The short answer: allow 2–4 weeks end to end. Most switches complete in about 14 days, roughly as the cooling-off window closes; the slow ones run to about 28 days, almost always because a detail in the registration didn’t match. Your supply is never touched at any point, however long it takes.
This is the timeline page. The step-by-step instructions live at how to switch energy supplier, and the reassurance tour of what changes (and what doesn’t) is at what happens when you switch.
How long does switching energy supplier really take?
The range every Irish supplier quotes is two to four weeks, and it is honest — but it hides a shape. Switches don’t spread evenly across that range. They cluster hard at the two-week mark, because the change-of-supplier registration that the new supplier lodges — with MRSO (inside ESB Networks) for electricity, with Gas Networks Ireland for gas — processes on a fairly fixed cadence when nothing goes wrong. The four-week tail belongs almost entirely to switches where something in the data didn’t line up and a human had to reconcile it.
So the useful way to think about the question is not “how long?” but “which lane am I in?” The fast lane is about 14 days and requires nothing from you after day 0. The slow lane runs up to about 28 and is nearly always self-inflicted at order time — a mistyped number, a mismatched name, a plan your meter can’t support. The whole second half of this page is about staying out of it.
One caveat on what this page is not: it can’t tell you who to switch to. matched.ie is not a CRU-accredited price-comparison site — the accredited comparators are listed on cru.ie. What we have is our own ranking of the nine suppliers we verify, at best energy in Ireland, with year-1 and year-2 costs side by side.
What happens on each day of an energy switch?
Here is the master timeline, from the moment you click “order” to the first bill at the new rates. Notice two things as you read it: everything you personally do sits inside day 0, and the long quiet stretch in the middle is normal — silence is the system working, not the system stuck.
| When | Stage | What is happening | What you’ll see |
|---|---|---|---|
| Day 0 | You place the order | You sign up with the new supplier — MPRN and/or GPRN, a meter reading, your details. This is the only day with homework on it. The cooling-off clock starts now: 14 days, or 30 on some doorstep and other off-premises contracts. | A confirmation email, usually within minutes. |
| Days 0–3 | Registration lodged · welcome letter | The new supplier lodges the change-of-supplier registration against your MPRN (with MRSO, inside ESB Networks) and your GPRN (with Gas Networks Ireland). The welcome letter or pack goes out with your exact rates, contract dates and cooling-off terms. | The welcome letter — read it, keep it. |
| Days 1–14 | Cooling-off runs · registration processes | The two clocks run side by side. The registration is validated — numbers, name, address, meter type — and your old supplier is notified through the system. This is where a debt flag (arrears of €225+, more than 60 days overdue) can pause everything, and where a data mismatch diverts you into the slow lane. | Usually nothing. Silence here is normal. |
| ~Day 14 | Completion — supply transfers | The switch completes. Your closing meter read (the one you submitted, or a remote smart read) ends the old account and opens the new one on the same number. The new unit rates start from this date — not from day 0. | Often a “your switch is complete” email or app note. |
| Days 14–28 | Final bill from the old supplier | The old supplier issues a final bill: units up to the completion date at the old rates, any exit fee, any credit refunded. Check its closing read matches the new supplier’s opening read — and pay it, because an unpaid final bill can age into a debt flag against your next switch. | The final bill, marked as such. |
| Up to ~Day 28 | The slow lane completes | Switches where something didn’t match — a mistyped MPRN, a name mismatch, a queried read, a flag being resolved — complete here instead. Supply is untouched throughout; only the paperwork is late. | Possibly a call or email asking you to confirm a detail. |
| Weeks 4–8 | First bill from the new supplier | Your first bill on the new rates arrives at the end of the new supplier’s first billing cycle — most bill monthly or every two months. Check the opening read and the unit rates against the welcome letter. | The first new bill. |
The dates flex a little by supplier and by fuel — a dual-fuel switch is two registrations running in parallel, and they don’t always complete on the same day, which is why a gas welcome note can land a few days after the electricity one. But the shape holds: order, welcome letter, quiet fortnight, completion, final bill, first new bill.
Why does the cooling-off period sit at the start?
A detail that surprises people: the cooling-off window is not tacked on at the end once the switch completes. It starts the moment you conclude the contract — in practice, the day you place the order — and runs during the same fortnight the registration is processing. On a typical ~14-day switch, the window and the transfer close at almost the same time.
That design is quietly in your favour. It means you can lock in a deal the day you see it and keep comparing at zero risk while the paperwork grinds: cancel inside the window and there is no exit fee and no penalty, even if the supply has already transferred — you just pay the new rates for the days you used. The window is 14 days on a normal online or phone switch, and the Consumer Rights Act 2022 stretches it to 30 days on certain doorstep and other off-premises contracts; the figure that applies to you is printed in your welcome pack, so use that one. The full mechanics — how to cancel, what reverts, what it can’t undo — are on the cooling-off page.
When do the new rates actually start?
The trap on this page: signing up tonight does not put tomorrow’s immersion on the new unit rate. The new rates start on the completion date — the day the registration finishes and your closing meter read splits the two accounts, typically about two weeks after you order. Every unit you burn before that date is billed by your old supplier at your old rates.
