Wednesday, 31 October 2012

Updating to Windows 8

Updating ought to have been easy, but I found it incredibly frustrating.

First, I went to the upgrade site, but after getting all the way through the purchase process, it stated that the upgrade wasn’t for commercial use.

OK.  Off to Curry’s to reserve a DVD which also prevents me having to download the whole thing: Get Windows 8 upgrade on DVD from Currys at £49.99 and apparently doesn’t have the commercial restriction, a premium of £25.00.

When I got there I started looking at a new laptop as well, but that’s another story.

So, I’m now installing from the DVD I purchased.

The first thing I need to do is uninstall the incompatible apps (some Dell stuff, an Intel USB3 driver?, and Security Essentials!?) followed by a reboot.

I chose to keep my existing, files, programs and settings.

After quite a long delay, my machine installed devices, then spent quite awhile longer preparing. 

Another reboot, and “Moving your settings” was the next task.

Following that, a personalize choice, followed by connecting to the network via wireless (I’ll do that later).  I then chose express settings, and entered my previous admin password, and chose sign in without a Microsoft account.  After “Finalising your settings” a disconcerting black screen before “Hi” Finally appeared along with the W8 intro stuff.

It eventually booted into W8, so after the initial confusion about licensing, not too bad.

Wednesday, 24 October 2012

Be careful when buying new tyres for your car

I was advised at my last service that I needed new tyres on the car, and was given 3 different prices.

I asked about fuel economy, and was pointed toward the most expensive offer, with the statement that they’re what you have at the moment.

So, I called around a few places and got quotes, and eventually the dealer matched the quote, so I had the tyres fitted this morning.

However, when I got back to the car, I noticed that the new front tyres weren’t Michelin Energy like the rear tyres, and so my hunt for the difference began.

Bridgestone has a good document that describes the efficiency.

tyre efficiency 

What I cant determine is if the increase in consumption is per tyre or per set of 4.   Let’s assume it’s per tyre (as that’s the worst case).

My new tyre is rated E, and the tyre available elsewhere is rated B, so that’s a difference between them of 0.04 l /100 km.

On this set of tyres, I drove 43,000 km (or 26,500 miles) so that looks like it will cost me 43,000 km * 0.04  l / 100 km = 17.2 l which at the current price of fuel for diesel at £1.42/l = £24.42.

That’s £100 if the rating is for each tyre, which is quite a difference for just fitting a different tyre to the car.

So, look for the label and choose wisely!  Clearly if the price per tyre is more than the savings a lower rating may be a better choice, though at the same price, it’s a no brainer.

Sunday, 30 September 2012

Solar PV a year on and some illuminating thoughts

At the beginning of September, our 2100 kWp Solar PV array had been installed for an entire year.  The output was 15% over what had been predicted by the installer, generating  just under 2000 kWh in the year, and the investment is still looking to pay off in just over 7 years.

I also noticed that for the price I paid, you can now get a system that’s twice as big, so even though the FIT rate has halved, you can still get your investment back in 7 years, while generating twice as much as I am.

However, in the Northern Hemisphere, the days are getting shorter (watch it change on your PC’s desktop with Terminator for Windows Desktop) and it’s got me thinking about how we can shave bit more off of our consumption.

Ikea have an offer on in the UK for the next few days, giving you £3 off each LED bulb you buy.  This website also looks promising:

Should I replace all my CFL bulbs?

For example, this 60W replacement (at £11.95) replacing an 11W CFL bulb to a 5W bulb will pay for itself after 100 kWh at 11p/kWh, or about 20000 hours.  Assuming the light is on for an average of 3 hours a day, that will take 18 years to pay for itself—maybe not worth it just yet, as you can currently get CFL bulbs for about 10p each in the UK (heavily subsidised).

What about CFL downlighters?

We do however also have 8 CFL downlights that are probably reaching the end of their life (they’re on many hours a day in the kitchen), and the best price I can find at the moment for them is Pack of 3 - Megaman BR0711i Ingenium GU10 Spot Bulb 11W Warm Whitefor £14.99.  Where these apparently direct replacement GU10 LED 4.5 W  lamps are £9.95.  If the lights are on 4 hours a day, I save 10p every five days, saving £7.30 per year.  Replacing all 8 bulbs (£40 difference in price) will take just over 5 years to repay the investment, so this probably is worth doing.

How about Fluorescent Tubes?

We also have some fluorescent tubes in our bathroom placed beside a large mirror.  Three of these at 30W uses quite a lot of electricity, and I actually don’t like them very much anyway.  Also, the seem to light up a lot of the box they’re in and not so much of the mirror.  But, these IP68 LED Tape Lamps look like they might be exactly what I need.  5 meters of tape should be enough for the job at 24W and output 1800 Lumens, and again will cost just under £40, and I’ll also need a driver for the LEDs that costs about £20.  Every 15 hours these are on, I’ll save 1Kw of electricity, so they’re paid for in 9000 hours, which at an hour a day for a bathroom will take around 24 years to pay back.

