"Unless you have insulation between this floor and the house, it is also an "uncontrollable heater/radiator" that limits how much heat you can store there without large fluctuations in interior temp. So tell us more about this aspect. I suggest that water is much better at storing heat on a per cubic foot basis and is easily controlled. But it is a more complex system and air ducts and insulation could address the control issue with concrete. "

Concrete floor is completely isolated from the outside in my case. You can see here a sort video of how the house is build including the foundation and thermal insulation  https://www.youtube.com/watch?v=Y3g4gmRvgko

Water per volume is 2x better but since I already have the large concrete floor that is part of the building and was specifically designed for this purpose I need no water storage.


"I recommend not using the term "obsolete" every time something doesn't work for your situation."

I promise I did not use that therm lightly. I'm an engineer and I did already the calculations. Is not just my particular case I'm sure is almost any case unless electricity is extremely expensive above 40 cent/kWh and you have no space for solar PV panels or really bad solar resources in winter like some European countries.
Most people are not able to calculate a cost amortisation else there will have been some answers to my question.
Also the therm obsolete is inside a question is not an affirmation at this point.

"1) I believe geothermal is USUALLY used for heating AND cooling.
If that doesn't apply in Saskatchewan, Waterfurnace will somehow
find a way to muddle through."

Cooling is also used here by probably over 90% of houses. Bad design with no thermal mass and little thermal insulation.
Question was about geothermal heating only but you can include a cost amortisation for cooling and compare that with a less expensive air to air cooling.
I'm sure it will not do as good for cooling also but maybe better that for heating.

"2) How much did that 14 cubic meters of concrete cost ... and
would it have been needed with an on-grid heating alternative?
It's always easy to cherry-pick the numbers to justify [whatever]."

No cost that concrete is part of the house structure so was needed anyway. See the link in the answer above if you want to see how the house is build.
Still question is more general and not about my particular house.

"3) Although lifetime cost-of-ownership is certainly a consideration,
for many homeowners (me) it's secondary to other things -- such as
time, comfort, and convenience. If you enjoy DIY cost-minimization,
and can tolerate the compromises (e.g., temperature droop) have a
blast! I'd rather write a check to the HVAC pros and spend my time
doing stuff that I care about (and/or get paid for)."

You may not care about the cost of energy that is your choice.
You can say something is obsolete if there are more cost effective methods to do the same thing.
You can have the same comfort I'm referring on the cost / unit of energy you can use as many units as you want.
 
"...is DIY homebuilding obsolete?"

It is most probably obsolete since the number of DIY build houses is extremely low compared with what was in the past.

Electrodacus - This thread has been bugging me... I am impressed with your abilities and your knowledge. And I think I understand the intent of your post, but do not agree with the manner in which you present your argument. I work and reside in a world where we rely on equipment and systems to keep us comfortable and allow me to provide for my family (i.e home and work). I am surrounded by technology at every turn. At any moment, someone is out there thinking of how they can improve on the machines we're using now. Once it's developed and marketed, are we supposed to dispense with what we invested in before? For me, it's not possible. With regard to geothermal specifically, I find the technology to be very viable. As such, I spend time on forums like this because I am now intimately involved with geo (as a result of installation at home), interested in the discussions (as a hobby almost), and on the lookout for posts that may relate to me which may help improve my own situation. I've found a community that appears to share at least some of these points. While you do put up a strong case for your methods, I don't think posting here somewhat negatively is the right thing to do. Maybe there's a way to share your findings with others that may be more receptive to listening. Try blogging?

"Electrodacus - This thread has been bugging me... I am impressed with your abilities and your knowledge. And I think I understand the intent of your post, but do not agree with the manner in which you present your argument."

