Those Lightbulbs again

[ChrisGwinn]

Using hiccup's numbers, if you went from 4 75W bulbs to 4 20W CF's, your furnace would have to be 400/(400-80) = 400/320 = 1.25 more effective at converting energy in to home heating than heating your home through light bulbs.

I'm not buying that. I'm guessing that furnaces turn energy in into home heating much better than twice as effectively as light bulbs do the same.

I was hoping you would show up.

Setting aside the make light/don't make light part of the energy usage for now, why would an electric furnace be more efficient at generating heat than a lightbulb? Or are you drawing a distinction between heat and heating?

[Kraken]

My little office doesn't have a radiator. During the winter, heat comes from a 60W light bulb and two computers. The computers dwarf the light bulb's contribution. During the summer, I use a window air conditioner to whisk away that heat. Your calculations should consider the cooling necessary to void light bulb heat, too, as long as you're getting nitpicky about energy budgets.

[The Meal]

Setting aside the make light/don't make light part of the energy usage for now, why would an electric furnace be more efficient at generating heat than a lightbulb? Or are you drawing a distinction between heat and heating?

I'm playing fast-and-loose, but yes, I'm considering the various methods of heat conveyance used by a home's heating system as opposed to that of incandescent lighbulbs placed throughout the home.

~Neal

[Hiccup]

Please correct me if I'm wrong, but what I think you are saying is in a strictly electric only household,

• during the heating season the CLF's savings is spent on heating to compensate for the loss of heat from standard bulbs.
• Conversely, the cooling season benefits more from CFL's in that the A/C system has to work less to cancel out the heat from standard bulbs.

In which I agree , if the situation was that cut and dry.

Combine CFL's with high efficentcy heating and cooling however and you are looking at $200+ savings per year on your electric bill. Depending on your utility service provider, most energy saving upgrades to your home are rebateable. On the business side there are even tax breaks (not sure about residential).

[brettmcd]

Please correct me if I'm wrong, but what I think you are saying is in a strictly electric only household,

• during the heating season the CLF's savings is spent on heating to compensate for the loss of heat from standard bulbs.
• Conversely, the cooling season benefits more from CFL's in that the A/C system has to work less to cancel out the heat from standard bulbs.

In which I agree , if the situation was that cut and dry.

Combine CFL's with high efficentcy heating and cooling however and you are looking at $200+ savings per year on your electric bill. Depending on your utility service provider, most energy saving upgrades to your home are rebateable. On the business side there are even tax breaks (not sure about residential).

I dont buy in any way that ill save over 200 dollars a year by switching to cfls. Sorry thats just not possible.

[noxiousdog]

I dont buy in any way that ill save over 200 dollars a year by switching to cfls. Sorry thats just not possible.

How many lightbulbs do you have in your house and how long are they on?

[The Meal]

I dont buy in any way that ill save over 200 dollars a year by switching to cfls. Sorry thats just not possible.

How many lightbulbs do you have in your house and how long are they on?

I'll go with 30 for a daily combined total of 40-bulb*hours.

~Neal

[ChrisGwinn]

Setting aside the make light/don't make light part of the energy usage for now, why would an electric furnace be more efficient at generating heat than a lightbulb? Or are you drawing a distinction between heat and heating?

I'm playing fast-and-loose, but yes, I'm considering the various methods of heat conveyance used by a home's heating system as opposed to that of incandescent lighbulbs placed throughout the home.

This may be part of where my confusion lies. I heat with a gas boiler and radiators, so my house doesn't really have any heat conveyance mechanisms other than making something hot and waiting for the heat to spread. When I did have electrical heat, it was those baseboard heater things.

And I'm genuinely curious about what makes one electrical heating system more efficient than another. Is there something going on other than running heat through a resistor and getting it hot?

