well, I know what, but thought I'd share something..  I had a conversation with a geothermal contractor today.   We don't have our plans completed yet, but I was looking for some ballpark numbers.  In the course of our conversation, the contractor said that he's not convinced that geothermal will make the most sense for us.  Because of the size of our lot, we will have to do vertical wells, which is going to add a couple grand to their "standard' horizontal install.  He said that the heating load of our house will likely be very low because of the relatively small size (1900-2000), ICF basement, and SIP walls & roof, which will make it more difficult to recoup the difference. 

We're still waiting to set up the meeting with the SIP guy to do our plans.  Once those are done, he (the geothermal contractor) said he can do a manual j to calculate systems for forced air furnace and geothermal.

I was dead-set on using geothermal, but now he has me wondering.  Has anyone else planned on using geothermal but after looking at the numbers, decided it wasn't worth it?

Sounds like he's giving you good info. The less btus your house needs the longer it takes to recover the additional cost of a geo system. When he can do the heat loss calc then you can run the numbers and make the best decision for your case. Don't forget to reduce the geo cost by the 30% tax credit if it will qualify.

Geo thermal is a choice. You are choosing to lower your monthly operating expenses by paying up front for the install of a system that does not burn fossil fuel, which is a commodity and subject to market pricing/shortages. In my opinion your choice of building materials and square footage will put you at a insanely low monthly expense to operate. If you throw in some rebates and incentives here and there what is the differance? I will garrauntee that geo will be cheaper to operate than anything else you choose.

Where are you located?  If you have much of a cooling load, I would be concerned about dehumidification with an ICF/SIP home.  Whatever you go with, I would recommend sticking real close to an accurate manual J for equipment sizing.  I built a pretty tight home in North Texas (HERS=52) and I ended up going with an Earthlinked system and pretty happy with it.  Because of the Earthlinked refrigerant flow controls, the evaporator coil is colder than other geo or conventional equipment.  The colder the coil, the better for dehumidification.

Regarding your question, you might explore getting someone to run the manual J through the Elite Energy Audit program, bake in the cost of the geo vs the cost of other solutions you are considering and see what the numbers tell you.

responding waterpirate & gregj.... yes, I was happy to hear his honesty.  In fact, he even said something like, "sure I'd love to sell you an expensive geo system, but I don't know if it would be right for your needs".  love that honesty...  ;)

Ballpark on a 2.5 ton system (what he was guessing based on the info I gave him) forced air with 600 feet of vertical wells would be between 25 & 30 before rebates.  After rebates, it comes down to 17,500-21000.  A natural gas system would be in the ballpark of 10-12, so we're looking at 7-10 grand more after all is said & done.  If my math is right, for a 10 year payback, we'd need to save between 58 & 83 dollars a month over natural gas.  In the winter, maybe, but I'm not sure if I'd average that much savings over the course of the year.  BUT I could be wrong..

waterpirate - I agree with you about fossil fuels.  This was one of the main reasons for wanting to do geo to begin with - however, electricity is a commodity that can flucuate, & is often coal-fueled, so i don't know if i can blindly use that argument.  

I realize that I'm getting ahead of myself.  I'll wait til we get our plans & manual j calcs to decide - just curious if anyone else was in the same position - ready to pull the trigger on geo & then reconsidered..

Thanks again for all of the responses, this is truly one of the best "places" I've found on the web!

Green Bay, WI.  Primarily heating loads, but it gets hot & humid in the summer too.  Last summer was a bit cooler than normal, but I only ran our AC maybe a couple weeks total the entire summer.  It's a personal choice as much as anything - I just prefer open windows & fresh air, even if it's a little warm.  drives my wife nuts...

About the manual j - the contractor I talked to today said that once we have our plans, he will do that for us.  He just asked that I don't "take advantage of him" and when it comes time to build, give him a shot to bid it out.

Just a few thoughts (not all of which will apply to your situation).

Are you saying that you will forgo AC? The incremental geothermal costs are probably cheaper than a divorce. Well, maybe after the tax credit!

If you consider options other than a furnace, remember that geothermal units last on average 25 years (or so I've heard). The ground loops should last much longer and based on what I've read, should be able to be reused when the units need replacing. People need to keep in mind that replacement costs for a geothermal system will be significantly less if the loop can be reused. Also, geothermal unit cost should also drop over time . The current tax credit is scheduled to expire in 2016 if memory serves. Seems a long way off, but only 7 years left to take advantage of it.