Is not my intention to bug anyone it is for sure not my intention. I came on the forum to post about my Solar BMS and noticed the Geothermal Heat Pumps category.
I still did not completed my solar heating. I still used the temporary propane heating this winter for my house but had just made a video about obsolete technologies related to low cost of solar PV panels.
On top of that I had considered almost all responsible heating sources about 3+ years ago when I was designing my house.
I was sure I will go with biodiesel for heating and had already a 10kW diesel heater but it failed to work last winter when I installed that. It worked for a few hours but then the combustion fan failed the plastic fan unglued from the motor axe. It was hard to glue back since it was already winter and cold and it was installed outside. It is also extremely cold here with -30 to -40C not unusual and even with normal diesel combustion will be hard to start.
I hated working in the cold trying to repair that and and get my hands full of diesel. So I ordered a small and inexpensive 10kW thankless propane heater and installed that instead to heat my house.
Diesel or biodiesel  was about 12 cent /kWh about less than half the price of propane in those small barbecue tanks and easier to get and store that is about 28 cent CAD/kWh at this moment.
In both cases burner efficiency is about 80% so price /kWh inside the house is actually 20% higher than the above quotes and the cost dose not include the amortization cost for the heaters.
Wood or pellets where both more expensive so for me the least expensive at this moment is PV direct heating at 8.8cent/kWh this includes everything as explained above is the most reliable and green.
I do have plans to use the extra energy so that 8.8$/kWh will go even lower than that.
The thing is that geothermal will not work for me more complexity higher cost so no gain.
So question is is there a place for geothermal for heating with the low cost electricity. I think in most of the world electricity rates are from 6 cent to 25 cent/kWh
So is a geothermal installation a cost effective solution? I think this is the best place to ask this question since many of you have a geothermal installation and know the real cost.
I'm sure the most expensive part is the ground loop and that one if done properly can last forever maybe but I think a decent amortization time for that needs to be 40 to 50 year any more than that will be a bit ridiculous. But then there are the other smaller initail investment like the heat pump that will need a few replacements over that 40 to 50 year amortization period for the ground loop.
Once you have all this in place like you do it make no sense to think about since is already there and there is probably no better alternative.
Question is for those that are thinking about that right now but did not made the investment.

Concrete floor is completely isolated from the outside in my case.

You missed the point. What is the temperature range of your thermal storage? 10C? What variation does this cause in the inside (interior air temp)?

Most homes, especially retrofit installations, are great candidates for geo. A new super insulated home with cheaper alternative power may not be. Many of us here fall into the former category.
When i compare the cost of oil that my house used to have vs electric (i don't have any other options like gas or wood), geo is a quarter of the cost. At that rate, payback for switching from oil is about 12 years.

Most people don't consider geo for just heating, so asking if there is a place for geo for heating is only half the question. I certainly can't use a pellet stove or resistive heaters to cool my home in summer when it's 95 outside. Those people thinking about geo should consider the cooling aspects as well.

Good luck with your build. I know you can't dig for the loop, so you're going with your pv-resistive system. Give us an update in a year. Do you have internet access at your new place? You could spring for a WEL system and feed all your temp and electric data to the web. I am fascinated by the concept of a small super insulated home that requires only a little electricity. I'd love to see how it performs over the seasons.

"You missed the point. What is the temperature range of your thermal storage? 10C? What variation does this cause in the inside (interior air temp)?"

For this 10C temperature variation to happen it needs at least 3 to 4 days without any heating and -20 to -30C outside temperature.
Air temperature can be kept constant with really small amounts of energy. Without heating the air the air temperature will be about the same as concrete floor maybe plus minus 1C.
When you have a few cloudy days the PV panels will produce 8 to 20% of what they produce in a sunny day but even that 8% is more than enough to keep the air temperature constant. 

"At that rate, payback for switching from oil is about 12 years."

Can you give a bit more details 12 years payback seems really good.
What was the cost of heating oil and what is the rate for electricity at your location?

"Most people don't consider geo for just heating, so asking if there is a place for geo for heating is only half the question. I certainly can't use a pellet stove or resistive heaters to cool my home in summer when it's 95 outside. Those people thinking about geo should consider the cooling aspects as well."

