I am in Central Florida (East Orlando).  Starting research on geothermal system.

Facts:

• Bit of a DIY person
• Finances tight
• House 20 years old, AC compressor is 20 years old
• 3050 sq ft house two story
• single 5 ton system
• seldom need heat.  But need lots of cool.
• Electric costs go from $120/mo to $450 mo during hot season, increase is the AC
• water is a few feet down, put in pump to water lawn at one point
• water/ground temp most likely in the 70-75 degree range

I plan to contact local dealers to get bid.  any suggestions?

Want to do as much as we can as possible.

Since we have water, what about open loop system?

I looked at and talked to Ingram’s any thoughts on that?

Any guess as the amount (%) of electricity might save?  Need that for cost savings estimate to decide if this is best thing.

Thanks, Doug

Ingrams has a few very unsatisfied customers if you do more than scratch the surface.
It is a common opinion with the pros here that sizing by square feet is not effective.
Start with envelope improvements to reduce size. Look for free ware for manual J heat gain calcs (or one time license on HVAC calc for $50).
Open loop is very doable for a competant do it yourselfer.
Find local support (if you are lucky you are in Engineers AO).
Stay here with questions and we can help.

Thanks Joe.

What does "if you are lucky you are in Engineers AO" mean?

Doug

You might as well research more insulation and a new, high efficiency air source unit at the same time and compare costs to geo. A ground loop that starts at 70-75F and then rises as heat is added won't be much more efficient than 95F air.

Doug, Engineer is one of the regular poster's to this forum. He has extensive experience in north Central Florida. Clay County area. He is probably one of the better people to advise regarding your (AO) area of operation. I learned he is only a few miles from my parents, so plan to consult with him when I can visit my folks and start steering them toward their replacement unit in the next couple years

@jonr this is the type of input I wanted.

@mtrentw thanks for the translation.  Every group has its own language, good to have a native to translate it.  Groups like this are so valuable in the learning experience.

Doug

I doubt that you are going to wind up with loops. That area is well suited to a pump and dumps, but we should await Mr. kinders arrival prior to any more speculation about his area. That would give you a entering water temp of around 60 I think for AC mode.
Eric

As always, analyze the costs of reducing the load before diving into 5 tons of geothermal. The first ton of geo is the most expensive, but the rest aren't free- far from it. (DIY geo design & implementation isn't advisable for 99% of the pretty-handy DIYers out there either.) To be effective you have to be cost effective, and that usually means plucking all the low and mid-hanging fruit on load reduction first.

Blower door tests & air sealing to reduce the latent load is probably going to be cost effective in most FL homes.

Things like re-roofing with "cool roof" finishes are cost effective when done during re-roofing. Depending on the roofing type some mop-on versions could be too. If roof tweaks are in the cards, if a product is not on the Cool Roof Rating Counsels third-party tested list, don't use it. http://www.coolroofs.org/

Like roofs, upgrading with replacement windows are usually an opportunity thing- not cost effective unless already undergoing replacement. In some instances low-E storm windows (particularly on the east, south, and especially west side of the house) can be retrofitted, cutting down on solar gains, and would likely cost far less than the reduced tonnage of geo for the higher load. (There's a DOE program subsidizing the price of low-E storms, if that's something you'd consider. See: http://www1.eere.energy.gov/buildings/windowsvolumepurchase/index.html )

If the ducts are in the attic, above the insulation layer, it's likely adding well over a ton of peak cooling load even if they're insulated. Routing ducts for the new system within the conditioned space may be cost effective (or not) relative to the cost of the geo to support the additional load.

Fla'63-
 Snow in  Clearwater seen at the beach by Grandma and me  (not seen on that  gulf-side beach sand, just in the air), -to also many visits with 'DIY' Grandpa, Prof.Emeritus, Metallurgy Egr., Inventor, astronomy author for local 'Clearwater Sun', who added greatly to enjoying OBJECTIVE practice in any necessity. Doug, he could have had anyone build whatever.. his friends/owners, former students, running Cinti Metcut, built things of great time and expense just in his proposing his Hyperberic Oxygenation process leading research... 1970's.
How much 'DIY' ?
since we know not - and you may have more enthusiasm and more skill than we will ever know- I will PRESUME this- may mean you want sufficient math, info of a better building, a better distribution and tiny HVAC-GT, A;HtP, or HW  (more detail below).
simple study, beyond a worksheet to improve has been posted
(0) How (much) DIY Doug?
IF trades and mechanical work is that which may not bug you at all:

(1) your consideration:) IF De-Regulaion has hit your town (and it will all I am told: 2015) what about a better cost of ut'y?

