Before you abandon the propane system, I guess I would think about  calculating paybacks vs the existing system. 
What do you pay per gallon for Propane (Average) this winter.  Do you own your own tank?  Is the tank large enough to do one fill per year only?  where I live the difference between getting a tank filled that you own vs the gas company owns is huge.   What is the efficiency of the existing boiler?
What is the cost of electricity? per kwh?  Does the switch make sense and what is the payback period?
Eric

Posted By eric anderson on 15 Apr 2010 10:29 AM
Before you abandon the propane system, I guess I would think about  calculating paybacks vs the existing system. 
What do you pay per gallon for Propane (Average) this winter.  Do you own your own tank?  Is the tank large enough to do one fill per year only?  where I live the difference between getting a tank filled that you own vs the gas company owns is huge.   What is the efficiency of the existing boiler?
What is the cost of electricity? per kwh?  Does the switch make sense and what is the payback period?
Eric

good questions...

i have 1000gal leased tank. propane was $$$ this year going upwards of 2.55 a gal at some point. average prob $2.45ish. we try to conserve, keep heat down, have flash water heater etc. So 1 fill a year on avg. probably.

not sure effic. of current boiler but its an american standard - put in the home new in 2004. got a 12 seer ac.

electricity is 14.9c/kwh i think

total system cost estimation is $23,000. minus 30% tax credit = $16,100

i would roughly estimate my electric and propane costs at $3200/ year - so just about 5 years. *(based on current energy/propane costs).

Thoughts?

Do you mean your "electric and propane net operational cost savings"?

Posted By jonr on 15 Apr 2010 01:18 PM
Do you mean your "electric and propane net operational cost savings"?

my mistake - thats my total cost ($3200). if geo saves 50% its ten years...

OK this will be very crude math, lots of marginally valid assumptions and a very rough estimate, but here it goes.
Propane = 2.45$ gallon and has 93000 btu/gallon, assume 80% efficiency for heating. 93000 *0.8 = 74,400 btu/ gallon net. Divide that by 2.45 = 30,370 btu’s per dollar spent. 

Resistance heat 1 kwh = 3412 btu and costs 0.149$ so 22,899 btu’s per dollar.  So clearly resistance heat is worse then propane.
A geothermal system will operate at a multiple of resistance heat in terms of efficiency so a COP of 3, = 68,700 btu’s/ dollar spent.  COP 4 = 91,600 btu’s/dollar spent.
 
You can do more detailed calcs yourself if you know total propane usage (does this include hot water, propane range, clothes dryer etc?).

Assuming you have a cop of 3, your heating bill should drop by about ½, COP of 4 it will drop to 1/3.  I am not attempting to calculate differences in costs of cooling the house in the summer, which will affect payback calculations and cost benefits.
 If you burn 1000 gallons of propane per year, this equals 2450$ year heating costs.  You could save potentially 1200- 1600$ per year with geothermal for a payback between 10 and 13 years (at current rates if the money does not cost you anything ie interest rates).

The first thing I would investigate is lowering demand. Dropping your heat loss by 50% has the same effect as cutting the cost per BTU by ½. Check to see if your state or utility company has a energy efficiency audit program you can take advantage of. It may not be possible to reduce heat loss in ½ without drastic measures that don’t make financial sense, but do the easy stuff. Then think about the harder stuff and see if it is worth it.

The second thing to investigate is if you can lower the cost of propane. Here in Connecticut propane costs vary wildly from company to company. Only the company that owns the tank can fill it so you can’t price shop once the tank is in, unless you own it. Here a 1000 gallon tank is 3300$ installed + excavation costs, so figure 4K for the tank, in the ground. I paid 1.33$ gallon last summer to fill a tank I own. Same sized tank (owned by a different company) would have been over 2$ gallon to fill the same day.
 
Ask around and find out if a gas company will deliver for a fixed markup over the cost at the bulk distribution plant.. I pay fixed markup of 0.39$ over the wholesale price at the Selkirk distribution terminal. I don’t know how it works in your state so my advice may be meaningless in your situation.
 
After that the order gets a bit vague, but-
 
Possibility 3 I think you stated elsewhere that you have solar photovoltaic panels. Can you add solar thermal? How about a simple solar air heater maybe a 4 panel solar air heater from “your solar home” installed on a south facing roof or walls.

