Here is my question to all. If you are going to build ICF to the roof, is it worth the extra $30,000 or so to put in a geo thermal system to supply the heat for the radiant or just save the extra money and put in a boiler. I just can't see a significant amount of savings to justify the cost. You are already much better of with ICF over stick built, even a low efficiency furnace would do just fine! Has anyone ever done a comparison and if so what have you found. When, if ever, will there be a break even point. Thanks Paul Stevens

Paul:
I think it is all relative to size of the project and loading, and in all actuality the fluctuating cost of fuel for the boiler vs. "fuel" for the geo will make it fiscally worthwhile or not at any given time.
I know this helps very little with regards to a "comparison" and "break even point", sorry.

We looked at these options ourselves and went with a geothermal. For a "normal" 3000 sq. ft house, no we wouldn't have invested in geothermal as the benefits wouldn't be there.
However, we have 3000 sq. ft two story w/ 10 ft. ceilings, a 600 sq. ft. insulated garage and 3000 sq. ft. shop with 18ft. ceilings, now the costs seem to work out....All electric home in Wyoming last month was $270.00 (with cloth diapers going nonstop....) with the shop set at 50 degrees. We also wanted the option of warming soil on the shop radiant floor to jumpstart spring germination for our someday greenhouse....And warm desuperheater water for shop use washing dogs, horses, trucks etc.

It was interesting to note that the HVAC guy would put a gas boiler in his own home for radiant, partially because it would be easier to run off a generator....Also he didn't like chilled water because of condensation issues if any portion of the piping is not insulated.
Our geo does hot water radiant in the shop and part of the home, hot deck in an air handler for forced air, and in the summer chilled water for cooling all off one system. As long as the geo is low/no maintenance the convenience alone sells it for me, but we'll see about that.

So my best answer is, for most conventional 2-3000sq. ft super insulated home, a boiler is most feasible.

And for the good of the people who don't understand humidity in tight structures, (like our geothermal installer who said 'there is no way in wyoming or montana that you will ever need to dehumidify') we have seen humidity climb to 80% inside while drywalling/painting etc. Running the air handler non-stop for 30 days gets the humidity down to only 45-50 degrees, not low enough to control window condensation when it is -10F on the outside...Newbies be warned, humidity control must be addressed during choosing an HVAC solution, especially in tight structures, and in every climate!

Kevin

Kevin, thank you very much for your detailed response, I am sure my homeowners will be thankful as well.
Paul Stevens

Hi Paul and Steven,

What I hear you saying is.... it's hard to justify ROI for a Geothermal system in a new well insulated home under 3000sqft.
I'm looking at a new construction 2000sq ft home with an ICF basement with polyurathane SIP's on top (single floor with radiant floor heat).
The cost is exceeding my original estimates and going with a high efficiency Heat Pump would save quite a bit over Geo.
I read this somewhere else too and I'm just about convinced.
Tell me, am I understanding this right?

Thanks,
Marc

One problem with that line of thinking is that the savings from geo will usually more than pay for any extra mortgage expense added by the geo. Also, there's the 30% uncapped tax credit now for geo.

Most people tend to have mortgages on new homes. When that's the case, ROI flies out the window, and is replaced by monthly cost.

To give a short example...
Mortgage w/ regular fossil fuel system = $1000/mo. (price of the home established this cost)
fossil fuel system avg. monthly operation = $150/mo.
Total cost of this home with fossil fuel = $1,150/mo.

Mortgage with geothermal (additional $15,000) = $1,075/mo.
Geo avg. monthly operation = $50/mo.
Total cost/mo. (out of pocket) = $1,125/mo.

Which house costs more? Answer = the geo house.

Obviously these are just examples...the real numbers can be determined for every home, though. It's typically the case that the overall cost of the home (out of pocket / mo.) is lower with geo than without, even though the price is higher.

Thanks Clark,
Some good examples. But don't you think the cost difference in a ICF/SIP home at 2000 sq ft with a 16 seer Heat pump may be less?
The Savings are less because the demand is less right?

There is also the cost savings is using goethermal to heat your hot water.  I have read and heard that the cost of heating hot water is next to the cost of heating your home. 

Another plus, although not related to cost, is that geothermal heating and cooling is always at a constant temperature - no hot and cold spots.  Your home should always be very comfortable.

Right, the higher the load, the greater the savings.

There are a lot of things that come in to play on one of these comparisons. Weather data/history, heating load, cost of electricity in winter and summer, cost of fossil fuel, type of heating system, if water is concerned, how many people occupy the house, and how they use the water...Obama's carbon emission restrictions increasing the cost of power up to 200%...and many other things.

I'd recommend, though, that before you knock the idea, have someone do an accurate load calculation and cost comparison for you.

Tuffluck driller, if you are comparing costs on an expense basis, you can't ignore amortization. Geothermal, being a mechanical system, will need replacement at some point. If we say it lasts as long as an air/air heat pump, or 15 years, you'd need to set aside an extra $1,000/ yr in your example, over and above amortizing the cost of replacing a boiler. Adding $83 a month, your geothermal home now costs more.
You are going to answer that replacement won't cost that much, so let's do the math the other way. If conscientious homeowners stuck their $25/month geothermal savings in the bank at 5 percent interest, they'd have $6,700 after 15 years -- and one hopes some serious questions about whether borrowing an extra $15k is worth the risk.

Why do you think a house with a GSHP would be more comfortable than with an ASHP?  They are both heat pumps (until aux heat kicks in)!  Granted, GSHP are much more effective in the north than ASHP.

Many believe that radiant has a higher "comfort factor" than forced air, but comfort is a mostly a matter of good design and construction.  