[ChrisGwinn]

Please correct me if I'm wrong, but what I think you are saying is in a strictly electric only household,

• during the heating season the CLF's savings is spent on heating to compensate for the loss of heat from standard bulbs.
• Conversely, the cooling season benefits more from CFL's in that the A/C system has to work less to cancel out the heat from standard bulbs.

In which I agree , if the situation was that cut and dry.

Combine CFL's with high efficentcy heating and cooling however and you are looking at $200+ savings per year on your electric bill. Depending on your utility service provider, most energy saving upgrades to your home are rebateable. On the business side there are even tax breaks (not sure about residential).

I dont buy in any way that ill save over 200 dollars a year by switching to cfls. Sorry thats just not possible.

What's your monthly electrical bill?

[noxiousdog]

I dont buy in any way that ill save over 200 dollars a year by switching to cfls. Sorry thats just not possible.

How many lightbulbs do you have in your house and how long are they on?

I'll go with 30 for a daily combined total of 40-bulb*hours.

~Neal

40*365 = 14,600 hours/year.

The first 323 hours/bulb get you to break even, so 323*30=9690 leaving 4910 hours for a return. The difference per hour is $0.0058. 4910*.0058=$28.

So in year 1, you'd save $28.
In year 2, you'd save 14,600*.0058 or $84.

This is priced at $0.28/bulb incandecent, $2.16/bulb CFL, $0.13/KWh electricity, and 60W bulb equivilent.

This ignores all burnout replacement costs.


(note: 40 bulb hours/day seems low to me. Just an hour's worth of bathroom use results in 7 hours of bulb use as we have vanity lighting. Our bedroom has a 3 light fixture. etc, so multiply as necessary)

[brettmcd]

Please correct me if I'm wrong, but what I think you are saying is in a strictly electric only household,

• during the heating season the CLF's savings is spent on heating to compensate for the loss of heat from standard bulbs.
• Conversely, the cooling season benefits more from CFL's in that the A/C system has to work less to cancel out the heat from standard bulbs.

In which I agree , if the situation was that cut and dry.

Combine CFL's with high efficentcy heating and cooling however and you are looking at $200+ savings per year on your electric bill. Depending on your utility service provider, most energy saving upgrades to your home are rebateable. On the business side there are even tax breaks (not sure about residential).

I dont buy in any way that ill save over 200 dollars a year by switching to cfls. Sorry thats just not possible.

What's your monthly electrical bill?

$55-60 per month.

[Hiccup]

Please correct me if I'm wrong, but what I think you are saying is in a strictly electric only household,

• during the heating season the CLF's savings is spent on heating to compensate for the loss of heat from standard bulbs.
• Conversely, the cooling season benefits more from CFL's in that the A/C system has to work less to cancel out the heat from standard bulbs.

In which I agree , if the situation was that cut and dry.

Combine CFL's with high efficentcy heating and cooling however and you are looking at $200+ savings per year on your electric bill. Depending on your utility service provider, most energy saving upgrades to your home are rebateable. On the business side there are even tax breaks (not sure about residential).

I dont buy in any way that ill save over 200 dollars a year by switching to cfls. Sorry thats just not possible.

Again Energy Savings Calculator

Also, you must have missed the first part of the sentance.

Combine CFL's with high efficentcy heating and cooling

Just CFL's alone switching 10 75w Incandescents with 10 20w CFL's saves ~$100 alone in energy costs per month.

[Hiccup]

$55-60 per month.

Let's go with the low end of $55 per month.

$55x12 = $660 Annually.

The average house has at least 20 light bulbs. (my 1 bedroom apartment has 18).

Lets again average those 20 light bulbs to be 60w bulbs, some will be higher, some lower but the average would be close to that 60w.

The CFL replacement for a 60w Incandescent is 13w.

Using the calculator I linked, replacing those 20 lightbulbs would save $177 a year on your electric bill.

[noxiousdog]

$55-60 per month.

Well, for the rest of us that have electricity in our homes, the savings are substantial.

[brettmcd]

$55-60 per month.

Let's go with the low end of $55 per month.

