American electrics

[Andrew Gabriel]

Probably faster heatup and more steam production.

Electric heaters here (and I think all 230V countries) are either 2kW or 3kW. Usually they can be switched down to 1kW if that's all you want. Two 1.5kW electric fires would be a pain to store, and twice as expensive to purchase. Two 1.5kW electric fires would overload a room circuit in the US.

I had an old Rowenta grill when I was a student which I think my parents now have, and that's 2kW.

One that I was using a few days ago -- wall paper stripper at 2.4kW. Another is hot air guns, a friend's one I've borrowed is 2.4kW. Pressure washers are available over 2kW.

Look at the input power, and look for combination ovens which have long since taken over from microwaves here. Mine, which is a bog standard Sharp one, is 2.65kW.

[bigcat]

Most I've have has been 3kW, 240v 13A. One ancient one was 240v 15A, from the round pin days.

heatup time. 3kW electric kettles are common here.

There are some, especially older ex-commercial equipment, but as you say the majority are under 2kW

Lol!

Even a 29kg road breaker is only 1.9kW. Welders are liable to be 13A or more. Screwfix chopsaw 32129 is 2.4kW, 63319 is 2.2kW. 130A welders eg

63152, 17764, 12219 run on a 13A plug.

input power is what counts. Output is only around 50% of input, if rated honestly. Theyre no longer rated honestly of course, since the late 90s high optimism IEE ratings took over.

IIUC american portable power appliances are rated very differently, often being rated on surge or startup power to give most optimistic figures. Makes it very hard to compare.

hard to know what those ratings really mean in US.

NT

[bigcat]

Our nukes range from 450w to 1kW output, with inputs of 900w to 2kW for vanilla nukes. Combi ovens are higher power, since almost all run the magnetron and 1kW element together, typically around 2.6 kW.

Note the newer power rating system confuses things somewhat, and obviously the lower power ovens dont have their output power marked on them.

A quick scan of screwfix reveals several 2-3kW tools, eg welders, wall chasers, compressors, 14A nailer guns, heat guns, steamers / wallpaper strippers, angle grinders, routers, universal woodworking machine, and many more in the 1.5-1.8 kW range as well. Portable ovens are mostly

3kW, except for the junk ones.

NT

[Pete C]

Sounds a bit unlikely, a 1kW microwave at 50% efficiency would also generate the same heat as a 1kW fan heater! That would require a lot more ventilation than they appear to have.

My combi oven is about 66% efficient, the Panasonic ones using an inverter are about 80% efficient:

The above 1200W oven can run off a single 15A supply in the US, not bad for about 50 quid!

cheers, Pete.

[Andrew Gabriel]

Original magetrons were only 50% efficient. Over the last few years, I think this has improved, but there was also a change in the way microwave output power was measured, which makes them look better than they used to look, for no actual change.

The waste heat comes from the magnetron, and in simple (non-combination) ovens, it was often blown through the oven compartment to help with the food heating.

[Martin Angove]

I've met quite a few nukes in my time, and I have to say that when you compare the ratings plate (which for legal reasons has to be pretty accurate about the absorbed power) with the declared power output, the ratio is usually quite close to 2:1. I'd love to meet one of these supposedly 80% efficient devices though.

Do they have ratings plates in the US?

Whether or not a 50% efficiency is going to be noticeable really depends on the type of use the oven gets. 60 seconds spent heating a cup of cocoa, even with 1kW dissipated as "waste" heat isn't going to be very obvious. Last time I had our (850W output) oven on for 5 minutes (doing a couple of bowls of supermarket-takeaway rice) it did get quite warm. There's definitely a fan in there somewhere...

Hwyl!

M.

[Pete C]

Mine's 1450W in for 900W out, making it 1.6:1

Here it is, got snipped out :

I tend to use mine for custard, which works really well.

Agreed, they must all have fans.

cheers, Pete.

[S Viemeister]

I'm currently in the US - so I took a look inside the microwave oven. The plate reads -

Input 120v 60hz 15 or 20 amp 3-wire only Output 650 watts 2450mhz 11 amp

It's an old unit, the label says it was manufactured in January 1989.

I don't remember the rating of the one we have in Scotland, but it cooks faster than this one.

Sheila

[Dave Plowman (News)]

Well, that doesn't tell you its power consumption - only that it's less than 1800 watts and it needs to be earthed.

That seems even worse. 650 watts at 120 volts is 5.4 amps.

[bigcat]

No microwave is 80% efficient. The invertor might be, but the magnetron isnt, and the oven as a whole isnt. Apart from invertor types, all are

50% efficient, but the newer IEC rating system makes it appear that output powers and efficiency have gone up: they havent. Think of them as like PMPO power ratings. The only significant advatnage of the invertors is reduced weight.

Chaos defrost is just more marketing nonsense, its no better than regularly cycled power.

NT

[Frank Erskine]

How odd. Eleven amps output?

:-)

[Andrew Gabriel]

Yes, so efficiency of about 50%, which is typical then. Power factor of microwave ovens is not quite 1, but it's near enough that can probably be ignored at this level.

Domestic UK ones are typically 600 to 1000W output, so your UK one could well be more powerful.

[S Viemeister]

Unfortunately, that's the only information on the label. I would hope that newer units are better, and that their labels more useful.

Sheila

[S Viemeister]

That _is_ what it says........

Sheila

[Pete C]

Bit of a sweeping statement, that...

Sounds interesting, do you have any web references?

cheers, Pete.

[Jim Michaels]

A 20amp appliance circuit in the kitchen has been required since 1947. Remove SPAMX from email address

[Jim Michaels]

Versatile Two 1.5s next to each other is the same as a 3. One 1.5 in each of two rooms does what no 3 can do.

As far as price we can get 1.5s for $10 to $15 which is so little as to be a non-issue.

US washing machines use hot water (often heated with gas).

How is saving energy inferior?

Remove SPAMX from email address

[Jim Michaels]

over 1,000watt commercial models that require dedicated circuits are available.

residential units are available to use with standard 15amp receptacles on standard 20amp kitchen circuits.

The standard Kitchen circuit is 20amps at 120V for a 2,400watt capacity. There is a restriction of 80% for a single item unless it is a single outlet circuit and often these circuits have receptacles rated at only 15amps.

The 15amp receptacle is also de rated to 80% if the device is expected to run over 3 hours (such as a fire). A microwave is permitted to use the full 1800watts that it's 15amp plug will provide. Remove SPAMX from email address

[Andy Hall]

The huge volume of water used in top loading machines.

[Christian McArdle]

US machines use many, many times the quantity of water and detergent and are an environmental nightmare.

European machines used to have heating elements and a separate hot fill to start it off. This is no longer done as the machines use so little water that there is no energy to be saved when you account for the lost hot water in the pipework every time it fills.

Christian.