Cole7 min read

Ghosts of home energy past: the cost of light, the 1900 electric car and your 3 am power

An hour of light now costs about a third of a cent. In 1900, 38% of American cars were electric. And our New Zealand house never drops below about 225 W, even at 3 am. Three Halloween hauntings, with the working shown.

Happy Halloween. This is a ghost story about three things that haunt a home: the power your house uses when nobody's home, what light costs, and the electric car that nearly won in 1900. Every number comes with its working, so you can redo it with your own figures. Our house is in New Zealand (NZ$), with notes for other countries where they differ.

Ghosts of home energy past, a Halloween special from The Electric Shed on YouTube.

The short version

  • Our 3 am: between 1 and 5 am, with the car not charging, our house draws about 350 W on a typical night and never much below 225 W. That is about 2,000 kWh, a bit over NZ$430, a year at the 22c overnight rate. On most nights our battery covers it.
  • Light: one bright 8 W LED bulb gives about 1,000 lumen-hours in 1.25 hours. At our 36c/kWh, that costs about 0.36c. In 1800, economist William Nordhaus found, the same light took more than five hours of work (check the paper for the exact figure).
  • The 1900 electric car: of the 4,192 cars made in the U.S. in 1900, 1,575 (38%) were electric, 1,681 steam and 936 petrol. Petrol took the lead around 1903.
  • Typical standby is 5–10% of a home's electricity. Each watt left on all year is 8.76 kWh, about NZ$2–3.

Haunting one: the ghost in our house

Our house draws power all night. Between 1 and 5 am, over 31 nights from 22 September to 21 October, with the car not charging:

Average house load by hour, with the 225 W night floor marked.
Our house load by hour, 22 Sep to 21 Oct 2026. The blue bars are 1 to 5 am.
  • The middle night is about 350 W (nightly range 279–434 W).
  • The floor, the lowest tenth of readings, is about 225 W.
  • A year of it: 225 W × 8,760 h ÷ 1,000 = 1,971 kWh, or about 2,000 kWh, a bit over NZ$430 at the 22c overnight rate.
  • Who pays: on most nights (25 of 30) our battery covers it, running the fridge and router on solar stored during the day. We don't buy that power, but it's power we could have sold at 14c. Without a battery, you'd pay for all of it.

That is a floor, not a bill: it assumes the floor holds all day, and the house uses more in the daytime.

Is that scary? Not really. The usual estimate for standby power is 5–10% of a home's electricity. The average New Zealand home uses about 7,084 kWh a year (MBIE), so that is roughly 350–700 kWh. Studies elsewhere found whole-house standby of 47–81 W (UK, Energy Saving Trust, 2012). An American monitoring company, Sense, says its average home has about 250 W always on. Our floor is higher because it isn't only standby: it's the fridge, the router, the little red lights, and the inverter and battery too. So we're normal.

Our night floor and median compared with whole-house standby and an average always-on load.
Always on: how we compare.

The usual vampires

Most of them come down to one setting.

A table of common standby draws and their yearly cost at 36c a kWh, plus the old garage fridge.
Typical standby draw. Measurements vary with settings and age, so check yours with a plug-in meter.
  • Xbox Series X on instant-on: about 9–13 W all day, against under 1 W on the energy-saving setting (NRDC; The Verge; AnandTech). At 10 W, that is 88 kWh, about NZ$31 a year.
  • Smart TV on quick start: 5–20 W in NRDC's 2015 study (13 W on average, up to 37 W in some). New ENERGY STAR sets use under 1 W in standby.
  • Router and modem: commonly 5–20 W, and they should stay on.
  • The bathroom light left on overnight: it depends what's in the ceiling. Four old 50 W halogen downlights for 8 hours use 1.6 kWh, about 35c at our 22c overnight rate. Four LED downlights of about 7 W use 0.22 kWh, about 5c. (Typical figures from retailers; check your own fittings.)
  • The old second fridge in the garage: not a standby load at all. Consumer NZ put a meter on one and found it cost over NZ$200 a year. If it only keeps a few drinks cold, it is an expensive drink.