(2)  For a kind of 'benchmark' any idea of how much Cooling do you think you need right now compared to what runs in your home?
(why - is below - if you make the notes.)

(3) I suppose since any creature wanting comfort or conditions met, you see in most posts: some  ABC's have been
 A.~ BETTER -building
 B.~Distribution
with some SIDE NOTES for Lifestyle/Comfort
AS YOU CONSIDER HOW MUCH COMFORT-TO-BUDGET in addition to choices of absolutely-relative necessities (D1 points out)
 C. ~ Tiny HtP machines for 'bundled' Ht/Cl/hybrid-HW as ONE SYSTEM (GT- one box) or Substantially better than GT:without-HW, is just very close to GT:HW-hybrids of little HW generator-DeSuperheaters to Full-Condensing HW DeSuperheating and both in Heating as well as Cooling, and INSTANT-On-Demand HW.

C.c.) GOOD NEWS !
There are  + more than substantial +  over 20  great 'green' machines that can OBJECTIVELY be compared-to a tiny Ht/Cl/HW bundle of system(s) TODAY.
Mostly of the more than 20 out there,
all are with even higher 2012 (minimal) Energy-Star(tm) COMPLIANCE and receive ut'y co and Fed/State Credits, etc, always, b/c ratings are not the end-all, by example, of what you may need or want, really. Rated units have been pulled and replaced by manufacturers (there entire expense) when COP's (Coef Performance to electricity as 1:100% COP of "1", EER is more engineering than SEER

You can purchase
 while noting compliance certification
 and having from any seller an appropriate PERFORMANCE COMPLIANCE guarantee.

That is so you can look at systems even patented since 1981 (which surely tied the hands of 'major-branding' marketeers) fairly in the very simple Ht/Cl/HW bundle with GT and A:HtP systems in one box. What rated units have sometimes is a VERY HIGHblower speed, then a tech changes it (now less efficient for a rating, but more efficient for the building longevity and your dryness) to having slower air across an HX (Heat Exchnager- 'coil' inside by the blower).

With proper (DIY- various) associates (paid just means "pro" , too) - I trust you will ask about of more than 5.
high in an efficiency, - as the new 2012 higher Energy Star(TM) -minimal regular H-Eff-'gas' (as to PREM) 
within a plan of some ROI (maybe)
and what is financially coming back in 8 or 10 years, or would go to additional equipment of HVAC (say into zoning more, a year or two after OBSERVING the new (DIY in mind) system. Buick's out ther in GT-Land are over 32 years running, no compressor chnages, COP's 4.1 htg open-loop, and cooling.


About HVAC-HW needs properly being met
on any budget: GeoThermal(GT) and Air HtP - too with 'reclaim' HW (dhw- domestic/other hot water heat-recovery, Energy Star(tm) requires,with GT- one little hybrid of HX (heat exchange(er)) to 'Instant' or reclaimed-100% full desuperheater HX for HW)
HT Cl HW - one shot tax credit, what are you considering now?


x. Heat Pumps of Air, Minisplits, GT-Mini-Splits and GeoThermal and HW needed.

a. Better fuel budget rates (by 2015 all states will be deregulated for competitive choice)
b. Better Building make up in/out, with posted recommendations and more
c.  Better distribution / duct, etc. as is to improve

I think there might have been a good point in there about de reg....almost missed it.......makes envelope improvement ever better.

Hi Doug,

As has been written, I work in NE Florida, Jacksonville and surrounding counties. We do deep and wide energy retrofits on existing homes as well as (not much) new construction. Some thoughts:

1) You are very lucky to have had your AC last 20 years. It may well be less than SEER 10, which became code in 1992

2) Comments above suggesting an improved envelope are well taken. We routinely drive production homes from 400-500 SF per ton to 800-1000 SF per ton. Most Florida homes have lots of ductwork in hot, vented attics. We address this by retrofitting sprayfoam insulation onto the roof sheathing, bringing the attic and its ductwork into the thermal and pressure envelope of the home. Ducts no longer leak to the outdoors, and their heat gain and loss to unconditioned space is eliminated.

