Tuesday 11 October 2011

Energy Saving Halogen Replacements

When we first moved into our house 15 years ago, we installed halogen lighting in our hall.  Back then, electricity wasn’t quite so expensive, and we didn’t use the room that much anyway, and there weren’t that many options for recessed lighting.

We opted for a mains voltage system that could go on the existing dimmer switch, and therefore didn’t require expensive transformers for each light of the eight downlights.

P1020728

Yesterday, I changed two of the lights over the table for the new Philips MASTER LEDspot PAR 20 MV dimmable LED lights.  I have to admit, I was ready to be disappointed, however the lights are very good.  Nearly as warm as the old lights, dimmable like the old lights, and fit in the sockets neatly as well.

I bought them from http://www.camelecws.co.uk/ in Cambridge.  I did get a quote from someone else for a discount of about £1.60 per lamp online, but I’d have had to buy 6 to get the discount.

Also on Amazon

 

The new lights have a slightly wider angle (40 degrees) but that was intentional, as the lighting was a bit too focused before anyway.

The downside?  These are really expensive (£26.34 each including VAT).

So, the break even calculations are:

£26.34 / £0.09 kWh = 293 kWh (amount of energy to break even at current prices)

293kWh / (50W – 7W) = 6813 hours (amount of time lights must be switched on to break even)

The old lamp has a life of 2500 hours, and they currently cost about £5.00 each, so it looks like we’d be replacing two of them during the payback period, so we put that back into the calculation:

(£26.34 - £10.00) / £0.09 kWh = 181 kWh

181 kWh / (50W – 7W) = 3693 hours

Now, we would like to leave these lights on in the evening from about 5pm until 10pm in the winter time, which probably averages out at 2 hours per night over the year.

3693 hours / 2  hours/day / 365 days/year  = 5 years.

That’s the payback for two of  the lights, but the 0ther 6 are more difficult, as they won’t be on nearly as often, probably averaging 20 minutes a day at best.  That makes it a 30 year payback, using the current levels of  lighting.

So the plan at the moment is to use up the stock of existing bulbs as they blow in the existing fixtures, and keep our fingers crossed that the prices come down over the next few years.

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