What are you paying for electricity (price per kWh)?

Discussion in 'Prime Fuel Economy & EV Range' started by Clark_Kent, Aug 16, 2019.

  1. hill

    hill High Fiber Member

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    they were very accommodating to us when we wanted issues of working around venting a certain way & conduit a certain way - all we had to do was ask.
     
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  2. hill

    hill High Fiber Member

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    OUCH!!
     
  3. Paladain55

    Paladain55 Member

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    here gasoline is $3.09/gal for 87, electricity is $0.182/kWh, and natural gas if you do the conversion from $/therm to $/kWh (since we only use it for heat appliances) is $0.078/kWh.
    Everything seems about right but it's crazy how cheap natural gas is.
     
  4. bisco

    bisco cookie crumbler

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    all good deals!
     
  5. fuzzy1

    fuzzy1 Senior Member

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    A quick calculation suggests that for home heating, that puts natural gas and electricity at fuel cost parity for heat pumps with HSPF of 8, which is on the low side of modern products.

    My older ductless heat pump on one end of the house has HSPF of 10, the newer at the other end is rated 12.5. And higher ratings are available.
     
  6. Paladain55

    Paladain55 Member

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    Nice! We were talking about that earlier. Some of my friends have their PE in HVAC design so i was asking them about gas central heat vs the reverse ac pumps. They also said it was about the same but didn't go too specific as they aren't as nerdy they just do it for work.
    I think the big kicker is I need to swap to a natural gas stove and dryer and will probably leave the water heater until it gives out and then swap to a gas instant.
    But no kidding I think thats very impressive for cost to run a central heating system from 2004. A long time ago when gas was like 1/2 of price per unit of electricity and electricity was around $0.08/kWh i calculated i would need an electric water heater with an efficiency rating of around 95% to match my ng tank unit from 2004 of 54% efficient in price for use.
    Hows the roi on the higher rated systems for heat? I've found about half the things i look at never pay off.
     
  7. pghyndman

    pghyndman Active Member

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    To take advantage of state, federal, and utility company incentives we upgraded our 100 amp service to 200 amp, installed a ChargePoint Home Flex (got back $100 more than the install cost), and an energy efficient ducted whole house heat pump/HVAC (SEER 24.0, HSPF 11.8). The jury is still out as for reductions in our heating bills (augmenting/replacing our oil-fired baseboard hot water system). The ductless systems appear to be more efficient, but the layout of our house would have required a hodgepodge of individual mini-splits scattered through several rooms.

    Our rate (EverSource CT) is $0.12/kwh but distribution (ripoff!) and other fees adds ~ $0.13/kwh to the mix.
     
  8. fuzzy1

    fuzzy1 Senior Member

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    Because some fuels experience considerable price variability, it can be difficult to make a recommendation just on cost criteria. If Climate Change factors are included, the choice may be easier.
    For the stove, electric induction is the winner for efficiency and indoor air quality, and should match the control and benefits of natural gas. For clothes dryers, electric heat pump models are available, but likely not yet a sufficiently mature market to meet your needs.

    For water, heat pump water heaters are very efficient even in my climate, and should be even better in The South. For people wanting energy efficiency, I'm trying to guide people away from electric instant heaters, which are only barely better than the best resistance heaters, which can no longer get EnergyStar ratings. Electric instant heaters should be reserved to niche applications where heat pumps are not a good fit.

    But this criticism doesn't apply to natural gas instant heaters.

    On that scale, my 9.5 year old heat pump water heater had a Northern Climate efficiency rating of 200%, the highest then available. But it has done better (I have an energy meter on it to track usage), probably because my climate is less cold than the rating scale definition. Efficiency goes up with warmer ambient temperature, and performance in The South should be great.

    The market is far more mature now, with very many choices in the 300-400% range.
     
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  9. Paladain55

    Paladain55 Member

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    Good stuff man. I love hearing about home efficiency stuff. Now that we are finally getting hit harder than the rest of my area on utility bills even things like solar could make sense for the first time in my life here recently. But bank account isn't big enough to go crazy so improve efficiency as much as possible first. The other day we got a chinese thermal camera for $600 and split it between a couple people. It similar in quality to a $3500 flir now. Went through and got to see how shoddy they build houses. Pretty much every corner of every wall leaks, every window, every door, every vent register, bathroom vents leaking in, insulation missing in the ceiling, leaking vent system up top, don't get me started on windows. Windows are just terrible (even at their best sadly but no windows is depressing). You need to get good insulating curtains for sure. I doubt when i fix a lot of this i will need an air exchange system so i don't die, but it will all help lol

    I would worry more about climate change but it needs to agree with a wallet first (like my 13 year old prius is just fine for now over anything else). I agree electric instant heaters vs ng instant heaters when you compare the efficiency ratings... You would have to be insane to pick an electric instant same as ng catalytic heaters vs resistive e heaters. But sometimes its that or nothing so i get why they have them.
    You know since we talked about this and I hate to get rid of old bulletproof appliances I'm going to try venting my dryer into an indoor home filter to get the humidity and temps up in the house for the winter. Hopefully the air flow and lent doesn't become a problem. I see the indoor vent kits, but its usually because people put those in their garages and want a bit less of a mess.

    What would you say the minimum outside operating temp for a heat pump heater is? I've heard if temps drop too much you have to heat the coils up or something.
     
  10. fuzzy1

    fuzzy1 Senior Member

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    That will depend on the model specs.

    My garage never really gets below freezing, and my old HPWH has always worked, though will sometimes trip out for a while at the coldest temperatures, then catch up after a rest period. A vendor blog about certain Rheem models says the heat pump portion works only above 45F, automatically switching to just the electric resistance elements below that. I think the very pricey SANCO2 models will work to something like -20F without any electric backup.

    These things are built to operate in most of the northern continental U.S., though are obviously less efficient when the backup electric kicks in. Check with your local electric utility for its recommendations. And rebates.

    In The South, for an added benefit, duct the exhaust and use a diverter valve to send the cold air someplace useful. It is free AC, which can offset your AC energy needs. Then just switch the diverter to outside during winter when you don't want AC.

    P.S. EnergyStar.gov says these units work best when installed in places that stay above 40F, but hybrid models still produce hot water when air temperatures get colder. Split-type systems can work down to -25F.

    EnergyStar: Do Heat Pump Water Heaters Work in Cold Climates?
     
    #170 fuzzy1, Nov 23, 2022 at 5:23 PM
    Last edited: Nov 23, 2022 at 5:29 PM
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