Possibility 4 is can you increase the efficiency of your existing propane system? Ask Dana’s advice or post in the radiant heat section where the boiler guys hang out.
 
Five, investigate the costs of changing to a high efficiency, right sized, mod con boiler plus indirect DHW tank system and the potential savings of that.

Sixth would be geothermal, but it sounds like you are already doing your homework on this. I don’t have the answers as to what the payoff would be for each option, but I would not commit to geothermal without doing your homework and figuring it out. A good energy audit  audit seems like a starting point. Cheers, Eric

It depends on the circumstances but typically >12 years or so translates to never paying off financially.

Posted By jonr on 15 Apr 2010 04:32 PM
It depends on the circumstances but typically >12 years or so translates to never paying off financially.

lol i hear that. but it will be worth it in others ways:

like stopping my wife's complaining the house is so cold because i keep it at 68~!

if propane costs go up - roi will be faster (of course increase in electricity cuts into that as well)

and i guess at some point *in the future* it could help the resale value of the home - but not sure how to put a $ on that.

plus i have a leased propane tank and i dont like being at the mercy of one company without ability to shop around...

realistically - what would a new, comparable propane based system cost me installed?

Posted By jonr on 15 Apr 2010 04:32 PM
It depends on the circumstances but typically >12 years or so translates to never paying off financially.

Loops may be able to be reused when replacing the geothermal unit in 15-30 years.  Could be a big financial benefit down the road for someone that lives long enough in the same geothermal house.

What were the quotes for your 5-ton system and what did the quote include? Also who did you get quotes from in SE - PA, I have a place up in Sullivan county and am looking to do the same - might be close enough to use the same people.

Posted By [email protected] on 15 Apr 2010 10:15 PM
What were the quotes for your 5-ton system and what did the quote include? Also who did you get quotes from in SE - PA, I have a place up in Sullivan county and am looking to do the same - might be close enough to use the same people.

I went to servicemagic to find geo installers. they came in 27-29kish. (including drilling, heat pump, and desuperheter with buffer tank and electric water heater tank too)

i then decided to see if i could do better (as thats frigin expensive) and was able to source the heat pump myself for a lot less than the hvac guys would sell it for. (climate master tranquility 27 5 ton)

i got 3 well drilling quotes. all were similar in price. i need vertical loops and that is the most expensive part of the job.

1 of the hvac guys agreed to just do the install.

so i'm estimating it will cost me 22k-23k max. most hvac guys told me straight out - if they could not sell me the health pump they didnt want the job! my guess is they mark up heat pump from anywhere 3-5k. but once hvac did offer extra warranty in price.

i dont want to refer anyone until they put the system in lol. pm me for more info

Here in PA we don't have any state-wide water well or geothermal borehole construction regulations and thus grouting boreholes is "optional". With that said, the right thing to do is to grout at least the upper 30' with a low permeability grout to prevent surface water from entering. Below this depth and into the water table, it can be perfectly environmentally responsible to backfill the borehole with a material of similar hydraulic conductivity as the material that was removed. This approach ensures that multiple aquifers aren't interconnected. This assumes all backfill can be replaced without bridging which often requires a tremie pipe and/or slow placement. This approach also requires a thorough understanding of the subsurface hydrostratigraphy. The reason drillers charge more for grout or charge more for thermally enhanced grout is they don't have the correct grouting equipment.

Regarding measuring groundwater advection, as a hydrogeologist we typically measure groundwater flow by measuring the potentiometric (water table) calculating the aquifers hydraulic conductivity and transmissivity via a pump test (measuring the aquifer response due to pumping over time). Darcy's law can then be used to calculate the Darcy (seepage) velocity. Dividing this by the effective porosity (interconnected pore space) yields the actual groundwater velocity.

All of the commercially available simulation software for geothermal applications use emperically-derived formulas. If you are going to run heat transfer simulations that involve variables such as groundwater convection, conduction, thermal/nonthermal grout conductivities, specific heats of the natural and backfill materials etc then finite difference software must be used capable of solving the multiple solutions of the differential equations.

-Adam

Posted By Down2Earth Geothermal on 15 Apr 2010 10:56 PM


All of the commercially available simulation software for geothermal applications use emperically-derived formulas. If you are going to run heat transfer simulations that involve variables such as groundwater convection, conduction, thermal/nonthermal grout conductivities, specific heats of the natural and backfill materials etc then finite difference software must be used capable of solving the multiple solutions of the differential equations.

