Ted, I agree that intuition oftentimes has to come into play in the decision, but intuition and emotion are two different things.
You wrote..."Keep in mind, when you take GOOD models and compare to actual they tend to be high." Your statement was contradictory. If the model is good, it WOULD accurately predict actual results. If it doesn't it's not a GOOD model
Lastly, not sure how the coal fired plant issue has anything to do with emotion. If there is a strong likelihood of stronger EPA emission controls, then we can LOGICALLY (not emotionally) conclude that the cost of electricity from coal fired plants will go up. There was no mention of whether I am for or against stronger EPA controls, an issue which could perhaps be regarded as an emotionally driven.
Lastly, I agree with you regarding anecdotal evidence....drives me crazy. However, your statement that you've "seen 40 year old ashp's still operating in Fairport and honeye falls" is just that...anecdotal evidence. We've all probably seen 50 year old rifrigerators still operating. If it happened to be a Frigidaire, that doesn't mean every Frigidaire is expected to last 50 years. Similarly, I replaced a 17 year old Carrier ASHP on my last house. I was not pleased at all with 17 years of service life but perhaps that is the norm.
Let's not open the DX vs water loop debate or we'll be at this ad finitum!
With regard to natural gas vs. HP (ASHP or Geothermal) I offer the following....
Assuming a 90% efficiency, a gas furnace will deliver a heat at a cost of about $ .97 per therm assuming a cost of $9.00 per thousand cubic feet which was about what Ohio consumers paid last winter. If electric is $ .10 per KwH and the HP has a COP of 3.0 the cost per therm will be about the same as for the NG example. Obviously, a COP of 4.0 or better will make the HP considerably more cost effective. This ignores maintenance costs and original equipment costs.
In the winter of '06/'07 Ohioans were paying about $15.00 for NG! At that cost and electreic still at $ .10 per KwH, the breakeven COP is only 2.0. In other words, at a heat pump COP of 2.0 or better, the HP has lower cost to deliver the same energy.
I see we're I failed. My simantics are poor, misleading. Sorry.
From my perspective inside the industry there are bad models, good models, and true models. Typically true models occur when you do a very accurate model and "true" it to historical consumption. Truing nearly always means DOWN to actual consumption, an average of 25-35%.
With an unbuilt house you can't have a true model, and good is pretty rare but really the best you can expect.
Also, your math on delivery is way too simplistic. Cop depends on a lot of factors that are continuously shifting, as does furnace efficiency. As just a simple example, what delivery efficiency will the hp deliver at 40f? At 10f? How much of the seasonal btu will be delivered at those two temps? How will duct design impact delivery at different flow? All of these things can have big swing in impact. Hindsight seems the only way to see it. I think a year after moving in this may become apparent.
Same on the gas furnace (which can typically deliver MORE eff as temps drop, as the hp goes the other way which makes hybrids a really nice option).
Finally, the plant delivering electricity to your ashp's will be the same as the plant delivering to your gshp.
This has been an interesting thread.
With the New modulating GS units that's probably how I'd lean. Many deciding factors would be emotional. I like cool technology. If carriers has load matching features (ala infinity systems) the decision would be certain. I wouldn't want to mow around an outdoor unit, and with the tax credit it might actually be cheaper than GREENSPEED. built in dehumidification would be an expensive option these systems have that i'd love. No weight would be because I'd be expecting much incremental energy savings, because I wouldn't be. If I can take Liz to dinner on the savings a few times, that's gravy.
I would definitely be testing water hardness, and hope for 17 years of operation.
What is Good?
A GOOD Load model should be < 15% overdesign.
Originally Posted by batman71
A GOOD Energy estimate is < 25% over the actual costs.
Accurate is a Relative term. "Exact" absolutely Never applies.
Science gets one a VERY LONG way to a problem resolution - -
but, with many variables ( equipment selection, location/house orientation, weather & owner lifestyle /preferences, one's effort to refine a model)
being somewhat indeterminant,
Judgment (art, experience, NOT emotion ) will Always come into play in Any design.
No exact answers exist in HVAC - there are Always at least 6 ways to solve an issue.
