Geothermal, Ground Source Heat Pump or GeoExchange?

Geothermal Heat Pump Cycle

Geothermal Heat Pump, Ground Source Heat Pump or GeoExchange — which is it?

Mankind has used the relatively constant temperature of the shallow Earth for climate control for thousands of years with structures like root cellars and caves. Energy from the Earth has been used to heat and air condition buildings using mechanical heat pumps for decades, and during that time these systems have been called many different things. Some of the most common variations include geothermal heat pump, ground source heat pump and geoexchange. So how are these different? Well, they really are not. All of these names are meant to describe essentially the same thing. The process that these names describe is the movement of heat from the ground into a building for heating and the movement of heat from a building into the ground for cooling using a heat pump.

Why not just use one name?

One name would make things simpler but that is probably not going to happen right away. What should we call the highest efficiency, lowest operating cost and most climate friendly way to heat and cool commercial buildings and residences? I think we can call it anything we want. There are people who wrinkle their noses if someone says ‘geothermal’ instead of ‘ground source heat pump’ or ‘geoexchange’ but I don’t put much weight in nose wrinkling. As a professional I believe all three names are good but imperfect.

WaterFurnace 7 Series

WaterFurnace 7 Series

  • ‘Geothermal Heat Pump’ is the most common name but also the most maligned. On the most basic technical level it is correct because we are working with earth (geo) heat (thermal) using a heat pump. There is the potential to confuse geothermal heat pumps with high temperature geothermal energy. The biggest problem with this is when someone starts to think they need to live on the slope of a volcano to heat their building geothermally. In dealing with clients, I find that simply ‘Geothermal’ or just ‘Geo’ is the most common name for what we do in public use and this has become my most used name.
  • ‘Ground Source Heat Pump’ is a technically correct option that I find second most common after ‘geothermal’. I use ‘GSHP’ nearly as often as I do ‘Geothermal’ and think it is a fine choice that helps avoid visions of volcanos. One problem is that GSHP is the common term for the equipment and does not stress the underground component as well as Geothermal does.
  • ‘GeoExchange’ is my least favorite but I won’t wrinkle my nose when it is used. GeoExchange may be the most technically accurate of the three choices here. GeoExchange refers to the entire process of using the GSHP in conjunction with the underground (or underwater) heat exchanger.  I think this term was coined in an effort to market geothermal heat pump technology and differentiate it from high temperature geothermal energy projects. For me, GeoEchange does not roll of the tongue and I don’t hear many clients using the term.

In truth, none of the three is a perfect naming choice. The issue will resolve itself over time. In the end, I just wish for more people to use and think about any (or all) of the names. Heating and cooling using the treasure under our feet is important to energy policy and the more it is talked about the better. Whatever name you use, you are still talking about using the heat stored in the Earth to save 60-75% of HVAC operating cost and reduce HVAC carbon footprint by the same 60-75%.



Installing Geothermal Systems for Massachusetts Homes & Commercial Properties

Achieve’s staff are members of the International Ground Source Heat Pump Association (IGSHPA) are are IGSHPA Accredited Installers. Achieve employs WaterFurnace factory-trained pipe fusion technicians and Factory Trained Service Technicians. Achieve is an authorized dealer for WaterFurnace Renewable Energy, Inc. In 2013, WaterFurnace celebrated its 30th anniversary of providing quality geothermal heating and cooling products.

Boston Natural Gas Prices Spike in December

December Natural Gas Prices in Boston

Boston saw natural gas prices spike in December. In a recent notice, the United States Energy Information Administration (EIA) shows that bidweek natural gas prices for December 2013 were nearly triple the November prices. The December settled at $14.52 per million Btu which compares to under $4 in October and $10 last December. The December 2013 prices are the highest ever recorded at the Algonquin hub that serves Boston. Nationally, prices have not risen to this degree. Factors contributing to the price spike include: pipeline/delivery constraints, cold weather in November, forecast below normal temperatures in December and maintenance downtime for secondary delivery systems. The full EIA report is available here.  Residential and commercial natural gas prices will inevitably rise in response to the increased cost for the Utilities to buy gas on the open market. Since about 40% of building energy expense is space heating, natural gas customers should plan for increased natural gas prices this winter. It looks like New England will not be able to sustain the low natural gas prices seen in recent years because of the limited pipeline capacity. The reasons for this are in the second EIA chart and our interpretation, below.

