[callalex]

I’m going to push back on this with a simple example. Go to your local hardware store and check out the electric space heater section. There will be a wide variety of units rated for small rooms, medium rooms, and large rooms, based on square footage. The heaters will have a variety of form factors and physical dimensions. Many of them will have mentions of “eco” and “efficiency”. Every single one of them, and I mean literally, will be a 1500W heater (or whatever your region’s equivalent maximum load per plug is which may vary in 240v countries). Exact same wattage, all 100% efficient because their only job is to produce heat, with wildly different dimensions and text on the box. Customers will swear up and down about the difference between these units.

[withinboredom]

I had to do this after my gas costs went well above my electric costs. Maybe you are in a country/area where your hardware store doesn’t supply a variety of heaters, but at my local store, no two models were the same wattage.

[supertrope]

It grinds my gears that electric lawn mowers are marketed by voltage even though that has no relation to grass cut per time.