Dithering - I need to make a decision very soon - advice?

Discussion in 'General Discussions' started by sunnyflies, Sep 3, 2009.

  1. sunnyflies

    sunnyflies Member Forum Leader

    Air, or air and water? I can't decide. I like the WF envision unit, I believe it would work well for my 2400 sq ft retrofit using existing ductwork and well for the 1500' addition I am planning to put on. But, the more I read about hydronic heat the more interesting it sounds. Warm floors in the bathrooms and some rooms of the new addition would be a nice and unacustomed luxury after years of feeling chilly.

    However, I understand that hydronic's much more expensive to install than plain hot air heat & air cooling. Also, it would mean I would have to switch from the envision with its 30 EER/5COP to a WF synergy unit which seems to have 23 EER/4.5 COP. Or, go with another company altogether.

    One installer has been trying hard to interest me in a Hydron combination unit that would give me air throughout and also hydronic heat. He told me WF didn't have such an animal, but when I looked through the WF site just now, it seems he's wrong. Are both company's units comparable? Is one better than the other? Is one unit louder than the other? I think I heard or read that Hydron was a bit noisier. Is one brand, or type less prone to problems than the other?

    What would the difference in the EER and COP numbers mean to me, the user. Is it that the all air unit would be more efficient, and a combination less so? Would it be noticable to me comfortwise? Does it mean the combination unit would have to work harder and longer to heat the house? And, does it mean the combination unit would cost more to run, as well as more to install the piping?

    Roughly, what would the difference in the cost of adding hydronic heating to 1500 sq ft of new building be. Are there ways of saving when putting it in?

    I know I have lots of questions and probably didn't express them very well, but I certainly would appreciate any advice. Thanks.
  2. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    Efficiency difference is scarcely discernable, %wise, but your electricity cost is high. I have no quarrel with either unit, and as always suggest dealer you like best.
    Ball park figure if you do none of it yourself, radiant could add $10sf.
  3. sunnyflies

    sunnyflies Member Forum Leader

    Thanks. I wondered about the efficiency % difference.

    "but your electricity cost is high" - Do you mean with both units, the air unit or just the combination unit? Does that mean one uses a lot more power than than other?

    I agree about dealers. That's why WF is on the top of my list, I like the dealer. He clearly knows his business and according to my local power company, has installed 100 geo units this year alone, plus his references checked out well when I called them. But, I am still going to talk to the Hydron guy again as I didn't have my plans completed when I spoke to him earlier. I've been told he's good.

    Does one brand make more noise than the other?
  4. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    1) your price per kw is high so while the % may be small the dollars may not be (regardless of brand)

    2) Noise? sounds like salesmans fluff, did they talk about decibles? Amana used to talk about quieter air conditioners and quote DB's (even as a dealer of their product I was unimpressed....what's a db sound like?).
    Fact is they are all quieter than what your used to.

    Don't get too OCD on this, trust your research and your instincts.
  5. geome

    geome Member Forum Leader

    Instead of a heated floor, why not use well placed bathroom rugs, towel to dry off, and put on slippers and a robe to stay warm and comfortable. Maybe I'm just old fashioned. [​IMG]
  6. sunnyflies

    sunnyflies Member Forum Leader

    I think you're right. Towels it will be!
  7. sunnyflies

    sunnyflies Member Forum Leader

    Don't get too OCD on this, trust your research and your instincts.
    Good advice, but hard to take. The more I talk to people, the more confusing things become and the less I trust what I thought I knew. This morning I thought I had decided on a Marathon electric water heater, but now, I am not so sure.

    A solar guy, who was recommended by my local power company, said I should get a propane tank to heat our water as an electric heater would be very expensive to use, given our high electric rates of .215 - one of the highest in the country.

    I am considering putting a solar system on the barn roof, but it sounds as if it will be very expensive, even with rebates totaling 50%. A solar system just to heat our water would run about $10,000, one to run our proposed geo system and our daily usage of power would run about $70,000 - without being enough to also heat the water, but I would get an immediate rebate of $35,000. Good grief!

    He also emphasised that geo will not pre heat my water in the winter, just in the summer. I thought it would in both winter and summer, and not so much, if at all, during the shoulder seasons. Who's right? Me, I think.
  8. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    You are on Long Island - everything is pricey there?!

