Geo-Thermal heat-pump?

[Wacky]

Any pros or cons?? My completely electric house has a outside heat-pump that is on its last legs. I was thinking of getting a Geo-Thermal heat pump/ furnace for my mid-entry home. Not sure of the costs of installation and general lifespan of the coils, or unit for that matter. Also not sure if it is as cost effective as it sounds. Any info will be helpful.

 

[Redneck in training]

I am assuming you have forced air unit. The advantage of the geothermal is that the efficiency is about the same regardless of the ambient temperature.
The longer the freezing season the better geo looks relative to an air unit. The ground loop is the additional cost the rest is about the same as air/air unit I suppose. Many utilities have rebate program for geo units that pays several hundred/ton and cheaper rate in the heating season. The life span of the geo heat pump is, according to manufacturer, about 20 to 25 years.

 

[Kays Supply]

My son sold them for a while. He had to quit because they couldn't find a driller that would backup his warranty on leaks in the Geo piping. If / when there was a leak in the underground piping the installer would say if my son's company would find the leak he would fix it for free. The wells were hundreds of feet deep. Do your homework on the piping installer as well as the HVAC installer. I just learned from another Geo installer that there is a break even point late in the heat and in the air seasons where the ground has given up it's heat and cool and the Geo unit doesn't get anymore from the ground. It is a great system just not perfect.

 

[boatyard]

Do your homework. They work best in a super insulated home. A friend has one installed at his house and he likes the idea, the reality is that his electric bill has been running about $300 per month during the heating season. If he runs the air conditioner, it cost almost as much. The upfront cost is very high. If you are on well water and the fluids in the unit leak you can have problems.
They are a great idea, but not the magic bullet that some would like you to believe.
Good luck. Let us know what you find out

 

[Tig]

I had one for 18 years and will reinstall it in my new home this fall. We drew water from a deep well and returned it to a shallow well. Very efficient and inexpensive way to heat and cool a house.

 

[Tig]

Air to air is good in fall, spring and moderate climate. But around here in the dead of winter there isn't much heat in the air to "pump". Ground temps are the same all year round.

 

[buckeyefarmer]

Check some of the geothermal threads in the past.

Some general comments regarding geothermal. Water Source heat pumps (geothermal) are much more efficient than air to air heat pumps. They are however costly to install. Most installers take responsibility for the entire install, including the loops. Most geothermal pipe is guaranteed for 40-50yrs. Some of the better known geothermal brands are Waterfurnace Envision and Climatemaster, but there are other good units. Geothermal deliver COP (coefficient of performance) of up to 5, meaning for each KW of electric used to run the system, it delivers 4 KW more of heating. This stays pretty constant, because of the constant temperature it uses for heat transfer. An air to air unit might have a COP of 5 on a cool day, but it drops significantly as the temperature drops, to the point it can't perform for heating, and has to use electric strip heat. An electic heat strip is 1 COP, 1KW of electric gives 1 KW of heat. For cooling, air to air uses SEER rating and geothermal uses EER rating, both which is btuh of cooling / watts used to produce. They are calculated differently, SEER is calculated using an average temperature, and the unit partly loaded, whereas EER is calculated at a steady state. EER of air to air is .875 x SEER. High end geothermal units are up to 30 EER while high end air to air are 15 SEER, which equate to around 13 EER. Again, much more efficient to cool based on a constant earth temperature than the hot air temperature. A good geothermal unit will be at least twice as efficient the best air to air units.
BTW, A ton is 12000 btu/h, which is derived from the amount of cooling achieved by melting 2000 pounds of ice.

 

[Raspy]

In-slab radiant heating is probably the best way to deliver geothermal heat to a house because it operates at the lowest temp and therefore the highest COP. I recently helped with one that had the tubing laid in a big pit about ten feet or so deep and maybe 50 ft X 50 ft square. I think there was 1600 linear feet of 1" poly tubing put in the ground. They get all their radiant and most of their hot water with it. They are all electric and I believe their electric bill is about $250 - $300. month, in the winter, for all heat, lights and hot water. They also have a small DWW solar system. The house is about 4,000 Sq. ft. and is at 4,900 feet elevation in Nevada.

These systems work well, but are expensive to install and complicated if you get a leak.

 

[Redneck in training]

WE have two propane fireplaces as a backup heat otherwise our house is 100% electric heated/cooled by geothermal system with floor heating and forced air cooling. We heat about 3800 sqft including 1800 sqft garage that is somewhat drafty. Our unit also heats domestic hot water. Our total electric bill is in average $210/month. Heating in Jan and Feb was about $90 bringing total elctric bill to $210. July and August are about the same in energy cost. Spring and fall are below 200/month.

 

[maybar]

Any pros or cons?? My completely electric house has a outside heat-pump that is on its last legs. I was thinking of getting a Geo-Thermal heat pump/ furnace for my mid-entry home. Not sure of the costs of installation and general lifespan of the coils, or unit for that matter. Also not sure if it is as cost effective as it sounds. Any info will be helpful.

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Due to the wide variation of electric rates, for someone to tell you how much it cost to run their system is of little value to you.

A better measure would be KW used and even then their needs, climate, structure size, type of structure, windows, insulation etc.etc. would need to be similar to yours to get a comparison of any merit.

Now, if those that had a record of KW used with an original heating/cooling system over a period of a few years and compare that to their Geo system of approximately the same time that would be of some value to someone contemplating a Geo system.

And while on the subject I have a question.

With a Geo system, what do we do in the Spring and Fall transition periods when heat is desirable one day but cooling may be needed the next day? In some zones this can easily be as long as a month or more twice a year.