$55x12 = $660 Annually.

The average house has at least 20 light bulbs. (my 1 bedroom apartment has 18).

Lets again average those 20 light bulbs to be 60w bulbs, some will be higher, some lower but the average would be close to that 60w.

The CFL replacement for a 60w Incandescent is 13w.

Using the calculator I linked, replacing those 20 lightbulbs would save $177 a year on your electric bill.

And I dont buy those numbers as being possible. Not a chance.

[brettmcd]

$55-60 per month.

Well, for the rest of us that have electricity in our homes, the savings are substantial.

Sure whatever.

[noxiousdog]

Just CFL's alone switching 10 75w Incandescents with 10 20w CFL's saves ~$100 alone in energy costs per month.

There's no way this is a real world application. I have access to measured data. A 60W incandecent uses .059 KW/hr, a 14W equivilent CFL used .014KWh. At 13c/kwh you'd have to use 2,222 hours of electricity or average 7 hours/day per bulb in your example. And that doesn't include purchasing costs which is substantial.

The math works, CFL's are cheaper, but let's not overhype.

[Poleaxe]

$55-60 per month.

In my entire adult life, I've never had an electric bill that low.

[malchior]

$55-60 per month.

Let's go with the low end of $55 per month.

$55x12 = $660 Annually.

The average house has at least 20 light bulbs. (my 1 bedroom apartment has 18).

Lets again average those 20 light bulbs to be 60w bulbs, some will be higher, some lower but the average would be close to that 60w.

The CFL replacement for a 60w Incandescent is 13w.

Using the calculator I linked, replacing those 20 lightbulbs would save $177 a year on your electric bill.

And I dont buy those numbers as being possible. Not a chance.

Why not? That is about a 26% savings over the year. I switched over completely to CFL and my next full billing cycle was 30% lower. I don't pay to heat my water and don't pay for heat, so I'm purely paying for my electronics use. I haven't needed to AC yet, so I can't come to any conclusion other than the change in light bulbs caused the energy savings. So the calculator is probably in the right ballpark.

[malchior]

$55-60 per month.

In my entire adult life, I've never had an electric bill that low.

Neither have I, but we don't necessarily live where he does.

[Poleaxe]

$55-60 per month.

In my entire adult life, I've never had an electric bill that low.

Neither have I, but we don't necessarily live where he does.

He would have to have gas heat and no AC usage, gas stove and hot water heater, gas clothes dryer. It's possible, I'm not saying it's not.

[Hiccup]

$55-60 per month.

Let's go with the low end of $55 per month.

$55x12 = $660 Annually.

The average house has at least 20 light bulbs. (my 1 bedroom apartment has 18).

Lets again average those 20 light bulbs to be 60w bulbs, some will be higher, some lower but the average would be close to that 60w.

The CFL replacement for a 60w Incandescent is 13w.

Using the calculator I linked, replacing those 20 lightbulbs would save $177 a year on your electric bill.

And I dont buy those numbers as being possible. Not a chance.

I'm trying to understand your position, I know that calcuator I linked estimates, but you can change the default values to fit your electric rate and such.

Please tell my WHY there is not a chance for those number to be right.

[The Meal]

(note: 40 bulb hours/day seems low to me. Just an hour's worth of bathroom use results in 7 hours of bulb use as we have vanity lighting. Our bedroom has a 3 light fixture. etc, so multiply as necessary)

You may be right. Let me work through this more systematically.

Outdoors: (8.25 hrs)
Dark-activated garage light (which the HoA gets on my case when I disable -- bastards) 8-hr.
Porch light. Infrequent use. We'll give it 0.25 hours/day average.

