The $538 we found hiding in one HDB flat
We built Ecovolt for buildings. Schools, offices, campuses, sites where energy waste hides in plain sight. But the more sites we deployed across, the more we kept hearing the same question from the people running them: can I put this in my own home?
13 May 2026
We built Ecovolt for buildings. Schools, offices, campuses, sites where energy waste hides in plain sight. But the more sites we deployed across, the more we kept hearing the same question from the people running them: can I put this in my own home?
So we did. Here is what happened when we installed Volta smart plugs in a regular HDB 4-room flat in Singapore, ran it for 30 days, and let the numbers speak.
The Challenge
Most Singaporean households have no idea where their electricity goes. SP Group sends one lump-sum bill at the end of every month, with no breakdown of which appliance drew what. According to NEA figures, aircon alone accounts for roughly 30% of household electricity. The rest, the TV that sits on standby, the water dispenser that reheats every hour, the printer that idles for weeks between jobs, the air purifier that never sleeps, sits invisible to the homeowner.
This invisible draw is what we call phantom energy. Our earlier research across commercial sites showed it can account for up to 16% of total consumption. We wanted to find out: does the same problem exist in homes? And if it does, is it worth solving for the average family?
The Test
One HDB 4-room flat. Four occupants. Standard appliance mix you would find in any Singaporean household.
We ran two consecutive 30-day windows back-to-back:
Month 1 (baseline): Volta smart plugs installed but only monitoring, not controlling. We just watched.
Month 2 (active): Same plugs, now running AI-generated schedules and idle cut-off. Daily routines unchanged, the family lived exactly the same way.
No behavioural changes. No “switch off your aircon” reminders. The system did the work.
The Results
After 30 days of active control, the household consumed 21% less electricity than the baseline month.
Extrapolated over a year, that is $538.08 straight back into the household, without anyone lifting a finger. The pattern is what we expected: bigger weekday savings (when the family is out and devices are idle) and smaller weekend savings (when devices are actively being used). You can see the learning curve too, the system takes about two days to figure out the household’s routine, then the savings settle in.
The green band is the energy the household no longer paid for. Same routines, same comfort, lower bill. Notice the weekday-weekend rhythm, this is where Ecovolt does its best work: catching idle draw during the hours nobody is home to notice it.
Where the savings came from
To understand the saving, we tracked which devices were drawing power when they should not have been. Six devices in the home accounted for $284.77 of wasted energy every year on their own, idle draw, standby loads, and “always-on” readiness that the household never benefited from.
Worth noting: the 6 devices above account for $284.77/year of the total $538.08/year saved. The rest comes from smaller phantom loads scattered across the home, chargers, set-top boxes, fans, and devices that draw small amounts continuously. Phantom energy is rarely one big culprit. It is many small ones adding up.
Why this matters
Here is the part that surprised us. A single 4-room flat saving $538 a year sounds modest. Now multiply.
Singapore has roughly 1.1 million HDB flats. If even a fraction of them ran on Ecovolt at the same 21% reduction, the cumulative impact on the national grid would be measured in gigawatt-hours, not kilowatt-hours. The carbon offset, given Singapore’s grid emission factor of around 0.4 kg CO₂ per kWh, runs into hundreds of tonnes per thousand homes.
We always knew commercial buildings were a high-leverage place to start. But this case study made one thing clear: the same problem exists in every home, and the savings scale with the country, not just the customer.
What comes next
This is why we are launching Ecovolt for consumers. Volta is now available for any household in Singapore that wants to stop paying for electricity they are not using. Plug it in, connect it to the Everest app, and let the system learn your home over 14 days. Savings start in the second half of the month.
We built this for buildings. It turns out homes need it just as much.
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