Number crunching

Discussion in 'Fred's House of Pancakes' started by Leadfoot J. McCoalroller, Apr 22, 2022.

  1. Salamander_King

    Salamander_King Senior Member

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    Well, since I have never lived in a house with a heat pump, I don't know if I feel differently about the same heat loss, say poorly insulated leaky house. But "comfort" is totally a subjective concept. Drafty cold air coming from the window may feel very comfortable in a toasty room for someone, while the same drafty cold air may feel unbearable for someone else who is cold sensitive. I would think the situation is similar either the room is heated by a heat pump or by an oil burner assuming the temperature setting is similar.

    I experience this all the time when I ride our PP with my wife either heated by a heat pump or by an engine. She likes steady warm air and a constant temp of 72F or above while I can't stand the heat setting anything higher than 68F and hate warm air blowing to my face or body. Even in the middle of winter, I prefer to crack open the window to get fresh air which my wife will absolutely despise.
     
  2. John321

    John321 Senior Member

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    Great thread, great comments, very interesting and informative.

    I can add a little about air temperature coming from a Heat Pump. We have a ducted system and a Carrier Heat Pump with a variable speed scroll compressor mated to a Carrier Air Handling unit with a variable speed blower. When the unit starts it runs on low as the unit begins to come up to temperature and doesn't really kick in until it comes up to temperature. In the winter the temperature out of the ducts will approach 110 degrees with no supplemental heat added.

    We have a gas furnace coupled to the system and the gas heat is certainly warmer out of the ducts and more humid but the heat with only Heat Pump is certainly comfortable and adequate. With a matched system and variable speed components the old situation where the initial air coming out of the system with a Heat Pump wasn't very warm can be avoided.
     
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  3. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    I've been crunching more numbers.

    Looks like we are reliably burning an average of 1050 gallons of oil per year. I think about 20% of that is for my domestic hot water, but it is hard to estimate. Local oil prices are up 317% in 24 months.

    Electric is up about 11% in the same time period, now about $0.13/kWh

    It's looking like I can convert to an air source heat pump water heater for about $8,500. (so far, another bid coming later)

    I think this can save me about $600 per year.

    Re-insulating the attics (plural) would run me about $3,500. I've decided to guess that this will make a flat 15% reduction in energy needs.

    I might be closer to busting the piggy bank and buying a bunch of solar panels than I thought.
     
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  4. John321

    John321 Senior Member

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    Energy improvements can be costly as you mention. One consolation is they will pay you dividends every day of every year your family lives in the home.
     
  5. bisco

    bisco cookie crumbler

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    our propane is $5.75 :eek:
     
  6. bisco

    bisco cookie crumbler

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    is the $8,500. after state and fed incentives?
     
  7. Salamander_King

    Salamander_King Senior Member

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    Yeah, the .gov propane price is for large volume "regular" customers only. The note reads "Average propane prices are 30-day cash/credit prices, based on consumption of at least 900 gallons a year. Households using propane just for cooking or hot water generally pay a higher per gallon price."

    Historically, the spot price of propane was always higher than the gasoline price. If I go out and buy a 20lb tank of propane, it would probably cost more.
     
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  8. bisco

    bisco cookie crumbler

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    i have 2 100lb tanks, and only use it for gas dryer and fireplace.

    my neighbor buried a 2500 lb tank, heats his house with it and belongs to some kind of consortium, and gets a better price, but idk how much.
     
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  9. Salamander_King

    Salamander_King Senior Member

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    When we first moved to our current home, the former owner had a propane heater in one of the rooms which I believe was an attached single-car garage when the house was first built, then converted into a more like a game room. Completely finished room, but did not have heating, so the former owner installed a propane space heater with a direct vent through the wall which was hooked up to a 100-gal tank outside.

    For the first year, I kept the heater with the pilot on, but never really used it. Still, pilot light used enough gas such that propane on auto-delivery along with the heating oil was replenished every 2-3 months. It was costing ~$30 for having just the pilot on. I got tired of paying for propane that I am not using, so I turned off the pilot. Then later I had to do some digging around the house for a drain. I disconnected the propane tank completely. The tank with almost full of propane sat for years not being used and not being filled. After for a while, the company that owns the tank came and removed it from our backyard. I did not get the money back for the propane I paid for. Yeah, I should have asked for the price of the propane in the tank.