Natural Gas Prices Spike in December - EIA Data


Delivery Infrastructure Problem

New England has infrastructure problems that limit delivery. There is simply not enough pipeline available to meet the expansion in natural gas demand that has occurred in recent years. Most of the natural gas entering New England is delivered via the Algonquin Gas Transmission pipeline system. This system has historically operated well below capacity except during peak demand. Because of increased natural gas use, the pipeline system has operated near capacity year round since 2011 and can no longer keep up with peak demand. Now,  demand peaks on top of the new normal monthly requirements can’t be met — especially if secondary delivery options are constrained. Constrained capacity results in increased natural gas prices. You can read more about the pipeline here. Here is a graph that shows how much demand for the pipeline has increased in recent years:

Natual Gas Prices are related to Algonquin Pipeline Load


Geothermal Heating and Cooling Just Keeps Getting Better

Geothermal Heating and Cooling equals efficiency!  This is particularly true with the latest and most advanced 7 Series line introduced by WaterFurnace and provided by Achieve Renewable Energy.  This state of the art system is considered the ‘best of the best’ and represents the industry’s FIRST fully launched variable capacity residential unit and the ONLY unit to surpass both the 41.0 EER and 5.3 COP efficiency barriers developed by the U.S. Department of Energy.


WaterFurnace 7 Series

How does it work?  Unlike traditional geothermal units, which typically use one or two fixed compressor speeds, the 7 Series scales the speed up and down based on actual need.  This allows the system to run more frequently at lower capacity thus resulting in an increase in efficiency that translates into over 30% savings over a typical Geo system and up to 70% savings on a more traditional fossil fuel system. The 7 Series works like a race car with a 10 speed transmission while traditional units are limited to 1 or 2.

The current market place for these variable speed or inverter-based units is just starting to develop. The only inverter-based GSHP in production that is readily available is the WaterFurnace 7 Series. Competing units from other manufacturers are anticipated in the coming year or two but are not currently available. Achieve has installed or is currently installing more WaterFurnace 7 Series units than any other WaterFurnace dealer in our area and we believe we have the most inverter-driven GSHP experience of any geothermal installer in the Commonwealth of Massachusetts.

Want to learn more?  Check out this recent article on ProudGreenHome that touts this next generation in geothermal technology, particularly the WaterFurnace 7 Series:

The Massachusetts Department of Energy Resources (DOER) is also convinced.  Their new $3,000,000 Financing Program for Renewable Thermal Investment specifically targets the development of renewable thermal technologies including ‘inverter driven air and ground source heat pumps.’   To learn more about this program or to further educate yourself about all of the amazing benefits of renewable energy, visit the DOER website at


Achieve is a registered WaterFurnce Geopro Master Dealer


Tower School Solar PV Production Exceeding Expectations

Tower School PV Array

Electricity produced from Solar PV is the whole point of installing the solar panels, right? What can you do to maximize the production from your small commercial or residential PV system? Maybe you should talk to Achieve about designing your system with micro-inverters. The Tower School solar array went live in August of 2012 and we now have performance data for the first year. Achieve built this 25 kW Solar PV system with individual Enphase Micro-inverters for each of the 105 solar panels. The micro-inverters are designed to minimize impact due to shading. Micro-inverters also allow each solar panel to start producing electricity at the first sign of morning light. This maximizes solar PV production. Having each solar panel independent has great advantages over more common central inverters. Central inverters that connect solar panels like strings of old-style Christmas Tree lights — if one has a problem they all have a problem. Using standard industry software, the Tower School array was predicted to produce 28 mega-watt hours per year. In the first year, Tower School produced 32 MWh. That is over 14% more than predicted. Tower benefited with the extra 4,000 kWh produced and with an extra 4 Solar Renewable Energy Credits (SRECs). That’s about $1,550 in extra cash due to increased solar PV production. Was it the micro-inverters? Hard to say for sure. We do know using micro-inverters make monitoring and troubleshooting a breeze. The graph below shows solar PV production predicted for the Tower School array and the actual production. Not every month exceeded the predicted output. The lower winter half of the year (October to March) had several months with lower than predicted PV production. All of the summer half of the year (April to September) had higher output.

