Where Do I Install my Generator?

When deciding where to install your residential generator, you need to consider the location in relationship to your house and the location in relationship to your panel.

How Close to my Electric Panel Should
my Residential Generator be Installed?

First, let's talk about where to install it in relationship to your electric panel.  Usually it makes sense to install your unit as close to your breaker panel as possible.  This is because it is more cost effective because you use less wire and because a drop in voltage can occur in long lines which can leave the residential generator underpowered. The good news is if you absolutely must have the unit installed a long distance from your house, it's possible to manage the voltage.  However, you'll likely pay quite a bit more.
  The National Electric Code (NEC) documents the current carrying capacity of wires. 
Lets look at a simple example:

• Kohler 18RES generator (an excellent generator, by the way) with a derated output of 70 Amps
• The cable length from the generator into your Automatic Transfer Switch (ATS) is 15 feet
• Cable is installed in electrical conduit

You would need to use #4 Copper conductors. This would limit the voltage drop to only 0.51% for each of the two 120 volt legs of the circuit

If you increased the distance from 15 feet to say, 100 feet, you would need to increase the wire size to #3 Copper. This would result in a voltage drop of 2.74% -- still within acceptable limits. Just a note, if you wanted to keep the voltage drop to less than 1%, your would have to increase the wire size to 4/0. This would increase your installation cost significantly!

As mentioned above, the NEC defines the acceptable types and sizes of electrical wire for all conceivable situations. You can save money by using Aluminum conductors instead of Copper, but you have to increase the size of the conductor. Be sure to check with your state and local codes before using Aluminum. It is acceptable in most places, but there are a few special things that must be done to do the job right.  Calculations taken from here.

How Close to my House

Should my Residential Generator be Installed?

Second, let's talk about where to install it in relationship to your home.  Installing your residential generator outside a window is not a good idea due to exhaust fumes.  In fact your installation specialist will probably choose to avoid this because of liability issues.  You can expect some noise from your generator when it runs its regular test cycle and when its supplying power during an outage.  It can be anywhere between 62dB and 78dB about 23 feet from the unit.  This is similar to the sound an air conditioner makes.  You can always check the spec sheet for your unit.  The manufacturer addresses this.  This is essential information for some home owners due to noise regulations from city government or home owners associations.