Bruce

To be clear on the point of whether geothermal buyers should look only at monthly expenses, as tuffluckdriller urges, let me add this. He wants you to borrow money for 30 years to buy a vital piece of equipment that will last perhaps 15 years. When you replace it, you will still owe the bank $10,300 of the original $15,000 premium you paid for the first system (at 5.25 percent on a 30-year loan.)
I struggled for a word to describe the need to accumulate interim replacement money, and settled on amortization. Under normal circumstances accountants would put this expense under depreciation. (In the second half of the note, you would in fact be depreciating the system.) I realized what amortization doesn't quite convey what tuffluckdriller has in mind. Lunacy is a better term.

Isn't the tax credit only on making existing homes more energy efficient? I don't think that there is any tax benefit on new home construction. At least in Canada thats the way it is!
Paul Stevens

There is no tax credits available for new construction in Ontario

On the point of how long a geothermal system will last, it is projected to be about 23 years on some systems, with most seeing at least a 30 year life. Air source heat pumps are projected to last 12-15 years. The geothermal will outlast the air source hands down because it is operating in a milder environment (ground temps instead of air temps.)

In the U.S., the new tax credit applies to new and existing homes for the geothermal portion. It is a 30% tax credit. 30% of the installed cost, no limit. We'll see how the IRS interprets this into their code for more specifics, but the law is that.

Did we agree on anything?

Heat comfort - Geo same as heat pump - Radiant rules. Home construction is a variable regardless of heat type.

Geo - High initial cost no matter the size, heat recovery for HW, System life is longer, unit cost more to replace, will work well in winter, more financing more interest, Tax break.

HE Heat Pump - Does not work well in winter, Lower initial cost, heat recovery for HW, System life is shorter, Unit cost less to replace. Tax break

Initial cost  - Geo $18,000.00 more
HW Recovery -  Same
Comfort - Same
Replacement - Geo $3000.00 more
Heat pump - Extra heating in winter x 25 years (solar backup)

I am still hung up on a couple of issues. 
Well insulated home should not be much difference in cooling but more heating bill if you have High Eff. Heat Pump.
Radiant floors should give comfort. My guesstimation is 2000sq ft or less home may not be worth Geo with a SIP or ICF home.
What else should be considered?

Seems that the advice to get a couple accurate load calculations and bids for each system would be the best place to start. Then you can look at the long-term costs and make an informed decision.

I have some questions regarding some numbers used in this thread. First, is your extra cost to go Geo really $30,000? That seems like a high up charge. But there are a number of things not discussed that would drive this number such as what type of ground loop is utilized and the associated installation cost as well as the increased cost for doing radiant heating with Geo as opposed to forced air. Also, what is the cost to replace the Geo unit at end of life compared to an air source heat pump?

I am no Geo authority in any way. On my Geo system, the up charge was only $5K, forced air, easy loop installation.

We do not know what is going to happen with the cost of electricity in the future. It is anyone’s guess. I feel very confident that we will not see 200% increases because of pollution controls. We can be assured that both electricity and gas prices will climb in the future. In the past decade, natural gas prices have risen faster than electricity, typically. As energy prices climb, the most efficient option will offer increased savings.

You also need to factor in domestic hot water. DHW typically accounts for about 18% of the energy cost in a house. With Geo, a portion of this heating energy is free. However, so would DHW from a solar hot water system for an additional 6 or 8K.

There are many options to consider.

I think it also wise to consider the actual floor space each system uses. Small homes often have a lack of utility room extra. Storage tanks, DSW etc. take up extra space and this could be factored in the geo up front cost as well.

I've come across people that have a desire to incorporate a geothermal system with an ICF house and more often than not, I have recommended against it. My reasoning is because of the length of time it will take to achieve the ROI like Marc&Kem mentioned above.

If I were to build lets say a 3000 sqft house with ICF walls, I would estimate that the average cost to heat and cool the home at $70 a month. If you were to put a geothermal system in the house, lets say that you drop the heating and cooling costs to an average of $35 a month. Under this senario, you will save $420 a year with the geothermal system. If the upcharge is only $5000 after tax breaks, etc (which would be a really good price in my opinion) then it will take about 12 years to break even. If the 12 years ROI worth it to the owner (for personal reasons or otherwise) then have them install the geothermal. If it were me, I honestly wouldn't spend the $$ on the geothermal systerm.

I think that there are many positive uses for geothermal, but I personally believe that it is more practical to invest in other ways (tankless water heater, etc) to make the home more energy efficient if you are building a house that is approximately 3000 sqft. As the house gets larger, my thoughts regarding geothermal change, but we are then talking about a pretty large house.

A little off topic but does anyone know how the life expectency of a mod/con boiler would be in comparison to a geo system

If you want to install a Geo system and save money, forced hot air is the way to go. In my mind using radiant heat, as nice as it is, is a bigger waste of money than using the Geo.

The new geo units with computer controlled fans, zone dampeners and the like can be as much as 500% efficient. Also the house being so tight it will still heat evenly. And lastly the same unit can also be used for cooling, where a geo connected to radiant cannot.

My example is that I am in the process of building two houses next to each other, both of similar size. One built to code with oil heat, and one built with ICF's, geothermal, open cell foam in the roof....you get the idea. The geo system is 4 ton, open loop, forced hot air, single unit divided into two zones, the most cost effective and efficient, way I am told. Installed cost $30000 plus the well (I needed the well for domestic anyway). Take 30% off for my tax credit, cost to me $21000. A good deal no doubt!!!

The code house has 6 tons of total heat divided among three units, one zone is radiant and the other two are forced hot air.Total system cost $32000. You do the math.

Oh, and I was told that the 'split' type systems are not eligible for the tax credit because the feds don't have a classification for them yet. That's just what I heard.