HI, I'm new to this site & this will be my first post. The new IRS/DOE 30% tax rebate has got me interested in geo technology! I live in Central Florida near Tampa, Needless to say, cooling is my main concern, as heat is only needed for a couple of weeks a year & usually only in the mornings. My home was built in 1993 & is a single level (no basement) 2500 sq. ft. cement block/stucco with a dark colored shingle roof & several large sliding glass doors. All windows are single pane & have been treated with the 3M brand window tint. The ceilings throughout are 11'4". My current AC is a 16+ year old Bryant split dual (1.5 & 3.5 ton) air to air heat pump with electric heat supplement. It has a rating of about 12 SEER. Both air handlers are horizontal & are installed above the garage in a small room. I have been very happy with these systems, except for the increasing cost to operate. The outlets are on the ceiling, so there is zero air handler noise. I have an irrigation well on the property & a salt water tidal canal behind the house. The property is only 100'x 125'. I am considering a single 5 ton geo system to replace both of the old HPs. Because I have a well, an open loop system would appear to be the most economical to install, but this would not be my first choice. I have not checked the flow rate of the well nor the water quality, but the temperature is about 75*. I have been told by an AC technician that my duct work feeds & returns could be converted over to the single 5 ton system with out too much difficulty. I would also like to take advantage of the de-superheat option for my electric water heater & possibly as a pool heater. I have been looking for a top of the line heat pump with the following features: R-410 A two stage with two speed fan,etc. In addition, I would want the optional de-superheater, cupronickel heat exchanger, heat strips, & probably a new thermostat. The systems that I have been looking at on the internet are: Water Furnace, Envision Series, Florida Heat Pump, Aquarius II-AP Series, Geocomfort GT Series, First Company, Hydrotech WSVC Series. *Can anyone suggest an experienced geo dealer in the Tampa Bay area? *I would appreciate any comments/criticisms about the direction I"m trying to go. *Does anyone know the rules on "Pump & Dump". *Has anyone had experience of going from a dual to a single system? *Any comments on features, costs, quality, maintenance, warranty, or availability of the various systems? If this thread gets much discussion I'm sure I'll have more questions.

I do geo systems near Jacksonville.

One of the south florida water management districts now requires reinjection of open loop geo water - no pump and dump. Your lot size suggests city water and sewer. Is your irrigation well shallow or deep? If it is shallow, both flow and quality may present problems.

If you want desuperheat plan for a second water tank. You shouldn't need heat strips with a geo system near Tampa. We don't install them in Jax where winter design temp is 5 or so degrees lower than Tampa.

Engineer, Thanks for the prompt response. I hadn't thought of SWFWMD, good idea. Yes, I have city water & sewer. I believe the well is 250' deep. I does have a rotten egg smell. probably not a good sign for an open loop system. My current systems have heat strips, so I thought I might still need them with geo. You say you don't install them in your area. Do you, also not install them with air to air systems or just with geo systems? Thanks again, My next task is to get the water quality checked. Any suggestions? I'm guessing the folks that check pools & water softner would not be the ones to ask about well water quality. Right?

In my opinion, I think just replacing the Air Source Heat Pumps would be your best opinion. Geothermal is really better suited for Heating, while it would save $ with cooling too, your savings would be modest in my opinion, I believe a cost/benefit analyst would show you that the cost of a Geothermal system compared to the saving really wouldn't worth it in the long run for your area.  A good 16 Seer or 18 Seer heat pump is the way to go.  Even with a 30% tax credit, Geothermal is still pricey, if your not going to see significant cost savings over a 16 or 18 Seer Air source Heat Pump, then it really doesn't make financial sense.
  

Not so fast, TG. Proximity to salt air shortens life of ASHPs and tilts the math toward geo. I don't disagree with the issues you raise, just need data before leaping to a conclusion.

A 250' well may or may not be in the aquifer. That's much deeper than a typical shallow or rock well.

Strips are still needed with air source units, not so much as for backup but to compensate for defrost cycles. Florida winters are mild, but humidity and the occasional night in the 30s causes air source units to frost up, and during defrost they switch back to cooling, which puts cold air into the ducts. Strips balance that, keeping occupants from getting cold drafts off their ducts during cold weather.