    I had both a propane boiler and an oil boiler installer stop by and write up an estimate for replacing our ~20 years old oil boiler/heater system last year. The price is similar either way, around $13K. But, now, I am thinking of replacing it with a pellet boiler which has a $6000 state incentive. The pellet fuel is way cheaper than either oil or propane at the current price and is renewable energy. Or if the single-zone mini-split heat pump proves to be effective for heating a room during our winter, then I may replace the oil boiler with a multi-zone heat pump and heat-pump water heater. I am just hoping our current oil boiler will last a bit longer so I can come up with a financing plan.
     
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  10. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    No, but it's only $300-500 on a water heater. The bid is suspiciously high; I have another contractor coming out to estimate the same project.

    It also includes an electrical subpanel as my main panel is full full full.
     
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  11. wjtracy

    wjtracy Senior Member

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    Oil hot water is very nice...when we lived in NJ years ago we converted to oil hot water when elec was expensive. We kept the oil water heater when nat gas become avail. it did not use much oil but I sure can't remember how much. PA is in probably favorable elec power cost scenario compared to other Northeast states, my mother lives there.
     
  12. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Yes, it works fine. And two years ago the running costs were lower than an electric. Now it's considerably more, with little sign of abatement.

    Electric is the future anyway. If I don't switch this year, I switch next year. It's a scheduling and finance exercise now.
     
  13. Salamander_King

    Salamander_King Senior Member

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    In your region with cheaper electricity, full electric conversion may make sense even without the cost of solar panels in the equation. But your annual oil usage seems very high to me. I don't know the size of your house and the number of people living in the house, but for us, annual heating oil consumption is an average of ~600 gal/year at an average of $2.66/gal over the last 10+ years. Of ~600 gals of oil, about 200 gals are used for domestic hot water year round and the rest 400 gals for the heating season mostly Nov-Apr 6 mo. The number is better for the last three years since the insulation improvement in the attic, such that it is now an average of 550 gal/yr being used.

    Our oil boiler is as old as the house is, so circa the 1990s built. That makes it ~30 years old. While a house 30 years old in New England is "new" construction, our house lacks many modern features and measures for energy conservation. It is certainly not built with the green and sustainable building codes of today. While I want to contribute to the sustainability effort and conversion to renewable energy for environmental consideration, the cost is the biggest hindrance. The solar panel's initial cost of $35K is for the most part too large for many families, and there are many, many horror stories of a solar installation gone wrong which made a financial disaster. Similarly, the total upgrading of the house heating systems is very costly. The replacement cost for the oil boiler (includes hot water heater) to a more efficient newer oil boiler system or cleaner propane boiler system cost about the same ~$13K for our case, but there are no subsidies for those systems. I have not checked with the installer, but the pellet boiler system currently has a $6000 state rebate and 26% fed tax credit. And at today's fuel cost, the annual saving on fuel cost would be about 50% of oil or ~$1500/yr. Depending on the installation and service cost, the pellet boiler seems to be a much better investment than solar for us.

    While we have very good heat pump water heater incentives in our state, our house does not have an electric water heater hook-up. And space requirement may prevent such hot water heater in our basement. Rather, I am looking into evacuated solar water heater tubes with a large storage tank. Those rooftop solar water heaters were once a very popular option but seem to be falling off the favor. I can't find any installer for them. If the upfront purchase and installation cost is manageable, it may be the biggest bang for a buck. While I don't anticipate total elimination of hot water heater fuel needs, preheating very cold well water before sending it to the heat exchanger to bring it up to 120F should reduce the fuel use dramatically, especially if we adjust our lifestyle to make sure to take shower in the late afternoon, not the first thing in the morning.
     
  14. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Electric conversion (even without solar) started making sense roughly when heating oil rose over $3.60. $5.20 today.

    My house is a tiny 1930s farm cottage that had an enormous addition built in 1960, and a smaller addition built onto the other end in 1980. So now it's 3,600sf of living space with varying degrees of insulation. Four in the house during heating season, including my elderly father who is fine with any conditions as long as it's 81°F where he sits. :rolleyes: We mostly make sure he sits closer to the woodstove than anyone else.