Giving the contractor a final shot at pricing is fine. Just remember his experience, references, etc., all need to check out too. I suggest to people that they get multiple quotes with a load calc from each company that is quoting. One company that quoted us majorly screwed up a load calc. I only caught it because I compared it to 4 other calcs from other quotes. The installers that quoted us were happy to do and provide me with the calcs, but some installers are reluctant to do so due to time invested.

Honesty is allways refreshing, I have told more than one customer that geo is not for everyone. Hard location,containment issues, yada yada. In the end it is a choice. When you get hard numbers back it will be easy for you to see a way clear to a happy outcome for your project. Right now it is still really good speculation. Keep us posted we are glad to help.

Jerkylips - If you go Geo, and install the DeSuperheater, you're in for a 30% of installed cost federal tax rebate. In the summer, when the AC is on, you get hot water from the Geo unit, which holds value.

Have you considered getting your home Energy Star Labeled? If so, there is another $2K rebate if you work it out with the builder. Subtract the cost of the HERS rater and Manual-J from the $2K credit to get the true value of the credit. The HERS rater should be able to perform the Manual-J calc using detailed info about windows, doors, appliances etc.

Geo may not be a perfect solution, for you, within the context of the present. But consider this in your decision making process: Are you certain the cost of natural gas will not skyrocket in the future? If it did, how would you adjust to the higher cost? The same truly can be said about electricity. However, if the unit was Geo, the impact of higher energy costs will be easier to manage because there are alternative sources of electricity available. It is possible to generate electricity on your own (generator, PV etc). But you cannot generate natural gas... For my wife and I, independence carries a lot of weight although it is based on emotion and beliefs. We live in an Energy Star labeled SIP home (HERS Index 49), with Geo, generator and PV and a small wood stove. The PV and generator have both been put to good use during weather emergencies. Most notably the tornado two years ago. An of course the traditional regular Alabama power outages.

I'm not trying to sell you on the Geo, just that the decision should not be based solely on dollars over time. What you and your wife believe the future holds should also carry significant weight. Your perception of independence and emergency preparedness is important as well. You and your wife might have a sense of security with one solution over another. Some guys on this forum may not agree with my point of view about Geo, PV, generators etc. etc. But! I bet nearly all will agree that there is significant and TANGIBLE value in having a wife who feels safe and secure knowing the cave will always be warm and lit up keeping the boogie man away while she is home alone.v Which reminds me... I was supposed to install the wood stove before winter arrived. OOOPS

John
p.s. You used the word "us" which I translated into wife. If "us" means the dog, cat, grandma, parole officer or something other then wife, please replace wife with that other one.

Geothermal may not be worth the investment for areas that are not heat dominated climates.  An Air Source heat Pump may make more economical sense in areas like South Florida, Southern Texas, California and Hawaii. I think any place where the temperature drops below freezing for more than a few weeks a year can benefit from a Geothermal system, it's just the paybacks may take longer.

I'm not completely understanding the contractors point, wouldn't a house with a smaller load require a smaller (and cheaper) system?
   

thanks for all of the replies. I'll try to respond to everything here... First, I agree with everyone who said "wait til you get your plans". We're not making any decisions now - it's just that I hadn't really even considered NOT doing geo til today. And "we" is myself, the wife, & our 6 lb cat. ;) The contractor's point about the smaller heat load was this - if the house is well-enough insulated, etc., that with a high efficiency furnace our bills are already very low, we can only save so much more with geo, and with the extra costs, the payback will likely be longer. I completely agree about the "insurance" against higher gas prices down the road, the sense of security, and independence to know that we could add solar & essentially be "off the grid". That IS important to me, & in a perfect world I would do it. BUT we've been talking about building for around 5 years now, & the time has come so we need to work within the budget that we have right now. Unfortunately, doing what makes the most sense long term isn't always possible. Case in point - I intend to be in this house for a very long time, so I would like to do a metal roof, but with the initial costs so high, that probably isn't going to happen.. oh, last thing--not planning to forego the air conditioning. My only point is that we generally don't use it that much, so the bills in the summer months tend to be very low anyway.