My house is well insulated and with the thermal storage dose not need cooling in summer. There are not may day with 35C or above here.
The expensive part of geothermal is the ground loop the heat pump is quite inexpensive in comparison and even an Air to Air heat pump will have good enough COP for cooling.

"Good luck with your build. I know you can't dig for the loop, so you're going with your pv-resistive system. Give us an update in a year. Do you have internet access at your new place? You could spring for a WEL system and feed all your temp and electric data to the web. I am fascinated by the concept of a small super insulated home that requires only a little electricity. I'd love to see how it performs over the seasons."

I already live here even if the house is not complexly done and heating is a temporary based on propane and a pex tube circulating hot water in the same concrete floor. I do have 4G internet here. I have my own Solar BMS charge controller that can do data logging. The new one that is just on kickstarter will have WiFi. I will design and build a Digital MPPT for the PV heating part soon that will also be able to data log.
There is on my website a 7 day energy production and consumption graph for the electricity that I use.
Currently I have 720W PV array and a 24V 100A LiFePO4 battery this allows me to use 60 to 90kWh/month. That is how I know for sure I need a 9kWh PV array for heating.
I also know the amount of heat I need since I use at most 10 to 12 20lb propane tanks each holds 100kWh of energy and the burner is about 80% efficient so peak month needs 1000kWh
But I knew this from thermal calculations also is just good that I was able to confirm with the propane heater.

Can you give a bit more details 12 years payback seems really good.
What was the cost of heating oil and what is the rate for electricity at your location?

Certainly. Pure mathematicians out there will probably cringe at e number of fudge factors involved here, but i will try to round down instead of up.

In years past, oil was between 3.50 and 4 per gallon. Granted it's lower now. Electric has always been about 12c per kwh.

My house under the previous owners was 1500 sq feet, not well insulated upstairs, and went through an average of $300 per month of oil for heat and hot water. I don't know the cost for the central ac for cooling....it was an old rusty 1992 air source heat pump.

The house is now 2000 sq ft but better insulated upstairs. So more space to heat and cool, but better able to retain heat and cool.

The geo system cost $18,000 to install. It takes care of the heat, hot water, and cooling.

It costs me $65 average per month to run.

Only counting the previous oil heat (not even the old rusty cooling cost), i am saving $250 per month. Even if oil has dropped by half in cost, i'd still be saving at least $125 per month, and getting cooling as well in the summer, which i'm not even including in this payback, but would make the payback even better.

So $18,000 up front. I'll use the savings number based on estimated oil now, not when it was $4 per gallon...if oil went up, the payback would be faster.
18,000/125=144 months to break even. 144/12=12 years to break even. After that, it's paid back and just costs $65 month year round.

Of course, we assume the system won't need a new compressor or anything major, and that the loops will be good for far beyond that.

We've had it since october 2009. So far, so good.

Well, I've had the geo system up for almost 3 heating seasons now, so I can compare some numbers:

For most of Saskatchewan the HDD varies from 5500 to 8000, I'm at 6400, so I should think a ball park comparison would be reasonable.

I also use 4 to 4.5 MWh/heating season, with a peak very close to 1MWh/month, so I'm using almost exactly the same energy that you are estimating, however my house is 4.1X as large as yours.

My end of season COP on my geo system is 3.8, with a start of 4.5. I did build my house as a "U" around a courtyard, with a lot of exterior doors, so my shell is probably not as efficient as yours, but overall pretty fair agreement between the size difference and the COP of the heat pump.

From your cost estimates it would run me 38 to 45 K$ to supply my heat as you are proposing, my DIY geo system cost me 12 K$. If I added on the solar system that you are proposing for your house I would be in for 22 K$, approximately half of your solution if applied in my situation.

So, as far as your original question as to if geo is obsolete I believe the answer to be no, however, the answer to perhaps the more interesting question of is geo a reasonable thing to do is it depends.

