My wife and I are in the design stage of building a 2200 sq. ft. home in North Central Florida. It is being designed to be a LEED Platnum certified home. We are building ICF walls, with Energy Star windows and a SIPs roof, so the home should be pritty tight.

 

My builder and I do geo around JAX. Year round, a properly designed geo and installed should still beat air source equipment although ROI may not match that in colder parts of the country.

We work with a Waterfurnace distributor out of Daytona who is also a well driller - he knows his stuff.

We use ICF almost exclusively. We prefer closed cell sprayfoam over SIPs for roofs owing to the added strength, similarly high R-value and air-tightness.

We prefer geo, especially for oceanfront homes where airsource units die early of salt spray, but we'll install whatever the customer wants. The latest inverter-based minisplits are coming into their own but nothing beats a properly designed and installed duct system for quietness and comfort. I think of the minisplits as more appropriate to a retrofit or addition situation where ductwork is inadequate or unavailable.

I don't want to be seen as hijacking this thread for personal gain, but you may be in or near our "combat radius", so feel free to PM me or email me - waterleo (at) comcast (dot) net if you'd like to discuss your situation.

Curt

If you indeed many many splits (vs split system heat pump) I would rate that last over ducted equipment. I share Engineer's impression that ROI is slower for geo in cooling dominated climates but someone looking to build a Leed home is concerned with more than ROI.
I have seen Curts contributions here for years and suspect you could do worse in a contractor.
Good luck,
Joe

Thanks Joe.

Dave, since you already have a contractor feel free to continue bouncing ideas of us here and at geoexchange.

If money is tight, consider dropping LEED - go ahead and build to LEED standards, but consider dropping all of the hefty fees that go along with certification. There are other cheaper certifications available.

Rainwater harvesting is cheap. Consider also separating grey and blackwater wastewater lines. Solar thermal is not cheap, solar electric is really expensive. Consider building the house 'solar ready' - leave chases and conduits for one or both technologies. A mainstream business mag recently predicted that solar electric panel prices will soon plummet, possibly as low as a buck a watt owing to a supply glut and softening demand. Now may not be the time to buy, but retrofitting will be much easier.

Homepower Magazine is a great resource for alternative energy - the folks there will say over and over that the best investment is negawatts - spend to conserve rather than to generate.

Make sure that whatever HVAC you choose that the building load is correctly calculated and individual room airflows are correctly designed into the ductwork. Assuming you don't have an acre of west glass or the need to cool into the 60s, you may see a whole house load down around 2 tons given the envelope technologies you are using.

Just a parenthetical comment on solar PV, that might be helpful:

I'm about to proceed with a solar PV system, on a lease purchase basis.

You may want to consider doing something like this too.  Just a suggestion to help you 'fit it all in.'

Best regards,

Bill

 

Hey Joe,

I don't have pricing for Rainwater Harvesting yet but, as you can imagine, been doing some preliminary searches on-line regarding that topic. I'm looking a a 6000 gal. or more in ground system, using it for a little irrigation, laundry, toilet flushing and even thinking of having a filter system for pottable water. Nice to have potable water available in a water shortage. It's not rocket science but it hasn't been done much in this area and because it's new I'm afaraid it will have another hefty price tag. Our conditioned space is 2200 sq. ft., but our roof is 4200 sq. ft. so it should be a dynamite water harvester.

I like the idea of using the Gray water too, I will ask for this when the we get to that stage. But if it comes down to using Gray water or getting Pottable water, Potable wins.


Our Leed team member for this project is calculating the HVAC system requirements and she has informed me that, typically HVAC are bigger than they need to be. I am pritty confident we will be in good shape here. Good advice though for anyone else reading your response.

Thanks for your input. It is helpful.

Hi Bill,

Dave, here in TX, the market rate for solar PV installation is about $6.00/w, plus or minus $0.50/w.

Incentives, tax credits, and proper sizing can get the payback period down to 11 - 12 years.  Still, this is long as compared to putting in geothermal HVAC, for example.  And the payback period gets longer as the solar PV system size gets larger, unless you want to get into the business of selling electricity to the grid and you have a utility company willing to pay retail for the electricity.

There are 3 purchase options: cash, conventional financing, and lease/purchase, and perpetual lease.

The last option, a perpetual lease, is what I was referring to earlier in the thread.