The rule of thumb: one watt left on all year is 8.76 kWh, about NZ$1.90 at 22c or NZ$3.15 at 36c. A 10 W Xbox is about NZ$31 a year to do nothing. Switch off what you can, and don't lose sleep over the rest.

Other countries: the sum is the same, only the price changes. At roughly A$0.30, £0.25 or US$0.17 a kWh, one watt all year costs about A$2.60, £2.20 or US$1.50 (check your own rate).

Haunting two: an hour of light

When light meant candles, buying it took real work. William Nordhaus, in a 1994 Cowles Foundation paper, built a "true price" of light back through candles, whale oil, gas and electric bulbs. His headline is that official price indexes miss the fall in the cost of light by a factor of between 900 and 1,600 since 1800.

Here is the modern end of the sum:

The sum: an 8 W LED for 1.25 hours is 10 Wh, or 0.01 kWh, which at 36c is 0.36c.
One bright LED bulb for 1.25 hours, the same 1,000 lumen-hours.
  • Bulb: about 8 W and 800 lumens (typical).
  • Time: 1,000 lumen-hours ÷ 800 lumens = 1.25 hours.
  • Energy: 8 W × 1.25 h = 10 Wh = 0.01 kWh.
  • Cost: 0.01 kWh × 36c = 0.36c.
Candle, gas and LED compared: five-plus hours of work in 1800, cheaper and brighter gas, and 0.36c for the same light today.
Candle, gas and LED, side by side.

Gas was cheaper and brighter than candles, but it was still an open flame in a house full of curtains. The Victorians were also wary of the new electric light. Early wiring could shock or start fires, from poor contacts and hot lamps, and there were no rules yet. Yet candles caused most house fires, and when London's Savoy Theatre went electric, an 1882 inspection judged it absolutely safe because the light didn't heat the air the way gas did.

What the Victorians feared about electric light, and what was true.
They were worried about the wrong flame.

A New Zealand footnote: in August 1888, the West Coast town of Reefton switched on the first public electricity supply in the southern hemisphere. Heritage New Zealand ranks it among the earliest public supplies in the world, alongside London, New York and Vienna.

Reefton in 1904, a mining town on the West Coast.
Reefton, 1904. Photo: Muir & Moodie studio, public domain, Wikimedia Commons.

Haunting three: the electric car that died in 1912

In 1900, 38% of the cars made in America were electric, not 38% of the cars on the road. They were quiet, clean, and nobody had to crank them by hand.

A bar chart of 1900 U.S. cars: steam 1,681, electric 1,575, petrol 936.
U.S. cars made in 1900 by power source.

What killed them was not one thing. Petrol took the lead around 1903. In 1912, Cadillac added an electric starter to a petrol car, and the hand crank went. Roads got longer and petrol got cheap. GM leased the EV1 in the 1990s, then recalled it, and most were crushed. Today's electric cars are the sequel.

A timeline from 1900 to today: 38% electric, petrol takes the lead, the electric starter, the EV1, and electric cars again.
The car that wouldn't stay buried.
A Detroit Electric car being charged from a shed in the early 1900s.
A Detroit Electric car charging, early 1900s. Photo: Cress-Dale Photo Co., public domain, Wikimedia Commons.

Ours is a GWM Ora 5, charged from a socket at home, much as that Detroit Electric was. For what that costs today, see what did that EV charge cost on Sweet Commute.

What to do with this

  1. Find your own floor: look at your smart meter or battery app between 1 and 5 am.
  2. Do the sum: watts × 8,760 ÷ 1,000 × your price.
  3. Switch off or unplug the old boxes you never use, and leave the fridge and router alone.

For more on where a home's power goes, see our home battery after nine months and a solar day with and without an EV.

Sources

Photos: Reefton, Muir & Moodie studio (public domain); Detroit Electric car, Cress-Dale Photo Co. (public domain); both Wikimedia Commons. Diagrams: The Electric Shed.

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