My situation is very similar to that just described by stuart.wyss.
Geo retrofit to a 1950's oil/hot_water_baseboard system (plus a
decrepit central air conditioning add-on). Energy costs reduced
by 80%. Break even time less than 10 yrs, cash-flow positive
from day #1.

And that's ignoring the major intangible benefits: quiet comfort,
no oil deliveries, no oil price panics, no smelly oil tank, sooty old
furnace room converted to clean & comfortable workshop, total
RFQ-to-completion in several weeks -- rather than ??? years.

Bottom line: There's a HUGE difference between "price" and "value."

...IMO, it fully paid for itself in the instant it was turned on,

Looby

"Certainly. Pure mathematicians out there will probably cringe at e number of fudge factors involved here, but i will try to round down instead of up.
In years past, oil was between 3.50 and 4 per gallon. Granted it's lower now. Electric has always been about 12c per kwh."

This is what I was looking for. Thanks for taking the time to post this.
Heating oil is at about 10kWh/liter and one gallon has about 37.8kW
So based on that and your 3.5 to $4 / gallon price was around 10cent/kWh for heating oil.
But burner efficiency can have a huge variation so even with a very good 80% efficiency oil is a bit more expensive than electricity at your location 12 cent/kWh

Was that 300$ average oil bill for the old house and old owner ?
It may be that the house thermal insulation plays a big role and it may also be that the old oil furnace was extremely inefficient.
You did not mention what was total bill for heating per year. I think there are only a few months a year requiring heating.

If the geothermal runs at an average COP of 3 and you bill is $68 then you probably have a saving of $136 / month in winter compared to using electric directly.
If the total cost for geothermal was 18k and you have around 5 months of heating / year you need about 26 years to recover the investment.
That is not bad if there are no other maintenance costs associated with this.

Can you give more details about the location and how was that 18k split between different parts like ground loop and the heatpump.
at $68 and COP of 3 that is $204 / 12 cent 1700kWh / month for heating on your 2000sqft house this seems extremely good but I do not know your location so not sure how cold is there.
Anyway thanks again for taking the time to answer.

Can I know your aprox location and do you have any photos with the house. That seems extremely impressive if it uses the same amount of energy and is 4x larger.
I took a look at HDD and is about 6000 in average for my location.
Not sure how you took my cost estimates. But your cost will be exactly the same as mine 10 K$ since you need the exact same amount of heat as I do so you need the same size heating.
But not sure how sunny is at your location if you have less hours of sun in winter than I do then you will need a bit more than 10 K$.
Please if there are some more details about your house I will be really interested to see.
I just realized that maybe your heating energy is based on what the heat pump uses and not the house that will make more sense since you say your heatpump has a COP of about 4 and house is 4x larger this makes more sense.
What is the electricity rate for your location ?
Also some details about the DIY geo system will be nice 12 K$ seems really good for a peak 4MWh/month heating load.
That 4000kWh / 30 day / 24h = 5.5kW if it works continues so I'm curios how large is your ground loop to support that for the entire heating season.
 

"...IMO, it fully paid for itself in the instant it was turned on,"

That is only true if the investment was 1$ :)
What is the COP of your heatpump? and what is the cost of electricity at your location?

Posted By electrodacus on 19 Mar 2015 01:44 PM
That is only true if the investment was 1$ :)

That is true if the ONLY thing you value is money.

What is the COP of your heatpump? and what is the cost of electricity at your location?

Since installing geo, my energy bills have been so low that I've
entirely lost interest in tracking such inconsequential details. It's
a 3-ton Waterfurnace Envision(?), vertical closed loop. All of the
other details have pretty much faded from memory since 2009.

"A cynic knows the price of everything and the value of nothing."
-- Oscar Wilde

>>Was that 300$ average oil bill for the old house and old owner ?
>>You did not mention what was total bill for heating per year. I think there are only a few months a year requiring heating.

