Why turn off lights?
 

We have a fairly well insulated home. We heat with hot air, gas fired furnaces. I am wondering if it really saves money by shutting off lights in rooms not constantly used in winter. My thinking is that since they are incandescant lights, in winter leaving them on, produces heat, which helps lessen the heat needed to be produced by the furnaces. Summer is obviously a different matter. Since energy is not lost, just changed in form, I am thinking the lights on approach is not very bad. I will acknowledge that the furnace is probably a more efficient way to produce heat, but we need light anyway. Any thoughts?

Being a reverse vampire I leave lights on. I found the cf buls work best, about a year on 24x7, then they burn out one dark night. :eek: The filiment bulbs ask about 39 days, then go poof. LED bulbs like to flicker when they go bad.

I had gas heat and in the winter would switch out to filiment bulbs to heat and reduce use of gas heat as it was noisy to have it on all the time. It made a good deal of heat, but it ran my power bill up 10 bucks a month with 3 of them on all the time.

in the winter, it's really a question of how much heat you're getting for the money... in the summer and above comfortable temperatures, anything that draws power gets evil glares from me.

Watts to Btus (IT)/Hour Conversion Calculator

that should give you a rough idea of how much heat you're generating, you'll have to figure out cost on your own since power rates are so incredibly variable depending on where you're located, time of year, even time of day for some people.

in my personal digging:

1500 watt electric heater = 5118 BTU/hr assuming it's running at 100% DC. BTW: electric heat is so close to 100% efficient, it's hilarious when ads run for those infrared heaters that claim to be better than a regular electric heater.

http://www.handymath.com/cgi-bin/electric.cgi

it costs me 11.6993 cents per KW/H last month for power.

if it ran at all times(24 hours X 30 days = 720 hours), it would end up costing 126.35 for 3,684,960 BTUs.

compare that to how much it costs you to run the gas furnace and you'll see if you're actually saving or losing money.

I have propane heat, one gallon of propane cost $1.50 and has 92,000 btu, furnace is just better than 90% efficent so I get about 83,000 btu of heat for $1.50, at 12(using the above cost, mine's closer to 15) cents a KWH, $1.50 buys 12.5 kwhs or (1 kwh = 3412 btu) or 42650 btu, about half the heat from electricity as from propane. Electric heat would cost me 2x as much per month.


Natural gas is way better, it's usually sold by the therm I think, which is 1,000,000 btus, last time I look it was about $4-5 a therm. one therm = 293 kwh which would cost $35 in electricity. Electric heat would cost 7-8x as much per month. (I don't and have never had natural gas so not sure on these numbers)

EDIT: forgot to factor in 90% efficient furnace with Natural Gas so closer to 1/6-1/7the cost of resistant electric heating.

In the Northwest, heating with gas is roughly 1/3 the cost of heating with electricity. I would bet just about anywhere in the country gas is 1/2 the cost or better.

Lights that tend to be used for extended periods of time are either CFL or LED. Lights that get cycled often such as closets and vanity are all incandescent. My outdoor lights are on a switch that knows when sunrise and sunset is, and acts accordingly.

There are many reasons to turn off the lights. I am an energy auditor by trade. As Roosterk0031 states above you will pay roughly 6-7 times as much to heat your home with electricity than with natural gas. There are many factors that can make it complicated: furnace efficiency 80-96%, incandescent bulb heating efficiency 95%, and transmission losses of 35% on average from the power plant to your home. The take away is that unless you are getting electricity for under 2 cents per kwh you will pay more.
Beyond saving you money, anytime you conserve electricity you are reducing emissions at the power plant. This is especially important if your powerplant burns coal. Coal is a dirty dirty fuel that emits greenhouse gases that are causing climate change.
You are best off using the gas furnace and supplementing with electric space heaters as little as possible. Change those incandescents out to LEDs or CFLs and see even more savings.

I once lived in an efficiency apartment that had a window unit . Refrigeration cool / resistance heat . With incandescent lamps , in cold weather , I turned on every light in the place . This gave a well distributed heat . I only turned on the resistance heat when it got really cold .

Since I was heating with electricity , it made little difference between the two methods . And with the incandescent lighting , I got plenty of light , also .

God bless
Wyr

For your situation, it seems that leaving lights on is nearly equivalent in efficiency compared with the resistance heater. If you prefer the extra light, then that is an excellent way to heat.

During summer months though, I would swap out the incandescents with CFL for the lights that tend to stay on long periods of time.

Weren't no CFL's . :-) This was back in the stone age , in my early / mid 20's .

I did skimp on the lighting in the summer .

Also , the apartment was on the 2nd of 3 floors . So the apartment had a conditioned space above me and below me . And only 2 outside walls . The side walls were common with conditioned space , also .

The disadvantage with the 2nd floor was toting my stuff up or down the stairs , when I moved in and moved out .

I now have CFL's all over the house . Been using them a LONG time . Since before they came down in price .

But , I have gas heat . Except for the 12,000 BTU mini split A/C - Heat Pump we installed this summer . I have been experimenting with the HP ( living room and dining room ) . So far , I think I like it .

God bless
Wyr

Aah, but the REAL question is: which co$t$ more, electricity for the lighting or electricity/gas/oil for heating?

