Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

How well do you control your energy usage

Tags:
  1. Oct 5, 2016 #1

    wolram

    User Avatar
    Gold Member

    Like is your house insulated to updated code, double glazed widows, cavity wall insulation, Do you control you energy usage
     
  2. jcsd
  3. Oct 5, 2016 #2
    Yes, I live in an insulated building and have new plastic (vocab?) windows. There are regulators on radiators and we try not to heat more than necessary.
     
  4. Oct 5, 2016 #3
    Well I live in a 1922 house so there are many energy issues. I have done my best to seal cracks, update storm windows on original windows and set a reasonable heat temp in winter.
     
  5. Oct 5, 2016 #4

    russ_watters

    User Avatar

    Staff: Mentor

    I monitor and control mine pretty well (because that's what I do!). Most of the building construction issues are taken care of by building codes, since my house isn't that old. But I did have an issue that my unfinished walk-out basement wasn't insulated, so I fixed that by finising and insulating it. That made a big difference.

    I am constantly adjusting HVAC vents (registers) to push heat/AC only where it needs to go, which also makes a big difference. Little things like turning off an entertainment center at the wall outlet add up too. And I have a real-time energy monitor installed.
     
  6. Oct 5, 2016 #5

    russ_watters

    User Avatar

    Staff: Mentor

    Heh - that is the one thing I will not do: I'll conserve where reasonable, but I will not make any changes that impact my comfort. I'm willing to pay a little more to be comfortable in my own home!
     
  7. Oct 5, 2016 #6

    wolram

    User Avatar
    Gold Member

    I agree one must be comfortable in ones own home, but would it be wise if one is feeling chilly to put a sweater on rather than crank up the air con .
    I have noticed a shed load of new houses being built in my area, non have solar cells fitted, I would have thought that all new builds should be required to have them.
    We have them and save about 20% on our electricity bill.
     
  8. Oct 5, 2016 #7

    mheslep

    User Avatar
    Gold Member

  9. Oct 5, 2016 #8

    mheslep

    User Avatar
    Gold Member

    On the contrary, some US states have blocked or discontinued the Net Metering plans that oblige the utility to pay the customer retail rates for generated solar electricity. Hawaii was the first to stop NM. The large majority of the average electric bill goes to building and maintaining the infrastructure of the electric grid; only a small part goes to pay for the fuel used for actual generation. So substantially reducing the electric bill while remaining connected to the grid pushes the costs onto the neighbors.
     
  10. Oct 6, 2016 #9

    Dr Transport

    User Avatar
    Science Advisor
    Gold Member

    I find it ironic that people cool their houses to [itex] 65^{\circ} [/itex] in the summer and keep the heat on to almost [itex] 80^{\circ} [/itex] in the winter and yes, I am accounting for the humidity difference.....
     
  11. Oct 6, 2016 #10

    Astronuc

    User Avatar
    Staff Emeritus
    Science Advisor

    The bulk of energy use is for heating or cooling. During cold period the house uses natural gas heating, but I open blinds to use sunlight to heat the house, and allow inside to get cool at night ~ 60 F. During the hot summer, I'll set the AC, but as much as possible, open windows at night to allow the cool outside air to cool the house. During the day, I'll let the temperature get to 80 F inside, open windows when the outside temperature drops.

    I'm looking at ways to shade the south side of the house, which gets direct sunlight and heat radiating from the driveway.

    I've been able to reduce peak electrical consumption by about 50%. For about 8 or 12 months in the last year, I used less than 280 kWh/month, and for 6 of those 8 months used less than 240 kWh/mo. Electrical demand increased during July, August and September, due to outside temperatures > 90 F (32.2 C), with several days at or above 100 F (37.8 C).
     
  12. Oct 7, 2016 #11
    Switching to LED lights doesn't hurt.
     
  13. Oct 7, 2016 #12
    ah yes I've done that too. Pricey at first, but my electric bills are quite a bit lower even compared to CFL.
     
  14. Oct 7, 2016 #13
    When 93 octane was well over $4/gal, I controlled my energy usage by not driving my 70 Chevelle with a 383 ci engine, 195 cc heads (runners), long duration cam with almost 0.5" lift, and a Holly 750cfm double pumper. 7 mpg around town, 10 mpg on the highway @ 60 mph. Now I just pour the fuel in, and run it rich :cool:

    My house is very energy efficient, my monthly electric bill running A/C all summer is about $100/mo.
     