Chart showing monthly Actual and Predicted Solar PV Production at Tower School

New Incentive on the way for Geothermal and SHW

There is a new incentive coming and this is a big deal for a lot of our clients because it creates an income stream from their renewable energy systems! Explaining things is a little regulation wonky we’ll try to be brief. If you have read our website then you know that there are tax credits and sales tax exemptions for geothermal systems Geothermal Drilling Rigand solar hot water (SHW). The tax incentives are great but the renewable thermal options have lagged behind solar PV in some states like Massachusetts. Those installations also qualify for Solar Renewable Energy Credits (SRECs) which are traded on an open market and provide ten years of income for owners of PV systems. Now both Massachusetts and New Hampshire are poised to be issuing renewable energy credits for each MWh of renewable thermal energy generated.

In Massachusetts, Senate bill S. 1593 is working its way through the legislature. The bill would include renewable thermal sources in the Solar Hot Water ArrayAlternative Energy Portfolio Standard. Achieve was at a meeting this week with Massachusetts Senator Downing who is the Senate chair for the Joint House/Senate Telecommunications, Utility and Energy Committee. Based upon discussion at the meeting, S. 1593 seems to be in a good position to move forward this year. Once the bill is passed, MassDOER will modify regulations to integrate renewable thermal technologies into the Alternative Energy Portfolio Standard (APS). There is an active set of regulation and trading system for the credits so adding in the renewable thermal technologies should not be too big a task. Achieve has had some informal discussions with regulators and expects the revised regulations will include a cutoff date for entering the program, an eligibility term, metering requirements and may have differing rules for residential and commercial projects regarding how the AECs are minted. One option that may be considered is providing owners of smaller systems a number of years of AEC ‘up front’ to further offset installation costs.

So what does this mean for your wallet? continue reading →

September NEGPA Meeting at Achieve on 9/10/13

On September 10th, Achieve Renewable Energy, LLC.  is hosting the New England Geothermal Professionals Association (NEGPA) Board Meeting. The meeting will be from 6 to 8 PM. A light meal and beverages will be provided. If non-members are interested in attending, please contact us at 877-646-9922 and we will make arrangements.

You can find out more about NEGPA at


Rooftop Solar Array Enhances Curriculum at Tower School

Screen Shot 2013-08-21 at 9.10.05 PMTower School announces the completion of their rooftop solar array and the installation of electronic monitoring stations, which became fully operational during the 2012-2013 school year.

Board member, and driving force behind the solar program at Tower, Susan Livingston, expressed her commitment to the program, “As we try to move beyond burning fossil fuels as a nation, demonstrating the active use of renewable energy in schools sets a wonderful example for the community and our students. The new Solar Array can be a practical teaching tool for our children to learn more about our energy future.”

Head of School, Peter Philip agrees: “We are pleased to set an example for our students and for the community through the installation of this Solar Array. As well, we are eager to witness how our teachers and their students weave this commitment to renewable energy into the curriculum.”

The 105 solar module system was installed by Beverly MA-based, Achieve Renewable Energy, and is designed to supply more than 28,000 kilowatt-hours per year. Larry Lessard, director and founder of Achieve Renewable Energy, LLC says, “We’re proud to partner with Tower School in deploying a solar-electric system that will generate renewable, carbon-free power for decades. Our final phase is the installation of electronic monitoring stations within the science lobby, so the re- newable energy system can be integrated into the science program. To me that is the most gratifying part of the project.”

To learn more about Tower’s rooftop solar array, and to arrange for a personal tour, contact Tower School’s Business Manager, Dean Sidell, at 781-631-5800. For information about Tower’s culture of environmental stewardship, or to read about student-driven sustainability initiatives, visit