How to compare power plans in NZ properly: usage, low user, discounts, tools

Most New Zealand households compare power plans the wrong way round. They look at an advertised rate or a joining credit, then try to work out whether it fits their house. It works better the other way: start with what your house actually uses, then let the plans compete for it. That takes about ten minutes once you have the right numbers.

What to have ready before you compare

Your ICP number. Every connection has a unique Installation Control Point number, a 15-character code printed on your bill. Comparison sites use it to work out which lines company you are on and which plans are actually available at your address. Powerswitch says it uses the ICP to find the plans for your home, and Billy tries to look it up from your address.

Your usage in kWh. A single bill tells you very little, because a July bill in Hamilton looks nothing like a January one. You want a full year. Many retailers show this in their app. If yours does not, ask: under the Electricity Industry Participation Code, a retailer that has supplied you in the past 24 months must give you your consumption information on request, by phone or email, within five business days, and it must not charge for a normal request. If you have a smart meter, ask for the half-hourly data. You need it to judge a time-of-use plan.

Your current plan details. Plan name, daily charge, unit rates, any discount, and whether you are on a fixed term with a break fee. Our bill guide shows where each of these sits on a typical bill.

Fixed term or open term?

An open-term plan lets you leave at any time, but the retailer can change prices with notice. A fixed-term plan locks you in for a set period, and the Electricity Authority warns there may be a break fee if you leave early.

Read what “fixed” actually fixes. Some offers with a one-year term still allow the retailer to change prices during it, and some fixed price plans leave GST and service fees outside the fixed part. A term is always a commitment from you; it is not always a price guarantee from them. If you want price certainty through 1 April 2027, check the wording, not the plan name. Our guide to joining credits and deals goes through real offer terms line by line.

Low user or standard user, and why April 2027 matters

Since 2004 retailers have had to offer a low fixed charge plan, originally capped at 30 cents a day plus GST. These plans have a small daily charge and a higher unit rate. Mercury, for example, says its low user plan works best for households using less than 8,000 to 9,000 kWh a year, depending on where you live.

The government started phasing the rules out in 2022, raising the maximum low user daily charge every year since, and on 1 April 2027 the regulations end altogether. The Electricity Authority wrote to lines companies on 22 September 2026 asking them to avoid sharp increases, but retailers will no longer have to offer a low user plan at all. Mercury has already told customers its low user plan will not be available from that date.

So compare both plan types on your real usage. Some small households will still come out ahead on a low daily charge plan where one is offered; others are already better off on standard. Our appliance calculator helps if you are unsure where your kWh go.

Prompt payment discounts

Some plans show a discounted price that only applies if you pay by the due date. That is fine if you pay by direct debit and never miss. It is expensive in the one month you do.

Check how the comparison treats the discount. Powerswitch includes ongoing prompt payment and dual-fuel discounts in its cost estimates, so its figure assumes you pay on time. If you have ever paid a power bill late, look up the undiscounted rates on the retailer’s price list and run the numbers again. A plan that wins only with the discount is a plan that punishes one forgotten payment.

Bundles with broadband or mobile

Power is often sold together with gas, broadband or mobile. A bundle can be good value, but it mixes several prices into one number. Consumer NZ warns that a cheap internet price can be offset by higher power and gas rates, and that bundles usually come with a fixed term of one to three years.

The fix is simple. Compare the power part on its own, then add what you would pay for broadband elsewhere, and see whether the bundle still wins.

Time-of-use plans

Since 1 July 2026, retailers with at least 5% of the market have had to offer a plan with cheaper off-peak power. Consumer NZ lists five that qualify: Mercury, Genesis, Contact, Meridian and Powershop. These plans need a smart meter that records half-hourly data.

They suit households that can move a lot of use to the night or the middle of the day, such as EV owners or homes with a hot water timer. They can cost more if your usage stays in the 7 to 9 pm rush. We explain how to test this on your own data in our guide to time-of-use plans.

Which comparison tool to use

All three tools below are free to use, and each is worth a look.

Billy (billy.govt.nz) was launched by the Electricity Authority on 26 March 2026. You upload a PDF of your bill or answer questions about your home, and it models your use on data from 27,000 New Zealand households. The Authority says it takes no commissions and does not promote any power company.

Powerswitch (powerswitch.org.nz) is run by Consumer NZ. It is funded mainly by a small fee retailers pay when someone switches through it, plus a little money from Consumer NZ and MBIE. Retailers listed on it cover about 97% of the residential market. Two details matter: it excludes one-off joining credits from its cost estimates, and some discounts and fixed-term prices that are not public do not appear.

Power Compare (powercompare.co.nz) is a commercial New Zealand comparison site run by Global Compare Group. It lists joining credits and bundle offers alongside plans, and says some plans are only available through it. It sends you to the retailer’s own site to sign up. Power Compare is a Switchly partner: if you switch through it from our compare page, we may be paid. That link is always labelled.

A sensible routine is to run your usage through Billy or Powerswitch for a clean price ranking, then check Power Compare for any joining offer that changes the picture. Our guide to joining credits shows how to weigh a credit against a lower rate. We do not name a “best” retailer, because the answer changes with your address, meter and usage.

A quick checklist

1. ICP number and 12 months of kWh, from your bill or your retailer.
2. Compare low user and standard plans until April 2027.
3. Note break fees and what a fixed term really fixes.
4. Count prompt payment discounts only if you always pay on time.
5. Price the power part of any bundle separately.
6. Consider time-of-use only with a smart meter and usage you can shift.
7. Run the comparison, then set a free contract alert for when your term ends.