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We took the mini plunge

Discussion in 'Environmental Discussion' started by tripp, Jan 4, 2009.

  1. tripp

    tripp Which it's a 'ybrid, ain't it?

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    OK. So after 4 days and 3.5 hours the new fridge has chewed up 2.87 kWh. That ends up being 0.69 kWh/day. That's 20.77 kWh/mo! Of course, during the summer we won't get that, I reckon, but still, that's superb. The real test will come in may. I'll have to monitor the fridge for another week to get a better sense for how it compares to the old one, but so far the results are really encouraging. I knew it would be good, but this is really excellent.
     
  2. icarus

    icarus Senior Member

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    Pretty good Tripp,

    We sorta figure in the Solar advice biz that anywhere near .5kwh/day for a fridge is pretty good, so you are right in there. Several of the "exotic" high efficiency fridges don't do any better than run of the mill energy star models.

    A couple of things to consider, make sure that fridges are kept pretty much full. If you don't have enough food, fill a couple of water jugs and keep them in the fridge. The cold thermal mass helps the fridge to run efficiently. Same for the freeze section, fill it up. (you do need to leave enough air space for circulation however.

    Icarus

    There may be a tax credit in 07 or 08,,, check into it.
     
  3. acdii

    acdii Active Member

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    I dont know about you guys, but I found replacing a 40 Gallon WH with 2 tankless units, has saved a large amount of money, especially since we have LP. I also have 2 furnaces that are 97% efficient, and properly sized so they run only enough to keep the house warm with short cycles. The main one can bring the house temps from 58 to 70 in about an hour and a half. (it did that because the heat exchanger needs to be replaced and keeps tripping a sensor) I keep the house roughly between 68 and 70 year round, the A/C in the summer is 13 SEER and runs only as needed, the house has lots of shade. My Electric bills are roughly the same year round, only slightly higher in summer. We used about 1600 gallons of LP a year to heat 6000 SqFt of house and for hot water and cooking, average electric bill is $200 a month. Changing most of the lights to CFL dropped the bill down too. If I happen upon a large amount of cash, then I would have a deep well drilled for thermo HVAC, and use solar for hot water, and a wind mill for electric. Right now my biggest expense is keeping the water pipes in the barn from freezing so my horses always have fresh water.
     
  4. tripp

    tripp Which it's a 'ybrid, ain't it?

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    If we ever do solar water heating we might replace our 40 gal water heater with a storage tank and then install a tankless water heater. Our space is a bit limited and I don't know if we really have room for two water storage tanks. In the mean time, I've wrapped the water heater (which is NG) with R-11 wrap and installed a 1.6 gpm low-flow shower head. I also put pipe insulation on the hot water lines coming out of the water heater. Well, the first 6 feet, which was all that I could reach.
     
  5. icarus

    icarus Senior Member

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    I don't know why you need 2 tanks, 1 tank for solar preheat, and a demand. If you need two, stack one above the other.

    Icarus
     
  6. tripp

    tripp Which it's a 'ybrid, ain't it?

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    basically if we wanted to keep our existing water heater. We can't stack 'em, not enough room. This project is for down the line, since you've been reading the insulation thread you know that the crawl space is a much higher priority than the water heater.
     
  7. jayman

    jayman Senior Member

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    If you combine geothermal exchange HVAC with a desuperheater for summer, your hot water is "free." According to Manitoba Hydro, there are substantial savings to doing so

    http://www.hydro.mb.ca/your_home/home_heating_comparisons.pdf

    I wish I had gone geothermal when I built the house at my hobby farm
     
  8. icarus

    icarus Senior Member

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    Capturing waste heat off the AC condenser is a great idea. If one lives in an AC climate it is a no brainer, since it gives you free hot water, AND it lets your AC run more efficiently. Combine that with demand gas and solar and your hot water heat is nearly free year 'round.

    Also, remember that water tanks don't have to be mounted vertically if they are only going to be used as storage or preheat tanks. (I really don't know why you couldn't run an electric horizontally, but it would cycle strangely.