-Adam

I was going to post this, but you beat me to  it

Posted By eric anderson on 15 Apr 2010 02:27 PM
OK this will be very crude math, lots of marginally valid assumptions and a very rough estimate, but here it goes.

Since you announced up front you were using poor calculations I should probably leave it alone but.......
Propane = 2.45$ gallon and has 93000 btu/gallon, assume 80% efficiency for heating. 93000 *0.8 = 74,400 btu/ gallon net. Divide that by 2.45 = 30,370 btu’s per dollar spent. 

Resistance heat 1 kwh = 3412 btu and costs 0.149$ so 22,899 btu’s per dollar.  So clearly resistance heat is worse then propane.
A geothermal system will operate at a multiple of resistance heat in terms of efficiency so a COP of 3, = 68,700 btu’s/ dollar spent.  COP 4 = 91,600 btu’s/dollar spent.
 80% is a peak efficiency seldom achieved in the field if average efficiency is closer to 70% the numbers get closer. Add to that the electricity that is also employed to make heat with a gas furnace and it may be a wash. Average heat pump COP will be ~3.

Assuming you have a cop of 3, your heating bill should drop by about ½, COP of 4 it will drop to 1/3.  I am not attempting to calculate differences in costs of cooling the house in the summer, which will affect payback calculations and cost benefits.
 If you burn 1000 gallons of propane per year, this equals 2450$ year heating costs.  
Again, burning 1000 gal/yr of propane costs more than the price of the propane, out side of the rare gravity/millivolt system (like a propane fireplace or vent less heater.

You could save potentially 1200- 1600$ per year with geothermal for a payback between 10 and 13 years (at current rates if the money does not cost you anything ie interest rates).
Plus savings on electric used to burn propane, contribution to hot water heating and summer savings (you are leaving out as much as 40% of the equation).

The first thing I would investigate is lowering demand. Dropping your heat loss by 50% has the same effect as cutting the cost per BTU by ½. Check to see if your state or utility company has a energy efficiency audit program you can take advantage of. It may not be possible to reduce heat loss in ½ without drastic measures that don’t make financial sense, but do the easy stuff. Then think about the harder stuff and see if it is worth it.
Good advice for anyone regardless of system. Again however not with out cost that should apply towards geo ROI.
The second thing to investigate is if you can lower the cost of propane. Here in Connecticut propane costs vary wildly from company to company. Only the company that owns the tank can fill it so you can’t price shop once the tank is in, unless you own it. Here a 1000 gallon tank is 3300$ installed + excavation costs, so figure 4K for the tank, in the ground. I paid 1.33$ gallon last summer to fill a tank I own. Same sized tank (owned by a different company) would have been over 2$ gallon to fill the same day.
Propane is affected among other ways by the strength of the US dollar. It will flux similarly to oil as it is not a domestic product. We did see a big drop in prices after the peak a couple springs ago, but like gasoline it will rise again and level off a bit higher than we are used to. $1.33/gal will go the way of the Do Do bird. 
That said if your suggestion is to save money by spending $4,000 on a tank let's apply that to our geo purchase and see what that does for ROI.

....so my advice may be meaningless in your situation.

Note my great self restraint.... :)
 
After that the order gets a bit vague, but-

Twice in a row even...... :) 
Possibility 3 I think you stated elsewhere that you have solar photovoltaic panels. Can you add solar thermal? How about a simple solar air heater maybe a 4 panel solar air heater from “your solar home” installed on a south facing roof or walls.
 
May we then deduct the price of this system from the geo system for our ROI? Solar is generally the slowest possible ROI.

Possibility 4 is can you increase the efficiency of your existing propane system? Ask Dana’s advice or post in the radiant heat section where the boiler guys hang out.

Boiler efficiency is fairly static, once the feds raised the minimum efficiency ~1992 you could get an 80 or a 90% boiler and little else. Poor ROI improvements could be made (ECM pump for instance) not much bang for the buck there. 
Five, investigate the costs of changing to a high efficiency, right sized, mod con boiler plus indirect DHW tank system and the potential savings of that.
~8-9K. Should drop propane consumption by most of 15%. Geo has shorter payback.


