UKC

A company called Energy Saving or something like that cold called me last night trying to sell me a product that connects to my electric consumer unit in my house and which they say will reduce electric bills by 20% - they say it works by reducing electrical surges. I'm no electical engineer. Is this likely to be a scam or does anyone have any experience of such things. They tried me on cavity wall insulation and loft insulation first. They wouldn't tell me even approximately what it would cost to install.
I live in Fort William - if that makes any odds.

In reply to John Workman:

I am no sparky but if "surges" comprise 20% of your electricity useage then I imagine that there is something very wrong with your supply. My money is on "scam"

In reply to John Workman: Is it a surge protector (they exist) and a fancy name for a smart meter? Smart meters can save you electricity because they show you what appliances are using what electricity. That said, many electricity companies will give them to you for free.

In reply to John Workman: It depends how clean your supply is and what kind of load you have.

I'll try not to get to mathematical but your meter can only read power consumption as volts x current. If you have a certain type of load it can affect the way the current is affected by the voltage. In a normal resistive load the current is at a peak when the voltage is at a peak. Most houses are like this. In an industrial situation you can have a lot of motors that affect the current and hold it back due to the way current works in a coil. This means that the power you read on your meter will be different to what you are actually using. This can be fixed by fitting capacitors to your supply. It's called power factor correction.

You could also be getting transient spikes if you live near an industrial area where plant is switched on an off and this is injected into the mains. They're very short but big. I would be surprised if your meter catches them but your household appliances, computers etc will.

Need more info about what it is and what it does really.

In reply to John Workman: I wonder if the surges they refer to are at the generating stage. We had a thread a while back about the suggestion that if power stations were experiencing a surge in demand, they would be able to remotely turn off non-vital pieces of equipment (eg. fridge) for a short time to relieve the load. Not sure if this is currently possible, or if it could save you 20%, but that could be the 'surge reduction' they're trying to sell you.

In reply to John Workman: They are actually voltage regulators and keep the voltage constant and at the bottom end of what's acceptable.

UK voltage is 230V +10% - 6% if you can keep the voltage to the -6% end rather than the +10% end you save as Energy (P)=Voltage(V) X Current(I)

You can’t change the current thing consume but you can change the voltage, to an extent.

In reply to owlart: This was floated as an idea a few years ago. I believe the response was one of absolute horror from the uneducated alarmist press. Seems like a really good idea to me.

In reply to krikoman:


That doesn't really work as most appliances these days have a control loop that adjust the current drawn to deliver the power needed regardless of voltage - for example fridges, ovens and switch mode power supplies (inside tv's, computers, consoles etc)

If a lot of your usage is on lighting or inductive devices such as motors or transformers (where higher voltages may saturate the ferrous core) you will see a saving, but that would be an atypical household.

In reply to krikoman:


Of course you can change the current. Changing the voltage will change the current!

In reply to EeeByGum:

The system exists already in France and many other EU countries for many years.
Basically for a discount you accept that the power company can remotly shut down your heating. Mostly they install this system in houses with electrical storage heating. Only in the UK, part of the US, and third world countries we have such poor electrical standards.

In reply to hokkyokusei:

^ this

V=IR, I=V/R

In reply to DancingOnRock:

I think the power meters actually measure power used, so as far as you are concerned the power factor of the load is irrelevent. For the supply company unbalanced and high power factor loads are a nightmare.

In reply to RomTheBear:

Can't speak for third world countries, but perhaps only in the UK and US has electricity up until now been so cheap?

In reply to Milesy:

Or, alternatively, fit lower power lightbulbs! Stuff like fridges will still use the same amount of electricity - even more - because to get the same amount of cooling the compressor has to run longer and probably less efficiently. Similarly cookers and kettles - the amount of energy needed to boil water doesn't change because you are using effectively a lower power kettle.

In reply to EeeByGum:

French (nuclear) electricity is cheaper to produce than ours. Thats why we import some of it.

