Overnight base load check

Two meter readings tell you what your home draws continuously, what it costs a year, and how to find what is responsible without touching anything unsafe.

Servers, network equipment, a second freezer, medical equipment — if you know roughly what they draw, put the total in. It is subtracted before the result is judged, because a high floor you have chosen is not the same as one you have not.

  • Enter both meter readings.

Why this is the measurement worth taking

Every list of what appliances cost is a national average applied to your house. This is a measurement of your house, and it costs two trips to the meter.

It catches the things nobody thinks to list — an immersion heater on a forgotten timer, a freezer in a garage with failing seals, a towel rail that has been on since March. Those are the expensive ones, and they are invisible to any calculator that works from typical appliances.

How to take the readings

Last thing at night, with everything off that you would expect to be off, read the meter and note the time. First thing in the morning, before anything is switched on, read it again. Leave fridges and freezers running — they are part of the answer.

Aim for at least four hours between readings, ideally a full night. A shorter window can land entirely inside or outside a fridge compressor cycle and be out by a factor of three.

A high base load is not automatically waste

If you run a home server, network equipment, a second freezer, an aquarium or anything medical, your floor is high for reasons you have chosen. Put roughly what those draw into the optional field and they are subtracted before the result is judged.

The number that matters is what is left over — the part you have not accounted for. That is the part worth chasing.

Turning watts into money

Multiply kilowatts by 8,766 for the annual kilowatt hours. A base load of 0.25 kW is about 2,190 kWh a year, which for many households is most of their electricity, used while everyone is asleep.

Safety

The method below is switching things off at their own switch and reading a meter. Nothing more. Do not open equipment, remove covers, or touch the consumer unit — if something needs more than its own switch to isolate, that is an electrician’s job.

And decide what has to stay on before you start: fridges and freezers, anything medical, heating and frost protection in cold weather, alarms. Nothing on this page is worth spoiled food, a frozen pipe or a device somebody relies on.

Once you have a suspect, the appliance running cost calculatorputs a year’s figure on it. If you came here from a bill that looked wrong, the bill check covers the other half of the question.