3) Is your home now zoned? We retrofit a minimum of 1 zone per floor.

4) Florida's surficial aquifer (fancy term for the water close to surface) is often not well suited for geothermal applications. It is of poor quality and often bears significant iron, playing havoc with open loop geo systems.

5) Closed loop geo systems in Florida are handicapped by our relatively high deep ground temperature. Near Jax, it is 71*F. Orlando's is likely 74. A typical closed loop design provides entering water temps +/- 15-20 degrees relative to the ground. That means entering water temperatures of ~90 during much of the summer, and that results in efficiencies not much better than premium air source heat pumps.

Higher efficiencies may be obtained using open loop bores into the deeper Floridan Aquifer. That taps good quality water and maintains EWT in the 70s, but that requires two pricey deep wells, one for source, one for reinjection. One needs to take care that power used by pumping system doesn't eat up savings from milder groundwater. Geo really shines up north by providing economic heat without burning pricey propane or oil. It serves as a range extender for heat pumps, providing high efficiency in climates ill-suited for air source heat pumps. Two wells into deep aquifer could alone run more than $10k

6) I have no experience with Ingram's, but suspect one would have to be a heckuva dedicated DIYer to successfully deploy an HVAC system sourced online. Beware loss of manufacturer warranty.

7) Investments in replacement windows or wall insulation are unlikely to pay back in less than 50 years

8) Avoid scams such as power factor correction devices, powered attic ventilators, radiant barrier rolled out on floor, strange additives to HVAC refrigeration loop

Recommendations:

1) Start with an investment grade energy audit. Determine annual HVAC cost vs house base load. A room by room load calculation and blower door test should be included. We start all major projects with a deep audit.

2) Run the numbers for sprayfoam - it is pricey but more reasonable for 2+ story homes since their roof area is smaller per unit floor area. Ensure that the spray foam is applied and tested for air leakage. Gaps in foam allowing air leakage play havoc with humidity control. We test using blower door and theatrical smoke generator.

3) Your sweet spot system may be a 16 SEER two stage air source heat pump with at least two zones. Sprayfoam, done right, might allow downsizing to 3 tons. Higher SEER systems are an option, but payback stretches out with increased SEER, and you wrote that money is tight.

4) If there are 2+ people in the home, consider a heat pump water heater (in the south these pay back faster than investments in high efficiency HVAC

5) If you have a pool, consider a variable speed pool pump (these pay back faster yet)

6) Any light burned more than an hour per day needs to be CFL (skip LED for now - too pricey)

If you are set on beating normal air source heat pump efficiency, a water storage tank to allow an air->water HP to run only at night is probably a better option than geo.

Thanks everyone this has been very helpful.

@engineer I appreciate your thoughts and recommendations.


Your thoughts

1.  Yes it is 20 years old and need of replacement, fear it will go out anytime, so I am sure almost any new system we will see great gains.

2.  Spayfoam, I will look into it.

3.  zoned, do you mean units that operate separate per floor?  We only have a single unit and no zones.  Not sure how it would be zoned.

4.  Aquifer, it does have iron in it, why we stopped using it for watering, turned sidewalks orange.

5.  closed loop, I feared it may be too hot.

7.  Investments in replacement windows or wall insulation, I have always thought the ROI was bad, good to have it confirmed.

8.  Good to know about these scams.

Your recommendations:

1.  energy audit.  Do you have east Orlando people to recommend for the audit?

2.  sprayfoam will look into that.

3.  "Your sweet spot system may be a 16 SEER two stage air source heat pump with at least two zones" good to know, again any recommendations of who to look into?

4.  heat pump water heater - will look into it

Thanks for the input.

Doug

Avoid scams such as ... powered attic ventilators

I have yet to see any data that shows that large, slow turning attic ventilators in a push/pull configuration are or aren't cost effective.

Posted By jonr on 27 Apr 2012 03:20 PM

Avoid scams such as ... powered attic ventilators

I have yet to see any data that shows that large, slow turning attic ventilators in a push/pull configuration are or aren't cost effective.

