- What the Nine Content Areas Actually Represent
- Legacy Status and Why It Shapes This Guide
- Domains 1-3: The Foundations
- Domains 4-6: The Design Core
- Domains 7-8: Site Conditions, Heat Pumps and Piping
- Domain 9: Economics of Design
- Sequencing the Nine Areas Into a Study Plan
- Existing Holders: Renewal Mechanics
- Frequently Asked Questions
- CRD means Certified Residential Geothermal Designer, issued through the International Ground Source Heat Pump Association (IGSHPA).
- The nine headings come from a historical course listing, not a current weighted exam blueprint.
- Load calculations, site and soil parameters, and heat pump and pipe design form the technical core.
- New-candidate availability is on hold until a current issuer-approved legacy offering is verified.
What the Nine Content Areas Actually Represent
The Certified Residential Geothermal Designer credential from IGSHPA is built around residential ground source heat pump (GSHP) design. The nine content areas covered in this guide are the preparation-topic headings that appeared in IGSHPA's historical listing for its Certified Residential Geothermal Designer course delivered online with HRAI. They map the territory a designer is expected to understand, from why a homeowner would choose geothermal to how the economics of a finished design are justified.
If you are new to the credential itself, start with our explainers on what CRD certification is and what CRD stands for, then return here for the content-area breakdown. For a broader preparation framework, see the CRD study guide.
Legacy Status and Why It Shapes This Guide
Before you invest study hours, you need to understand where this credential sits today. IGSHPA's White Paper 251229 (revision 260114, dated January 14, 2026) addresses the sunsetting of its legacy training courses and certifications. The paper reports that normal legacy training was to be replaced by the end of 2025.
| Situation | What the sources indicate |
|---|---|
| Active CRD holders | May continue renewing indefinitely with required continuing education, provided the certification does not lapse |
| Lapsed CRD holders | IGSHPA's FAQ states lapsed legacy credentials cannot be reinstated |
| New candidates | Legacy courses are considered case by case and offered only when a utility, state, or provincial program requires them; availability is unverified |
| GRSD examination | A separate, optional upgrade path, not an automatic renaming of CRD |
One conflicting signal exists: HRAI's 2025-26 course schedule advertised a virtual CRD course for February 24-26, 2026. A past schedule does not prove the course ran or that enrollment is open today, so confirm directly with IGSHPA before planning around it. Our CRD requirements guide and CRD exam dates guide track how eligibility and scheduling questions apply.
Domains 1-3: The Foundations
The first three areas establish the vocabulary and equipment knowledge on which every later calculation depends. Candidates who rush through them often struggle later, because the design questions assume fluency with these basics.
Domain 1: Ground Source Heat Pump Benefits
This area covers why GSHP technology is chosen over conventional heating and cooling, and how a designer communicates that value to a homeowner.
- How using the ground as a heat source and sink affects efficiency
- Comfort, operating-cost, and environmental arguments for geothermal
- Realistic framing of benefits versus installed cost, which connects forward to Domain 9
Domain 2: System Components
Designers must be able to name, locate, and explain the function of every major piece of a residential GSHP system.
- The heat pump unit, ground loop, circulating pumps, and flow centers
- How the indoor distribution side (ductwork or hydronic) interacts with the loop
- The role of controls and accessories in a complete installation
Domain 3: Heat Pump Types
Not all ground source heat pumps are the same, and selecting the wrong type undermines a design before any loop is sized.
- Water-to-air versus water-to-water equipment and where each fits
- How the type of distribution system influences equipment choice
- Matching equipment characteristics to the home's heating and cooling needs
Why these three come first
Heat pump selection (Domain 3) and component knowledge (Domain 2) reappear inside the later design and piping questions. If a question asks you to size a loop, it silently assumes you already know which equipment it serves. Build this base first, then move to the design core.
Domains 4-6: The Design Core
Domains 4 through 6 are where the credential earns its name. This is the "designer" part of Certified Residential Geothermal Designer: a repeatable process that begins with the building and ends with numbers you can defend.
Domain 4: Design Process
This area is about order of operations. A competent designer follows a sequence rather than jumping straight to loop length.
- Gathering site and building information before any calculation
- Moving from load determination to equipment selection to loop design
- Documenting assumptions so the design can be checked and revised
Domain 5: Energy Requirements
Here the focus shifts from the building's peak demand to its annual energy behavior.
- How seasonal energy use differs from peak load
- The relationship between equipment efficiency and operating consumption
- Energy figures that feed the economic comparison in Domain 9
Domain 6: Load Calculations
Load calculation is the numerical foundation of the whole design. An error here propagates into equipment size, loop length, and cost.
- Heating and cooling load determination for a residential structure
- The inputs that move a load figure: envelope, infiltration, climate, and internal gains
- Why oversizing and undersizing both create performance and cost problems
Because the downstream numbers all depend on the load, many candidates find this stretch the most demanding part of preparation. Our difficulty guide discusses how quantitative content affects the overall experience, and the CRD cheat sheet condenses the must-know relationships into a quick review.
