Tariff D27d: when it pays off for EV charging

What it is

The distribution tariff sets what you pay for delivering electricity to your home. Households fall into category D, and tariff D27d is the one intended for electric vehicle owners. Businesses have an equivalent in category C as C 27d.

The principle is simple: part of the day is a low tariff, the rest is high. Charge during the cheap hours and you save. Charge whenever, and you save nothing — you may even end up worse off.

When it pays off

Assume it makes sense when all of these are true at once:

• you drive enough that charging is a substantial share of household consumption,
• the car sits at home overnight and can charge in the low tariff,
• you can also shift other large loads — water heater, washing machine, dishwasher.

If you drive a few kilometres a week, the saving will not cover the fact that the high tariff costs more than a standard one. This is the most common mistake.

What you have to prove

You cannot get the tariff just by asking. The operator wants evidence that you actually own an EV and charging equipment:

• vehicle documentation,
• documentation of the charging equipment and its installation,
• the commissioning inspection report — there is no way around it.

So it pays to sort the tariff after installation, when you hold the report. More on that in our article on the commissioning inspection.

Watch out for

The tariff is changed with your supplier, but the conditions are set by the distribution operator. You will not switch it by tapping a tariff in your supplier's app.

Low-tariff hours are not the same every day. Do not assume cheap always starts at ten in the evening. The wallbox or the car app should follow the actual signal, not a fixed hour you typed in.

Do the maths first. Compare the annual cost on your current tariff and on D27d using your real consumption. With low mileage the line between "worth it" and "losing money" is surprisingly thin.

What we do

At the site visit we tell you whether the tariff makes sense in your case, and set the charger to run in the cheap hours. You get the commissioning inspection report from us, so you have the evidence.

If the numbers say it is not worth switching, we will say so. There is nothing in it for us.