# How much energy?



## Muttley1900 (Dec 23, 2008)

Unscientific, I know, but I've just had this quarters electric bill and it is less than normal. 

Looking back at past bills, my electric consumption costs have been more or less the same, give or take £5. This quarters bill I am nearly £20 better off, and the only difference I can see on my usage is that I now do not have a S1 and free-serve digibox, but do have the BT Vision+ box. This change was done 5 weeks ago.

Could the removal of the S1 and digi box and swapping in the BT Vision box make that much difference? If so, then retiring the S1 and digi box is going to save me in excess of £45 a quarter.


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## djqster (Oct 22, 2010)

The S1 TiVo is a bit of an energy hog. According to my smart meter the TiVo + Sky box drew IIRC 60w 24/7 which adds up....

My current Humax Foxsat HDR pulls 1w in standby, which is nice.


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## velocitysurfer1 (Sep 6, 2006)

I wouldn't have thought so!
Rather than looking at the cost you need to compare your kilowatt hours as this is energy usage rather than energy cost.

Maths lesson coming up:
If we assume TiVo uses a constant 30 watts, this is 0.03kwh. This equates to 0.72kwh per day, 5.04 kwh per week, or 262.08kwh per year.

Working out how much this costs is tricky as it depends on the cost of your electricity. The majority of suppliers have a high rate for the first "lot" of leccy per quarter, and then a low rate for the remainder. If like me you have economy 7, then the night rate is even lower.

However, for ease of maths, lets assume your flat rate for electricity is 20p per kwh (inc vat).

262.08 kwh x £0.20 = £52.42 per year or £13 per quarter.​
Assuming that the digibox used the same as I've assumed for TiVo, you are only looking at £26 per quarter. However your BT Vision box is probably using £13 per quarter.


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## Automan (Oct 29, 2000)

40 watts for Tivo and 20 watts for a Sky+ box.

11p is a good price for a kWh

So 60w x 24*365/1000=525.6kwh

At 11p 0.11 x 525.6=£57.81 a year.

A Freesat Humax HDR in low power standby eats under 1 watt of power and about 19 watts when in use.

As a rough guide, 1 watt in use all year cost £1

Automan.


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## spitfires (Dec 19, 2006)

Automan said:


> 11p is a good price for a kWh


he he - I'd love to know where you can get electricity for that! Don't forget you have to add on a proportion of the "daily charge" or other fixed cost and then add vat.

A good working price is 15 p/kWh

link to Electricity Savings Example
link to Electricity Running Costs Calculator


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## Pete77 (Aug 1, 2006)

Muttley1900 said:


> Looking back at past bills, my electric consumption costs have been more or less the same, give or take £5. This quarters bill I am nearly £20 better off, and the only difference I can see on my usage is that I now do not have a S1 and free-serve digibox, but do have the BT Vision+ box. This change was done 5 weeks ago.


What is your normal quarterly bill and what percentage of that does this change represent?

However removing a Tivo from service probably saves £50 per annum and the Freesat box say £20 per annum (depending how much of the time it was recording) so your savings sound roughly right.

Also are you comparing this quarter this year with this quarter last year as consumption in the spring and summer quarters is always lower.


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## Muttley1900 (Dec 23, 2008)

Thanks for all the in-depth responses, so in conclusion, the Tivo/freeview box retirement is contributing a good proportion of this saving, but I need to work out where the other proportion has come from. 

Mmmm, thinking about it, it could be from replacing my old (8 years old) Pc with this imac - both were/are on near enough 24/7.

I think a small investment for a smart meter of some sort is called for...

... Now for some research into those...


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## Pete77 (Aug 1, 2006)

Muttley1900 said:


> Mmmm, thinking about it, it could be from replacing my old (8 years old) Pc with this imac - both were/are on near enough 24/7.


Average desktop PC would be closer to 100W per hour or more than that with a CRT rather than a TFT monitor.

Average laptop eats 20W to 30W per hour when not charging the battery (i.e. most of the time) and about 60W per hour when the battery is charging.