Like all things, there's pluses and minuses.  A big plus for you is elimination of the capital expense to put in solar PV, making it more probable to do it now versus later as part of your LEEDS plan.  A minus is that 12 years from now, you won't be able to start receiving large benefit - your benefit remains 'capped' forever.

You also have to be particularly careful to size the system such that you can use all of the PV generated power.  Unless again you want to get into the business of selling to the grid, and you have a company will to pay retail.

This should probably be in another thread, in another forum, to continue with details, but, wanted to at least try to briefly respond here, to help you appreciate that you may not have to wait until later to put in solar PV as part of your LEEDS plans.

Best regards,

Bill

Hi Bill,

Good food for thought. Yeah I agree on the careful sizing, we are going Energy Star everywhere, but have ruled out LED lighting because the extreme costs. Another Green technology that will soon become less expensive, but won't drop in time for our build. We will put LED bulbs in standard outlets as an alternative. Strategic located Solar Tube lighting in low light areas is also in our thinking. All things considered it should take a lot less energy to run this home than did our last.

I don't think lease options for PV systems are available where we are building, but I will check. I will respond here on the outcome once I have a handle on costs so far, I learn of any other Solar PV lease options and the state of the technology at decision time.

Thanks for the clearification.

Think Green,

DaveS

Dave, I believe this company, Infinergy Wind and Solar, will do a lease/purchase option in Florida (or cash of course).  Contact Murray Hambrick, President, at 301-540-1569 ( http://www.infinergywindandsolar.com/ ).

This is the company I'm working with to proceed with a 3.5 KW system lease/purchase.

Best regards,

Bill

So as to not further dilute this geothermal related topic, I started a new thread, in the Solar and Wind Power subforum here, on the subject of doing a lease/purchase for solar PV as a creative means to to proceed with solar PV now.

Best regards,

Bill

Make sure building inspectors are on board with bringing non-potable water in for toilets, etc. I wasn't suggesting that in my earlier post - I was merely suggesting separating grey and black outflows for better septic performance and possible use of the grey water for irrigation.

Your LEED person is right - in a nutshell many if not most HVAC systems are oversized and underducted resulting in expensive discomfort. Getting it right isn't rocket science but will require contractor well versed in ACCA manuals J and D and manuals S and T thrown in for good measure.

If a HVAC contractor can't or won't do Manual J and D calcs find another. Those that meet the higher standard expect and deserve to be compensated for their above-average competence

Just out of curiousity, what is the estimated cooling load for the house? If the unit is small enough the cost may be very competitive (i.e. the largest cost for a GSHP is generally the heat sink).

Also, since you are building the house you might be able to install horizonal lines fairly inexpensively. The digging could be done by the builder while his backhoe is on site (no mobilization costs). Truth is the construction industry is slow here in FL so they should be willing to dig fairly cheaply. Same is not true for vertical wells as well drillers are still doing a fairly brisk business.

Economically speaking you would be far, far better off to install the GSHP with a buffer desuperheater tank and do like Engineer suggested and make your house PV ready. This could provide you with a good bit of low/no cost hot water. Especially if you put in a solar circulator for the DSH pump instead of the regular one. Keep in mind too that there is a nice tax rebate for GSHP at the moment.

Best of luck to you.

Hey Alex,

The cooling and heating load calculations are being done as we speak. That is a question I am waiting anxiously for.

I hear you on the horizontal loop being cheaper vs the well drilling, but with the water table fluctuating so much and the sandy soil, it seems the well loop will be more effective.

GSHP is looking real good right now and yes we will heat water with a desuperheater tank. I am giving GSHP a very high priority on my wish list. But than I don't really want to eliminate anything off my Green list. I should know in a few weeks when the number come in. Everyone has our preliminary building plans to estimate to.

Agree on the PV ready, that is the least we will do.

Thanks,
DaveS

Are you suggesting that geo is at odds with your green list. Savings equates to dollars and energy. Whichever one saves you the most each year is greenest.
j

DaveS,
Would you be willing to share the actual cost analysis numbers that led to a 15-20 year payback?  I'm in a similar boat.
Thanks.

Dave, when considering payback, are you looking at (geothermal cost - alternative system cost)/the incremental savings geothermal would provide? I would factor in an estimate of annual electric rate increases to the denominator above.  I would use figures after the tax credits as well.  30% for geothermal (no cap) and perhaps $1,500 max for the alternative system.  Check with your tax adviser since I am not a tax professional.