With 2021 ending with a collective sigh, we look to ’22 with hope that the new year brings a
sentiment of “we got through it!”, not “hold my beer”. To be on the safe side, many residents in
our valley continue to invest in emergency power options – primarily generators. There are a
few key considerations to installing a whole house generator.
Backing up a whole house will involve an electrical service rebuild. For example, a 200 amp
service will likely consist of a 200 amp meter socket, 200 amp main panel, with one or more sub
panels. For the entire house to be backed up, the whole 200 amps must be wired through a
transfer switch. A transfer switch takes power from either the grid or the generator – never
both, always separate. There is no other code-compliant way to tie a generator into a home.
Furthermore, if the service is rated for 200 amps, the transfer switch must be rated for 200
amps.
There are two main classes of whole house generators: air-cooled and liquid cooled. Air-cooled
models use engines like what you might find on a UTV or a commercial zero-turn mower. They
come in a small, unobtrusive housing that isn’t going to compel the HOA president to… “get
excited”. Maximum output is about 24kW, which is 100 amps – usually plenty to run an entire
house, and run on liquid propane or natural gas. The liquid-cooled models are substantially
larger, housing an in-line, four-cylinder engine with a radiator – much like you’d find in a small
import car. These units start at about 20kW and run up to 60kW and can run on LP, NG or
diesel. They are ideal for large estates, with multiple buildings and other significant loads, such
as pools, large well houses, detached living spaces, etc. While the smaller units are available
with a few weeks lead time, the large units are 32+ weeks out.
A good strategy for a home nearing the limit of an air-cooled unit is to employ management
modules. These load shedding devices are installed on one or more large loads, such as an
HVAC furnace, and serve to protect the generator if it approaches overload. It achieves this by
temporarily shutting down its respective load if it senses the generator is reaching redline.
Thus, the heat shuts off for about 5 minutes to keep the generator for shutting everything off.