Has your electric bill gone down if you have a lot of LED bulbs?

[BrokeFarmerJohn]

That being said that's what I learned in HVAC school 7-9 years ago. That's how I set my system up to swing for 2 degrees and no more.

For example my heating schedule in my stat is this. From 1pm-10pm it's 66 degrees in the house, I get home around 11pm from work, from 10pm-12am it's 68 degrees which I'm usually up watching tv around then before bed. From 12am-10am it's 66 degrees, when I'm usually sleeping ext. 10am-1pm it's 68, an average when I wake up and till I leave for work.

So it's only at 68 for 5 hours of the day, when I'm home the most and it's 66 the other 19 or so hours of the day.

I do change the temp depending if I'm hot or cold as needed but that's an example the schedule I run. Saturday and Sunday are different, those days it's mostly 68 due to heavier traffic in the house, more company ext.

 

[BrokeFarmerJohn]

A quick pic of my stat, it's been in the 60s during the day, the house picked up enough heat that at 1am it's still 70 in the house which means it barely ran at all today.

 

[Looking4new]

I just got my electric bill and the comparison from Feb 13, 2016 to Mar. 16, 2016 32 days I averaged 27 kwh/day.
Fast forward to this year and Feb, 14, 2017 to Mar. 16, 2017 30 days and I used 25 kwh/day. Why can't they (the powers that write up these bills) be consistent? The number of days in the monthly usage vary wildly. So I have to admit that getting the hybrid hot water heater saved me 2 kwh/day, I think.
It could be a lot of hocus-pocus to make me think I am saving money, too. Cynical you say? You bet! I don't trust big business, nor goobermint.

 

[fordmantpw]

The savings from turning your heat down (or your A/C temp up) has to do with heat loss. If a perfect world where there is no heat loss, there would be no cost difference to keep your house at 72 vs. 64, once your house reaches that temperature. The cost savings comes in due to heat loss to the outside of your house through the laws of thermodynamics.

Basically, the greater the temperature difference between two objects (the inside and outside of your house for instance), the greater the heat transfer. Let's say the temperature outside is 0 degrees. This means that more heat is transferred to the outside of your house with the 72 degree difference vs. the 64 degree difference (in the scenario above). So, if you set your thermostat to 64 instead of 72, you are actually losing less heat to the outside for that time the temp is lowered. This is all part of the laws of thermodynamics.

Now, I'm sure there is a sweet spot for setting the temp back, but I'm not sure what that is, and it would vary for each house due to the HVAC system, the size of the house, and how much stuff is in the house, etc. For geothermal systems, it's normally best to leave the temp set at a constant value, because as the temp difference between actual and set-point increases, it increases the usage for the variable pump. Basically, they are more efficient running at the lower setting for longer periods of time (keeping your house at 72) than they are at running at a higher setting for a shorter period (heating your house up from 64 to 72). With that said, we set ours back one degree in our bedroom at night for more comfortable sleeping, and my office gets set back a few degrees at night since I'm not in it from 5:00 PM to 5:30 AM and I don't want to heat it during those times.

Back to the LED question, when we built our house back in 2014, we put in all LEDs with the exception of a few CFLs in closets. Our electric bill stayed about the same, but our house size increased and we spend more on HVAC now than before, and the LED conversion is saving that money.

 

[techman]

Rheostats were probably last used in the 50s. They are large and made a lot of heat. They are just a variable resistor.

Rheostats were rarely, if ever used. Most older dimmers that looked like rheostats were actually variable autotransformers (variacs). They were big and usually had large knobs. Efficiency of them was actually quite good. If a rheostat was used, losses could be as much as 50 watts, which would cause a large amount of heat.

paul

 

[CobyRupert]

LED's typically use 1/5 (20%) the energy than an incandescent bulb of equal lumens.
So how much you save depends on how much of your bill was because of lighting.
If 100% of you electricity was incandescent, you're going to see an 80% reduction in your energy consumption. (But note there might be some fixed costs on your bill, example: If you use 0 electricity, your bill doesn't go to $0).

So if you only save a little with LED's, that tells you that a lot of your bill isn't from lighting. Usually much of the bill is from large heating loads (elec. heat, ovens, dryer, hot water heater) or A/C.

 

[Larry Caldwell]

Are you ahead, or behind money, 20 years later?