So there you have the rest of your saving.

So rather a lot seems to have actually changed recently in your 24/7 electricity using applicances..............


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## Muttley1900 (Dec 23, 2008)

Pete77 said:


> So rather a lot seems to have actually changed recently in your 24/7 electricity using applicances..............


On reflection, you are right, but in my pea sized brain not a lot has changed - used to have a pc, now have an imac surely not a lot of difference there, but of course yes there is as an 8 year old p.c. is considerably less energy efficient than a new computer and likewise with the S1 TiVo, used have a Tivo pvr, now have a BT Vision pvr, surely not much difference there, but again, yes there is.

I suppose I'm "new" to the energy saving game, as the capital cost of changing something discourages me from making the long term savings of the running costs. As well as all the issues of changing something that I am relatively happy with and the back and forth of is it more energy efficient to carry on using product x, or buying replacement product y (which may use less energy with running costs, but what about the energy to create it in the first place).

Do I replace the gas boiler I have had for the last 15 years, that is working fine, with a new one that is more energy efficient? No. But when I do need to change it, then yes I will look at the energy efficiency comparisons with new gas boilers.

J.


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## AMc (Mar 22, 2002)

Muttley1900 said:


> I think a small investment for a smart meter of some sort is called for...
> 
> ... Now for some research into those...


Check out Automan's extensive research here...
http://www.tivocommunity.com/tivo-vb/showthread.php?t=359566&highlight=power+monitor


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## Pete77 (Aug 1, 2006)

Muttley1900 said:


> Do I replace the gas boiler I have had for the last 15 years, that is working fine, with a new one that is more energy efficient? No. But when I do need to change it, then yes I will look at the energy efficiency comparisons with new gas boilers.


You would only replace a boiler before the end of its natural life if you have very high energy use. Its also much less likely that you would replace a gas boiler before the end of its natural life than say if you were considering replacing an oil boiler (now very expensive to run compared to gas) with a gas boiler before the end of its natural life.

My 20 year old Glowworm boiler uses £450 a year of gas. Even if a new boiler is 30% more efficient (about the best possible case) that's only £135 per annum. A new boiler will cost at least £2,000 installed. So clearly not worth replacing it early. However my mother has a 17 year old oil boiler using £1,800 of oil per annum. If she replaced it with a modern gas boiler her annual energy cost on her detached 5 bed house (a bit energy efficient due to single glazing) might very easily fall to £1,100 per annum. The new boiler might cost say £2,500.

So if you think my mum's boiler will last another 8 years (the old one lasted 25 years) its worth replacing it early now as the £5,600 saved in oil use in the next 8 years is double the replacement cost of replacing it now. However if her boiler fails in only 2 years time it would have been better to have waited until it failed. So rather more of a difficult decision in this case (also she might move in the next two years even if the boiler does not fail in that time). However on a 20 year boiler life view gas prices might suddenly go up a lot more than other energy costs as natural gas stocks dwindle. So is an electric boiler more viable as energy generators will use whatever method is currently cheapest (one hopes) to generate electricity. Except of course that the government is encouraging the creation of more expensive green energy sources for electricity.......

Regarding your PC its the switch from a PC to a laptop that is significant and/or the elminination of a CRT monitor that is significant. A modern laptop of the same size as an 8 year old one will use a very similar amount of electricity. My mum's brand new Samsung Core i3 uses just the same amount of electricity as my six year old HP Centrino notebook.

Regarding energy monitors you really want one that does the whole current supply in use and one that can accurately monitor the consumption of any individual plug in appliance.


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## AMc (Mar 22, 2002)

Pete77 said:


> So if you think my mum's boiler will last another 8 years (the old one lasted 25 years) its worth replacing it early now as the £5,600 saved in oil use in the next 8 years is double the replacement cost of replacing it now....


