geothermal questions and possible DIY

[JimRB]

Our house has seen weeks of cold weather. Our geothermal just runs longer when it is really cold. No booster heat. It got down to 8F last year. House stayed warm but as someone mentioned it was sized for cooling more than heating.

When they guy was doing horizontal trenches for our unit he was digging in Georgia clay. I do not recall how deep but I am guessing 8 feet deep. I think technically that is trench shore equipment deep. I do not think I would trust trenches that deep in sand. Plenty of articles about shoring. http://constructionsafetyconsultant.com/articles/excavation.PDF

 

[Pixguy]

I've got to look closer at water to water so that I can do radiant floor heating.

 

[KubotainNH]

I've got to look closer at water to water so that I can do radiant floor heating.

This is what would interest me also. I built my house in 03 and installed a radiant system heated by a Bock oil fired water heater. It does really well but oil has been quite expensive the last few years. It would be nice to do Geo but I don't have a lot of yardage but it is very sandy. Looking forward to seeing more info in this thread. I'm in the Northeast, it can get quite cold here. A couple years ago we went through a straight month of below 0 weather, that year must have had some cold ground temps when at their lowest.

 

[dodge man]

If you don't have much yard space they can go vertical.

 

[techman]

I've got to look closer at water to water so that I can do radiant floor heating.

I have installed a couple w-w units. The big thing is that the water temps out of a geo unit are relatively low, generally about 110-120 deg. This is not a problem as long as the radiant is designed for those temps, which requires higher tube density.

paul

 

[jix]

I have installed a couple w-w units. The big thing is that the water temps out of a geo unit are relatively low, generally about 110-120 deg. This is not a problem as long as the radiant is designed for those temps, which requires higher tube density.

paul

this is true..W-W heat output is not hot..just high in volume..Radiant heat in floors would be slow to rise, but heat is heat.
My only experience is with forced air..it works well, but the air out of the heatpump radiator is warm, not hot as if it were from an oil burning furnace..maybe I would not use geothermal for radiant heating concrete floors... I am not competent to say. One thing tho..radiant floor heat does not require a radiator nor a forced air fan, so no electrical energy is lost moving air around. Design of such a system is beyond my practical experience level. Theoretical knowledge just ain't 'nuff, so you gotta get someone with more experience than I have to opinionate. I would be BS ing you if I did that

 

[LD1]

OP here.

Got a few more contractors scheduled to show up today. We will see what they have to say.

To recap, A 4-ton 2-stage air to air unit was $5500 installed + $3500 for duct work.

A 4-ton 2-stage geo unit was $15,000 installed + $3500 for duct work + $3600 for excavation (which I am doing myself).

Looking at the price of what I can buy furnaces for online (somewhere in the 7-10k range) I think the $15k price tag for the geo unit is a good bit high.

I do not see there being a difference (or much of one) in labor. SO this first guy was basically telling me that that all the material required for the geo unit is $9500 higher than air-source.

Granted I am not a dealer or HVAC tech. But looking at what it would cost ME to purchase a geo online vs a similar air-air unit, I am seeing a cost difference for material of only about 4k.

We will see what these next two contractors say.

 

[Pixguy]

I I

OP here.

Got a few more contractors scheduled to show up today. We will see what they have to say.

To recap, A 4-ton 2-stage air to air unit was $5500 installed + $3500 for duct work.

A 4-ton 2-stage geo unit was $15,000 installed + $3500 for duct work + $3600 for excavation (which I am doing myself).

Looking at the price of what I can buy furnaces for online (somewhere in the 7-10k range) I think the $15k price tag for the geo unit is a good bit high.

I do not see there being a difference (or much of one) in labor. SO this first guy was basically telling me that that all the material required for the geo unit is $9500 higher than air-source.

Granted I am not a dealer or HVAC tech. But looking at what it would cost ME to purchase a geo online vs a similar air-air unit, I am seeing a cost difference for material of only about 4k.

We will see what these next two contractors say.

Thanks for keeping us informed. What you find can help many of us. :drink:

 

[dodge man]

Those numbers you are throwing around are in the ballpark for what I paid and was quoted. I think the regular heat pump we were quoted was a little higher than you listed. Keep in mind the tax saving with a geothermal unit.

 

[techman]

A 4-ton 2-stage geo unit was $15,000 installed + $3500 for duct work + $3600 for excavation (which I am doing myself).

If you are doing the excavation yourself, the add'l costs are installing the piping, flow module, plus the heat pump. $10 K for those is steep. I would estimate about a $5K adder.

paul