I haven't determined a good source for geo-compatible water tests. It is on my to-do list The parameters to test are listed in geo unit install manuals

Agreed, but since he stated his existing Air Source Heat pump is 16 years old, this would indict to me he's far enough inland that the salt air isn't affecting the equipment.  He did however indict a Salt water tidal canal behind the house, so I'm not sure what to think. 16 years is a long lifespan for equipment exposed to any salt air. I tried to find some facts determine how far inland the corrosive effects of salt air go, but turned up nothing. So I would guess that anything more than 10 miles from the ocean is enough distance to escape the effects of the salt air.  

I'm located on the east side of Tampa Bay, less than a 1/2 mile in from the bay. I don't get the salt spray in the air like the east coast of Florida, but every thing gets rustsy here. The a/c units are approximately 50' from the canal & are elevated about 4' above grade level. Both units are just below the eves (no gutters used on this side of house) & really get washed down during the rain, this may have helped the longevity. Reguarding payback, As indicated earlier in this thread, there is better geo heat pump pay back in colder climates, but I think I read that there is better hot water(de-superheat) payback, in hotter climates. Would this help balance the equasion? I'm not understanding the comments about the well being or not being in the aquifer. Can you clarify? Thanks.

A desuper can reduce hot water costs by 50-75% at nearly zero cost of operation. To estimate payback you'd need to get a handle on your present hot water costs which average $500 nationally assuming electric heat but vary widely with location, # of occupants and their hot water use patterns, in roughly that order. In FL the national average of $500 probably drops to $300 on the strength of much higher cold water inlet temps and lower standby losses. From there count how many live in your house and their hot water habits.

For most folks the desuper hot water is a peripheral benefit rather than a deal maker / breaker.

As to well depths and aquifers - most of FL has a really good aquifer relatively deep - 200-500' or more. My experience so far is that it is water suitable for geo if it can be accessed cheaply and legally and responsibly. Water at shallower depths is hit or miss - variable in quantity and quality, and I wouldn't bet on it for geo. Per my (older) builder partner, use of shallow, so-called "rock" wells for water source geo in the 1970s led to many premature failures and gave open loop geo a very bad name down here.

You did mention you didn't have a basement, are you planning on installing a Split system like you have now?  If so you'll be exposing the unit to the same salt air conditions that the Air source heat pumps are in.  I would expect a shortened life for the unit, you did say your existing air source heat pumps were 16 years old, what kind of repairs did they need over the years?

For hot water, I would investigate a heat pump water heater. Completely inside (no salt), will heat 100% of your water and provide some cooling in the process.

http://www.energy.wsu.edu/documents/building/res/ht_pmp_water_htrs.pdf

That link is a good summary but the advice may be premature. I have a Geyser unit under test and preliminary data indicate good savings, but the ROI is likely long. There is a 30% tax credit on HPWHs but the only one certified and tax eligible is a unit by AirGenerate LLC that may not meet codes protecting potable water from contamination by refrigerant - this is normally done using a double walled and vented heat exchanger

There's this one made by Rheem that just came out:
http://www.rheem.com/Products/tank_water_heaters/hpwh/hpwhhomeowner/

Forgive me if that's the same as the AirGenerate LLC. I know that out of a few comes many brands.

I called my local guy and he never called back with a price. Rheem said the ESRP was like 2K, but that was years ago. They stopped making them and started again. The Web site promises ROI in "2 years" and say it saves $300 a year. Taking all of this in, I would assume the thing can't cost more than 1K.

Here are a few others:
http://www.aceee.org/consumerguide/waterheating.htm#heatpump

Seems like a good idea. The AirGenerate is only $700. Seems like a decent payback but yea I don't want any refrigerant in my water. By "may not meet codes" do you mean it doesn't? or more info is needed? I'm very interested in the HPWH's but there's little info out there.

