'DIY SOS' - 240V to 220V

[DeadJoe]

I don't know if any of you watch it (I bet some of you do, just to see how they're winding Billy the electrician up this week) - it's a TV show on the beeb, where a bunch of novelty tradesmen do something nice for deserving people in dire straits...

Anyway, this week featured a gizmo which is connected to the household electricity supply (immediately before the CU, they implied) with the intention of reducing the incoming voltage from 240V down to 220V, with a claimed saving of 10% on the overall electricity bill.

It sounds a bit unlikely to me, but what do I know?

So, you people who do know - can it work?

 

[Steve]

inevitably this device will use energy. Probably some kind of big SMPSU to regulate the voltage. The thing is, a watt is a watt whatever the voltage.

Dont call billy an electrician - he isnt.

 

[aptsys]

It'll only work on appliances that don't have switching power supplies.

 

[aptsys]

The thing is, a watt is a watt whatever the voltage.

Yes, but appliances without switching regulators will use less power at lower voltages.

 

[DeadJoe]

I read somewhere that computer equipment can be damaged by under-voltages. OK, so this is only a 10% or less under-voltage, but the device is going to sustain it for as long as it is there...

 

[flameport]

This useless device has been discussed before.
It won't save anything. It will however cost a significant amount of money to buy and install.

Anything electronic won't be affected, the current will increase as the voltage is reduced, so the power used is the same (switch mode power supplies as found in 99% of electronic items)

Incandescent light bulbs will use less power, but will be significantly dimmer and will probably end up replaced with higher wattages.

Heating appliances like kettles and toasters will just take longer to heat up.

Motors might use slightly less power. Equally likely is that they overheat or not work at all.

 

[OwainDIYer]

The thing is, a watt is a watt whatever the voltage.

Yes, but appliances without switching regulators will use less power at lower voltages.

The main consumers of electricity in the home is space / water heating and cooking. That will just take a bit longer on the lower voltage, the total kWh consumed will be the same.

Filament lighting will consume slightly less power, but will be significantly dimmer, the actual efficiency of the lamp will fall and you will be paying more £ per lumen.

 

[JohnD]

the big energy users are those with heating elements - like cookers, washing machines, tumble driers, immersion heaters.

If the voltage is reduced, they will just take longer to reach their set temperature, so the heater will run for longer and use a bit more energy (due to the increased time when heat is being lost)

stupid idea.

edit: too slow

 

[ban-all-sheds]

 

[DeadJoe]

It annoys me that there are companies out there willing to sell something which doesn't work as a 'Green' product. I'm even more annoyed that it got free advertising on the BBC. And come to think of it, I'm cross that what looks to be a scam has been linked with sustainability and renewables - it just gives the scoffers something else to bang on about. If the so called 'expert' on DIY SOS can be wrong about this device, then it makes it easier to claim that all the rest of it is nonsense as well...

 

[ban-all-sheds]

Nearly all of the rest of it is nonsense.

 

[DeadJoe]

Well BAS, certainly the two days they spent on DIY SOS burying a big container in concrete under the garden so that the toilet would flush rain water is nonsense. And I was surprised to see their 'expert' missed the opportunity to blight the house with one of those silly windmills - after all, he did seem to just be adding stuff at random.

But low energy lighting, draft exclusion, and insulation seem sound. No-one would describe these as 'nonsense', surely?

I am pretty confident that solar water heating is an environmental winner even if the economics are a bit harder to justify. Solar PV has the opposite problem - the economics works (now), but I am unconvinced by the environmental advantage.

Then there's ground and air source heat pumps - not reliable enough perhaps, but the general principle doesn't sound crazy.

The bottom line has to be that as gas and oil get steadily more expensive, the borderline technologies will become more and more attractive. You don't even have to believe in global warming to benefit!

 

[big-all]

certainly the two days they spent on DIY SOS burying a big container in concrete under the garden so that the toilet would flush rain water is nonsense.

they claim £150 a year saving an impossible acheivment i think £35 is nearer the mark

£3 a week is nearly 2 tonnes or or the full contents off the store plus a bit extra
so you need 3 good periods off rain a fortnight evenly spaced to keep up with demand
3 weeks without rain your £7 out off pocket

the full 1500L only cost £2.50p and last 5 or six days

i am all for saving but at a probable saving off perhaps £50 a year you have to offset the purchase instilation running and maintainance cost this may take 40 years to pay for its self if it lasts that long

 

[ericmark]

Seems a barrel full of laughs does this program replace Last of the Summer Wine?

As to reducing voltage. With florescent lamps using induction ballasts having the voltage spot on will reduce power but I would have thought using switch mode HF inverter type would be better idea.

Anything using switch mode supply would just compensate for voltage change and would use exactly the same power.

Most things that heat will use more power. If it takes the washing machine 20 minutes instead of 18 minutes to heat the water to a given temperature it will mean the motor will have been running for 2 minutes more so will use more power.

And the kettle of course is not insulated so the longer it takes to boil the more heat will be pumped into the surrounding so again will take more power. Try using a caravan kettle a 1 litre kettle at 2kw will take around 9 minutes but a 1kw version will take 20 minutes not 18 and that's due to heat into room.

Microwaves at low power could have all sorts of problems and the fan heater will be thermostat controlled so will just run for longer although will low voltage there could be a problem with fan stalling and going on fire.

Old TV's and radios without switch mode supplies will start to hum and I can't see the point of reducing the voltage to whole house when it will really only help with discharge lights.

Seems just the sort of thing Seymour would have invented in Last of Summer Wine and I enjoyed watch that so now it is finishing maybe I should start watching this one instead?

 

[dingbat]

Dont call billy an electrician - he isnt.

Actually - and regrettably - he is!

Merriam-Webster: one who installs, maintains, operates or repairs electrical equipment
Cambridge: a person who puts in and checks electrical wires
Collins: a person trained to install and repair electrical equipment,
Chambers: a person whose job is to install, maintain and repair electrical equipment