Correct. The $300/month was an average for the previous owner. That would be $300 x 12 = $3,600 per year. Yes, higher in winter, lower in summer. They were on a budget billing system, the same amount per month. It was heating the house in Winter, and then summer hot water. Note I did not include the cost of cooling. Geo isn't just for heating.

>>If the geothermal runs at an average COP of 3 and you bill is $68 then you probably have a saving of $136 / month in winter compared to using electric directly.
>>If the total cost for geothermal was 18k and you have around 5 months of heating / year you need about 26 years to recover the investment.

I am not replacing electric heat, so we cannot compare to just electric heating. My payback was based on the cost of oil. My yearly heating AND cooling cost is now: $65 * 12 = $780 per year, VS $3,600.

We also not factoring in the cooling cost of the old AC, the drop in price of oil at the moment, and the size/insulation change of the house.

"Correct. The $300/month was an average for the previous owner. That would be $300 x 12 = $3,600 per year. Yes, higher in winter, lower in summer."

I had no idea this was an average for the year. This seems quite high.
But is hard to compare this non insulate building with a different owner.


"I am not replacing electric heat, so we cannot compare to just electric heating. My payback was based on the cost of oil. My yearly heating AND cooling cost is now: $65 * 12 = $780 per year, VS $3,600."

Not a fair comparison even if you got cooling cost included. Since it may be that most of the saving is from additional thermal insulation and not geothermal.
An air to air cooling will not be quite as efficient but not far from geothermal and way less expensive.
As for heating you could have used direct electricity at 12 cent/kWh with no need for an expensive ground loop. Cost amortization seems to be around 26 years in this case if no additional maintenance cost will exist.
Oil is expensive even at this current half price so it make no sense to use in this comparison. If it was natural gas that will have been a different story since that is around 3 to 4 cent/kWh I think and geothermal had no chance at that level.
With a geothermal with real average COP of 3 the saving from 12 cent /kWh electricity is about 8 cent/kWh and as I mentioned that will need about 26 years with no additional expenses to amortize the cost of geothermal.
Do you have any backup heating in case electricity is lost ? Did that happened since you moved ?
If I was able to use all the energy from PV panels and had enough space for PV on the property then they can get at around 4 cent/kWh as amortization cost.
My 8.8 cent amortization cost for heating comes from the fact that I consider them just for heating and not used at all in the summer.
I do have plans to use them in summer and have quite a bit of alternative use in winter.
One good example of use that will completely recover the investment is distilled water.
We drink distilled water about one gallon / day and at the moment we purchase that at around 2$ / gallon from the store (When I had grid power I produced the distilled water at around 3.6kWh/gallon)
Now 2$/day x 365 day/year is about 700$/year.
So if I use electricity from PV to produce distilled water I save 700$/year and if you remember the amortization cost of PV array was 400$/year for 25 years so it more pay for it self just by making distilled water so the heating is free.
Distilled water uses just a small percentage 10 to 12% of the energy from the PV and the by-product is distilled water and heat so no loss on heating. Thus there is a lot of excess left in to do other stuff with that electricity just need to find them.
So you can see for me PV heating is way more than superior to geothermal.
There is no maintainable cost all solid state no moving parts pumps or liquids and I do not depend of any utility or fuel.
Thing is that you need a relatively good insulated house and a large thermal mass to store heat during a few days without sun. You also need relatively enough space for the PV panels (I live on a 20 acre lot so is absolutely no problem).   

Quote from Nooboo

"The relevant term is ( I think) locked rotor amps. To turn the motors, one would need some amperage, and in the land of ice and snow in December, using PV, with batteries, and maybe even a properly sized (oversized to start the pumps) generator, I think the issue is moot. You need to run the pumps. Did I miss your point? What I focus on is you say "reduce the size of the PV" when it seems you would need a bigger PV array to run a GSHP, not a reduced size."

It comes down to an apples to oranges comparison. You really can't do Geo without the grid or large expensive batteries.

And we can't heat our houses with direct PV

"As for heating you could have used direct electricity at 12 cent/kWh with no need for an expensive ground loop."