    Icarus
     
  9. hyo silver

    hyo silver Awaaaaay

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    Is it too late? It sounds like you've got the room for it, and certainly the knowledge to retrofit the controls. I would guess in your climate a deep pipe would be better than a shallow field, but you'd know best. Could you go a step further and build in something to store summer heat underground? Ultimately, between solar, geothermal and earth sheltered design, we should be making money on energy, rather than getting a monthly bill.
     
  10. tripp

    tripp Which it's a 'ybrid, ain't it?

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    It's sad, but true. The tough bit is that we should have been doing this 3 decades ago. The US wouldn't be importing NG now, that's for sure.
     
  11. Trollbait

    Trollbait It's a D&D thing

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    I see a couple things wrong with mounting a standard steel tank horizontally while trying to get the longest service life out of it. Draining out sediment needs to be considered, though the sediment is really a problem with a working heater. Mainly, you won't be able to check or replace the anodes without draining the tank..
     
  12. icarus

    icarus Senior Member

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    You are correct about needing to drain to replace the anode. Where I live we never have to replace them due to our water so it is not something I think about. Do you really need anodes if the tank is not using electricity? I have no idea.

    As for flushing the tank, if you install the tank on its side, with the T&P valve down, and install a boiler drain in it's place, (teeing in a T&P if needed) than you can flush one just fine. Also, it is likely that only the first tank will need regular flushing.

    Icarus.
     
  13. patsparks

    patsparks An Aussie perspective

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    Your house is 557.418 m²! Are you kidding? Do you opperate a boarding house or small industry from home?

    The best way to reduce your energy bill is to reduce the size of your living space. My 3 person family with friends around almost daily rattles in our 135m² home we have so much room, I can't imagine a private home 4 times bigger.
     
  14. icarus

    icarus Senior Member

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    Wow, 6000 sq ft, 1500 gal/propane, $2400 for electricity!

    We live ~1/2 the year in 600 ft sq, the other half in ~900. In the former we use ~6 gal propane/month for cooking and water heat and fridge. All the electricity is solar. We also burn ~ 1/2 cord of wood/month, some of that for the hot tub. We also use ~5 gallons of gasoline/month for shop tools, topping up the solar batteries etc.

    In the latter, we use 100 gallon of propane/year for cooking, water heat, and some space heat. Electrical bill (on grid) ~8 kwh/day Plus about 1/2 cord of wood per month during heating season. This energy use includes two shops that are used ~1/2 time.

    Icarus
     
  15. tripp

    tripp Which it's a 'ybrid, ain't it?

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    6000 is insanely massive. We've got 1300 sqft. 2100 would be really nice, but we're doing just fine, and our mortgage is reasonable. Sooooo glad we didn't move to a bigger house in the heady days of the real estate boom. The added stress of a bigger mortgage would have been unpleasant to say the least. Also, it's kinda hard to live by my values in a really large house (assuming that I could actually afford one). We've basically committed to staying in this house, so I'm keen to optimize it. One could probably make a killing around here (denver area) improving the efficiency of houses (my crawl space is NOT unique at all, so much energy wasted there).
     
  16. tripp

    tripp Which it's a 'ybrid, ain't it?

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    Well aren't you a precise l'il bugger. :p
     
  17. Celtic Blue

    Celtic Blue New Member

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    Surprisingly to me on a "per square foot basis" your usages appear to be similar. acdii has a lot more potential for reducing consumption of course.

    Without knowing acdii's location and the actual kWh (I assume $0.1/kWh for simplicity) it is hard to size up the electric. However, I'm surprised at running 68-70 F in Summer. We stay pretty comfortable at ~78 F during cooling season. I'll sometimes kick it down a degree for an hour or two to dehumidify when we are near the balance point and opening the windows doesn't help because it is stuffy.

    If acdii is using 2,000 kWh as a base electric load that appears to be pretty high. Determine the base load in a non-heating/non-cooling month or two in both Spring and Fall or use Winter although blower operation will likely raise it a little over baseline. Summer is a good time to determine base water heating load if it is using the same fuel as the furnace.