I've just put solar PV in, one of the companies I spoke to was mad keen to put in a voltage optimiser to step the voltage down to 220V (which is what a lot of European appliances will be designed around). It won't be a blanket 20% saving though. Your lights will use less power, but give less light, so you might end up putting a brighter bulb in. Different appliances react differently, eg your fridge motor might run at lower power but stay on longer to maintain temparature...

http://www.yougen.co.uk/blog-entry/1948/Is+domestic+voltage+optimisation+al...

In reply to GrahamD: A lectures once told us about his flatmate in the 70's tying to make the load of their house inductive. It was easy to fiddle with the meter back then.

In reply to John Workman: Electricity in the US is, in my experience extremely expensive and, thanks to the poor regulation of a 3rd world standard power network, extremely variable in quality so surge protectors there are a default if you want to keep anything sensitive (like a computer) in the house.

I would guess it's a surge protector and choking the voltage a bit, but whether you can save that much I do not know.

In reply to Milesy: You can't change the current!!

The current changes because you've changed the voltage FFS!!

If you power a 100W light how do you change the current except by changing the voltage. The resistance stays the same (within normal voltage fluctuations) So tell my how you alter the current?

The box referred to keeps the voltage at the low end of what normal electrical items are guaranteed to run.

@WIntree Most items!?!?! some items have a loop on the output to the appliance, most don't and the current delivered remains the same.

If the current remained the same and you lower the voltage you have also lowered the power consumed.

In reply to krikoman:

I was agreeing with you ya tube. That's why I pointed to your post and said "^ this"

In reply to Milesy: Sorry replied to wrong bloke :-/

Most consumer electronics needs a power supply rated for 220-240V so it works in most countries and a portable device you're likely to travel with is usually rated 100-240V & 50-60Hz so they'll work anywhere. An efficient or well designed power supply doesn't even get warm so any changes to the supply voltage will have no effect on power consumption.

The losses in a cheap power supply may vary with supply voltage but that should be marginal. If it wasn't marginal the power supply would risk overheating at some supply voltages.

On non-electronic resistive loads like incandescent bulbs & heating any reduced power will mean less light and less heat.

Reactive loads like motors for fridge/freezer/central heating/air-con may consume less power but they'll produce less output so it' difficult to say if they'll be more or less efficient.

Overall if somebody is selling a clever box that sounds strange and they won't tell you the price then it is a scam.

In reply to krikoman:


The only thing in my house that doesn't adjust it's current draw to counteract a lower voltage are the lights.

Fridge - Oven - Kettle - these are the if power users and all adjust.
Hair dryer - guess what? You use it longer
Tumble dryer - you either run if longer or have clothes less dried
TV - Desktop computer - laptop charger - phone charger - electronic photo frame - miniature dyson charger - and many more. All off these are switch mode power supplies which by the very means they operate adjust their current draw to deliver the required power.
Microwave - you could argue the toss on this one
Dyson - I don't know if Mr Dyson's clever digital motors adjust.

So I stand by what I said. We use power to get things done. Reduce the supply level and we use it for longer.

Now cheap induction motors may be less wasteful @220V than 240V so you cold win there by lowering the voltage, but induction motors typically represent a small fraction of domestic use in the UK. Different if you have air conditioning.

In reply to John Workman:

Get yourself signed up to the TPS.

In reply to krikoman:

As I say I didn't want to get into the heavy maths and physics but

http://en.wikipedia.org/wiki/Electrical_reactance

In reply to John Workman:
It's a scam. I've heard of it before.
It's a worthless device that effectively drops the mains voltage a bit. If you are running loads of incandescent lamps it might save you a little, at the cost of dimmer bulbs, but stuff like fridges and heaters are on a thermostat. If they run at lower power then they need to run for longer.
The fact that they cold called should ring alarm bells. No reputable company cold calls.

In reply to John Workman:
Just think about it... If the device actually worked, every business with a significant electricity bill would fit one.