    It would be worth doing the math to compare cost per btu burning propane vs electric resistance. Perhaps you'd be a good candidate for a heat pump water heater.

    I'm not a fan of tankless water heaters but they offer a clear efficiency advantage in the case of gas firing over conventional center flue tank models. OTOH, I've heard of some very efficient gas fired tank units - saw it in FineHomebuilding, beleive the brand is Polaris.

    How many people live in the home? - that makes a huge difference in hot water costs. I believe most units provide desuperheat recovery for domestic hot water in both heating and cooling modes. Some may stop the desuper during stage two (high heat) or stage 3 (high heat + heat strips) calls to maximize space heating, but if the system is sized and installed correctly stage one provides enough heat as well as some hot water.

    I'd dislike having to give up on radiant floors, but sometimes something has to give.

    I like my WF Envision - quiet and efficient. WF also makes water to water units for both radiant and domestic hot water, but multiple units makes for complexity and higher first cost. I agree with Joe that the differences between brands are most likely minimal.
  9. sunnyflies

    sunnyflies Member Forum Leader

    I've been thinking about a heat pump water heater. Will make some calls about them tomorrow. So far no one I've talked to has recommended them or knows much about them, but I have noticed that some are energy star rated. I will check on the polaris also, I think I'd read about it a while back.

    It's nice to hear that you are happy with your WF envision, and that its quiet. It's what I am thinking of getting.
  10. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    DSH contributes in the winter and summer (essentially when ever the compressor is on and the aux. isn't).
    Solar guy also neglected to mention that significant conditioned air (that has to be replaced) is discharged from the home by gas water heaters.
    At some point Sunny you begin to split hairs and risk either alienating your contractor or accepting responsibility for the design by micro-managing the project.
    I had a conversation with a homeowner 2 days ago who has created $4,700 in extra (duplicate) work and essentially accepted responsibility for air delivery through attic duct work. He decided to change the system after consulting with the electrician, the plumber and the concrete guy (all HVAC experts :). Apparently the sofitt ductwork that we agreed on and installed (that delivered air in shortest possible path) was no longer acceptable. He is a very nice man, but has decided to be his own general contractor and it is costing him 10's of thousands of dollars.
  11. sunnyflies

    sunnyflies Member Forum Leader

    Not trying to split hairs, here. I will be deciding on a geo installer by the beginning of next week and will trust whoever it is to work out the right ducting, etc. However, I have to remove the buried oil tank to make way for the addition's foundation, so I am trying to figure out what type of water heater, gas or electric, would work most efficiently for me with a DSH, in place of the oil HWH I have now. And, I am going to need it right away.

    As I do not know much about water heaters, I've been talking to the plumbers who are giving me estimates for the addition I am putting on, as well as to the propane guys (I have to move the buried gas tank also) because both trades deal with water heaters all the time. All of them suggested an on demand unit which I have read on this forum is not a good idea with geo due to possible problems with legionella. So, I asked the solar guy yesterday to get his opinion. I figured he's talked with lots of people putting in geo systems, which it seems he has, and he might know what would be best.

    However, it seems that wasn't a good idea as he just confused me. He's supposed to be an expert in efficient energy use energy and solar in particular - according to my local power company from whom I got his name. I assumed he would know what kind of water heater might work best with a geo system. When he told me, twice, emphatically that I would get no heat at all from the DSH during the winter I was taken aback, because I thought I would. It seems, he doesn't know as much as he ought about geo, especially considering that he told me he knew a lot and would be "happy to help advise me".

    He did try several times to get me to call one of his friend's company to get another estimate for a geo system, however I had already talked to that company about five months ago and wasn't impressed. They are excellent with fossil fuel HVAC and have a sterling reputation in that field. But, they knew little about geothermal systems, even though they were installing the units. They were one of several local HVAC companies just entering the geo field which told me they would put in a geo unit for me but I would have to get my own well people and do the electric myself as they didn't do either. It wasn't confidence building to someone just looking into getting a geothermal system.

