On Friday, July 17, 2015 at 10:03:32 AM UTC-4, TomR wrote:
I live in New Jersey but this is for a friend of mine who lives in Virginia
in the suburbs near Richmond.

She lives in a 4 BR single family home in a development which (in case it
matters) is governed by a homeowners association. She seems to have at
least one or two major power outages a year due to summer storm damage, as
well as winter snow storm damage. The power outages are almost always
caused by wires down in her area from falling tree limbs etc., and her area
is almost always one of the last to get their power back on. When she has a
power outage, it is often for several days up to a week or more. Her home
is all electric -- meaning electric heat pump, electric central A/C,
electric hot water, and electric stove/oven etc. None of the homes in her
area have natural gas service, but she believes that there may be a natural
gas line that runs along the roadway behind her house. So, one possible
option may be for her to get a natural gas connection to her home from
there, and she is going to ask the natural gas utility company about that.

Due to the frequency and length of the power outages, she is considering
getting a back-up generator system installed. One option seems to be to get
a propane generator. And, I think that it may be a good idea to have it
connected by an electrician to one of those manual switch-over (cross-over?)
breaker devices in the main electric panel. Then, if there was a power
outage, she could do the switchover to the generator power and not be
without power for days on end.

Here are a few of my questions:

1) Can anyone give a rough idea of the size (wattage) propane generator that
she may need? She probably would only need some basic items powered, but I
wonder what she would need if she also wanted to be able to keep the heat
pump on in the winter and the central air on in the summer, plus some
lighting, the refrigerator/freezer, etc.


The heat pump is probably the largest load. The eqpt will have
a label that will tell you the actual data, but I'd guess typical
could be in the range of 30A, assuming that electric resistance
supplemental heat is disabled. So, that's 7200W right there, with
more needed to get it started. Electric water heater is probably
next large load, if she can get by with just the water in the tank
and not heat it, that would reduce the load. Also, depends if
she's willing to manage the loads so that they aren't on at the same
time or wants the possibility that they are all on, etc.
I'd say she's probably looking at ~~15KW unit. You can probably get
by with smaller, but the cost difference for say a 15, vs a 10 isn't
that much. Especially when the cost of installation of gas lines,
propane tanks, etc is involved. The grill sized tanks aren't going
to last long running a heat pump. You can probably figure out the
run time with various size propane tanks by looking at the generator
specs, how much fuel it uses, etc.