    I think we are using about 200-250 gallons for our hot water- I took an average of what it cost to top off the tank for fall across a few years to figure out summer usage, then doubled it to account for winter HW usage. It's not a clean method, but I haven't got much better.

    Converting to wood pellets was an interesting idea, but I really think the technology is too young. Not enough choice in the automated boilers, not enough experience in the installers and repairmen yet. Reminds me of solar in 1995. In addition, I can only find one bulk pellet distributor near me. They've got a slick setup where their special truck can blow a few tons of pellets through a hose into the bunker storage in your basement. But they are the only ones, and we aren't going to put up with bagged fuel for a system this big.
     
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  15. bisco

    bisco cookie crumbler

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    3,000' cape with addition, radiant heat, 15 year old high efficiency boiler, hot water through heat transfer plates, 2-3000 gallons a year, i'd have to look it up. temp goes up a degree every year with my age.
     
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  16. Salamander_King

    Salamander_King Senior Member

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    Sound like your house is much larger and older than ours. Ours is a small raised ranch or more accurately described as a bi-level earth bermed house ~2,000 square foot living area with very simple rectangular shape with a low pitch gable roof (crawl space attic). I would think you can improve the energy efficiency by insulating more, but with an old house and complicated shape, it can be a challenge.

    I did a similar thing as you did to estimate the fuel used for water heating. In our case, we fill our 275 gal tank three times a year, each time ~200 gal delivery to fill up. It happens at the beginning of the heating season at the end of Oct to the beginning of Nov, then a second fill-up during the heating season usually in Jan. Then the final fill-up takes place in late spring at the end of the heating season in April/May. So, the oil for the single fill from May to Nov is used exclusively for the hot water, with no heat. During winter, our hot water use increases a bit due to the use of hot water outside for our mini-farm. But due to the use of a boiler for heating purposes, I think the oil use for hot water portion is less than summer time. In any case, more than 30% of oil is used for domestic hot water heating in our house, so if I can get that fuel use say by half with a solar water heater, that would cut down our annual oil use by 15%.

    Our oil boiler is too old to be rated for EPA efficiency rating, but the boiler installer told me older boilers of that age are somewhere around 70% efficiency. If I replace it with today's high-efficiency oil boiler having 90% efficiency, then that would be an instant 20% cost saving. The propane boiler will have even higher efficiency ~95% and burn cleaner, but since propane has less BTU per pound, it won't save the amount of fuel used for the same heating unit as compared to an oil boiler. Right now, propane is cheaper than oil price, but historically the opposite has been the norm in our area. The cost of propane conversion is similar to an oil boiler replacement at around $13K for our house.

    Yeah, I have to do more number crunching to see if the pellet boiler conversion makes sense for our house or not. But the cheapest and simplest way at the operational level is to capture more free solar energy to heat our house by remodeling our south-facing wall into a passive solar Trombe wall, but so far I have not found a contractor who is willing to give me an estimate.
     
    #96 Salamander_King, Jul 2, 2022
    Last edited: Jul 2, 2022
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  17. Louis19

    Louis19 Junior Member

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    Hi , if you are seeking for an energy audit , I strongly suggest The blower door test .The blower door test is an instrumented test that evaluates a home's tightness, the quantity of cold air infiltrations, and the location of leaks requiring draft proofing. In my house I reduced by 15% air escaping , the culprit was the damper of my fireplace in my finished basement. The report suggested other cures but the main problem was resolved easely and cheaply.
     

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  18. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Well aware of it... the trick is finding somebody with enough experience to matter to come to my house and execute.

    I've tried a few state government and utility-owned search engines and they all come back with variations of "sorry nobody within 100 miles."

    I really am serious about kitting up and learning to do it myself. Beyond wanting to learn new skills it could be a business opportunity worth exploiting if there's more demand than just me. Today's energy prices might be tomorrow's demand for audits.
     
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  19. ChapmanF

    ChapmanF Senior Member

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    Hmm. Maybe something I could use those two blowers for that I saved out of the last two furnaces I carted away.
     
  20. bisco

    bisco cookie crumbler

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    if i put one split system in our mbr, i could keep it cooler in summer and turn up the a/c thermometer a few degrees, which is in the kitchen, and tends to be cooler because the return is there.

    for heat, idk, we keep the mbr cool for sleeping anyway.
     
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