourself if this is the case.  Also be certain you can control the timing of the maintenance schedule. You probably would not want the engine to start up at 3:00 am and possibly awaken you and your neighbors!

If you have a generator, what items have you needed that we have not mentioned? If you don’t have a generator and are thinking about installing one, if you have questions or comments, please leave them and we will respond!

About shenandoah

Hi! I'm Shenandoah, an ancient gardener, attempting to age in place at home and in my garden. I'm in dream zone 7a able to grow just about anything. I want to help others plan their garden and living experience to age in place and never grow old in their hearts!

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