Sixth would be geothermal, but it sounds like you are already doing your homework on this. I don’t have the answers as to what the payoff would be for each option, but I would not commit to geothermal without doing your homework and figuring it out. A good energy audit  audit seems like a starting point. Cheers, Eric

Ok Eric,
I agree an energy aucit makes sense anywhere.
I don't agree that flawed math has great value in a discussion.
Every alternative you suggested has a price tag. Any of these would be a credit applied towards geo purchase improving ROI.
Fact is, seldom will geo not kick propane out of the water for home heating. OP has also mentioned that he wishes to maintain a higher operating temp which again improves ROI.
You could also look at longevity, as average age of furnace replaced is about 15 years vs geo at 20 (based on my experience in the field....I'm replacing a 12 year old furnace today). Next geo unit costs little more than a high end furnace and A/C.
Finally if OP were not admitedly oversizing equipment, ROI would improve further.
Roi is definately better than 10 years here (based on information provided). Nothing in most portfolios compares to that ROI. Further it creates an immediate positive cash flow in a home, therefore while money borrowed affects ROI, it does not necessarily negatively impact a household budget.

OP,
I'm disappointed that you were able to purchase a Climatemaster over the counter. Dealers must go through training with CM before they may purchase them. Whoever sold it to you is probably breaking a dealer agreement, so you may not want to trust them (as they have demonstrated their word is no good).
I assist DIY's with design and over the counter sales to turn key, but products available to those folks are not systems where manufacturers' require in house training to purchase equipment. 
When mentioning price disparity between DIY and what you were quoted I saw no mention of electrical, DSH buffer tank etc. Are you telling us that you are saving $8,000 by doing it yourself? Or are you neglecting to calculate the sundries....~3-4k more like it.

Joe

Posted By joe.ami on 16 Apr 2010 09:29 AM

OP,
I'm disappointed that you were able to purchase a Climatemaster over the counter. Dealers must go through training with CM before they may purchase them. Whoever sold it to you is probably breaking a dealer agreement, so you may not want to trust them (as they have demonstrated their word is no good).
I assist DIY's with design and over the counter sales to turn key, but products available to those folks are not systems where manufacturers' require in house training to purchase equipment. 
When mentioning price disparity between DIY and what you were quoted I saw no mention of electrical, DSH buffer tank etc. Are you telling us that you are saving $8,000 by doing it yourself? Or are you neglecting to calculate the sundries....~3-4k more like it.

Joe

hi joe,

not sure why your claling me 'OP' - but whatever works.. :)

i bought the unit from a dealer i found online who is shipping it to me.

im having a local professional who is trained and installed many systems to do the install - i'm not handy in any way... so it is not fair to call this DIY.

i think i will save a max of 7k min of 4k in doing it myself - if installer does a decent job. this includes buffer tanks and other misc. 'sundires'

it seems to me that there is not much wiggle room in well drilling prices (i tried with all 3 quotes - they all said no :( ). so the savings I am realizing are on the cost of the unit and install fees (i think) - in the sense i have priced each so i know what it costs...

i figure most of the savigs is in saving the large markup on the hear pump.

im using some of the savings to better insulate my attic.

also i have a 3200 sq ft home bult in 2004. i have 750sq ft finished space in basement in addition (but no ducts there). is 5 ton to large assming i have 2x4 constructions with batts in the walls and soon to be about r 45ish in attic?

> All of the commercially available simulation software for geothermal applications use emperically-derived formulas.

I doubt that exactly what is done in all commercial software is known outside of the authors. But in any case, I'll take an emperically-derived formula in good, verified software over guesses based on flawed knowledge of thermodynamics.

Simple questions like "does thermally enhanced grout perform better than regular grout" have been looked at by many and the experts say yes - using software or using borehole tests.

Joe, I've held my tongue since I'm a relative newbie on this group, but your consistent biased bashing of others' postings, mixed with an overly authoratative presentation needs correction. You claim that the 80% rating of a propane furnace is peak efficiency. That's incorrect. AFUE is not peak, it's seasonally measured, under controlled conditions. While not a perfect measure, it's a lot better than most other measures. Eric was being very conservative in using 80% also, as any base-model propane furnace will have an efficiency several points higher than this. And, if you factor in a good condensing furnace with variable speed air handler, you're looking at more like 95% efficiency. Unlike boilers, which can have very substantial standby losses, furnaces do not. Virtually all the heat transfered to the heat exchangers goes to the air and there is essentially no standby loss. The realized efficiency of the system will be extremely close to the quoted AFUE. If you have published data from an independent source that shows otherwise, I'm happy to read it. But without that, all we have are your biased opinions based on here-say. However, there's mixed discussion of furnaces and boilers here, with some talk of radiant. Even in that case, with a well designed system with a condensing boiler, you can achieve true efficiencies well up in the 80's.