And if such data existed, you can bet the vendors would be all over it.  In the absence of data, you'd have to take your own, but most of us don't live in laboratory houses.

Most of the grid-powered ventilated attic data is from exhaust-only ventilation, and over a wide range of types and speeds the data largely indicate that grid powered attic ventilation result in an INCREASE total cooling power use. Even with a pretty-good kinda-balanced approach, the higher the SEER of the cooling system, the more perfect any balanced-flow attic ventilation system would have to be to avoid that issue.

Since even low volume heat recovery ventilation systems with the intake & exhaust impellers driven on the same shaft & motor have to be tweaked into balance, any balanced attic ventilation scheme would have to be similarly locked  to not produce pressure differentials driving air infiltration.

BTW: On dimmable circuits it's sometimes "worth it" to swap in LED lighting (especially where subsidized) since Edison base dimmable CFLs are downright crummy, with a very limited dimming range, whereas some of the better LEDs work remarkably well with $15-20 wall dimmers. The LED units (with the exception of the $50 Phillips L-prize winner 60W bulb replacement) are not dramatically more efficient than cheap CFLs, but the light quality tends to be noticeably better (often better than run-of-the mill incandescent bulbs that use 4-6x the power.)

With heat pump water heaters compressor & fan noise is significant, so consider where to place the thing if you go that route. They also need good air-communication with a larger space, so stuffing it in a closet to avoid the sound isn't an option. (Yankees can just put 'em in the basement next to the furnace, but most FL homes are slab-on-grade.)

any balanced attic ventilation scheme would have to be similarly locked  to not produce pressure differentials driving air infiltration

Wind would throw it off. I'd use a differential pressure sensor and variable speed fans to create a perfect pressure balance with the interior, even with push/pull fans on opposite ends of the attic. End result - even LESS infiltration than no fans. Also, the fans would run in the heating season only as needed for humidity or ice dam control. Result - warmer attic, less heat loss. Payback? - no idea.

In your area Doug: search FLORIDA GETHERMAL PONDS IN FLORIDA
there might be some practicalinsight IF IT FITS
there are many
very many more, you can talk with

Calls? - seems C U in a few days.

Well-oranged results !
... unless your under 2PPM of the iron reading (1 is easier, if coming out like that) and it is dry, not with a bacterial slime, - I have DIY customers that runs a cotton-string ball on a choke cable to his adapter at the well casing and pulls the pump in a plastic narrow bucket to flush-clean (check what to use, etc., things work fine for my customers)

next thought
Manufacturer's and their distributors can be found also from AQUACAL (StPete)
and ADDISON or Weatherking Piecing together ideas for you is hekpful , if ever pool heating.

At Aquacals plant in 1995 then had very hi-efficiency equipment was seen for Cooling/Heating pools and heat-recovery to Spas.

Heat Controller HVAC too

WaterFurnace lists dist/dealers
althoug EnergyStar(tm) only requires a little add-on, that called DSH desuper-heating with GT heat pumps in for qualifying for 30% credits. Some 'add-ons' are no more than in line refrigerant tubing before the reversing valve for getting the first heat off the compressor in all modes. All hybrid for HW heating as a requirement as E-Star dictates.
A longer tubing of heat exchange on a SMALLER unit to a significant amount of cooling (but part of a system) may fit (well maintained--- determined in yet for more wellwater to be tested) or with a deep loop, if water levels and others can show you more results.


DIY customers dig their own at 10ft... a deputy in PA at 12 ft , ~ we hit water in a few feet at Clearwater.

HOW DIY do you have others tell you you are good at?

would depend on family size as well, for that 100% HW recovery fit.


- easy to ask around "Have you done this paractically?" of any HW heat-recovery installer.

Again AQUACAL has info on all kinds of geothermal

Do it, take data. Then you'll know.

Zoning lets a single system separately condition different sections of a home. Each zone has its own thermostat, and motorized dampers direct air only to rooms within the zone whose thermostat is calling. A two floor house works much better with a zone for each floor. A two stage system runs in low stage when just one zone calls.

I think that if you found a good local home energy auditor, he / she should know of a satisfactory HVAC contractor. I don't have any contacts near Orlando...two hour drive