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Pure sine vs modified sine inverter

Updated: October 2026

You are looking at a cheaper inverter on amazon.co.uk because the title still says 1000 W. A pure sine vs modified sine inverter choice is a real difference in the shape of the 230 V wave. Pure sine is the default unless every load is a simple resistive heater you already understand, and even then a pure-sine unit still runs that heater. Modified sine is the saving only when you will not add a charger, a television or a motor later. Prices are amazon.co.uk figures from 19 October 2026. The Products Compared editorial team did not measure waveforms in a lab. A qualifying purchase can earn a commission at no extra cost to you. The stored rows sit on the [1000W power inverter comparison](/hub/electrical-equipment/1000w-power-inverter).

You are looking at a cheaper inverter on amazon.co.uk because the title still says 1000 W. A pure sine vs modified sine inverter choice is a real difference in the shape of the 230 V wave.

Our top picks

Novopal Novopal DLCD1000PUK12 1000W

Best overall

Novopal Novopal DLCD1000PUK12 1000W
9.2/10about £159.99
View offer
Renogy Renogy 1000W pure sine inverter

Best value

Renogy Renogy 1000W pure sine inverter
9.0/10about £113.99
View offer
Cantonape Cantonape 1000W modified inverter

Rank 3

Cantonape Cantonape 1000W modified inverter
8.2/10about £64.99
View offer
On this page
  1. 1.What the two waves are
  2. 2.Loads that object
  3. 3.Loads that usually cope
  4. 4.How that split lands on these listings

What the two waves are

Mains electricity from a UK socket is a smooth sine wave at about 230 V and 50 Hz. A pure-sine inverter tries to reproduce that shape. A modified-sine inverter builds a stepped approximation. The Camping and Caravanning Club describes pure sine as the waveform that matches mains and the one they point at any load type. A modified wave can still light a simple heater. If the listing says pure sine, you still have the rest of the title to check, because the wrong battery voltage or the wrong mains voltage is a separate failure.

Loads that object

Camperlands, writing about the Streetwize 1000 W modified-sine unit they sell, says modified sine is not recommended for CPAP machines with humidifiers, some AC-motor tools, some televisions, timers, fluorescent lights and audio gear. Resistive loads are the list they call suitable. That is a modified-sine retailer’s own exclusion list. A motor can run hot or buzz. A timer can mis-count. Audio can hum. A television can refuse to start. None of those outcomes is guaranteed on every modified unit, and none of them is a reason to try the load on a machine you cannot replace. One Cantonape review says a television and a Chromecast would not run together.
Novopal Novopal DLCD1000PUK12 1000W

Testsieger

Novopal Novopal DLCD1000PUK12 1000W
9.2/10about £159.99
View offer

Loads that usually cope

A simple resistive heater is the load a modified wave usually copes with. If the plate is above 1000 W continuous, the waveform is beside the point because this inverter class is already too small. The moment the socket might grow a second job, the saving collapses. The van version of this limit is the 1000W inverter for a campervan page.

How that split lands on these listings

Two listings in this set are modified sine. Cantonape B07WRQX9RS is £64.99, 12 V to 230 V, and the wattage field says 2000 W against a 1000 W title. Jectse B0B137KTP2 is £37.37, 24 V in and 220 V out. On a 12 V leisure battery the input voltage rules it out before the wave does. The pure-sine claims sit on Renogy, both Novopal listings, Giandel, MINGHAOXIN and SUDOKEJI. SUDOKEJI’s title still conflicts between 120 V and 240 V. Buy modified only for a resistive load you will not expand.

Common questions

Will a laptop charger survive on modified sine?
Sometimes it will, and that is not a rule you can buy on. Switch-mode chargers differ. Some run, some buzz or shut down, and a successful afternoon does not mean the supply is happy for a year. This set has no test of laptop chargers on Cantonape or Jectse. If the laptop matters, use a pure-sine listing and check that the charger’s plate fits under 1000 W.
What about a CPAP machine?
Ask the machine maker. Prepared Britain reports ResMed guidance that prefers a DC converter for several current machines, and pure sine where an older model’s instructions allow an inverter. Camperlands, on the Streetwize modified unit, says modified sine is not recommended for CPAP with a humidifier. A pure-sine title in this set is still a consumer inverter. Skip Cantonape and Jectse for this job.
Will a kettle work on modified sine?
A simple element often will, if the kettle’s plate is under 1000 W continuous. Many kettles are not. The element is a resistive load, which is the case modified sine is least likely to object to. A 2000 W peak printed on the inverter does not raise the kettle’s plate. If you might later plug a charger into the same socket, buy pure sine now. Pure sine also runs the element.
Why do modified units still show 230 V?
Many meters measure a voltage and ignore the shape of the wave. Cantonape is specified as 12 V to 230 V and modified sine, so a reading near 230 V would agree with the title and still say nothing about the shape. Jectse is printed as 220 V out, on a 24 V input. The waveform line on the listing is the fact you use.
Which inverters in this set are modified sine?
Cantonape B07WRQX9RS at £64.99 and Jectse B0B137KTP2 at £37.37. Jectse is also 24 V to 220 V, so the wave is not the only mismatch for a 12 V UK leisure battery. Renogy, both Novopal listings, Giandel and MINGHAOXIN claim pure sine on 12 V units. SUDOKEJI claims pure sine at £55.99 and still conflicts on 120 V versus 240 V.
If I might add a microwave later, which way do I buy?
Buy pure sine, and still check the microwave’s input watts against 1000 W continuous. An 800 W cooking rating can hide a higher plug load. Modified sine is the wrong bet if the socket is allowed to gain a microwave, a television or a charger later. The condition for modified sine is a resistive load you will not expand.

Related pages

Best 1000W pure sine inverter

1000W inverter buying guide

1000W power inverter

1000W inverter for a campervan: battery and hook-up

How to wire a 1000W inverter from a leisure battery

Sources

Public UK sources from the research digest, last checked on 19 October 2026. Shelf prices and star lines are the amazon.co.uk figures in the display file.

  1. Camping and Caravanning Club, inverter guide (retrieved 19 October 2026)
  2. Camping and Caravanning Club, campsite electricity (retrieved 19 October 2026)
  3. IET Wiring Matters, BS 7671 section 721 (retrieved 19 October 2026)
  4. IET, electrical installations in caravan camping parks, caravans and motor caravans (retrieved 19 October 2026)
  5. Plugs and Sockets etc. (Safety) Regulations 1994 (retrieved 19 October 2026)
  6. 12 Volt Planet FAQs (retrieved 19 October 2026)
  7. REUK, fuses for power inverters (retrieved 19 October 2026)
  8. GOV.UK plug-in solar interim product specification (retrieved 19 October 2026)
  9. Renogy 1000W inverter, amazon.co.uk B08Z34PK5Y (retrieved 19 October 2026)