How could stuart.wyss have done that? If he is getting a COP of 3 to 4, he would pay 3 or 4 cents and get 12 cents worth of energy.

PV is not less then 1 dollar a watt, maybe you can buy just the panels. Wire for DC use of a 9KW array has to be very expensive.

"So you can see for me PV heating is way more than superior to geothermal." Yes for you!

I am trying to follow what your going to do. Right now you heat water and send it through plastic pipe in the cement slab. Your going to change to electric resistant wire heating elements? How are you going to get the wires in the slab? I didn't see wire in the cement in your video.

Chris

"It comes down to an apples to oranges comparison. You really can't do Geo without the grid or large expensive batteries.
And we can't heat our houses with direct PV"

You can use geothermal with no battery direct PV you only run the geo when you have sun and store that heat in a large thermal mass for times when there is no sun. Is the same ad direct PV heating that I will be doing.
Why do you think you can not heat your house with direct PV? The only reason you will not be able to do that is if you do not have enough space for the PV array (that is quite possible if you have limited space and house is not insulated and needs a lot of heat so PV array will be quite large). So is mostly about the space and sun availability in the winter. In some European countries with almost no sun in winter months this will not work probably but in most other places it will work.

"How could stuart.wyss have done that? If he is getting a COP of 3 to 4, he would pay 3 or 4 cents and get 12 cents worth of energy."

I think at best the COP is 3 not sure he included all the parameters in his evaluation. Even 3 may be a bit optimistic it depends on how well he dimensioned the ground loop.
Anyway the thing is he invested in the ground loop and heat pump and that needs to be amortized and it will need about 26years with COP of 3 that if he will have no other maintenance cost in that period.

"PV is not less then 1 dollar a watt, maybe you can buy just the panels. Wire for DC use of a 9KW array has to be very expensive."

PV panels are under $1/Watt and DC cable is about 15% of the cost of panels not that much I included that and the ground mount in my calculations.

" I am trying to follow what your going to do. Right now you heat water and send it through plastic pipe in the cement slab. Your going to change to electric resistant wire heating elements? How are you going to get the wires in the slab? I didn't see wire in the cement in your video."

At that time I was not thinking about PV heating but luckily I did not installed the ceramic tiles that I intended to install all over the house so I will embed the heating wires under the ceramic tiles quite close together about 4cm (less than 2" apart) so the heat distribution will be uniform. I only need about 100W/sqm (less than 10W/sqft) so not a bit problem.
I will make sure to document everything on my youtube channel. At the moment I'm busy with other projects and I do not have the money to invest right now.
I may get a part of the PV array installed so that I have 3kW total including the 720W already there and later install the additional 6kW.
If I had the money I will have done all at once but probably will not happen for next winter so I will still use mostly propane with a bit of PV for distiled water and heating.
I also need to build a Digital MPPT I will explain why that one is needed for heating and will be open source as all my other projects.

Posted By electrodacus on 19 Mar 2015 04:47 PM
... do not have the money to invest right now ... I may get a part of
the PV array installed ... probably will not happen for next winter ...
will still use mostly propane ... I also need to build a Digital MPPT

Sounds like some difficult-to-quantify costs -- typical of ambitious
DIY projects. In contrast, it was easy to finance a professional geo
installation (at less than 2% interest, net of taxes) -- thus getting
the installation completed in less than 2 months. Compared to a
DIY schedule, the "amortization clock" starts running years earlier.
Again, the professional installation was highly cash-flow positive
from the very beginning -- so delays would be rather expensive.

I'm not saying DIY isn't for anyone, but many homeowners will
find it more productive and profitable to spend their time and
effort generating income from their professions. I don't know
how you'd do an NPV calculation on that, but there's NO WAY
that I could have benefitted financially by doing it myself.

It would be instructive to compare the costs of soup-to-nuts
professionally contracted installations of geo vs. [whatever].