That’s not a great return, but I might do it anyway.  I can probably build it in such a way that if they don’t work there, I can repurpose the strip of lights for use somewhere else.

Monday, 19 March 2012

More energy price hikes

I just got notice that my current tariff for electricity is set to end.

Lo and behold!  Prices are now going to go up 12% for electricity, and 6% for gas for me if I switch to their cheapest deal.

Or I can opt for a fix until July 1, 2013, at about the same levels as I’m currently paying.

Does anyone think prices might actually drop over the winter period before then, as that’s the period where we use the bulk of the electricity?  If so, let me know.  At this moment, I’m tempted to go for the fixed rate based on the cynical winter price rises we’ve seen for the past few years.

By the way, for anyone interested in the existing rates from Scottish power.

Your energy details at a glance

Electricity prices Your current prices Your new prices from
1st May 20121
Your alternative Offer2

Online Energy Saver 13* Standard monthly Direct Debit* Online Energy Saver 18*
First 225kWh used each quarter 21.006p 22.267p 20.975p
All/Day remaining kWh 9.777p 11.706p 11.027p
Night Units per kWh 5.174p 5.837p 5.498p

Gas prices Your current prices Your new prices from
1st May 20121
Your alternative Offer2

Online Energy Saver 13* Standard monthly Direct Debit* Online Energy Saver 18*
First 670kWh used each quarter 6.730p 7.606p 7.164p
All/Day remaining kWh 2.992p 3.382p 3.185p



Energy consumption down, but efficiency is too

It’s been a warmer than average winter, only 75% as cold as last year according to an independent source, and my calculations bear that out too.

Season Degree Days @17.5C Average Per Day
2008-2009 2134 10.51
2009-2010 2121 10.45
2010-2011 2072 10.21
2011-2012 1567 7.71

This smaller temperature difference  complicates things, as we now have a much bigger effect from our baseline usage, which had been ignored in previous calculations.

  Low Rate
High Rate Electricity
Per Degree Day
08-09 7.20 16.30 71.90 95.40 9.08
09-10 7.09 16.18 62.52 85.79 8.21
10-11 7.14 18.46 60.73 86.33 8.46
11-12 5.49 15.38 50.42 71.29 9.24

As you can see, our total energy use per degree day has actually increased, despite the changes made with better lighting and timed radiator valves.  In addition, we reduced the heating to only 7.5 degrees in a 3m x 4m room at the back of the house with 3 outside walls which uses electrical heating.  I have to admit, I’m disappointed.

Maybe if we look at the numbers differently.  Our baseline gas usage appears to be about 12 kWh/ day, and our electricity usage about 8 kWh for high rate, and 4 kWh for low rate.

Below is the table with units of kWh per degree day.

  Low Rate
High Rate Electricity
10-11 0.307 1.024 4.772 6.104
11-12 0.193 0.958 4.983 6.134

While this is better, you can see that the overall usage is still the same, with no measurable effect from the changes, though High Rate electricity is actually down 7 per cent, and low rate is down 38 per cent, but gas usage is actually up 4 per cent, overall though we used 0.5% more energy per degree day than last year.

I’ll have to put this down the the fact that we have the gas fire on in the lounge in the evenings, and it is really toasty in there.

The other good news though is that we did manage to generate .45 kWh of high rate electricity per degree day over the period, which is included in the consumption figures above.

So in terms of fossil fuels, our consumption has dropped by 7% over the period.

In terms of absolute cost, we used 18%  less energy we did in the previous heating season, but that was unfortunately offset by an 18% rise in prices over the same period, so costs were similar to the previous year.

Friday, 2 March 2012

LED Lighting photos

Yesterday, my sister complained there weren’t any pictures.  Well, here they are:


First, the light fixture the LED’s were replaced into in the bathroom.  The one on the right is the LED, as is the one you can’t see on the left.  I had to leave one halogen, so left it in the middle pointing to the mirror.  This fixture used to be 60W, it’s now 26, and the light appears to be the same warm color from both the LEDs and the halogen.  Output is 285 Lumens, but they are not dimmable.


The photo on the right is of the lamp directly above the mirror.

This is a 240V 50W halogen equivalent led drawing 6W with a GU10 fitting.  Again, the light is a very warm color.  You can see in the reflection on the tiles, the 3 individual LEDs.

This was done before, and isn’t counted in the costs below.


P1000059Finally, the rebuilt desk lamp that had failed.  The old plastic head is on the desk for comparison, with its 20W capsule halogen, compared to the new 3W LED.