You mention "electricity that is also employed to make heat with a gas furnace." What other electricity are you talking about? Once the flame has started, with an essentially zero draw electronic starter, the running electricity is the air handler or circulating pumps for radiant, same as a geo system or any other forced air system.
In fact, when you look at geo systems and their payback, you rarely see the energy consumed by the water circulation pump, which can add substantially to the operational costs. A 1/2 HP pump, for example, adds about 500w of load any time the geo runs, decreasing the true COP of the system by 10%-20%. So if you're going to criticize others for their rough calculations, you better include all the loads imposed by the geo system.

You also mention lifespan, as it seems does every discussion of geo vs. other technologies. I routinely see furnaces that are 20+ years old and boilers that are much older than that. On the other hand, circulation pumps take a beating and need more regular replacement. Plus the increased maintenance cost for a geo - flushing heat exchangers, replacing anti-freeze etc. I don't know what you charge for a yearly service contract, but around here, they typically go for $1000 and up. Compared with about $250 for a furnace or boiler. So you need to add that into your ROI calculations.

Plus, we always have to go back to the home's energy efficiency. A modest sized, efficient home costs very little to heat and cool. The more efficient, the lower the cost and the lower the savings. And we should all be striving for the most efficient homes, which makes geo less and less cost effective from a ROI perspective.

I should note that I'm not at all saying that propane or gas systems will be cheaper to operate than geo. Geo systems can be great, but I'm tired of seeing over-inflated claims of how wonderful they are without a fair treatment of their actual total cost of operation.

Adam,
While slightly off topic from the op question, I take great offense at the statement " that the reason drillers charge more for grout is that they do not have the right equipment".
You admitadely live in a state with minimum grout standards. Rock drillers often reintroduce the cuttings back into the hole. Which costs more money? The cuttings that came out of the ground, or something they purchased, ie grout? That is why we/they charge extra monies for grout.
Please be more carefull when making broad statements regarding others business practices and rates they charge.
Respectfully

Joe,
Take a deep breath.
 I am not attacking geothermal. I am simply putting out options to consider before spending 16,000+ dollars.
 
First off without specifics, there is no way to do more than ballpark things. Guess what, none of the geo installers did a manual J calc so they are ball parking it also.
 We are not talking about a new housel.
 Blackflag has a functional, 6 year old heating system, that is likely to last another 20 years before replacing it, with a calculable yearly cost to operate.

Best case it is going to cost him 16000$ to install a geothermal system and the ROI is 10 years plus not including yearly servicing. On average, how much do your clients pay per year to maintain the geo system? My neighbor pays 400$ year to have his serviced.
You can do a lot of stuff with 16000$.  Reducing demand through weatherization is almost always the best bang for the buck. Plus you can claim a 30% credit up to 1500$ for it.
IF spending 4000$ on a tank reduces your net cost per gallon 40 cents, You have a 10 year ROI.
Tanks reliably last 40 years here with the sacrificial anodes. If you look at a plot of the cost of propane per month, over a 20 year period, you will notice buying all the propane at the beginning of the season vs mid heating season saves 10-12% on average (I realize not every year).
 
Second, yes Propane tracks roughly with crude oil generally in terms of price. Propane is a byproduct from crude oil distillation and also from Natural gas production. It is not in fact all imported ~ 10 % is imported directly, 45% is a byproduct of natural gas production, and 45% is from crude oil distillation. Considering the fact that the US deposits of Natural gas are huge and production is likely to increase, Propane prices in the future should be more closely tied to that of Natural gas. I am not an economist by any means, but that is what the  energy trackers say.
 
Where I live, based on the solar insolation data, a flat plate solar air collector on a south facing wall or roof mount can be calculated to have a payoff of around 10 years. As long as you don’t throw a rock through the glass, it should last much, much longer then a geothermal system.
 
As far as longevity, my sisters gas boiler was built in the 70’s My parents furnace lasted 34 years.