    Base electric load shouldn't change all that much with varying home size for a given number of occupants. In looking back at my last five residences the base electric (excluding electric water heat in one) has shown about 20% range across them...and the lowest base load is in the home that is twice as large as the smallest. The major differences I detect in comparing the homes are some appliance changes and CFL conversions (and the aforementioned elec. water heater.) I should be able to shave off another 20% as I replace some electronics and the fridge.

    The real problem with house size is HVAC operating cost which is far more proportional to square footage. Even with ideal insulation, air infiltration/minimum air exchange requirements result in substantial load as the home volume increases.
     
  18. acdii

    acdii Active Member

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    That 6000 SqFt includes the basement, which in mostly bedrooms and a play room for the kids, the rest of it is storage for "junk". It seems like a lot of room, but the rooms are rather small. The bedrooms, if you put in a queen size bed, you don't have room for anything else. It has 3 bedrooms in the original part, a master bedroom in an addition, and 2 more downstairs, plus an office and play room. The largest room is the kitchen, and I included an existing garage that was converted to a living space, but is not heated or conditioned. I am in northern IL near Rockford, and electric rates are high, my usage has dropped by 30% over the past few years by the improvements I made. It is a ranch house that is very long, but narrow, only 26' wide, really poor design, but has brick fascia and is well insulated. Because of its length we needed two separate zones for HVAC and water. I also use programmable thermostats so when we are not home the temps go up or down depending on the season. Reason I keep the temps low is I sweat very easily, and even in 50* weather I can work up a sweat, so it isn't just a matter of comfort, its to keep me from being dehydrated. I hate it, but that's how I am.

    I did an experiment with the AC one year and discovered that the on time for the units when set at 78, and 72 was identical, so keeping it ~72* during the summer doesn't cost me anymore than keeping it at 78*! Its getting it down to that temp that eats up the juice, so if I keep the temp set at that all the time, it costs less. I also know the systems are running efficiently when the outside temp is 92 and the units are cycling instead of constant on as they were at my other house. My old house was a two story 1500SqFt house that actually cost me more in energy than this one and that was keeping the temps up during the summer, and low in the winter. I will take a look at my bill and see what my actual usage is.

    I also have a horse barn with electric heat tape on the water pipes and troughs, and those use up a bit of electric, so it is hard to determine the overall usage of the house alone. Since it has been so cold these past few months, with temps hovering around 0 for quite some time now, those tapes have been doing a lot of work. I can also tell how well the insulation is by my roof, there is still a lot of snow in it with no icicles forming. I see a few homes that have no snow on them, or a lot of icicles, and can tell they aren't insulated very well.

    Those who have kids can probably agree with this, it is very hard to get them to turn off a darn light! I have a 14YO constantly yelling hey turn of that damn light, while my 3 yo, has no problem turning them off. GRRR.
     
  19. icarus

    icarus Senior Member

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    ACDII,

    A couple of thoughts,

    There are a number of semi-conductor heat tapes out there that draw only fractions of the amount of power as conventional heat tapes. The are also approved for installation under pipe insulation and over plastic pipe, all dropping energy demand by a factor of ~100. There are also some that can be installed INSIDE the pipe. Frostex and Wintergard heat tape price sheet, heat tapes custom made to specifications. Buried water pipe heat tapes also.

    As for turning off the lights,, consider motion detectors in the room switches. As long as someone is in the room, the lights will remain lit, as soon as they leave,,,out go the lights.

    Also, consider modifying your AC system to use the waste heat from the Condenser to heat domestic hot water. These systems have two benefits, the first is to reduce the energy cost of the hot water, with the side benefit of making the AC run much more efficiently. A good HVAC contractor can do the work, and the pay off would be very quick.

    Icarus
     
  20. tripp

    tripp Which it's a 'ybrid, ain't it?

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    ha ha. Yeah, it's all about training. My 6 yr old is getting pretty good and the 3 yr old is learning fast. The nice thing about our house is that it gets good ambient light during the day so there are really only a few lights that actually need to be turned on during the bulk of the day.