You can see that the clamps cause the arms to splay out slightly, but it doesn’t appear to be putting any excessive strain on the fitting.

The lamp is quite a bit larger than the one that was originally in this fitting, but I don’t think it looks too bad from the angle I see it from most of the time.

The total cost of this project was £17.94, and given I replaced a desk lamp that was broken, I think was very good value.  And £10 of the total was an Amazon gift voucher for using their credit card!

Payback time on the project on energy costs alone looks like this:

Old wattage: 60+20 = 80 W
New wattage: 3 + 20 + 3 + 3 = 29 W
Difference = 51 W

Cost savings per hour at 51W = £0.0055

so £17.94 / £0.0055 per hour = 3261 hours

At two hours a day that’s 5 years, and a CO2 saving of 1400 kg to boot.  Lifetime of the lamps is forecast to be 50000 hours, so I should never have to replace them.  We’ll see how they cope in the moist environment of the shower room.

Thursday, 1 March 2012

More LED Lamps

Yesterday, I ordered some new 3W LED 12V bulbs to replace the 3 20W lamps currently in the kids bathroom.  I had been warned that I might need a new transformer, and that they might not work without changing it.

My brother-in-law is an electrician in France, and I asked him about the likelihood that they wouldn’t work, and he thought it would probably be worth a shot, but he had said that electronic transformers might not like such a low current draw.

Well, I plugged all three in, and it appeared to work, however after a short time, I noticed a distinctive hum.

The solution of course is to plug in one of the original 20W halogens, taking the load of the light from 60W to 26W with the new bulbs.  Still a big improvement!

As for the third bulb, I happened to have a failure simultaneously of my halogen desk lamp, which has a transformer, and two antennae which carry the 12V AC.  And from our redecoration of the kitchen several years back, I had kept an old halogen light fitting that clamped onto two rails.

So, a quick unscrew of the old fitting, and a clamp on of the new and I have a new desk lamp that also draws only 3W!


Thursday, 12 January 2012

Financing University Study in England for £150 a month!

My son is going to study Engineering here in the UK.  It’s a 4 year course, and we have to find some way to finance it.

The cost of tuition is £9000 a year, and the living expenses are about £1000 for each of 3 terms.

Where will we get the money?

Anyone can apply for a loan of £9000 for tuition, and for living expenses up to £5500 a year if you live away from home outside London.  The living expenses is means tested, but anyone can apply for 65%, so there’s 3575 available.

That brings the annual loan funds available to £12,575, or over the entire course, £50,300.  After you add the 3%, you get a total of £51,809 in todays money at the end of the course owed.

For reference, here’s a link to the page on loans

How does interest accrue?

The loan costs RPI + 3% while studying.
After you leave, if  you earn £21,000 or less, RPI
£21,000-£41,000 RPI + rate between 0-3%
£41,000+ RPI+3%


As a side note, it is not apparent whether the RPI changes year on year or not.

How is the loan Paid Back

The loan is for a fixed period of 25 years from the date you finish. 

You repay 9% of the amount you earn over a threshold (£21,000 a year), and if after 25 years, it’s not repaid, the debt is wiped out, or if it’s not repaid by the age of 50, or if you die or are unfit to work!

How much do you need to earn to pay this back?

51,809 / .09 = £575655.  Divide this by 25 years, and you get an average annual salary of £23,000 over the threshold required to pay this back, giving an average  monthly cost in today’s money of £172.50, but the reality is slightly different.

Assume you earn the worst possible situation for accruing interest, that is income of £41000 a year, so you get hit with the full 3% + RPI.

After 25 years, you’ll end up having repaid 46,800 of the £50,300 originally borrowed.  That’s a savings of  £3500!

If you average £50,000 a year, your loan still is not paid back, in full, leaving a balance of £13,000, but the effective interest rate you borrowed the money at is 1.2%  + RPI

Try getting that rate from a bank for a mortgage!

If you average £60,000 a year, you finally pay back your obligation:  After 20 years!  The effective rate is 1.9% + RPI in that case.

Finally, let’s say you get really lucky and earn £100,000 a year.  Then payback happens after 9 years, at an interest rate of 3.9% + RPI.

Am I better off with a smaller loan? Probably Not!

Lets assume you have some money put aside, and you use that to fund the maintenance expenses entirely.

Your total borrowing drops to £36,000, Initial loan starts at £37,080.

£100,000 salary pays back after ~5 years at about %4.2 + RPI
£60,000 salary pays back after ~12 years at 2.0% + RPI
£50,000 salary pays back after ~18 years at 1.8% + RPI
£41,000 salary leaves a balance of £12,010, but you’ve repaid an extra £10,800 at a cost of 1.05% + RPI.

All of these outcomes are worse!