Downstairs: ( hrs) (9.25 hrs)
Kitchen: 1-hr * 4 bulbs = 4-hr.
Dining area: 0.5-hr * 4 bulbs = 2-hr.
Bathroom: infrequent use = 0.25-hr average.
Living room: 3-hr

Upstairs: (19.5 hrs)
Main area: infrequent momentary use * 3 bulbs = 0.25-hr.
Master bedroom: 1-hr * 2 bulbs = 2-hr.
Master bath: 1-hr * 6 bulbs = 6-hr.
Office: infrequent use = 0.25 hr
Bedroom: 4-hr * 2 bulbs = 8-hr.
Bath: 1.5-hr * 2 bulbs = 3-hr.

Total = 8.25 + 9.25 + 19.5 = 37 hours. Hey, I was in the ballpark with my guess!

We're not much for evening-time illumination. We blow our energy budget with other light-producing devices (PC/TV/laptops).

~Neal

[The Meal]

$55-60 per month.

In my entire adult life, I've never had an electric bill that low.

Neither have I, but we don't necessarily live where he does.

He would have to have gas heat and no AC usage, gas stove and hot water heater, gas clothes dryer. It's possible, I'm not saying it's not.

When I lived alone in Minnesota, that described my situation exactly, minus the clothes dryer (which I didn't have at all). I think I was paying closer to $35-$40/month in electricity at the time. $50ish seems a perfectly reasonable monthly electricty bill to me.

~Neal

[noxiousdog]

FYI: I hate you non-AC users. May you be cursed with insanely high gas bills.

[brettmcd]

$55-60 per month.

In my entire adult life, I've never had an electric bill that low.

Neither have I, but we don't necessarily live where he does.

He would have to have gas heat and no AC usage, gas stove and hot water heater, gas clothes dryer. It's possible, I'm not saying it's not.

When I lived alone in Minnesota, that described my situation exactly, minus the clothes dryer (which I didn't have at all). I think I was paying closer to $35-$40/month in electricity at the time. $50ish seems a perfectly reasonable monthly electricty bill to me.

~Neal

Thats exactly my situation, all gas appliances and I never run the ac, just use fans.

[Poleaxe]

FYI: I hate you non-AC users. May you be cursed with insanely high gas bills.

They'll take my AC when they pry it from my cold, dead fingers.

[naednek]

$55-60 per month.

In my entire adult life, I've never had an electric bill that low.

I rent a house, and our electrical bill is rarely over $60. The last 3 months it's been in the low 50's. So, it is possible, and realistic.

I leave my computer on all day, we fans that are on most of the day, and we use the heater/airconditioner at least 6 hours a day, more on the weekends.

We also have PG&E which is only to heat the water. Everything else is electricity. That bill is never over $20, and yesterday the bill came in and it was $14.

[Poleaxe]

$55-60 per month.

In my entire adult life, I've never had an electric bill that low.

I rent a house, and our electrical bill is rarely over $60. The last 3 months it's been in the low 50's. So, it is possible, and realistic.

I leave my computer on all day, we fans that are on most of the day, and we use the heater/airconditioner at least 6 hours a day, more on the weekends.

Where do you live?

[ChrisGwinn]

Please correct me if I'm wrong, but what I think you are saying is in a strictly electric only household,

• during the heating season the CLF's savings is spent on heating to compensate for the loss of heat from standard bulbs.
• Conversely, the cooling season benefits more from CFL's in that the A/C system has to work less to cancel out the heat from standard bulbs.

In which I agree , if the situation was that cut and dry.

Combine CFL's with high efficentcy heating and cooling however and you are looking at $200+ savings per year on your electric bill. Depending on your utility service provider, most energy saving upgrades to your home are rebateable. On the business side there are even tax breaks (not sure about residential).

I dont buy in any way that ill save over 200 dollars a year by switching to cfls. Sorry thats just not possible.

What's your monthly electrical bill?

$55-60 per month.

So $200 is roughly 30% of your yearly energy use. If moving to a CFL reduces energy use of a light by 80%, then basic algebra tells us that you'll save > $200 if your incandescent lights are roughly 40% or more of your overall electrical usage.

What percentage do you think they are? Why?

[naednek]

$55-60 per month.