  15. Oct 7, 2016 #14

    OCR

    User Avatar

    Well, I was skeptical at first... but, now I know.[COLOR=#black]..[/COLOR] :oldcool:[COLOR=#black] ..[/COLOR]:thumbup:
     
  16. Oct 8, 2016 #15
    Yeah, bored and stroked. Rotating assembly balance to within 0.5 g. Blue printed the engine myself. :cool:
     
  17. Oct 8, 2016 #16
    Split by hand with an ax or a maul. And we make a fire daily in the cold season (living at 9100 ft).
    Fire_zpshqqp0vdh.jpg

    Start_zpsq4nmjzeo.jpg

    Done_zpssfkpjknw.jpg
     
  18. Oct 8, 2016 #17

    OmCheeto

    User Avatar
    Gold Member

    Did you consult with PF members before sealing cracks, and updating storm windows?
    I haven't researched the "cracks" thing yet, but "storm windows" can be a waste of money, if you don't understand the physics behind them.

    I talked my mother into installing storm windows, about 35 years ago.
    I was very embarrassed when I discovered that my suggestion was, um, "Sorry about that. But these are nearly worthless." :redface:
     
  19. Oct 8, 2016 #18
    hmmm I have some old thin single pane windows facing west and north. Last windows there was noticeable drafts. I tried various weather striping, but it's a pain and looks terrible. Wouldn't adding storm windows reduce that and help protect the original windows?
     
  20. Oct 9, 2016 #19

    OmCheeto

    User Avatar
    Gold Member

    Yes.
    In looking over my notes from 1989, it would appear that all of my numbers were "theoretical".
    Having looked at about 15 different websites this morning, it would appear that "empirical" numbers are quite a bit different.

    In my defense, I will quote energy.gov; "Even though storm windows add little to the insulating performance of single-glazed windows (that are in good condition)"

    And in your defense, I will finish their quote; "field studies have found that they can help reduce air movement into and out of existing windows. Therefore, they help reduce heating and cooling costs."

    I guess this means, that I have to start doing window experiments now. :biggrin:
     
  21. Oct 10, 2016 #20

    OmCheeto

    User Avatar
    Gold Member

    I've done all of that, with the exception of looking at insulation codes.
    Which I've just done, and found the title somewhat odd: Additional Measures / Required Options
    Isn't the phrase "Required Options" a bit oxymoronic?

    Anyways, my house is definitely not up to code, nor do I think it ever will be. But the improvements, so far, have cut my costs in half.

    I also don't quite have double glazed windows, as such improvements always seemed a bit labor and capital expensive.
    So I opted for the lowest price option: Shrink wrapping! About $1.50 per window.
    On the windows which do not receive sunlight, the system lasts quite a while.
    On those that do receive sun, the double sided tape eventually gives up the ghost, due to the temperature.
    But, there's always duct tape, and then they're back to spec.

    My sister, a couple of years ago, talked me into building a solar thermal collector.
    I had vacillated over building one, for at least a decade, as I didn't really think it would work, precisely where I live, exactly when I needed it.
    It is sitting in my living room.
    But! About a week ago, I started a project, which I had designed in my head, about 10 years ago. (04-07-2007 11:09 AM, to be exact)
    atticheat.JPG

    Of course, as a pauper, my current incarnation little resembles the above drawing.
    If you throw out all the watery stuff, replace the "radiator and fan" with a garage sale "bathroom fan" ($6, new!), and the "plastic pipe" with "dryer exhaust hose", you will have a pretty good picture of what's going on.
    So far, my numbers have been a bit "iffy", as the weather has turned a bit "Londony".
    But I've been collecting said numbers since September 21st, and plan on collecting them until spring.

    The other thing I tried this year, was reducing the temperature of my water heater, in the summer, to make bathing just tolerable.

    water.heater.summer.OmDelocks.setting.png
    summer setting​

    It made no sense to me, to have that much thermal mass, just sitting there, at 125°F, just counteracting upon what I was trying to accomplish.

    water.heater.winter.setting.png
    winter setting​

    But, of course, in our latitudes, this time of year, 120°F kind of makes sense.
     
