How to read and compare EV charger installation quotes

Three quotes arrive. One says $1,380, one says $2,400, one says $3,900. They are supposedly for the same job. Here is how to work out which of them is actually comparable, and which is cheap because it has left something out.

First: is it a quote, or an estimate?

In New Zealand these are two different things, and the difference is a consumer protection, not a formality.

A quote is a fixed price. Consumer Protection NZ puts it plainly: “If you have been given a fixed quote, the service provider must complete the work within the quoted cost, unless you agree to a variation.” Once you accept a quote, the provider cannot charge you more unless you agree to extra work or the scope of the job changes (Consumer Protection, quotes and estimates, verified September 2026).

An estimate is a best guess. It is the provider’s view of the likely cost based on experience. There is no legal difference between a verbal and a written estimate, and the final total “should generally be within 10 to 15 percent” of it (same source).

So the first question to ask about any document you receive is which one it is. If it does not say, ask. For a job of this size, get it in writing as a quote.

Consumer Protection also sets out what a quote or estimate should show: what work will be done, any other costs such as materials, the hourly rate for the people doing the work, and how long the work will take. If a document you have been sent is just a figure and a business name, it is not enough to compare against anything.

What a complete EV charger quote should itemise

Use this as your checklist. A quote that covers all of it can be compared with another that covers all of it. Anything missing is not necessarily dishonest, but it is a question to ask.

• The charger. Make, model, power rating, and tethered or untethered. “7kW smart charger” is not a model. And confirm whether the charger is even in the price, or whether you are buying it separately.
• The cable run. The assumed distance from switchboard to charger, and how it is routed: surface conduit, in a wall cavity, through the ceiling, or buried. This is the biggest variable in the whole job and the most common reason two quotes diverge.
• The dedicated circuit and its protection. WorkSafe’s guidelines say a home charging station should run on its own dedicated final sub-circuit, with RCD protection suitable for EV charging, rather than sharing your existing power circuits.
• The switchboard. Either an upgrade is included and priced, or the quote states it is excluded and says what happens if one turns out to be needed.
• Mounting and making good. Bracket, fixings, weatherproofing for an outdoor install, and any patching or sealing.
• Commissioning. Powering up, testing, connecting a smart charger to your Wi-Fi, pairing the app, and setting current limits or load management.
• The Certificate of Compliance. It is legally required, so it should never be an optional extra, but it should be named.
• GST. Check every quote is on the same side of it. A GST-exclusive quote against a GST-inclusive one is a 15 percent phantom difference.
• Travel or call-out, if it is charged separately.
• How long the quote is valid, and the payment terms.

Why two honest quotes still differ by $1,000

Most of the gap between two legitimate quotes comes from four places.

Different charger. Home wallboxes range widely on price. A basic unit and a premium solar-diverting one are different products, and a quote built on each will never match. Compare the install labour separately from the hardware if you can.

Different cable assumption. One electrician has assumed a 5 metre run along an internal garage wall. The other has walked the site and priced 18 metres with a section in conduit outside. The second is more expensive and more likely to be right.

Switchboard in or out. This is the big one. A switchboard upgrade commonly adds $1,500–$3,000 on top of the install, so a quote that includes one and a quote that excludes one are not remotely comparable. If your board is older or full, treat any quote that does not mention it as incomplete. See do I need a switchboard upgrade?.

Single-phase versus three-phase. An 11kW or 22kW charger needs three-phase supply. If one quote is for a 7kW single-phase unit and another for a 22kW three-phase one, you are comparing two different projects.

For context, a typical 7kW wall-mounted install in New Zealand lands around $1,500–$2,500 all in. That is a range, not a promise, and your switchboard and cable run move it. A quote well below that range is not automatically wrong, but it is worth asking exactly what it covers.

What a suspiciously cheap quote is usually missing

Work through these before you accept the lowest number:

• The charger is not in it. Supply-and-install versus install-only is the single most common reason a quote looks dramatically cheaper.
• GST is not in it.
• Commissioning is not in it, so the charger gets mounted and energised but you are on your own for the app, the schedule and the current limit.
• A short cable run has been assumed without anyone looking at your property.
• No switchboard assessment has happened. If nobody asked for a photo of your board or looked at it, the quote is built on a guess.
• No Certificate of Compliance is mentioned. This one is not a pricing question, it is a walk-away question. See can any electrician install an EV charger?

Provisional sums and the switchboard unknown

Sometimes an electrician genuinely cannot price part of the job until they open something up. A provisional sum is a labelled placeholder for that work, and seeing one is a sign of care rather than evasion.

What makes a provisional sum acceptable:

• It is clearly labelled as provisional, not buried in the total.
• The quote says what would trigger it, for example “if the existing board has no spare ways”.
• The final figure is agreed with you before the work is done.

What makes one a problem: a vague “extra work charged at cost” line with no cap, no trigger, and no agreement step. That is not a fixed quote, whatever the heading says.

Comparing like for like

A practical way to do it. Put the three quotes side by side and answer these for each:

1. Is this a quote or an estimate?
2. Same charger make, model and power rating?
3. Same assumed cable run length and routing method?
4. Is a switchboard upgrade included, excluded, or provisional?
5. Is commissioning and app setup included?
6. Is the Certificate of Compliance named?
7. All GST-inclusive, or all GST-exclusive?
8. Same warranty on workmanship, and same charger warranty?

If two quotes answer those eight identically, the cheaper one is genuinely cheaper. If they do not, go back to each installer and ask them to re-quote on the same scope. A good electrician will not mind. It is a normal request, and it is far cheaper than discovering the gap on install day.

If the final bill is higher than the quote

For a fixed quote, the work has to be completed within the quoted cost unless you agreed to a variation. If a bill arrives higher than the quote and you did not agree to extra work in advance, raise it in writing with the installer first and refer to the quote you accepted. Consumer Protection NZ’s guidance on quotes and estimates, and on overcharging, sets out where you stand.

The practical defence is earlier than that, though: agree variations before the work happens, in writing, even if it is only a text message confirming the extra amount. Install day is not the moment to be negotiating price with a wall already drilled. What happens on the day is covered in what to expect on install day.

Getting quotes that are comparable in the first place

The reason quotes vary so much is that installers are often working from different information. Give all of them the same brief and the spread narrows dramatically:

• A clear photo of your switchboard, door open if it is safe to do so.
• A photo of the parking area with roughly where you want the charger.
• Your best estimate of the distance from switchboard to that spot.
• Your EV model, and whether you have single-phase or three-phase supply if you know.
• Any charger preference, or “no preference” if you want them to recommend.

Send that same package to everyone you ask, and you will get quotes you can actually put next to each other.