Why Elaborate Christmas Light Shows Won’t Blow out Your Power Bill

Michael St Clair is putting the finishing touches on one of Darwin’s most elaborate Christmas light displays, and, believe it or not, it will cost him less than a carton of beer to run.

The display has about 25,000 lights and takes more than 40 hours to set up.

Mr St Clair’s family, who describe themselves as Christmas light fanatics, recently added a piece of computer-controlled software that makes the lights flash in sync with music.

But this year’s grand new addition will be a light-adorned Ferris wheel with 3D-printed parts.

“We generally start in September putting some stuff up for our Halloween display, and then I continue with small pieces over October and November putting it all up,” Mr St Clair said.

Despite this extravagance, he expects the display will add just $30 to $40 to his electricity bill for the entire month of December.

“It costs about $1 to $1.20 a day to run the show, so about a carton of beer for the month of December.”

“Our power bill doesn’t actually change very much. It’s very minimal. It’s actually the air conditioners that change our bill,” his partner Sally St Clair added.

But it wasn’t always this way.

Over the six years they’ve been running these blinding displays, the family were initially paying up to 10 times that amount.

An electrical engineer, Mr St Clair has gradually whittled down the amount of energy the display consumes.

The extravagant tangles of ornamental lights might be a headache for people worried about their power bills, but it doesn’t take an engineer to keep the Christmas power bill low.

Bill breakdown

Mr St Clair’s first tip for cutting electricity use is something many people already do — use LEDs, which consume about 90 per cent less energy than incandescent globes.

“When we first started setting up, we had a lot more incandescent and I guess older styles of globes,” he said.

As the more costly globes were increasingly phased out of the Christmas light market, the family transitioned to the much cheaper LED bulbs.

Northern Territory energy retailer Jacana Energy estimates an elaborate display could run for all of December for less than $10 if LEDs are deployed.

“The average Christmas lights will only use 1.2W to 2W per 100 light bulbs, which is very minimal,” a Jacana spokesperson said.

Taking into account the current electricity tariff of 25.67 cents per kilowatt hour, a single rope of lights could be run for the 31 days of December for between 10 and 30 cents.

This means a display with the following combinations of lights would come in at under $10 for the month.

Lights Wattage Quantity Cost (31 days)
30m LED rope (720 bulbs) 7.2W 15 ropes $4.29
LED fairy lights string (200 bulbs) 3.6W 10 strings $1.43
LED reindeer (150 bulbs) 3.6W 10 deer $1.43
LED star (72 bulbs) 6W 5 stars $1.19
LED waterfall icicles (600 bulbs) 9W 2 sets $0.72
Total cost of the installation for the festive season $9.06

(Energy usage and costs are indicative only and taken from various sources for comparable LED products)

How else can I save?

The most cost-effective lights are solar powered, though these aren’t always viable when clouds begin to move over Darwin this time of year.

Mr St Clair also attributed his slim electricity bill to the movement of the lights, which flash on and off throughout the night.

“So probably about 40 per cent of the lights run at any one time and they’re dimmed down to a level which makes it more efficient as well,” he said.

“To dim them down, what they do is switch them on and off very, very rapidly, multiple times per second.”

But Jacana Energy says even the most energy-efficient LEDs use twice as much energy if they’re displayed on a flash setting.

But at the end of the day, this would only add at most a few dollars to the bill.

Based on the retailer’s information, it’s reasonable to claim that the most energy-efficient displays might use multiple low-consumption light ropes and just a few high-consumption centrepiece displays.

While the St Clairs have also made savings by repurposing home materials and 3D printing their own parts, they say the large sums of money they spend importing custom lights from overseas is what really sets them back.

But all their efforts can’t stop the effect air conditioning has on their power bill as it combats end-of-year weather — a curse borne by most Darwinites this time of year.