We changed from oil to electric air source heat pumps as a result of renovation and some conditions of the building control permissions.
The >10 year old oil boiler was removed working and fetched >£400 on eBay 

If natural gas is available then it will be cheaper than electric heating. The cost per KWh is increased in electricity by losses in transmission even if the original production was cheaper. Gas boilers converting gas into heat are much more efficient than converting coal to steam to electricity to heat (in transmission) then back heat in the home - I doubt this will change in the lifetime of a current gas appliance unless someone cracks nuclear fusion in a eureka moment (unlikely).
If you look at what has been happening to the oil price recently I expect oil heating to get progressively more expensive in relation to other forms of heating fuel, even though I expect them all to get relatively more expensive as supply dwindles and worldwide demand increases.

You may also choose to consider the expectation of failure, inconvenience of break down and the cost of repair as the boiler moves towards the end of life. The older non condensers were very reliable, I'm lead to believe that condensing oil boilers are more prone to failure. A modern gas boiler should come with a guaranty and then of course can be added to an annual service contract which is less common with oil. When our oil broke down it took a whole day on the phone to find someone to fix it that day with one company cheerfully suggesting an appointment 6 weeks on - in January!

We moved from the pain and hassle of having oil deliveries, doing price comparison and unexpectedly running out when the weather was unseasonably cold moving to a fixed utility supply was a major plus.


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## Pete77 (Aug 1, 2006)

AMc said:


> If natural gas is available then it will be cheaper than electric heating. The cost per KWh is increased in electricity by losses in transmission even if the original production was cheaper. Gas boilers converting gas into heat are much more efficient than converting coal to steam to electricity to heat (in transmission) then back heat in the home - I doubt this will change in the lifetime of a current gas appliance unless someone cracks nuclear fusion in a eureka moment (unlikely).


Thanks AMc. Useful thoughts. She does have a mains gas supply sitting capped off at a point in a flowerbed outside the front door. It was disconnected at this point after an old gas cooker (converted from town to natural gas) caused rather a bad fire in the premises in 1970 that also took out the kitchen roof. I think a pistol thing for lighting the gas hobs some how malfunctioned and started a fire that my mum discovered when she got back home from picking us up from school that by then had thick black smoke billowing out of the windows. Whilst the fire brigade came in 20 minutes the kitchen roof collapsed and the house was full of soot that made us move out for 6 months while the kitchen was rebuilt and the soot was eliminated and the house redecorated. Gas was disconnected from the house at this time although the oil boiler replaced a very inconvenient coal one some time in 1968. Oil was cheap at this stage. This boiler lasted for 25 years.

As she is now at home all the time compared to the house standing empty five days a week five years ago and the oil price has gone mad since she first started living there again full time it would make sense to replace this boiler with a gas boiler. The boiler is an early 1994 non condensing type. Noisy in a comforting sort of way when it fires up but very reliable. It had one minor component failure 6 or 7 years ago that was very easily and cheaply fixed.



> If you look at what has been happening to the oil price recently I expect oil heating to get progressively more expensive in relation to other forms of heating fuel, even though I expect them all to get relatively more expensive as supply dwindles and worldwide demand increases.


Agreed the future for the oil price looks grim due to the Chinese and Indians all beginning to drive cars. The gas powered car by contrast appears impractical on the whole due to the relative loss of space involved.



> You may also choose to consider the expectation of failure, inconvenience of break down and the cost of repair as the boiler moves towards the end of life. The older non condensers were very reliable, I'm lead to believe that condensing oil boilers are more prone to failure.


The last oil boiler just rusted through on its water jacket after 25 years but it never gave any trouble before it failed. Some minor components were replaced during servicing along the way. As this one is also a non condensor type I don't expect it to be unreliable during the last few years of its life. It might even last for 30 years. The gas boilers in the office block in Woking I was based in till 2003 and its control systems (the latter were crap sadly) dated from the early 1970s. These things do last a long time. Apparently the boilers were finally replaced at my old office about four years ago.