Domains 7-8: Site Conditions, Heat Pumps and Piping
The last two technical areas turn the abstract design into something that works on a specific lot, in specific ground, with specific hardware.
Domain 7: Parameters That Affect Heat Pump Performance, Site, Geology and Soil Conditions
This is the longest-named heading in the list, and for good reason: it spans how performance varies across heat pump types and how the ground itself changes the design.
- How soil and rock thermal properties influence loop length
- Site constraints that favor one loop configuration over another
- Moisture, groundwater, and geology as inputs to a defensible design
- How entering fluid temperature affects equipment output and efficiency
Domain 8: Heat Pump and Pipe Design
Here the designer brings equipment and loop together into a hydraulically sound system.
- Pipe sizing, flow rates, and pressure considerations
- Selecting and matching the heat pump to the loop design
- Layout decisions that affect installation practicality and long-term reliability
The interaction between Domains 7 and 8
These two areas are inseparable in practice. Ground conditions from Domain 7 determine how much loop you need; Domain 8 determines how that loop is plumbed and matched to the heat pump. A question that looks like a piping problem may hinge on a soil assumption, and vice versa. Study them as a pair.
Domain 9: Economics of Design
The final area closes the loop between engineering and the homeowner's decision. A technically excellent design that cannot be justified financially rarely gets built.
Domain 9: Economics of Design
Candidates should be able to evaluate a GSHP installation as an investment, not just as a mechanical system.
- Comparing installed cost and operating cost against conventional alternatives
- Understanding how design choices change both first cost and long-term savings
- Presenting economic results honestly, using the energy figures from Domain 5
Economics also connects to career questions. If you are weighing the credential against its costs and market value, our ROI analysis, cost breakdown, and earnings analysis take that thread further, and CRD jobs covers the kinds of roles where residential geothermal design skills apply.
Sequencing the Nine Areas Into a Study Plan
Generic scheduling advice matters less than ordering the content correctly. Because later domains depend on earlier ones, a dependency-based sequence works better than studying in whatever order feels comfortable. Here is one way to stage the material over six weeks, adjustable to your own background.
Foundations: Domains 1-3
- Learn the benefits case and the full component list
- Compare heat pump types and what each pairs with
Process and Energy: Domains 4-5
- Memorize the design sequence from building data to loop
- Separate peak load thinking from annual energy thinking
Load Calculations: Domain 6
- Work multiple residential examples end to end
- Change one input at a time and trace the consequences
Site and Piping: Domains 7-8
- Study soil and geology effects alongside loop and pipe design
- Connect entering fluid temperature to equipment performance
Economics and Review: Domain 9
- Build a simple cost comparison using your own earlier design
- Revisit your weakest earlier domain
Load calculations get two weeks because every later domain inherits their output. For question practice that mirrors this structure, use the main practice test site, and see the CRD study guide for deeper preparation tactics.
Key Takeaway
Study in dependency order, not interest order. Domain 6 feeds Domains 7, 8, and 9, so a weak load-calculation foundation quietly damages your performance across the entire back half of the material.
Existing Holders: Renewal Mechanics
For many readers, the practical question is not how to pass but how to keep an existing credential alive. IGSHPA's renewal policy, effective January 1, 2024, offers one-, two-, or three-year renewal terms. The fees below are renewal charges, not initial exam fees.
| Item | Detail |
|---|---|
| Member renewal rate | $75 per year |
| Non-member renewal rate | $225 per year |
| Term options | One, two, or three years |
| CEU requirement | Documentation required for processing; IGSHPA describes eight CEU points per three-year cycle, not eight classroom hours |
| Membership requirement | The membership term must cover the discounted certification-renewal term |
| Individual membership | $125 per year for currently employed professionals; unnecessary if covered by an eligible business, community, or utility membership |
Holders who want to move beyond the legacy credential may consider the separate GRSD examination. That is an optional upgrade path with its own objectives and rules, which are not covered here and should not be assumed to mirror CRD content. For orientation on the credential's identity, see CRD meaning and CRD training.
Frequently Asked Questions
No. They are historical preparation-topic headings from an IGSHPA course listing. No current legacy-exam weighting, question count, time limit, or passing mark has been verified, so no domain can be called the highest weighted.
Without an official weighting, base this on your own gaps. Most candidates find load calculations and the site, geology, and soil parameters the most demanding because later design and piping work depends on them.
New-candidate availability is unverified. IGSHPA considers legacy courses case by case, typically when a utility, state, or provincial program requires them. Confirm directly with IGSHPA before assuming you can enroll.
Current renewal products are $75 per year for members and $225 per year for non-members, in one-, two-, or three-year terms. CEU documentation is required, and the membership term must cover the discounted renewal term.
No. The GRSD examination is a separate optional upgrade path, not an automatic renaming or replacement of the CRD credential.
For pass-rate and scoring questions, see our pass rate analysis and passing score guide, which explain what can and cannot be verified. When you are ready to test your recall across all nine areas, head to the CRD practice test platform.