If electricity is less costly (as I think it is), then lights can be beneficial for reducing heat loss, but certainly NOT useful for creating enough heat to offset outside cold.

Here, in ariz-zona, where summer A/C isn't cheap, I religously turn OFF anything that's not absolutely needed...or actually IN USE.

...and, I've found that LED lamps are slightly more efficient (9W vs. 14W for 800-Lumen, 5K lamps) than CFL's at power consumption, but vastly better at survivability when installed pointing downward. CFL's tend to "cook" their electronics when oriented base-UP/globe-DOWN...causing their electronics to "cook" and fail WAY too often. Hence, we've switched to LED's.

slightly? 9 vs 14 = 55.5% more energy needed for the CFL.

in the end, it's only 5 watts, but the LED use just over half the power the CFL does to create the same amount of light.

I'll match that and see you one better: I use those yellow halogen worklights in the winter as "extreme zone heating" and besides the fact that they throw out lots of nice heat, they throw lots of light too thus enabling me to keep the regular- and not very good at emitting heat- lighting off.

Disclaimer: This works great for me but do it at your own risk: Take the glass out of the worklamps and replace that with screen for better heat transfer with some small measure of safety retained.

I don't like the idea of using regular ceiling lighting for heat because heat rises and my ceiling and attic get heated quite enough already. And, they are too far away to feel any of their heat. In fact, I got the idea for using the worklamps as zone heaters because I had been considering adding a heatlamp or heated floor to my bathroom when I had the insight that I didn't want my heat source up above, trying to run heat downward. So I place them on the floor or on a countertop; when the heat rises up and out I can really feel it. This radiant heat is actually nicer- feels warmer- than what space heaters put out, radiant or fan-assisted.

Frank,

Do you place a small computer fan behind the light to help distribute the heat? Probably only cost a couple extra watts.
JJ

I keep a small table fan behind the light I have on the counter by the bathroom sink. The ones on the floor work fantastic with radiation only.

I lived in a townhouse once that had 2 shared walls. I wondered if the house wasn't warmed or cooled, if it would leach any significant energy from the surrounding units. Would be interesting to see how cool it gets in the winter with zero heating.

Heat pump should be more economical until about 40 degrees outside temperature I believe, depending on local utility rates.

From 3/7/13
in Iowa, apparently?
I don`t think I`ve ever bought propane at that price here in northern NV, certainly not in the 3 years that I`ve been tracking my gas purchases. As it happens, my tank did get filled in Mar of this year... at $3.54/Gal. Last month it was the highest I`ve ever been hit with at $4.05

What are other people paying around the globe for LP?

The problem with heating with light bulbs is a great deal of the heat is infrared, so if you have a light bulb next to a window then nearly half of the heat from that light bulb is shinning out the window and you are slowly heating the outside, even a room darkening shade over the windows will help keep the heat in, a space blanket over the window will reflect even more of the heat back in to the living space.

Working around with lamps for heating is too dangerous, and it would still not be so efficient as a purpose-built heater.

It all comes down to how much a unit of energy costs from your electric (light) and from your regular heating. In England, 1 kWh of energy from electricity costs about 15p, but an equivalent 1kWh of energy from natural gas costs about 5p. So for a 100W incandescent bulb, the approx 90W of waste heat is about 3x more expensive than if you let it come from your gas heating. But 90W is a drop in the ocean of our total heating costs here... It's worth using LED/CFL in summer when you don't need any extra heat input, but less worth worrying about it in winter.

Since we have had near 0 f weather here I can see why a regular or hid bulb would be used over a cf one. This cold weather makes the cf bulbs dim,very dim. No idea if they use more power when they are dimmer vs full brightness,but the mercury vapor one we have had no change in brightness.

I recently purchased a keroscene round heater to use to supplement our heat pump. As you may of may not know they start to slack off as the temps go below freezing of water. Its all electric at that point. Ive used the keroscene heater on its lowest setting af ew hour every evening and its very fuel efficient. Think a gallon is like 3,50 a gallon. Nice to have incase the power fails.

CFL bulbs are dim until they warm up, and they do warm up inside. I'm using leftover incandescent bulbs during the winter; rather than chucking them before they burn out. And I'm switching over to LED's, now, so no more recycling the mercury and instant on, longer life, etc.

I tried using a small 750 watt heaver vs my 3 stage heat pump in my 800 sq ft condo since it was just me there to save power. I would move the space heater set to 70 degrees between the living room and bed room with the hvac set to 58 degrees. Seldom did the hvac turn on. The electric portable heater would cycle off and on in either room. My power bill was slightly more than when usng the heat pump set t 72 for the whole place.

An electric heater cant hold a candle to a keroscene heater. What I like to do it put a tea kettle on top with water in it to further reflect heat down low and add moisture to the air.

Yeah, I hear propane is going up. Funny thing the Richmond DUP has been advertising recently to use MORE PROPANE for some reason. Guess as the price goes up and if you increase demand you pockets become greener for the suppliers?

Since most heat pumps stop working at the temp water freezes, wonder if you can like put a shed over it and use a propane heater to heat the air above its operating temp and come out ahead vs using the propane directly in the home?

No. The heat pump merely pumps the heat from one location to another. It's more efficient to generate the heat where you want it in the first place.