    I am beginning to think I need to make the decision on the installer, then ask him what he thinks would be the best HWH. No installer ever suggested a water heater possibility to me, so it did not occur to me to ask them. Again, I am not trying to split hairs, I'm just trying to do my best to learn what would work most efficiently to heat my water. I hate cold showers :D
  12. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    Regarding tankless, on-demand water heaters, I am one of their critics but let me be clear that Legionella is NOT one of my concerns with them.

    I suggest doing a standard geo arrangement of two electric storage tanks, one powered, one for DSH buffer. That is a simple, relatively inexpensive and well-documented system. You can always go back and retrofit solar, an air source or watersourced heat pump water heater if measurements (sub meter or hourmeter on the electric storage tank heater's elements) suggest reasonable ROI on one or more of those systems. All are relatively uncommon, relatively expensive, and add may be adding too much complexity

    Don't let the hot water 'tail' wag the whole dog - winter is coming, you need to get the show on the road.

    As an engineer, I can assure you that it is entirely possible to overanalyze a situation and micromanage a contractor, driving away good ones and driving up costs...been there, done that.
  13. sunnyflies

    sunnyflies Member Forum Leader

    Thank you for your suggestion, and your gentle warning. I certainly do not want to micromanage; but, I have to ask people questions in order to learn. I am going to be the contractor on the addition to our house. It's the only way I can afford to build what we need and I have done it before, but not on so large a scale. I am doing my darnedest to find the best people in each trade and I will trust them to make the right decisions once I do, not tell them what to do. I hope I will be placing my trust correctly in each case - and I am checking references.

    I had originally thought I ought to go with an electric WH tank, with a storage tank in series, but wondered if propane would have been more cost efficient, given our sky high electric rates. I decided to look into propane heaters because I didn't want to find out later I'd made the wrong decision. I think will go with electric, as you suggest. A marathon, probably, because of our acid and mineral water problems.

    And, you are right, winter is coming. I need to make several big decisions right after this weekend, and sign some contracts. Making the plunge is always scary.
  14. geome

    geome Member Forum Leader

    You could go with a Marathon for a buffer tank (not wired) and a propane water heater as a finishing tank. You would just need to replace the steel tank when it goes bad. We decided not to go with a steel tank as I don't want to be be bothered replacing it, and our electric rates are relatively low (currently).

    If you don't mind replacing the tank, I think the decision boils down to overall cost. Will it pay to go with a propane water heater and have the tank cost, estimated propane cost, and tank replacement cost when the steel tank(s) goes bad (unit and labor if you need to pay someone to install it), OR will it pay to go with a Marathon water heater and have the tank cost and estimated electricity cost? You would need to make some assumptions to do this calculation, but it may be helpful in your decision making process. In the summer and winter months when the geothermal system runs a lot, I ballparked 50% of normal utilities for the water heater (I have no idea if this is accurate) to take into account the benefit from the desuperheater.
  15. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    Sunnyflies - sounds like you have the right philosophy and are on the right track - balance need to learn ask and know against questioning a sub's every move.

    Geome, 50% reduction of hot water utility costs is probably as good a ballpark guess as any, but individual variation in results is likely very wide

    Factors include:

    1) building loads / installed tonnage
    2) # of residents and their use of hotwater

    A couple living alone in a Mcmansion with 8 tons installed will have a different outcome from a family of 6-8 living in a superinsulated Not-So-Big house with only 2-3 tons of geo.

    Also important are EWTs for both the geo system and domestic hot water. A 410a geo system with 50 EWT operating in cooling mode will have relatively little useful superheat available to heat domestic water, especially if the domestic water comes from relatively warmer surface sources

    My own system supplies anywhere from 15-85% of hot water energy, depending on time of year
  16. Looby

    Looby Member Forum Leader

    He doesn't have a clue. My Envision DSH supplied vastly more
    preheat last winter than it did this summer -- due to cool weather
    (in southeastern PA), very little A/C run-time, and the resulting low
    EWT while the A/C was on.

    Why not just go with an electric water tank (plus DSH buffer tank)
    for starters? The initial investment is minimal, and I don't think it
    would complicate a solar or propane retrofit in the future -- after
    your geo system is up and running.

    good luck,

  17. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader

    I haven't read the whole thread,( not sure if you are looking a DX) but the above is true of a DX system.
  18. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader


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