That's a simple question with a complex answer. The windows, doors and insulation made a big difference in the liveability of the house in addition to saving money. Replacing the appliances was necessary - washing machines and computers don't last forever. The 22 year old heat pump is still working, but a new one is probably on the horizon, and I have the $4900 in pocket to install a new one. Generally I think I'm money ahead. The subfloor insulation was only 12 years ago, but insulation is a gift that just keeps on giving. I didn't expect it to make the huge difference it did, but we can walk around barefoot in the winter without freezing our toes off.

If you figure all the energy upgrades have saved me $100/month for 10 years, I'm not quite even yet, but there are other considerations. I don't know if I will ever get a payback when I sell the place. People generally don't pay attention to upgrades they can't see, and home inspection reports don't happen until after an offer has been made. My wife was not in favor of spending all the money on insulation until she actually felt the difference in liveability, and then she became a believer -- about the first time she stepped out of a hot shower onto a warm floor.

 

[Zerk]

Now take that house that was 70 degrees and lower it to 60 degrees, it cools off everything in the house, when you flip the stat back up to 70 degrees it now has to heat up the whole house again, it has to run harder and longer to catch up, the harder and longer it's running to catch up exceeds the energy it originally took to keep the load at a consistent temp.

e.

While this makes sense you can write the same story by saying you are not heating it as much gone. Th question is how much do you save by not heating it, and how much does it cost to get it back to temp. I'd like to see more on this. Because you can tell the story either way, that it makes sense, if you don't use any math.

With forced air that recovers quick, I suspect it is ok to let it go down. With my boiler maybe not as much.

I put some research into this 10 years ago, and ended up letting it swing. i won't swear that it is right. But that was the conclusion.

 

[Zerk]

That's a simple question with a complex answer. The windows, doors and insulation made a big difference in the liveability of the house in addition to saving money. Replacing the appliances was necessary - washing machines and computers don't last forever. The 22 year old heat pump is still working, but a new one is probably on the horizon, and I have the $4900 in pocket to install a new one. Generally I think I'm money ahead. The subfloor insulation was only 12 years ago, but insulation is a gift that just keeps on giving. I didn't expect it to make the huge difference it did, but we can walk around barefoot in the winter without freezing our toes off.

If you figure all the energy upgrades have saved me $100/month for 10 years, I'm not quite even yet, but there are other considerations. I don't know if I will ever get a payback when I sell the place. People generally don't pay attention to upgrades they can't see, and home inspection reports don't happen until after an offer has been made. My wife was not in favor of spending all the money on insulation until she actually felt the difference in liveability, and then she became a believer -- about the first time she stepped out of a hot shower onto a warm floor.

I don't think you ever make up your money on doors and windows. I bought a house with them. And it is nice. First house I lived in, without drafts. I can turn heat down lower.

Realtor told me on a house I was selling wouldn't change the appraisal if I added new windows. The house had windows before you put them in. Changes curb appeal.

 

[Zerk]

That being said that's what I learned in HVAC school 7-9 years ago. That's how I set my system up to swing for 2 degrees and no more.
t.

I think it depends on the school and what their goal was. To TS and install or fundamentals? I never went to school, but worked for company installing boilers and furnaces. I bent tin, sweated copper ect. We had techs come and dial the natural gas in. Though some of plumbers felt they could do it too, but it was factory warranty thing. To trouble shoot and install you don't need theory. That is why they have tech schools and engineering.

Maybe yours covered it.


When it is around 0 out, I do leave it at constant temp, figuring in that case it is more efficient. Again all of this is from bowels.


Below are not technical articles, so maybe you are right. But the first 3 sites i came to disagree with you. Googled how low should I turn down my furnace.
Heat pumps,are different. But we don't tend to use those up here. Unless you are a hippie and want to save the penguins.
turn your thermostat down 7-10 degrees.
Turn Your Heat Down, Not Off, to Save On Your Heating Bill


A 10-degree drop could be 10 percent savings.
Common heating myths that can raise energy bills - Chicago Tribune


When your home will be empty for 8 hours or longer, set your thermostat 5°-8° higher in the summer and 10°-15° lower in the winter.
When you get home, set the thermostat back to your comfortable setting.
Doing so can save you 5-15% on your yearly energy costs, according to the U.S. Department of Energy.
3 Dumb Things You Do With Your Thermostat That Cost You Money - Minneapolis Saint Paul Plumbing Heating Air