

Making your own power

[1]After last summer and fall’s long term outages, lots of homeowners are pricing generators, either for the entire house or just a few critical appliances.  Anyone who lost a refridgerator full of food can understand why.

A relatively low cost portable generator can run a refrigerator and save a weeks worth of groceries.  These smaller, cheaper portable generators can be very handy.  However with all the electronics built-into modern refrigerators we have to be careful about the generator we plug it into. A typical home refrigerator can draw as much as 1200 watts on startup and then require a constant 400 watts to run. The generator probably needs to be  at least a 2000 watt model, which can be had for under $200.


[2]Portable problems

The cheapest generators turn out cheap power at the expense of not being “clean” and “pure sine wave.”  That’s fine for power tools at a job site.  A drill or a circular saw doesn’t care. However, computers, TVs  and some appliances don’t work well with this kind of unrefined power.  Using a “job site” generator for household appliances  can end in an expensive disaster.  The price of more “refined power” triples the cost of a portable generator, but it’s better than ruining a bunch of stuff that’s even more expensive.

Why a household generator?

There may be reasons why a homeowner would consider an even larger generator investment.  More comfort and options when the power goes out or perhaps having medical equipment to run, or, as in our case, working from home.

Two major factors brought us to consider an investment in a household generator.  First we work at home and have two offices to run.  We can’t just whip down to Dunkin Donuts, the library or an “Internet cafe” and work.  Well, I suppose we could, but not for very long.  Conference calls, printing, and multiple large graphic displays don’t go over well for long at those places.

The second reason makes an even stronger case.  Our house uses an ejector pump to pump our household sewage up to the street.  The sewer line is actually higher than our house, so all our waste water (and everything else) has to go up the hill to get to the sewer.  When the power goes out we have a holding capacity of somewhat less than 50 gallons.  50 gallons goes pretty fast with 5 people flushing toilets. Forget about doing the dishes.

[3]Ok, so how big a generator do we need?

In order to determine just how big a generator we would need an electrician did a survey of our household appliances (something that’s pretty easy to do yourself) and discussed the various options for keeping power in certain rooms and hallways.  Once you make the decision to get a household generator it comes down to two options.  Either you buy one big enough to power the entire house or cut back on the cost by settling for some subset of of rooms and appliances.

That’s what we decided was best.  We identified what we absolutely had to have (Ejector pump, refrigerators, furnace in the winter, and two offices) and then increased the capacity by 20%, just in case.  That brought us to 10 kW (kilowatts) delivering about 62 amps of power when running at 80% of capacity.  Total cost just under $7,000, installed, inspected and guaranteed for 3 years.   It was a price we could live with, especially considering that a whole house unit would have been more like $11,000.  Of course now that we’ve taken the plunge the power will probably never go out again.

We also opted for a generator powered by natural gas.  That’s what our furnace runs on and it means no one has to fill a hot generator with gas (in the rain/snow/middle of the night) nor do we have to keep propane tanks topped off just in case.  The generator will run forever as long as the gas company keeps supplying gas (and as long as we keep paying the bill).

[4]How it works

Household generators automatically start when the utility power goes out and stop when it comes back on.   That can be good and bad.  First they don’t start immediately, so the house is going to go dark for at least a minute, possibly longer.  A generator needs time to start up and get up to speed before it switches over to power the house.  Second, when the utility power comes back it might fail again almost immediately which is another couple of minutes in darkness.  Computers, refrigerators and all sorts of other appliances hate sudden changes in power, and can die a grizzly death in the process.

Really valuable appliances should also have a UPS (battery backup system) to get them through those minutes of sudden power loss.

The other part of the generator puzzle is the transfer switch.  This is either a manual or automatic switch that switches over to the generator when utility power dies and switches back when it returns.  The transfer switch has two jobs.  First it stops the generator’s power from going out into the entire neighborhood (and electrocuting some poor lineman whose trying to restore the power) and second it stops momentary bursts of power when power lines are being worked on from blasting into your home.  Transfer switches look like circuit breaker boxes for partial house installations and plain big grey boxes for whole house setups.


A household generator usually starts itself once a week in a quieter “reduced power mode” to check that everything is OK and running smoothly.  The system doesn’t switch over the power during these tests, it just runs the motor for 15 minutes or so to warm the oil and lubricate all the parts.  Generators are made to runs hundreds of hours without stopping so it’s good to exercise them once in a while.

There really isn’t much to do on a modern generator.  The oil has to be changed once a year, whether you’ve used the generator or not.  Oil gets old just sitting there.  The Air filter also needs to be changed every 2 years or after 500 hours of run time.  Spark plugs are changed every 2 years or 500 hours as well.  The only other thing an owner needs to do is keep the vents on the generator outside cover clean and clear of bushes and debris.  Pretty simple stuff.

[6]Last words

Modern household generators are quiet while running and look kind of like an air conditioning condenser unit.  The gas and electrical conduits (pipes) that connect the generator to the house are easy to hide with bushes or just about anything else.   The generator usually needs to be about 5 feet from the house for maintenance and because they create exhaust fumes like any other engine.   They don’y smell any worse than a very small car though, natural gas and propane burns very clean.

Household generators run from about $4000 installed, and the price goes up depending on size, options, and if there is other work that needs to be done.  We though briefly about going with a larger one than we got but that would have meant getting a larger gas line run to the house at an additional cost of $3500.  It’s quite possible to do all the installation yourself if you’re part electrician, but for a natural gas or propane generator you’ll need to be part plumber as well.  It will all have to be inspected whether you or professionals do it.  Professional installations, getting the necessary permits and inspections can take a long time (months), so start early and think tranquil thoughts.

[7]In case you were wondering a 10kW natural gas generator produces a kilowatt-hour of electricity for about 55 cents (not including generator cost), the local power company (FirstEnergy) sells a kilowatt-hour to me for just over 12 cents.  Looks like I’m not going into the power business…

Prentiss Gray is a writer and stay at home Dad with 27 years in the information systems and technology business.  His favorite saying is “If you have to read the manual to use it, I don’t want one.”  He can be reached via his website www.prentissgray.com [8]. More of his work can be seen on Speak Without Interruption. [9]