What is GOOD ?
... it is a final set-up where a customer is satisfied > 85% of the time.
I actually have only been to training on products, never a geo sales class. I just firmly believe in the technology since every customer we have put it in so far is incredibly happy they didn't go with AS heat pump or gas etc. and the changeouts we have done have all been so happy with the geo they put in 20 years ago that they did it again.
Originally Posted by energy star
Maybe 15 years ago WF did not market to gas but they do now and gas is at 5 year lows. WaterFurnace now has specific dual fuel pricing guides to compete against air source and either propane or NG as a backup. Yes is mostly for LP but it's a cost effective add on solution for somebody that has a newer gas furnace but wants the best.
I just so often see the argument to only do geothermal if the numbers logically work out which they do in this case, yet when I bought my high end SUV I bought it for its features, not because it was more fuel efficient so why do so many treat geo in a cost savings only manner and even still the only touch on the parts of the system that have not cost savings were its nice not to have to mow around it. That's what needs to be brought up more. Plus what were energy costs 20 years ago, look forward 10+ years and you know energy will not cost the same. Here in Oregon we rate houses with an Energy Performance Score and an Invertor air source rates the same as a 9.0 HSPF air source while a geo rates much higher. So resale value will also be recouped for many reasons. Like I said, no sales classes just customers that are happier than my XL20i customers and Invertor heat pump customers.
Sky, let me get this straight. Keeping the utility bill out of the equation (cause it's not about that!).
If you walked in the front door of a house, are you saying that you could tell the difference between a geo thermal system and a top of the line 20i from comfort alone? (or even a 16i) As you said, you GT customers are happier, is that just from a mower stand point or the 10 year warranty when the 20i is twelve?
All I can say is I guess my customers are different than yours. I had a customer with a $40 a month electric bill switch from an 8 year old heat pump to geo, I had anger customer delay a car purchase to be able to afford his geo system first even though the numbers showed a 9HSPF would have been a better investment than geo. I did not lie to or falsely promise, these customers came to me looking for what geo offers. They wanted zero electric bill because that's what was important to them, the wanted the luxury of never hearing or looking at an outdoor unit because they had minimal land but enough to drill. I have customers that buy because even though it is not cost effective they are more self sufficient with this type of system and often no need for backup heat(depending on design)
Originally Posted by energy star
Now I understand that the above is not the norm, but in my area that's how about 30% or more of my customers feel. So if there is a customer looking at payback I'm saying you need to assign cost savings to things that you want as a consumer even though they don't save you on utility bills. No outdoor unit is huge to many, even with 2 acres so many homeowners in my area with 4,000 half million dollar homes hate ANY outdoor unit location. And from my car examples below I am saying things like heated seats never save you any gas(they add to the cost of fuel) but how many people flock to by them. Geo has these same benefits and I am saying that there are benefits associated with that, therefore it deserves better numbers.
So I was correct, you can't tell. To be self sufficient, do you offer or up-sell generators? Enough of this thread for me. We have lots that cost 150k to 2 Million around my home. I just don't believe in the whole Geo game. I will say it has been brought to my attention that the new Geo systems that use no water have me interested in this new latest technology. That said, I would still be reluctant to purchase for my home. I will say I admire your enthusiasm in the HVAC biz!, and enjoy talking on this forum with you.
Direct exchange is not new. It also does not have the ability to modulate refrigerant flow (orafices are 70ft under ground!). I believe huge EE opportunity comes from load matching - I suspect these new inverter geo units will be dramatically altering how closed loop is done.
The geo business is like any other, without tracking there is no accountability. Without accountability everything becomes a race to the bottom. What corners can be cut to be able to offer the lowest bid.
This may mean a homeowner spends $2000 per year on energy instead of $800, but all they remember is the $4500 they were spending on oil.
What a terrible missed opportunity. Nobody really is to blame, it's a chain with links missing.
Tracking results will expose which emperors have no clothes, and provide a metric that allows contractors to compete on a quality metric that is actually measurable.
Holy crap. That goes deep in the ground?
Be careful what you say doesn't exist, next week you'll be wrong.