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Comment by nostromo | Hacker News Reader

We switched to LEDs about two years ago and have switched back to halogen bulbs recently for few reasons.

1) It didn't actually make much difference on our electricity bill. I believe this is because we use most of our lighting during the winter, and the wasted heat from the traditional bulbs isn't really wasted at all -- we just shifted more work to our electric heating system.

2) Many of the bulbs had burnt out. I am now very skeptical of all the "20 year lifetime" claims since we lost many expensive bulbs in two years.

3) The light quality just isn't great. People will argue this point, and I can't point to any evidence to support my claim, but our perception was that the light was either too blue, or too yellow, and just "looked weird." I wonder if it's related to the strobing of the LEDs.

LED slow motion: https://www.youtube.com/watch?v=zAfWKcg8Bq0

Halogen slow motion: https://www.youtube.com/watch?v=sCD5BMr6LsA

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> 1) It didn't actually make much difference on our electricity bill. I believe this is because we use most of our lighting during the winter, and the wasted heat from the traditional bulbs isn't really wasted at all -- we just shifted more work to our electric heating system.

The only reason people expect them to is the, IMO, obsolete idea that lighting load is a significant driver of power usage.

> 2) Many of the bulbs had burnt out. I am now very skeptical of all the "20 year lifetime" claims since we've lost lots of expensive bulbs in two years.

Maybe I have just been lucky, but the LED floods I put on the exterior of my house have been working like champs. I used to go through halogen and CFL bulbs like crazy out there. The Cree LED retrofits for my dimmable can lights have also been solid.

I'm not sure this is an obsolete idea. The lighting in my house is simply an astounding use of electricity. In fact, I think people underestimate how much power it consumes.

My house's baseline load is about 200w; networking/computer equipment mostly. The fridge that cycles on and off, and an instant-hot tap that cycles on and off to keep up to temperature.

Each bedroom had 60w floodlights in 4 cans. Sure, we don't have them on all the time, but 4x3x60 = 720watts. That's half a hairdryer! Our living room+hallway was even worse. There were a bunch of MR16s at 50w. With 16 of them in the house, that's another 800w. When we're home in the evenings, the living room lights are on all the time, because it's in the main part of the house. To be fair, the payback on the $500+ in LED bulbs I put in is way out there, but a big driver in my spending was to keep temps down during the summer. It seems so silly to artificially heat the house with wasted electricity.

In the winter, we don't use much heat, and the gas forced air heat is a hell of a lot better than using lightbulbs.

> My house's baseline load is about 200w

I don't know offhand what my baseline is. Still, this works out to 2.4 kWh baseline energy usage for you.

> Each bedroom had 60w floodlights in 4 cans. Sure, we don't have them on all the time, but 4x3x60 = 720watts. That's half a hairdryer! Our living room+hallway was even worse. There were a bunch of MR16s at 50w. With 16 of them in the house, that's another 800w. When we're home in the evenings, the living room lights are on all the time, because it's in the main part of the house.

That's a hell of a lot more lighting than I have. Our bedrooms have single-bulb overhead lights. The guest bedroom is rarely used, the master has two 25W lamps that are used infrequently, and the third is my lab with has light on maybe two hours a day (I prefer it off unless I am at my workbench). We have a bunch of cans, but except for one that is always dimmed they are usually off. The lights that are typically on when we are home are T8 fluorescent tubes in the kitchen.

Anyway, going back to your example, the typical assumption for lighting is that a given fixture is used on average 3 hours per day. Using that assumption for all your lights gives 4.6 kWh for lighting, or only about twice your baseline load. Noticeable, but far from astounding.

> an instant-hot tap that cycles on and off to keep up to temperature

It doesn't get anymore first world wasteful than this.

most electric water heaters work the same way, just further from the tap

At much greater cost, I might add. I ran my kill-a-watt for a few days, and, IIRC, it uses something negligible like 7 cents a day. I'm looking at Emerson's webpage and they're quoting 6 cents per day at $0.0986/Kwh so my 7 cents seems about right in a more temperate climate but with electricity costs more like 15-16 cents/kwh. Their numbers say .6kwh, so call it 219watt-hours in a year. Or, in other words, 1/365th of my house's normal standby power consumption when nobody is home.

And I've got a tankless hot water heater for our main hot water supply which is of course a savings in orders of magnitude more than is 'lost' by the instant hot.

The instant hot also probably uses negligibly more energy than the other ways we heat water; microwave (for beverages) or running a burner on the stove on full blast for minutes at a time just to get a large pot of water up to boiling.