In my entire adult life, I've never had an electric bill that low.

I rent a house, and our electrical bill is rarely over $60. The last 3 months it's been in the low 50's. So, it is possible, and realistic.

I leave my computer on all day, we fans that are on most of the day, and we use the heater/airconditioner at least 6 hours a day, more on the weekends.

Where do you live?

I live in Sacramento CA. Normally weather isn't too cold during the winter, but we had a pretty cold winter (colder than normal) where day temps were in the 30's. The last month the weather has been in the high 80's low 90's. So we have been using our appliances more than I normally would.

[brettmcd]

Please correct me if I'm wrong, but what I think you are saying is in a strictly electric only household,

• during the heating season the CLF's savings is spent on heating to compensate for the loss of heat from standard bulbs.
• Conversely, the cooling season benefits more from CFL's in that the A/C system has to work less to cancel out the heat from standard bulbs.

In which I agree , if the situation was that cut and dry.

Combine CFL's with high efficentcy heating and cooling however and you are looking at $200+ savings per year on your electric bill. Depending on your utility service provider, most energy saving upgrades to your home are rebateable. On the business side there are even tax breaks (not sure about residential).

I dont buy in any way that ill save over 200 dollars a year by switching to cfls. Sorry thats just not possible.

What's your monthly electrical bill?

$55-60 per month.

So $200 is roughly 30% of your yearly energy use. If moving to a CFL reduces energy use of a light by 80%, then basic algebra tells us that you'll save > $200 if your incandescent lights are roughly 40% or more of your overall electrical usage.

What percentage do you think they are? Why?

Less then that. As I said I just dont believe that switching to cfls is going to give a 40% reduction in energy costs. The savings are being inflated somewhere, for what reasons I dont know, but they are.

[noxiousdog]

Less then that. As I said I just dont believe that switching to cfls is going to give a 40% reduction in energy costs. The savings are being inflated somewhere, for what reasons I dont know, but they are.

Do you know what a watt is?

[ChrisGwinn]

Less then that. As I said I just dont believe that switching to cfls is going to give a 40% reduction in energy costs. The savings are being inflated somewhere, for what reasons I dont know, but they are.

Unfortunately for you, the numbers all are out in the open. Barring some of my wacky theories about electrical heating (which wouldn't apply to you), electrical use by CFLs, electrical use by incandescents, the price of electricity and the cost of lightbulbs are the only numbers in the equation, and they're all well-known values.

Now it's certainly possible that you don't have enough lights to see the $200 savings claimed earlier, but all the numbers scale up or down the electricity usage scale.

Either you need to show that one of the numbers in the equation is wrong, or you are. This is math - opinions don't count.

[Poleaxe]

$55-60 per month.

In my entire adult life, I've never had an electric bill that low.

I rent a house, and our electrical bill is rarely over $60. The last 3 months it's been in the low 50's. So, it is possible, and realistic.

I leave my computer on all day, we fans that are on most of the day, and we use the heater/airconditioner at least 6 hours a day, more on the weekends.

Where do you live?

I live in Sacramento CA. Normally weather isn't too cold during the winter, but we had a pretty cold winter (colder than normal) where day temps were in the 30's. The last month the weather has been in the high 80's low 90's. So we have been using our appliances more than I normally would.

Hmmm... Not sure why the difference, maybe higher AC usage- I do live in a sub tropical climate. I looked at your utility company and they actually charge about a penny less per kwh. One thing though, they said their average residential customer used 9000 kwh per year, and my last month usage of 1425 was a low month. Also, not sure what your family situation is, but we have a family of four and an electric stove and clothes dryer- buth of which get a workout.

But as I said, even as a young adult 20 years ago I don't believe I ever had an electric bill as low as 60 dollars.

[brettmcd]

Less then that. As I said I just dont believe that switching to cfls is going to give a 40% reduction in energy costs. The savings are being inflated somewhere, for what reasons I dont know, but they are.

