Geothermal heat pump: first winter results

[techman]

Here to compare:

 

[MacLawn]

Thanks for that chart, techman. Looks like my savings would be like this:

Heat Pump $.10 $16.25

Geothermal $.10 $8.39

Hmmmm, looks pretty good to me, as long as I stay comfortable winter/summer, for me because of fibromyalgia pain, that means about 74° winter, 73° summer. And, maintenance is cheaper than my current heat pump (I just figured out that when y'all boys use "HP", ye mean heat pump, not Hewitt Packard!).

 

[truckdiagnostics]

Fordmantpw, the 7 series by water furnace is the Mac Daddy of Furnaces. If one is concerned about back up heat, install the water coil in the plenum of a gas furnace(use the 500R011), use it as an air handler, then you have the gas for back up. You will loose the electric coil in the plenum and maybe some of the ramp up features. The kid and I have talked about it, if you got the right gas furnace you might be able to get the ramp up in fan speed. A heat pump when it runs and the geothermal for that matter puts out a cooler heat. So, if memory serves me correct when the WF (unit that comes with the air handler) starts up the electric grid will turn on for a while giving the initial warm up of air. That is why I unplugged mine. I have a zone with a water coil running off the shop unit as a zone. Cold start up? yes, but you can hold the fan until water temp gets higher and minimize that.
As for things to watch for having a big enough loop and deep enough. Saskatchewan, Moose jaw Regina area 10 ft depth, central Wisconsin I'm at 6ft should have gone 8' or maybe bigger loop for the shop. I buried those two loops side by-side, everything was sized for the shop, then I added an 800 sq ft office using an air handler and it has to work hard, its maxed out.
In the summer, depending on the unit, you have free hot water for your pool. A water to water ex-changer and you have free heat.

 

[techman]

Thanks for that chart, techman. Looks like my savings would be like this:

Heat Pump $.10 $16.25

Geothermal $.10 $8.39

Hmmmm, looks pretty good to me, as long as I stay comfortable winter/summer, for me because of fibromyalgia pain, that means about 74° winter, 73° summer. And, maintenance is cheaper than my current heat pump (I just figured out that when y'all boys use "HP", ye mean heat pump, not Hewitt Packard!).

You will get more heat from a geo heat pump than an air unit. Do to the higher temps of water compared to air (in the winter).

paul

 

[fordmantpw]

Fordmantpw, the 7 series by water furnace is the Mac Daddy of Furnaces.

Yeah, I really like the 7 series. It's the only way we could get separate zones for my office and our sun room, each about 170 square feet. I work from home, so I want to keep that room at a constant temp. Our sun room has 10 3'x5' windows, so I felt we needed something there to make it a four seasons room.

The unit is a 5 ton unit, but we had 6 ton worth of loops put in. That is the only way the co-op would give us the rebate. He wasn't comfortable with the sun room, and felt we would come back on him for too high of an electric bill. The HVAC company was 100% comfortable with the 5 ton, so I didn't really care what the co-op guy thought. We spent the extra few hundred bucks to keep him happy and avoid issues, but I think that was the right thing to do anyway. Nobody ever says you have too much capacity!

 

[truckdiagnostics]

Yeah, I really like the 7 series. It's the only way we could get separate zones for my office and our sun room, each about 170 square feet. I work from home, so I want to keep that room at a constant temp. Our sun room has 10 3'x5' windows, so I felt we needed something there to make it a four seasons room.

The unit is a 5 ton unit, but we had 6 ton worth of loops put in. That is the only way the co-op would give us the rebate. He wasn't comfortable with the sun room, and felt we would come back on him for too high of an electric bill. The HVAC company was 100% comfortable with the 5 ton, so I didn't really care what the co-op guy thought. We spent the extra few hundred bucks to keep him happy and avoid issues, but I think that was the right thing to do anyway. Nobody ever says you have too much capacity!

Adding to the loop was smart and I believe the co-op guy was right. When the unit gets to max. It can actually freeze or cool the ground around it such that it can not get as mush heat out of it. Therefore having to work harder. That is the advantage of using water from well. Issue there the discharge, and if you have a place for the discharge that is the way to go. back to your loop.... when they figure the loop size they figure the unit will shut off, therefore giving the ground time to warm back up so to speak. I will have issues with the unit in the shop, some springs when the frost pushes deep or I run it really hard for extended periods. So, whoever sized your loop new what they where doing! And having the loop size checked and the installation making sure it is actually at the depth they said it is going to be is a big deal. Go out there with a tape measure and check it. They use a sub contract to dig and back fill the whole.

 

[fordmantpw]

Adding to the loop was smart and I believe the co-op guy was right. When the unit gets to max. It can actually freeze or cool the ground around it such that it can not get as mush heat out of it. Therefore having to work harder. That is the advantage of using water from well. Issue there the discharge, and if you have a place for the discharge that is the way to go. back to your loop.... when they figure the loop size they figure the unit will shut off, therefore giving the ground time to warm back up so to speak. I will have issues with the unit in the shop, some springs when the frost pushes deep or I run it really hard for extended periods. So, whoever sized your loop new what they where doing! And having the loop size checked and the installation making sure it is actually at the depth they said it is going to be is a big deal. Go out there with a tape measure and check it. They use a sub contract to dig and back fill the whole.

How am I supposed to measure holes 150' deep?

I trust the folks that did the installation. I personally know the folks that drilled the wells (distant family) and hooked up the loops. I'm confident that they did it right.

I considered an open loop system, but we have really hard water hear and didn't want the hassle and issues associated with that. We plan to build a lake in a few years, and the discharge would have been perfect to keep fresh water running into the lake (albeit slowly ). Practically nobody in our area does open loop.

Our unit has never run at max. Even when we were sub-zero here, we had lots of reserve left on the unit (running at ~50% power for short periods, then backing down to 30-40%). I credit our tight, well-insulated house for a lot of that.

Another thing that needs to be mentioned (if it hasn't already) is that geothermal units are not meant to be used with a programmable thermostat. My office is in the basement, and I had it programmed to drop to 66 at night, then back to 70 by 8:00 am. The unit would run all morning to warm it up to 70 by noon because it would run at such a low power. This would negate any savings by setting it back at night, so we shut it off. We do typically drop the temp in our bedroom 1 degree at night in the summer because we like it cooler, but the unit can recover a lot quicker when it is cooling than when it is heating.

 

[buckeyefarmer]

What lengths of loops and how many do people have?

i have 5 loops, each 700' long total pipe in slinkies. slinkies are 3' wide by 70' each.

 

[fordmantpw]

I have 5 holes 180' deep (I think).

 

[buckeyefarmer]

I should have added i have 5 tons in 2 units.