What I said was that all these things MAY have a better return on your investment dollar then Geo. I am not arguing that GEO is bad. It has its place in very large and poorly insulated houses.
It is not the answer to every problem.

Cheers, Eric

Tinoue,
I re read my previous post and am unable to find anything that is "bashing". You may be refering to a different post elsewhere (perhaps you could direct us). As you mentioned you are newer here and may not be privy to all that has transpired before (here or elsewhere). You might indeed sense impatience with me from time to time, but it is generally not universally applied. It tends to be targeted at charlatons, or peaves such as having to ask the same question 3 times to try to help.
That said if disagreeing is "bashing" I'll consider myself "bashed" by your contribution.
As far as bias, I confess to a geo bias on this geo forum. However, I am not a one solution dealer (perhaps you noticed mention of a furnace install yesterday), I can safely say more than once I have suggested to folks that their application may not be good for geo.
Regarding AFUE you are of course correct that it is not a "peak measurement". In a case of fingers typing faster than brain....I was under the impression that we have a standard boiler. Not a modulating one. I do not happen to agree that average efficiency will be 80% for a standard boiler with electronic vent damper. If it happens to be induced draft gas consumption will decrease, but electric consumption will climb. In fairness actual usage might be closer to high 70's but I used conservative numbers not only for the boiler, but for the geo (suggesting COP~3 when it will more likely be ~3.75).
I submit to you if I lowballed both = no harm, no foul.
Your second point about electric consumption is partially answered by the above. I will add that a circulator for a closed loop adds about the same as a circulator for a boiler (not 1/2 horse) and is included in geo op cost calculations when I run them so (IOW factored in ROI) so why would we not factor them in boiler op cost?
Regarding lifespan, it is my field experience and ARI that suggest geo last longer than furnaces. Compared to an iron boiler, I would suggest the boiler whens if installed correctly. Compared to a modern furnace or modulating boiler, there is no doubt (in my mind or ARI's) a modern geo will last longer.
I agreed that improving the envelope is always a good idea, and have made the point before that it can be a wiser investment than anything else when building or remodeling. Where this case is concerned I simply suggest that if all other things are equal (10 year pay back) then I'll take the one that will continue to save me the most after 10 years.
On your final point, I don't think you'll find anyone less likely to exagerate geo op cost savings than me (again I'll point you to the ~3COP comment in the post you took exception to).
I'm truly sorry you took offense to this or other posts of mine. But I confess to confusion that this one inspired you to respond so harshly. Was it the bold print?
J

Eric,
Is it the bold print that makes you think I was excited? I even threw in a little self effacing humor followed by a to take the edge off....
I don't mind a discussion of options I simply pointed out flaws in your theory as you have in mind. Nothing wrong with an exchange of ideas...and to that end:
You are correct that it is all ball park with out loss calc (which is something some of us asked for early on). However regardless of load, the op cost disparity is static and therefore calcuable.
You mention that Blackflag has a system that may last 20 more years and if it is an iron boiler I agree. Curiously if we multiply his projected $1,600/yr savings times 20, his already paid for heating system will cost 32,000 more to operate than the geo he's planning (net loss as much as $16,000). Why doesn't anyone ask the boiler to pay for itself?
How much do my geo clients pay for annual checks on their systems? $20 more than my warm air customers and the same as boiler customers. Has mostly to do with equipment involved and education of technician. ~$100.
I agree that envelope improvements are a good idea, as is buying your own LP tank, but if all things will pay me back in 10 years I'll take the one that gives me the most savings when 10 years are up.
My impression was source of propane was more than 10% off shore but I will stand corrected. Fact remains that it will not paralell nat gas pricing until it is delivered like natural gas.
Again longevity of modern furnaces is about 15 years and to soon to tell but my guess is moduating condensing boilers properly installed may be close to that. Furnaces the lasted 30 years are out the window with efficiency race (all things are a trade).
Solar has some exciting improvements going on that I have been watching. A plumber friend and I have a project coming up to employ a system on a pole barn that doesn't have to be 70 degrees but can't freeze.
I'm not prepared to heat homes in MI with it.
I do not submit geo is a one size fits all solution. However this is a geo forum and I am a geo advocate and it is in most cases the most efficient heating system available regardless of insulation. That is not the same as best ROI in every case which is why I don't recommend it in every case.
My apologies if I offended you, frankly this discussion has just jumped several notches in interest to me. Perhaps that's the excitement you detect.
J