Do you know what a watt is?

Guess not, I must be a complete idiot who doesnt know something that is taught in elementary science classes.

What a silly question.

[naednek]

$55-60 per month.

In my entire adult life, I've never had an electric bill that low.

I rent a house, and our electrical bill is rarely over $60. The last 3 months it's been in the low 50's. So, it is possible, and realistic.

I leave my computer on all day, we fans that are on most of the day, and we use the heater/airconditioner at least 6 hours a day, more on the weekends.

Where do you live?

I live in Sacramento CA. Normally weather isn't too cold during the winter, but we had a pretty cold winter (colder than normal) where day temps were in the 30's. The last month the weather has been in the high 80's low 90's. So we have been using our appliances more than I normally would.

Hmmm... Not sure why the difference, maybe higher AC usage- I do live in a sub tropical climate. I looked at your utility company and they actually charge about a penny less per kwh. One thing though, they said their average residential customer used 9000 kwh per year, and my last month usage of 1425 was a low month. Also, not sure what your family situation is, but we have a family of four and an electric stove and clothes dryer- buth of which get a workout.

But as I said, even as a young adult 20 years ago I don't believe I ever had an electric bill as low as 60 dollars.

Oh I wasn't doubting your observation. I just wanted to validate brettmcd, because I myself fall in that range and it's great. I expected my bill to almost double since we went from an apt to a house. However our house is only about 150 sq ft bigger than the apt, but you probably know that apartments tend to self regulate on temperature. I rarely used the heater in winter, because of the shared walls.


I'm recently married and it's just the two of us with no kids. We do laundry every weekend, watch TV, play on the computer, have all electrical appliances besides the water heater.

[brettmcd]

Less then that. As I said I just dont believe that switching to cfls is going to give a 40% reduction in energy costs. The savings are being inflated somewhere, for what reasons I dont know, but they are.

Unfortunately for you, the numbers all are out in the open. Barring some of my wacky theories about electrical heating (which wouldn't apply to you), electrical use by CFLs, electrical use by incandescents, the price of electricity and the cost of lightbulbs are the only numbers in the equation, and they're all well-known values.

Now it's certainly possible that you don't have enough lights to see the $200 savings claimed earlier, but all the numbers scale up or down the electricity usage scale.

Either you need to show that one of the numbers in the equation is wrong, or you are. This is math - opinions don't count.

I can absolutely guarantee you that if i changed every light bulb in my house my bills would not drop to under 40 bucks a month. I have a grand total of 13 lightbulbs where I live, one of them already a crappy cfl floor/room lamp that was a gift that I cannot stand but am too lazy to replace.

[noxiousdog]

Less then that. As I said I just dont believe that switching to cfls is going to give a 40% reduction in energy costs. The savings are being inflated somewhere, for what reasons I dont know, but they are.

Do you know what a watt is?

Guess not, I must be a complete idiot who doesnt know something that is taught in elementary science classes.

What a silly question.

Well, if a incandecent uses 60 of them to produce x lumens, and a CFL uses 14 of them to produce x lumens, then a CFL will use 25% of the electricity of a incandecent. Therefore to get a 40% reduction in household electricity costs, it simply requires that 54% of your electricity is used by lighting.

Is it your contention that that is impossible?

[brettmcd]

Less then that. As I said I just dont believe that switching to cfls is going to give a 40% reduction in energy costs. The savings are being inflated somewhere, for what reasons I dont know, but they are.

Do you know what a watt is?

Guess not, I must be a complete idiot who doesnt know something that is taught in elementary science classes.

What a silly question.

Well, if a incandecent uses 60 of them to produce x lumens, and a CFL uses 14 of them to produce x lumens, then a CFL will use 25% of the electricity of a incandecent. Therefore to get a 40% reduction in household electricity costs, it simply requires that 54% of your electricity is used by lighting.

Is it your contention that that is impossible?

Yes. As 54% of a normal houses energy cost is not lighting.