Of course, you can see from the fact that I bother measuring electricity of new devices with my kill-a-watt (and replacing all bulbs with LEDs at great cost) that I'm somewhat sensitive to electricity consumption. But I choose to spend my consumption where I think it makes the most sense.

Sorry but I can't understand your first paragraph since I can't figure out the pronouns and specifically what objects you're measuring/looking up the wattages of. Can you clarify?

Sorry, "it" was in reference to the instant-hot water tap that was referred to as a first world problem.

Good points. I still use LEDs outside and they last a very long time. I suspect it's because they stay cool, which extends the lifetime of LEDs. I'm also not as sensitive to light quality for outdoor lighting.

It's easy to do the science behind the light quality from different bulbs, but no one seems to bother doing it. You just need to print a graph of the spectrum that the bulb emits and compare it to whatever your favorite bulb is like. Would love to have this information available on the box, but of course that would make comparison too easy.

Instead we're stuck with a simplification where a very high-dimensional property is reduced to a single number, and even that with low precision since few LED bulbs have emission spectra that resemble a black body.

http://www.gl-leds.com/led-bulbs/img/b60-led-bulb-spectrum.j...

Here's hoping TM-30-15 gets wide adoption. If every bulb listed its fidelity index, gamut index, and color vector diagram, you'd actually be able to tell which ones are awful.

http://energy.gov/sites/prod/files/2015/09/f26/tm30-intro-we... [PDF]

Most likely the ones not listing it.

The problem is that comparing a spectrum isn't actually meaningful. I really don't care about the spectral shape of the light if it's not perceptible to me. You want some sort of quantitative estimate of what you care about.

If you're looking at a white piece of paper with black text, you won't be able to tell the difference.

But if you're looking at color (flowers, a painting, human skin) then spectral shape becomes very important.

Look at all of the shades of color you're not seeing under a typical CFL: http://www.bealecorner.org/best/measure/cf-spectrum/spectrum...

I'm not disputing the fact that there is a difference. But whether it's perceptible depends on where in the spectrum the differences are in relation to what you are looking at and the response curves of your cones. Not to mention your expectations.

I'm a pretty picky person when it comes to color when working with photos. But I don't have a single incandescent in my house and I can't even remember the time when I've been bothered by not being able to discriminate colors.

I have to agree. Every few years I'll try again with LEDs and energy efficient bulbs. I'll look online, buy a few different brands and specifically look for the ones with a "cool" colour temperature that should look natural.

In every instance the lighting was terrible. I really haven't yet found an energy efficient bulb that didn't make my place look like a jail cell.

My current place has halogen track lighting and I really like it.

Halogen is very much not a cool color temperature. If you're trying to match your existing halogen lighting, stick to lights labeled "warm white". If they list a color temperature, 2700K is a reasonable option, 3000K works in a pinch. Halogen bulbs are typically a bit over 3000K, but they'll shift warmer as they're dimmed, which is a pretty common use case.

The vocabulary is a bit weird, since "warm white" corresponds to "low color temperature". It's because we mentally associate blue with cold/ice and orange with fire, but the color temperature scales are based on the color an object glows as you heat it. To make a black body glow blue you have to heat it pretty damn hot.

You don't want "natural" lighting if you want it to look like an incandescent. "Natural", ie "day" light is very blue. You specifically want a non-natural, warm color temperature.

Fire is plenty natural.

In architectural lighting, the reference spectrum depends on color temperature. Warm whites are measured against the black body spectrum, cool whites are measured against the daylight spectrum.

What do you mean? Daylight is very close to a blackbody.

Close but not quite, atmospheric effects block some portions. We use the CIE d-series illuminants as an approximation: https://en.m.wikipedia.org/wiki/Standard_illuminant#Illumina...

That's done because it's very unusual to get a black body radiator that hot on Earth, so if you're talking about something on the cool white end odds are high it's daylight or trying to approximate it, not a tungsten filament or a campfire.

If you are looking for "natural" indoor lighting (like for a bedroom or living room), you probably want a "warm"er color, on the range of 2400k to 2600k.

http://go/wiki/Color_temperature#Categorizing_different_ligh...

Cree for type A and downlights with 90+ CRI. I'm using Soraa single-source MR16s elsewhere in my house, with a CRI of 93+.

The problem with the light quality might be to do with the color rendering:

https://en.m.wikipedia.org/wiki/Color_rendering_index

Basically, LEDs have a much more irregular spectrum than incandescents or halogens, so objects may look weird colours under them.

I don't know if the 20 year lifetime claim will pan out, but I replaced as many lights in my apartment that I could with LEDs a couple of years ago and haven't had a single one die yet, including in the bathroom, where I used to have to replace a bulb almost once a month.

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