Sounds like you have a good contractor. Such a small tight house will have minimal heating and cooling loads, and with just 2 on board the hot water savings won't be as much either.

My guess is the Man J would suggest at or near the very smallest 2 stage units available, about 2.25 tons, so that you won't be too oversized in cooling. Payback may well be longer in smaller tonnage applications.

Run the numbers - gas is cheap now but hasn't always been so.

And as geome pointed out, remember to add the cost of the cooling system to the total installed cost of a system (I know it's much less, but it's part of your overall HVAC). Whether you put in a traditional system or geo, it's still an up front cost.

When we decided to install geo, the cost of adding a cooling system played a strong role in our choice and payback analysis. If we hadn't wanted one, geo would have taken a lot longer to pay back (because we did not have a duct system) and we may not have decided to install geo.

Hey, I forgot to mention something in my post yesterday.  The geo guy said that since we have essentially a city lot & have natural gas hookups, it makes the most sense to use the natural gas as the emergency/stage 3 heat.  I've only heard references to electric emergency heat before that.  It seems to me that if we did that, we'd essentially be installing geothermal and a furnace (although I'm sure a very small furnace).  I'm wondering if that was driving up his estimate some, and if that really is the right way to go.

THEN it got me thinking.  If I undersized the geo a little, assuming that I would be using the 'emergency' heat occasionally, would the smaller sizing help get the costs down a little.

 

THEN it got me thinking about the SIPS.  I'm assuming that we're using 6" SIPs, but what about going with a furnace instead of geo, and using the money saved to go with 8" SIP walls.  ugh........

If you're not going crazy yet, you soon will be. LoL

As auxiliary heat, it's my understanding that a gas furnace cannot run at the same time as a geothermal heat pump unless the system is set up in a very particular way so as to to avoid the furnace heating the heat pump coil and damaging the compressor (is this correct pros?). You may also need a split geothermal system if you want a furnace instead of a packaged or all-in-one unit.

If aux heat is electric, it can run at the same time as your geothermal system. As a backup heat source, electric or a furnace wouldn't have the geothermal system running anyway (because it's a backup heat source). In a well insulated house, I would lean toward electric backup unless you want a generator to provide heat during a power outage. A furnace shouldn't take as much power to run as a heat pump, so a smaller generator may work. So may now have different generator costs to include as well. Sorry about possibly adding to the confusion.

P.S. The furnace would need to be sized for the heat load of the house if used as a backup heat source, unless you want to go smaller just to protect the pipes from freezing, but it will be colder inside though.

The AUX/Backup heat is a electric coil mounted above the Geothermal unit, in the beginning part of the vents. When the system is using AUX heat, the Geothermal unit is on. The Geothermal Unit only shuts down when the system is on emergancy heat.

Although your correct, the Gas Furnace couldn't use the same heat exchanger as the Geothermal system, I don't see why it couldn't be mounted after the Geothermal system's heat exchanger. You could even have baffles that redirect the air flow to bypass one system or the other depending of which system is running.  Although it's proably not a standard configuration available for the geothermal supplier, any HVAC contractor should be able to adapt different systems together without too much trouble.

With gas it's not so much the fuel price as it is the fixed monthly fee, especially with any partial gas setup. Be sure you figure the costs for TWO monthly base charges if you plan to go gas heat or partial.

Dick

valid point, but we are going to have a gas fireplace and gas range (I'm the cook in the house & I HATE electric stoves, so that's a dealbreaker) so I think we'd have those same fixed costs no matter what.  right?

just to make sure i'm thinking the same thing you are, you're basically talking about the gas meter hookup/fee, right?

Jerkylips - If you are going to save some cash on the HVAC system consider these options:

- don't spend it and reduce cost.
- If already have 6-1/2" SIP walls, keep them. If 4-1/2", upgrade to 6-1/2". I put 4-1/2" walls in my house but wish they were 6-1/2". All I install for clients now is 6-1/2". Too thick is overkill/waste.
- Upgraded windows for efficiency/quality if not already.
- Upgrade to the metal roof you wanted.
- Wood stove for emergency / enjoyment?
- Get something special for your wife for putting up with all the hassles of building a new home. Possibly a Craftsman Professional Series tool chest and cabinet filled with mechanics tools or a wire fed Mig welder so you can build that kit car you dreamed of. I mean that she dreamed of.