Regarding gas boilers what are your thoughts on condensing units there as whilst slightly more economical they seem more unreliable and potentially also have shorter lives (due to expensive and unaffordable failure of the more complex components involved and/or more corrosion problems).


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## RichardJH (Oct 7, 2002)

> Regarding gas boilers what are your thoughts on condensing units


Very off topic for a Tivo Forum but Pete you may have no option but to have a condensing boiler these days. see http://www.energysavingtrust.org.uk/Home-improvements-and-products/Heating-and-hot-water


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## velocitysurfer1 (Sep 6, 2006)

Muttley1900 said:


> I think a small investment for a smart meter of some sort is called for...
> 
> ... Now for some research into those...


From looking at the Energy companys tariffs, do not go on a tariff with a "free" energy monitor. I say this because the pence per kwh is normally a lot higher than the cheapest internet tariff from the same provider.

My biggest cost saving came from moving energy supplier, whilst my biggest energy saving came from replacing the light bulbs with "energy saving" light bulbs. The biggest savings in both cases comes from not using energy in the first place.


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## Pete77 (Aug 1, 2006)

RichardJH said:


> Very off topic for a Tivo Forum but Pete you may have no option but to have a condensing boiler these days. see http://www.energysavingtrust.org.uk/Home-improvements-and-products/Heating-and-hot-water


Richard its hardly my fault that the OP did not start this thread in the Off Topic UK forum where it clearly belongs.

Regarding the propaganda from the Energy Saving Trust I know for a fact that an existing gas boiler does not have to be replaced with a condensing one even though you will initially get the impression from suppliers that a condensing boiler is your only option. It may be that a wholly new gas boiler installation does (but what about where it is a replacing an also non condensing oil boiler in the same location with the same lack of the required water circuit). From memory I think there is a get out if it can be cited that providing the water supply etc is not practical. That probably applies on a new gas boiler in an old kitchen even though I suspect a new build house probably does have to have a condensing boiler under the regs. Also new houses get checked up on by local councils and existing houses do not by and large......


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## RichardJH (Oct 7, 2002)

Pete77 said:


> Richard its hardly my fault that the OP did not start this thread in the Off Topic UK forum where it clearly belongs.
> 
> Regarding the propaganda from the Energy Saving Trust I know for a fact that an existing gas boiler does not have to be replaced with a condensing one even though you will initially get the impression from suppliers that a condensing boiler is your only option. It may be that a wholly new gas boiler installation does (but what about where it is a replacing an also non condensing oil boiler in the same location with the same lack of the required water circuit). From memory I think there is a get out if it can be cited that providing the water supply etc is not practical. That probably applies on a new gas boiler in an old kitchen even though I suspect a new build house probably does have to have a condensing boiler under the regs. Also new houses get checked up on by local councils and existing houses do not by and large......


Pete I wasn't criticizing you about the off topic. As far as boiler replacement AFAIK you can replace like for like but you may not be able to replace gas for oil under the same rules.

Building control regs seem to be everywhere now such that since taking early retirement and being unwilling to spend thousands on gaining new certification I no longer carry out work for others in the property maintenance sector anymore


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## Muttley1900 (Dec 23, 2008)

Pete77 said:


> Richard its hardly my fault that the OP did not start this thread in the Off Topic UK forum where it clearly belongs.


That's right, the bigger boys made you do it.


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## AMc (Mar 22, 2002)

FWIW discussion of the power consumption of an S1 Tivo is on topic for this forum.

The power monitoring question has been more than adequately investigated in the Chit Chat thread - hence the link 

Discussion of oil vs. gas vs. building regs probably belongs in Chit Chat but I'm not a mod and thread drift isn't harshly policed here and never has been.


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## Automan (Oct 29, 2000)

Indeed, early US Tivo's were one of the only few home appliances to not get a EPA approval due to their high power consumption.

I assume the new models spin their drives down and use a SSD for the buffer?

Automan


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## AMc (Mar 22, 2002)

Dunno - a more efficient power supply and a modern drive should use less power anyway I think?


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