Pond Boss Forums INTRO Questions & Observations Geo Project

Would geo be beneficial in Arkansas? It's not nearly as extreme as Minnesota in the winter and we usually have HOT summers. We will start building our house this year. It will be about 5000 square feet, and we will be using foam insulation so the house should be pretty airtight.

It doesn't seem like geo should cost 2-3X more than conventional HVAC. It's not that much more equipment, if any. You have the cost of the tubing. Am I missing something??

I don't think aerators or circulators are intrinsically bad for Geo. We have a circulator that in many ways functions like an aerator as both move water and a lot of it. The location of the aerator/circulator is what is important.
Our circulator is within 30 feet of our geo-loop. The geo-loop sits on the bottom the pond in ten feet of water. The circulator is in 2 feet of water so it has very little effect on the water on the bottom where the loop lies.


You need to talk to a geothermal contractor in you area to get some idea of the potential. Once you have that, you can do your own research to determine what you want to do. Every situation/location is different.


Geo-units are complex and it is not inexpensive to run a backhoe (or whatever earth digging/moving equipment) for a couple days.

I know that excavation and heavy machinery usage can get quite expensive. But if the loops are at the bottom of the pond, there isn't much excavation. That's where I'm confused. Seems that there's about the same amount of equipment, maybe a little more, as regular HVAC.

My plan is to use my pond as the heat exchange point. The pond is 28 ft. deep at the deepest spot. This is where I would like to place the loops. Later on, I plan on placing an aerator about 15-18 ft. deep. Hopefully, this won't interfere with the bottom layer of water and I won't have problems with the geo.

I found this:

1: Why are Geothermal Systems so expensive?

Answer: The equipment costs close to the same as a quality name brand high efficiency furnace and air conditioner. The additional cost involves the installation. An open loop usually requires less capital investment than a closed loop system if the well and discharge are already existing.
A horizontal loop requires excavation equipment and pipe installation.
A vertical loop requires drilling and excavation equipment and pipe installation.
Special tools are required to fuse the plastic pipe together underground.
Special flushing and charging equipment is required to clean, air purge and freeze protect the earth loop once it is connected to the geothermal unit.
Ductwork is somewhat larger than with other furnaces because geothermal systems move about 40% more air than fossil fuel systems of similar heating capacity.

Dwight:

I didn't know this, nor did the geo company say anything about this when they quoted me a system. They were going to use the same ductwork.

I believe you switched to geo, correct? If so, was your duct work increased in size? Your system seems to work very effeciently and the way that your system works is how I'd expect a geo system to work, that's why I'm asking.

There are thousands of Geo-systems working just fine that have been fitted to existing homes. The 40% larger ducting is ideal in new construction.

Since Geo-systems move more air you will notice an increase in the "breeze" when directly in front of a register. Do they still call them registers?

This 40% rule is for heat pumps. It's not restricted to geo systems. The heat rise is lower with a heat pump than most other systems. More air at a lower heat rise has to be moved in order to have an equivalent heating capacity.

If the duct work is not sized properly you can have a system that is noisy and feels very uncomfortable even though the system can maintain the set point on the T-Stat. This is the most common complaint about heat pumps.

The problem is actually compounded in a retrofit because most duct systems are undersized to begin with. A natural gas unit with a supply temp of 120F. feels warm even at high velocity. A contractor/builder can add profit by undersizing the duct system with few complaints.

A heat pump with a 90F supply temp will feel cold if you are in the air stream. Your wife wont care if the building temp is "correct" if she feels cold.

The heat pump should be sized according to Manual "J".
The duct system should be sized according to Manual "D".

If your contractor is not using industry standards you will likely end up with a poorly functioning system.

So are you saying tejasrojas that a geo-system is not a good retrofit in a house with an existing duct work or that if retrofitting you just have to ensure it is sized properly? (just trying to understand for future reference).

Geo System Cost.........................+$ 17,100
One Time 30% Tax Credit.................-$ 5,130
Year One LP Cost Reduction..............-$ 5,186
Year One Electric Power Cost Increase...+$ 288

First Year Investment Recovery.......... $ 10,028

Remaining Cost to Recover............... $ 7,072

I our case the Geo system will pay for itself in less than three years with the tax credit!!