    Last edited: Oct 10, 2016
  22. Oct 11, 2016 #21
    There are different views on heating.
    Is it generally better to heat only when you're at home (so you have to maximise heating after arrival) or is it better to set to medium temperature for all day?
    I suppose the second option is better and cheaper but I can't do the calculations to prove it.

    Also, is it wise to turn the heating off in rooms that are not used? How much extra heat will be needed in rooms that are heated because some heat will be lost in the cold room?

    I've heard several theories but my physics education nor experience is sufficient to objectively decide what is correct

    I'm asking about apartment located on the highest floor (10th) in the south - east corner of the house, if that matters to the answer. The regulators on the radiators can't be set to a certain temperature. You can only manually regulate flow of hot water, but there's no automatic thermostat.
     
  23. Oct 11, 2016 #22
    I don't consume much power. I have a 10 watt LED bulb and I use it with a dimmer. I don't have a TV either because I felt I was becoming dumber with the stuff they had to show (specially the news) so I got rid of it.

    I just wish I had an air conditioner. I'd want to drop temperatures, not raise them. At least to 83F or 80F. I conform with that. Rare nights when temperature has dropped to 83F I have had to use my thick blanket to sleep. Otherwise I cannot sleep much because I feel cold as time goes by (I'd sleep like 3-4 hours at most without my blanket). That temperature is okay for me as long as I have a blanket to sleep with. Just being able to drop room temp to 83F: that's all I need.

    All in all I monitor my watt usage. Since I already use very little, I don't skimp on it when it comes to using a little more.

    Edit:
    I think that it is better left for experimental data on a per building basis. Theoretical calculations would require knowledge of the whole building structure and materials. I think experimental would be less of a hassle since all one would need are devices to measure energy consumption of the heater and room temperature. Then running the experiment to gather the data, and make conclusions from there with it. Although it would apply only to the building and specific place that the experiment was made on.
     
    Last edited: Oct 11, 2016
  24. Oct 11, 2016 #23

    russ_watters

    User Avatar

    Staff: Mentor

    These are often stated as controversial, but really do have straightforward answers as long as the questions are sensibly stated:

    1. Is it better to set back your house temperature during the day or does the extra energy for the "catch-up" when you return home negate the savings(or even cost more)?
    Answer: It is better to set back the temperature because heat loss/gain is proportional to the temperature difference through the wall. So the total amount of heating/cooling required is lower even with a high demand "catch-up" period.

    2. Is it better to close vents in rooms you aren't occupying or does the extra heat transfer betweeen the occupied and unoccupied rooms negate the savings?
    Answer: It is better to close the vents in the rooms you aren't occupying. The only heat transfer that matters is the heat transfer through the outside walls, and you're reducing it.

    Now, caveat: the way you worded the first question implies you mean three different setpoints instead of two (a "medium" temperature is in between a high and low?). If that's really what you meant, the question is unanswerable because it depends on the specific setpoints and times. But why would you want to do such a thing anyway? The issues should be totally independent of each other: if you are comfortable at that "medium" temperature, you should be using that when you are home.
     
  25. Oct 11, 2016 #24

    russ_watters

    User Avatar

    Staff: Mentor

    It is also worth noting that in most areas in the USA, there is a lot more energy to be saved in air conditioning than in heating, for a couple of reasons:
    1. You are home when you need the most heat (at night), but away at work when you need the most air conditioning.
    2. The temperature differences are wider in heating, so you get less benefit from a temperature setback.

    Example for #2:
    Summer Outside Temp: 95F
    Summer Inside Temp:75F
    Winter Outside Temp: 20F
    Winter Inside Temp: 70F

    Summer Delata-T: 20F
    Winter Delta-T: 50F

    So a 1F setback reduces your cooling energy usage 2.5x more than it reduces your heating energy usage. And for unoccupied setback (when you are at work during the day), the sun makes the savings difference even bigger.
     
  26. Oct 11, 2016 #25
    Thanks for the answer, now I understand it better. I also like the way you posted the questions, that's exactly what I meant!
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted