Some of these questions may seem too technical and have you thinking “who cares”, but they’re really not.  It’s a good idea to educate yourself about this technology before making a substantial purchase.  I see it kind of like hiring an attorney.  You can drop off a stack of files, say take care of it, and then forget about it.  The results you get may not have your best interests in mind.  It’s always better to educate a little, and then help yourself as much as you can along the way.  Contractors will be eager to inform, and surprised by your knowledge base.  Good luck…

General

1. What factors will determine the size of equipment that best fits my needs?
2. Would my home benefit from a zone system?
3. Can the system adjust its output capacity and airflow to serve small zones?
4. Will my existing ductwork handle the system being proposed?
5. What impact does undersized ductwork have on the system?
6. Can I monitor the exact energy consumption of my system and compare to my power bill?
7. Try to compare bids “apples to apples”.  Does the system proposed:
   1. Have two-stage operation?
   2. Have a variable speed blower?
   3. Have a full 10 year parts and labor warranty?
   4. Include excavation / trenching / plumbing / electrical / zoning?
   5. Include ductwork modifications and what are they?
   6. Include the “Hot Water Generator” option and associated plumbing?

Open Loop System:

1. Who will be performing the water quality testing on my well water?
2. Is the testing directly related to the water quality specification provided by the equipment manufacturer?
3. Will there be water noise during operation?  How will this be addressed?
4. Will you (the heating contractor) be installing all plumbing & components to support the unit?
5. How will I know the water flow rate through my heat pump?
6. What is the required flow rate for my heat pump?
7. Where in the plumbing is the water control valve located and why?
8. How will we address discharge water location?
9. What do I need to monitor during the first few weeks after installation?

Closed Loop System:

1. How will my ground loop / pond loop be sized?
2. What are the maximum and minimum temperatures of my ground loop?
3. Is the old saying “1 loop per ton” adequate for my system?
4. How long is each loop?
5. How much does it cost for an additional loop?
6. Why should I care about how many loops my system has?
7. Is the fluid flow in my ground loop laminar or turbulent and how do we know?
8. Why do fluid flow properties matter?
9. What is used for freeze protection?  Why?  Down to what temperature?
10. How will a circulation pump be selected for my ground loop?
11. Will my ground loop have a hydration system?
12. Can I monitor the temperature of my ground loop year-round?

Auxiliary Back-up Strip Heaters:

1. How much aux. back-up heat do you recommend?  Why should it matter?
2. Can I turn the aux heaters off?
3. How will I know if the aux. heaters are running?
4. Can I still set my temperature back down to 60 degrees overnite & then back to 70 for the daytime?

Knowledge of the System & Equipment Being Installed:

1. What is Heat of Extraction / Heat of Rejection?
2. Why is Heat of Extraction less than the units rated capacity?
3. What diagnostics will be performed at start-up to verify operation?
4. Can a COP / EER or efficiency be calculated directly after install?

“Open loop” and “closed loop” refers to the source.  The source side is the location where the heat pump will be extracting or rejecting heat to.  The load side is the home we’re trying to heat or cool.  Let’s start by looking at the pros and cons for each geothermal source.  Remember that efficiencies for ALL water source heat pumps exceed that of any other heating system today:

Open Loop Source (“pump & dump” or “once-through”):

Refers to running domestic well water through the system and discharging somewhere

Pros:                                                                                         Cons:

Less expensive install costs                                            Increased well pump usage

• In most cases                                                         Water quality concerns

Consistent entering water temperature                          Additional water control valve required

Slightly more capacity in late winter                                Discharge water location / design required

                                                                                                Additional energy usage due to well pump

Closed Loop Source (Horizontal pit or trench, vertical bore, horizontal bore):

Refers to circulating the fluid out through the ground and back through the heat pump in a continuous loop with high density PE pipe

Pros:                                                                                        Cons:

Control over water / brine quality                              Typically higher initial install costs

No scaling or build-up concern                                 Requires yard space

Less maintenance                                                       Lower entering water temperatures (heating)

No water usage from well                                             

No well pump running

If a contractor tells you that open loop systems are more efficient, most likely they either don’t know how to, or don’t want to install a closed loop.  It’s much easier to set a unit, pipe water to it and be done.  Furthermore, designing a closed loop requires the installer to know more about the product they are selling.  So do they really know how to commission a system and verify proper operation (another another topic ”Selecting a Geothermal Contractor”)?

Lets get back to comparing these two source options.  From the list above, open loop systems have the benefit of a consistent entering water temperature (EWT).  Your well water temp doesn’t change much year-round.  The output heating capacity of the system is dependant on the EWT.  The unit is extracting heat from the entering water, so if the temp of that water is higher, it has more capacity to heat your home (and consequently, it will also operate more efficiently).  Closed loop systems circulate the same freeze protected fluid (brine) forever.  This brine is extracting heat from the earth and EWT’s can get down to 30 degrees in late winter.  For example, let’s look at the spec book and examine the heating capacity and efficiency of a 4-Ton unit and assume it’s late winter:

                                               Open Loop                        Closed Loop

EWT:                                    50 degrees                        30 degrees

Heating Capacity:          47,800 Btu/hr                       37,500 Btu/hr

Power:                                3.22 KW                                2.97 KW

COP:                                     4.35                                    3.71

So the open loop system is providing 10,300 more BTU’s than the closed loop system due to the elevated EWT.  Open loop system is 435% eff vs. the closed loop operating at 371% eff.  The thing that’s missing is the well pump.  The well pump runs 100% of the time that the heat pump is running (obviously turns off when the heat pump shuts down).  A residential variable speed well pump will draw ~ 5 amps or more at lower flow rates.  This equates to another 1.2 KW and takes the total COP down to 3.12. (or 312% eff).  At this rate the closed loop system is more efficient with less operating costs.  It’s the turtle that wins the race in this example.

Our experience has been great with both open and closed loop systems.  We have learned that open loops require a little more attention in the weeks directly following install.  It’s good to check a new system frequently.  Inspect the flow meter to verify correct water flow.  This is important in the spring when sprinkler systems come on.  Sprinklers, or other large water demand on the well, can reduce the water flow rate through your heat pump.  Sprinkler system start-up can also send quite a large amount of sand or other sediment up the pipe.  You’ll want to check the sediment trap at the unit location and clean when needed.  Once dialed in the system typically runs good with simple filter changes every 3 months.

The install cost is another factor worth discussing.  Just because you already have a well doesn’t mean the open loop will always be the cheapest to install.  Finding a good way to discharge the water can also cost money.  One method is to take a backhoe and dig a big hole, backfill with washed rock, and then see if the ground will take it all back in.  This works well in sandy soils but could still cost you $1,500 in backhoe time and labor.  If you have a surface pond you could discharge in there pretty cheap.  We have had customers who want to drill both a supply and discharge well for an open loop.  The cost of that would be equal to or more than simply installing a ground loop.

At the end of the day both systems are going to far exceed the efficiency of anything else you could install.  Air-source heat pumps have come a long way.  However, they’ll never achieve the eff of a geothermal system because it’s just too difficult to extract heat from air that’s 20 degrees (winter in Idaho).  It’s ~ 30 times easier to transfer heat using water than with air.  Water source heat pumps are moving onward as well.  We already have systems rated up to 500% eff.  The next generation has new design features that will significantly increase even this number.

WaterFurnace Envision by Idaho Geothermal

The quality of construction on this new home is amazing.  The total energy bills for Dec, Jan, and Feb 2011 are lower than a typical 2,500 sqft home in this valley.  A single 6-Ton WaterFurnace geothermal forced air system provides all of the heating  and cooling needs.  The ground loop is designed large enough to support a future water-to-water geothermal heat pump.  The future unit will power the radiant floor tubing that’s currently installed and ready.

WaterFurance Envision by Idaho Geothermal

As the geothermal contractor on this project, we spent a week inside this home updating the ductwork system.  A new main trunk line was added to support a two-zone system.  This also included additions and modifications to the existing ductwork.  Fortunately the first snow didn’t fall up there until the day after we backfilled this ground loop. This type of geothermal heating and cooling system featuring a WaterFurnace water source heat pump will become the most sought after heating system in McCall.

Half way there...

The home originally had a propane furnace and propane gas fireplaces that were not adquate for heating this amount of space.  The new ductwork system is working well and we also integrated with the owners security controls contractor.  He can now control the heating and A/C from the anywhere via the internet

The start of a long day spreading slinky loops

WaterFurnace Envision by Idaho Geothermal

Soil conditions in Hidden Springs have been just as good as the Eagle area for installing ground loops.  The weather could have been better but oh well.  Geothermal heating systems make a lot of sense for new construction homes.  When considering the alternative cost of a natural gas system install and the tax incentives, the pay back time on a geothermal system upgrade is relatively short.

7,200 sqft home – retro-fit

WaterFurnace Envision

Heating Contractor: Idaho Geothermal

This home was recently purchased in 2010.  We removed two heating systems and replaced them with a single Waterfurnace Envision on a new geothermal loopfield.  Now the entire 7,200 sqft is heated by a single water source heat pump.   This became the third home over 7,000 sqft that we have heated with a single unit.

WaterFurnace Envision

Heating Contractor: Idaho Geothermal

This is a standard building lot in Hidden Springs.  The loopfield took most of the back yard, but once backfilled one would never know it’s there. Our geothermal heating and cooling system will provide higher efficiencies and lower heating bills than a conventional system.

WaterFurnace Envison

Heating Contractor: Idaho Geothermal

The soil in Eagle is excellent for ground source heat pump systems!  These are 1,000 ft slinky loops serving a 6 Ton Waterfurnace Envision unit.  A single unit heats this home on 4 independent zones (Intellizone system from Waterfurnace).

Private Residence  Homedale, Idaho

WaterFurance Envision

Heating Contractor: Idaho Geothermal

Our second closed loop system in Homedale during summer 2010.  This one is new construction and the home is ~3,200 sqft.  This system was paying back the day these homeowners moved in.  More info below…

After the tax incentives, the cost to upgrade this home to geothermal (vs. a propane gas system) was minimal.  This cost to upgrade was rolled into the mortgage at closing.  The monthly energy savings are actually more than the increased payment of the end loan, so these owners have more money in their pocket at the end of every month as opposed to a propane system.  The geothermal system was paying back on day one.

Just kidding, this job is in Homedale.  There are vinyards out there and more planned however.  This homeowner did say something about wine and roses when the propane company came to remove their tank.  He is not spending $3,500 – $4,000 per year in propane any longer.

The presence of lava rock will sometimes dictate the shape of your ground loop pit or trench.  It certainly is not a show stopper though.  We simply trucked in some clean top soil to bed our loop pipe.  Once the slinky loops are covered, you can then backfill with the native soil / rock and be confident that your pipe is safe.  This loop is serving a 5 Ton WaterFurnace Envision and a 3,800 sqft new home.

Hopps Field
Private Residence
2800 sq ft, Greenleaf Idaho
Retrofit:  Removed existing 80% propane furnace and A/C

Replacing propane systems with a Geothermal Heat Pump has been a huge part of our business.  The payback for a geothermal system when compared to the cost of propane is generally 2 years or less!  The 30% Federal tax credit has helped homeowners even more.  Homeowners receive a tax credit equal to 30% of the complete system install cost (with no cap).  This along with the Idaho Power Incentive check ($1,000 written directly to the owners) basically cuts the cost of a system in half!  We installed an underground drain field on this system as well.

Black Canyon
Private Residence
2200 sq ft, Emmett Idaho
New construction

3 Ton WaterFurnace Envision system.  Ground water in this Emmett area is abundant and close to the surface which is excellent for open loop systems.  This homeowner was able to discharge into a warm water slough on his property and save money in initial install costs.  As with all our systems, the Hot Water Generator (HWG) is included.  The HWG connects directly to a stand alone water heater.  Whenever the unit is either heating or cooling the home, it is also injecting heat into the water heater to provide additional savings.  This energy is absolutely free in the summer (heat is a by-product in cooling mode).  After a month the customer said the same thing we’ve heard many times…”For some reason we’re keeping our house 2 degrees cooler than in the past?  It just feels warmer and we’re comfortable there.”  The system doesn’t dry the air like gas furnaces and provides more even heat due to longer run cycles.  This makes the home feel warmer at the same temperature on the T-stat.

Lake Lowell
Private Residence
4200 sq ft, Caldwell Idaho
New construction

6 Ton Carrier system with a 3-zone control board and NO back-up electric elements.  This homeowner connected the Hot Water Generator (HWG) from this unit to two Marathon water heaters.  Largest power bill for this home last winter was $250.  This is a complete energy bill for all hot water, cooking, lights, etc.

Frozen Dog

3 Ton WaterFurnace Envision.  This homeowner installed an underground drainfield based on our input.  Supply water is again from the domestic well (open loop).  After running through the WaterFurnace, the water is injected into the drainfield ~ 5ft below the surface where it drains back into the ground.  This is an effective and inexpensive way to discharge water with an open loop system.  Performance depends on soil type in the area.

Pear Blossom #3
Private Residence 3500 sq ft,
Meridian Idaho
Retrofit: Removed existing (2) 80% propane furnaces & (2) 10 SEER A/C units

Open loop WaterFurnace Envision system. Again with the Intellizone multi-zone control. All the Envision systems feature R410A earth friendly refrigerant, variable speed blower motors, and 2-stage compressor operation. The system is extremely quiet and makes about as much noise as a standard refrigerator. As with all open loop systems, we install components in the plumbing package to ensure any water noise is kept to a minimum. This is significant for anyone considering an open loop. With well pressures at 60psi, the water noise can be much louder than the heat pump if not installed correctly.

Pear Blossom #2
Private Residence 3400 sq ft,
Meridian Idaho
Retrofit: Removed existing (2) 80% propane furnaces & (2) 10 SEER A/C units

Existing propane systems were replaced with a WaterFurnace Synergy 3D unit and Intellizone control. The Synergy 3D unit will provide heating, A/C, domestic hot water, as well as hot water for radiant floor heat. The Intellizone system allows for independent temperature control both upstairs and down. As with almost all (of our) open loop systems, no back-up electric heat elements are installed. This home is heated entirely with the geothermal heat pump at 427% efficient (as measured at start-up).

Simply put “geo” means earth and “thermal” means heat. Therefore, geothermal heating and cooling transfers heat from the earth to the home or office when using a water source heat pump (WSHP).  Due to the constant temperature of the earth…

geothermal heating can achieve an efficiency (COP) of up to 5.0. This means that for every unit of energy put into the WSHP, it can remove up to 5 units of energy to utilize for space conditioning.

Benefits of geothermal heating and cooling include:

1. Energy savings up to 70%- compared to gas furnaces and air conditioners

2. Improved aesthetics- geothermal heating and cooling systems utilize a packaged unit that eliminates the need for an outdoor AC. this reduces noise and ear and tear.

3. Longer Life- water source heat pumps have a much longer life expectancy than conventional systems. They have a lower maintenance cost

4. Eco friendly- Water source heat pumps are recognized by the DOE and the EPA for their superior efficiency.

5. Positive Cash Flow- The monthly utility  savings often are greater than the added cost of a system.

Private Residence 4800 sq ft, Eagle Idaho
Retrofit – Removed air-source heat pump and electric air handler

5 Ton WaterFurnace Envision and earth loop. After the install, this customer downloaded “Smart Meter” data from Idaho Power. He compared energy consumption over the last two years for the same two-month period. The WaterFurnace system was using half of the KWhrs per heating degree day. This is great data considering we replaced an air-source heat pump which are more efficient than std. gas furnaces.

Even better is the fact that the customers keep their home warmer now, and still save 35% – 50% on energy each month. Aside from the smart meters, we have installed metering devices directly to the ground-loop heat pumps on several systems. The customer can look (at any time) and determine exactly what they are spending to stay comfortable.

Private Residence 5000 sq ft, Eagle Idaho
Retrofit – Removed (2) propane furnaces and (2) A/C units

2-Stage WaterFurnace Envision and Intellizone system allows us to once again replace two heating systems with one geothermal unit.  Connecting the ductwork from both units and installing the zones were challenging here, but ended up working great.  We also went into the attic and replaced all the supply air ductwork to ensure proper flow to the upper level zone.

Notice the  main wall return right beside the unit in the basement.  We will pull most of the return air from the basement area with by-pass ducts connecting the main living areas upstairs.  This will cycle the air throughout the home and ensure constant pressure.  Located near Firebird Raceway.

Private Residence 4200 sq ft, Caldwell Idaho
New Construction

6 Ton water source heat pump and closed loop system. Zone controls allow three independent heating areas. The horizontal slinky loop configuration continues to be the most cost effective install in this area. Soil conditions and the heat load of the house always dictate the size of the loopfield. Depth is also a big factor. More below

We could install all our loopfields at a depth of 1ft, but it would be the size of a football field. The deeper you dig, the less pipe you need. Goal is to select the depth and loop length that is most cost effective to install. This customer keeps their home at 72 degrees 24/7 during the winter.

Private Residence 7400 sq ft Residence, 3300 sq ft Woodshop, Office, Apartment Space
New Construction

This horizontal closed loop serves over 10,000 sq ft of heated space, domestic hot water, radiant floor, and hydronic air handlers. We installed a single WaterFurnace Envision to heat the 7400 sq ft home with four separate heating zones. A WaterFurnace E-Series water-to-water heat pump provides hot water which will heat the detached buildings and radiant floors. Both Geothermal Heat Pumps are connected to the same loopfield shown here. More below

This home is insulated with closed cell spray foam which significantly reduces the heating loads. The system maintained 72 degrees throughout the house this December 2009. Based on the total amp draw (and $.072/KWHr), the system could run 24/7 (on high speed) for an entire month and the power bill would never exceed $260 for heating. Obviously it won’t run constantly, and the owner will enjoy even lower heating bills for this very large home.

Private Residence 2811 sq ft, Mountain Home Idaho
Retrofit – Removed propane furnace and A/C unit

This customer purchased this home, and immediately contacted us to install a geoexchange system. When he called the propane company to come and get his tank, they said “We are very sorry to loose you as a customer.” Apparently the propane truck was a frequent visitor during heating months. This is another earth loop that got modified due to lava rock.  More below

We changed the shape of the pit, and for the first time, brought in some clean fill dirt to backfill over the loop piping. This was a small expense compared to the savings over the life of the geothermal system. On a side note, this customer’s domestic water well was ~450ft deep with limited capacity. This made the closed loop system a much better choice.

Installing this ground loop was challenging due to the sloped hillside. You can see the soil contained a large amount of river rock which made for a tedious backfill process as well. We are often able to remove two separate heating systems in a home, connect the ductwork together, and install a single WaterFurnace geo unit. The Intellizone control plays a huge part in the ability to do this. This home is experiencing much less than half the heating bill from winters past.