The completion date is in the switch-complete confirmation, and the closing read is the boundary line: old rates up to it, new rates after it. There is no backdating in either direction.
This matters for more than pedantry. If you switched to escape a steep standard rate, you have roughly a fortnight of it left to run — worth knowing before you judge the first bill. If you timed a switch around a price rise at your old supplier, the completion date, not the order date, decides which side of the rise your final units fall on. And if you are moving to a time-of-use plan, the cheap night window only means anything once the new plan is live; running the dryer at 2am on day 3 of the switch saves you nothing that your current tariff wasn’t already offering.
The flip side is worth a sentence too: because the old rates run to completion, there is no gap where you are unbilled or double-billed. One meter read closes one account and opens the other on the same number. If the final bill and the first new bill don’t meet cleanly at that read, that — not the switch itself — is the thing to query.
What paperwork arrives during the switch?
Three documents, in a fixed order, and each has one job worth doing when it lands.
- The welcome letter (days 0–3, from the new supplier). Your plan name, unit rates, standing charge, discount and contract end dates, exit fee, cooling-off terms. Read it against what you thought you bought — this is the cheapest possible moment to catch a wrong plan, because cancelling is still free.
- The final bill (days 14–28, from the old supplier). Units to the completion date at the old rates, any exit fee, any credit refunded. Check the closing read, then pay it — an unpaid final bill quietly ages into exactly the kind of arrears that can flag your next switch.
- The first new bill (weeks 4–8, from the new supplier). Check the opening read matches the final bill’s closing read, and the rates match the welcome letter. If your first bill looks estimated rather than read, the page on estimated readings covers what an E on the bill means and how to correct it.
If a document is late, chase in this order: welcome letter late → the new supplier (your order may not have gone through); final bill very late → the old supplier (a missing closing read is the usual cause); first new bill odd → the new supplier, welcome letter in hand.
What can delay an energy switch — and what fixes each one?
Five causes account for nearly every switch that runs past a fortnight. None of them cuts your supply, and all five are either preventable at order time or fixable with one phone call to the new supplier — they lodged the registration, so they can see which check it is stuck on.
| Delay cause | What it does to the clock | The fix |
|---|---|---|
| Wrong or mistyped MPRN / GPRN | The registration bounces, or attaches to the wrong address entirely, and has to be cancelled and re-lodged. | Copy the numbers from a bill, never from memory: the MPRN is 11 digits starting with 10, the GPRN is 7 digits. |
| Name or address mismatch | The details on your order don’t match the account or the network record, so the registration sits in a validation queue until someone reconciles them. | Sign up in the exact name on the existing account, with the address written as it appears on the bill. |
| Debt flag from the old supplier | Arrears of €225 or more, over 60 days overdue, let the old supplier object to the registration — the switch is blocked or delayed until the balance is dealt with. | Clear the arrears or agree a payment plan before you order. A previous tenant’s debt cannot flag you. |
| Meter-type mismatch | The plan you chose needs a meter you don’t have — smart time-of-use or dynamic plans need a smart meter, NightSaver plans need a NightSaver (MCC02) meter — so the order stalls or is re-quoted. | Match the plan to the meter you have today, or get the meter changed first and switch after. |
| A queried or missing meter read | No read, or a read that looks implausible against your history, triggers a validation query — the most common reason a 14-day switch becomes a 28-day one. | Submit a read the day you order and photograph the meter. Smart meters dodge this: the read is collected remotely. |
Two of these deserve a pointer each. The meter-point numbers are the commonest stumble simply because people type them from memory: if you can’t find yours, finding your MPRN and finding your GPRN walk through every place they’re printed. And the debt flag has an entire page of its own — switching with arrears — including the crucial carve-out that a previous tenant’s debt belongs to their account, not to your address, and cannot delay you.
What is not on the list: your old supplier dragging their feet to keep you. They have no lever to slow a clean registration — the process runs through MRSO and Gas Networks Ireland, not through their goodwill. The only legitimate objection they hold is the debt flag, and it has hard thresholds: €225 or more, more than 60 days overdue. Anything less lands on the final bill and the switch rolls on.
How do I keep my switch on the 14-day track?
Everything above collapses into five habits at order time. This is the whole checklist — there is genuinely nothing to do after day 0 except read the post.
- Copy the MPRN / GPRN from a bill, never from memory — 11 digits starting with 10 for electricity, 7 digits for gas.
- Order in the exact name and address on the existing account, spelled as the bill spells them.
- Submit a meter reading on day 0 and photograph the meter. On a smart meter the read is collected remotely — the photo is still your evidence.
- Match the plan to the meter you have today. Smart time-of-use and dynamic plans need a smart meter; NightSaver rates need a NightSaver meter. The smart meter guide covers what your meter can and can’t support.
- Deal with arrears before you order — cleared, or on an agreed payment plan — so there is nothing to flag.
Do those five and the realistic expectation is: welcome letter this week, a quiet fortnight, completion around day 14, final bill inside the month, and the new rates on every unit from completion day forward. If you are still deciding whether to switch at all, year 1 vs year 2 pricing is the argument, and how to switch is the doing. If you are mid-contract and wondering whether the wait is worth it, switching mid-contract runs the exit-fee maths.