In reply to GrahamD:

Yes, that's what I thought. I'm not sure how you can reduce the voltage though, other than putting in a transformer. Putting the whole house on a transformer sounds pretty dodgy, Where will you put a 14KVA transformer?

In reply to Hooo:

Many do! Voltage Optimisation has been around a fair while in industry, is a proven technology and can be extremely effective. The recent trend towards domestic units is a constant source of discussion/argument amongst electricians and engineers. Some swear by its effectiveness and others think it nothing more than a scam. To satisfy myself, I fitted a unit in my own home about 18 months ago (I was approached by one manufacturer to supply/install them). My consumption appears to have reduced by around 7-8%. The 20% figures usually bandied about are over-ambitious and rarely, if ever, achievable in a domestic situation. The units work most effectively (but not exclusively) on resistive loads that do not work on a thermostat, therefore lighting and basic electric showers are the prime candidates. Lighting does dim slightly when the unit kicks in, but it is barely perceptible. Certainly not enough to worry about.

Would I have one of these units fitted if I was paying for it with my own money? Nope. Too expensive for too small a saving. Fit low energy or LED lamps instead and turn them off when you ain't using them. Voltage Optimisation certainly works - there's no black magic involved, but not enough in a domestic situation to make it worthwhile IMO. And any company cold calling to sell it you is unlikely to offer it at a good price.

In reply to Wulfrunian: if it was worth doing , it would be recommended by the department of Energy and feature on energy saving advice.

20% is approx the amount of overcapacity in our whole system to accommodate for power outages on stations, and of course the intermittency of renewables, it would be a no brainier to change the building codes for new installations to ensure that new homes would have them I would have thought. I don't believe they have.

In reply to krikoman:
>

You do know that P is for power not energy?

http://muller.lbl.gov/teaching/physics10/old%20physics%2010/physics%2010%20...

In reply to wintertree:

All wrong do you really know anything about electrical engineering?

Power factor too is a major waste of energy, that's why industial units are made with huge banks of capacitors in them to get as close to a power factor of 1 as is possible.

Powere factor is the relationship of the voltage sin wave to the current sin wave.

In reply to marsbar:
>

Energy is Power over time so both useful you pay your bills on energy kWh and the power consumed (instantaneous) is in (W)atts

In reply to John Workman: to the OP.

No they aren't worth it in the home.

In reply to John Workman:

Thanks for all the useful advice. I won't be going any further with this.

Its good to have UKC where you can air & discuss even stuff like this.

JW

In reply to krikoman:

>

Poor power factor in itself doesn't waste energy - it buggers up the distribution, though, which is why there is legislation over low power factor loads.

In reply to GrahamD:

It most certainly does waste energy and as a consumer you end up paying for more energy.

For example, if the load power factor were as low as 0.7, the apparent power would be 1.4 times the real power used by the load. This 1.4 times is what goes through you meter.

In reply to krikoman:

The meter responds to instantaneous IV, and therefore only measures actual power dissipated (the component of I and V that are in phase), not average V.A.

As a thought experiment, connect a pure reactive load to the mains. Where exactly is your energy being wasted ? what dissipates it ? a pure inductor or capacitor can't.

In reply to GrahamD: You are of course correct, I'll go and stand in the corner for a period of time.

In reply to GrahamD: Although all of my work is in an industrial environment when PF is a significant cost.

In reply to krikoman:

PF is a cost on an industrial scale. You get fined heavily for exceeing power factor limits and this is because losses do occur with poor power factor loads - they occur in the distribution network because peak currents have to increase to deliver the same power.

On a household level , I think it gets dealt with these days by putting the onus on the household equipment suppliers to fall within limits and not put the onus on the householder.

In reply to GrahamD: You also have heat losses in the cables and if your PF is low then you need larger cables to carry the higher current.

In houses there are a mix of inductive and capacitive loads which will hopefully cancel out.