Sorry for overposting, but it looks like the AirGenerate LLC may NOT be eligible for the tax rebate because it is an add-on unit. Here are some that qualify:
http://www.energystar.gov/index.cfm?fuseaction=heat_pump.display_products_html

My plans were to Remove the old 3.5 ton air handler & install a packaged (combined AH & outside unit) geo unit where the 3.5 ton unit currently resides. This, by the way, is almost directly above my water heater which is elevated but on the main level of the garage. The air handlers are in a room above the garage. I could then use all of the current electrical hook up & duct work plus the duct work from my second 1.5 ton air handler. The old 1.5 system would be used to cool my garage which is 3 car & is currently being cooled with the 1.5 ton unit through a diverter system.

Thanks for the further explanation. I found my well drillers invoice. The well was drilled in Feb 2000 & permitted by SWFWMD. It is a 4.5" 200' deep, 1 1/4" pipe, with a 1 HP. 230V, 27 CFM pump. That's almost 10 years ago, I never have checked the wells actual output. I assume that rated pump output would be with the open 1 1/4" pipe & not through a garden hose? Wow! Only $9.00 a foot back then!

Thanks for the suggestion.

Agree with engineer on his thoughts. You are going to get faster corrosion - but by having the unit inside it will not be as much as we get on the east coast (Merritt Island area - East of Orlando).

You might be in the floridan aquifer and have an artisian well. You can't use the irrigation pump (it would be grossly over powered for your system) and you will need a second "dump well". Figure about $3000 - $4000 for that (I can get one here for $3,000).

The desuper heater will not provide enough heat to make any difference in your pool. A 15,000 gallon pool takes about 125,000 BTU per 1 degree F temp change. Desuperheaters put out around 5,000 BTU per hour (varies but that is a reasonable estimate). The desuperheater is definitely a go for hot water here in Florida. From May - early Sept you might even be able to turn your electric water heater off.

Lastly, get a manual J calculation on your house. I think you have way to much AC. I have a 4 ton and a 1.5 ton with lots and lots of glass and about 3,400 SF. I did not get a manual J calculation (wish I had). I think I could have gotten by with a 3.5 ton unit downstairs - maybe even a 3 ton unit because the upstairs unit reduces the downstairs load.

Not turning you off of GT because I think it has its place. Just not positive it is right for those of us here in central Florida.

Best of luck to you.

Alex

You will get really low heating bills but cooling bills may not be that much lower. Your groundwater temp is probably 75-79 degrees (yes maps show less but our data from monitoring wells shows we average about 77F here and it is hotter over by the Gulf of Mexico than here by the Atlantic).

Economically speaking I would suggest you price out a two speed 18 SEER Amana Air Source Heat pump for the larger unit and maybe a 15 SEER Goodman for the smaller unit. Thats what I did two years ago. The payback on a 2 speed small unit takes a very, very long time.

Best of luck to you.

Alex.

Thanks Alex_in_FL, I have particular interest in the opinions of folks that are in Central & Northern Florida & am learning alot from you guys. Reguarding the well pump, why would I need a different pump? Over powered? Wouldn't valves & or restrictors be able to control the pump pressure/volume? Different kind of pump? Not sure what you mean. Isn't an Artesian well one that flows without a pump? Yes, I had considered a second well for returing the water, even though (if legal) I have an accessable salt water canal behind my home. My well water temp this time of year is in the mid 70's. Reguarding, a/c size, my ceilings throughout the house are 11' 4" adding more volume than you would have in a standard 8' ceiling home. Also, I had planned to combine the 1.5 & 3.5 ton systems in to one 5 ton system. I didn't know if sizing with a smaller unit would be wise based on my satisfaction with the current combined 5 ton systems. Unless some of the new hi-tech effiencies like 2 speed comp. & mutiple speed fan, etc. make this a wise move. There are several improvements to the home that may allow for a smaller unit, I have added tinted window film & an awning arrangement that shades one of the 8' X 16' South East facing glass sliding doors. Reguarding brands & SEER/EER, are the high efficient units (two speed comp. multi speed fan, etc)that much more expensive than the basic single speed units? I have been reading about SEER levels of 24+ & EER levels of 30+. Are these numbers all BS? Also, I think I would be saving some money on a single unit vs. buying two units. Thanks again.