Is 2.745Kw of domestic lighting over the top?

[big-all]

if we assume 15p perkw = 41.25p an hour is £9.90 a day =£69 70p a week =£3600 a year
now you can possibly half the number off light at any one time and half again for time off day but even that is £900 a year with leds you can remove 85% off the costs down to £540/135 a year and would expect a further 25% saving if downlighters and spots are changed for pendants

 

[JohnW2]

if we assume 15p perkw = 41.25p an hour is £9.90 a day =£69 70p a week =£3600 a year
now you can possibly half the number off light at any one time and half again for time off day but even that is £900 a year with leds you can remove 85% off the costs down to £540/135 a year and would expect a further 25% saving if downlighters and spots are changed for pendants

All essentially true, but I suspect that the actual consumption is probably far less than you are assuming. About half of his total potential lighting loads relate to bedrooms/bathrooms/dressing rooms, where the lights are probably only on for an hour or two per day, at most, or places (like loft and spare bedroom) where the lights are probably hardly ever used at all.

Whilst there are clearly considerable savings to be had by changing to LEDs (or CFLs), and/or by using more efficient/sensible light fittings, I doubt that those savings would be anything like as great as your figures imply. As others have said, the one room where things currently seem rather ridiculous is the kitchen (I suspect a 'kitchen/diner'),which currently accounts for over a third of the total potential lighting loads - and, particularly given that those lights are probably on quite a lot, there is a lot of saving to be had by addressing that room alone.

My kitchen/breakfast room has what, at least traditionally, appeared to be extravagant lighting, with 16 candle bulbs, but now that they are all 3W LEDs, that's less than 50W in total, and extremely light!

Kind Regards, John

 

[AndyPRK]

You and the previous owner like candle bulbs.

Was in 2 per fitting?

 

[big-all]

yes i agree johnw2
its more for illustration
as i frequently say my lighting bill is between about £12-18 so even 25% off the lower amount would have me worried

 

[JohnW2]

You and the previous owner like candle bulbs.

I suppose so. We largely stuck with the previous concepts but replaced with similar new fittings.

Was in 2 per fitting?

Three, actually ... 5 fittings with 3 each, plus one single in a sort-of alcove.

Kind Regards, John

 

[JohnW2]

yes i agree johnw2
its more for illustration ... as i frequently say my lighting bill is between about £12-18 so even 25% off the lower amount would have me worried

Fair enough. In turn, I was attempting to point out that on has to be careful about adding up the wattage of all the bulbs/lamps/tubes in a house and thinking that has necessarily got much to do with running costs. There are certainly some of the rooms in my house in which the lights are used so rarely, and even then for only short periods, that it would not be appropriate to include them in the equation, even if they had 2kW of bulbs in each of them!

Kind Regards, John

 

[ericmark]

if we assume 15p perkw = 41.25p an hour

So with 8 hours day light and 8 hours sleeping then max of 8 hours a day winter and likely just a couple in summer and not all on at the same time lets assume 1/2 are on and year around on for 4 hours average.

So £600 a year but some of that also reduces the heating bill so likely no more than £400 a year.

Since most of it is to heat kitchen which likely does not want heating to that extent then the kitchen has to be the first room to correct but this could change the taste of the food as less sweat is added.

 

[JohnW2]

.. So with 8 hours day light and 8 hours sleeping then max of 8 hours a day winter and likely just a couple in summer and not all on at the same time lets assume 1/2 are on and year around on for 4 hours average. ... So £600 a year ...

If all of the 2.745 kW's worth were on for an average of 4 hours per day, that would be about £600 per year (at 15p per kWh). However, as I've said, I find it hard to believe that lights in bedrooms, bathrooms dressing rooms etc. would usually be on for anything like 4 hours/day, even in winter - so I would expect the average for those rooms to be a lot less than 4 h/day over the year.

Kind Regards, John

 

[eveares]

Video of my lights: https://www.youtube.com/watch?v=pV3jb2Zrcok

Edit: I pay 13p per Kwh plus a daily standing charge of 27.4p

 

[big-all]

nice house

standing charge in this instance makes no difference to the calculations as they are paid regardless