> By: The Cooling Company > Published: 2025-12-29 > Last updated: 2025-12-29
Geothermal radiant floor systems use a ground-source heat pump to warm water that runs through floor tubing. They deliver even heat from the floor up while running the heat pump at lower supply temperatures. Many homeowners see higher comfort and lower electricity bills compared to forced-air and resistance heat. (Source: Energy gov Heat Pump Tips)
Key Takeaways
- Radiant + GSHP works best with supply water near 95–110°F for many floor types.
- Expected GSHP seasonal COPs often fall in the 3.0–5.0 range.
- Typical installed cost for a single-family GSHP plus loops ranges roughly $25k–$60k.
What is a geothermal radiant floor system?
A geothermal radiant floor system brings heat from below ground into a home and spreads it through tubing in the floor. A ground-source heat pump exchanges heat with a buried loop. That loop moves heat into water, and the water circulates through PEX tubing in a slab or overlay.
Homes feel warmer at lower air setpoints with radiant floors because the floor radiates heat upward. These systems cut drafts and hot-air stratification. For many owners, the result is quieter, more even comfort with lower electrical use than electric resistance systems.
How does a ground source heat pump work?
A ground-source heat pump moves heat between the earth and a refrigerant loop. In heating mode the refrigerant picks up heat in the ground loop. The compressor raises refrigerant temperature and dumps heat into the hydronic side.
A reversing valve flips operation for cooling to move heat from the house to the ground. The ground acts as a stable temperature sink which helps efficiency. Proper refrigerant charge and correct pump flow are key to reliable operation.
What components make up the system?
A typical system includes the ground loop, a heat pump, circulating pumps, manifolds, and controls. PEX tubing runs in the slab or in a thin overlay and ties to a manifold. The heat pump connects to the loop and to the hydronic circuit. (Source: Energy gov Heat Pump Tips)
Some installs use buffer tanks to reduce short cycling and to stabilize water temperatures. Zone valves and thermostats give room control. Electrical work, backup heat, and desuperheaters can be added depending on needs.
Why pair GSHP with in-floor hydronics?
Ground-source heat pumps match radiant floors well because both run at low water temps. Radiant floors often need water at 85–120°F depending on finish. GSHPs deliver these lower temperatures while keeping high efficiency and a strong seasonal COP.
The floor mass stores heat and releases it slowly, cutting short cycling and smoothing indoor temperature swings. That steady output gives better perceived comfort. In many climates a GSHP plus radiant floor gives steadier winter performance than air-source systems.
How do slab versus subfloor installations differ?
Concrete slab systems embed tubing directly, which gives high thermal mass and slow, steady heat release. Slabs work great in new builds. They lower peak demand and can reduce required supply temperatures.
Subfloor or overlay systems heat faster because less mass is involved. Retrofits often use thin-slab overlays or timber systems to avoid major demo. These systems need closer tube spacing or slightly higher water temperature for the same output.
What water temperatures does radiant flooring need?
Most modern radiant floors work well with supply water between 85°F and 120°F. For best GSHP efficiency aim for 95–110°F near living areas. Tile and stone transfer heat well at lower temps while carpet or thick wood need warmer water or closer tube spacing.
Designers pick tube spacing and supply temperature by floor finish and room load. Typical PEX spacing runs 6 to 12 inches. Denser spacing raises heat output for a given water temperature and helps meet design loads.
How are ground loops installed?
Ground loops come in horizontal trenches, vertical boreholes, or open groundwater systems. Horizontal loops need yard space and trenches about 4–6 feet deep. Vertical bores drill 100–400 feet per bore and work where surface space is tight.
Open-loop groundwater systems pump water through a heat exchanger and return it to the source or drain. They can be cost-effective when water quality and local rules allow. All loop types need proper sizing and permitting for long-term performance.
What loop types exist and which suits my site?
Horizontal loops cost less in labor but need more land area. They fit rural lots and new construction when space is available. Vertical loops save surface area and are common on small lots in urban zones. [Point 1] (Source: Energy gov Heat Pump Tips)
Open-loop systems can be cheaper but need a stable, clean groundwater source. Local permitting and water treatment often apply. A site survey and soil or bore report guide the best loop choice.
How do soil and geology affect loop design and cost?
Soil thermal conductivity sets the loop length needed per ton of heating. Clay and rock tend to conduct heat better than dry sand, which can cut loop length. Drilling into rock can raise per-foot costs even if loop length falls.
Fractured rock, high groundwater, and shallow bedrock change drilling methods and costs. Geotech or thermal conductivity testing often improves loop sizing accuracy. Buyers should ask for the soil or bore report used to size the loop.
How much does installation cost?
Installed cost depends on loop type, drilling depth, equipment size, and retrofit complexity. For single-family homes expect full GSHP systems with loops to fall between about $25,000 and $60,000 in many regions. Vertical bores drive the high end on small lots.
Radiant floor work adds cost too. New-slab installs keep per-square-foot costs lower when coordinated with construction. Retrofits using overlays often cost more per square foot because of demo and added materials. Always ask for itemized bids.
What drives GSHP system price?
Major cost drivers include drilling or trenching, heat pump model, and labor hours. Drilling rigs and bore depth can add tens of thousands for vertical fields. Larger heat pumps and higher-efficiency models also add upfront cost.
Permits, geotech studies, electrical service upgrades, and landscape restoration add to price. Manifolds, circulators, and control systems also matter. Ask contractors to separate loop costs from equipment and labor for clear comparison.
What incentives and rebates apply?
Federal tax credits often apply to geothermal heat pump equipment. State and local programs, utilities, and some municipalities add rebates or loan programs. Incentive levels change, so check current listings before signing a contract.
Many incentives require certified installers or specific equipment ratings. Keep all invoices and equipment specs to claim credits. Contractors familiar with GSHP installs can often help you find and file for rebates.
How efficient is GSHP with radiant floors?
GSHPs paired with low-temperature radiant floors tend to reach high seasonal COPs. Typical residential seasonal COPs run between 3.0 and 5.0. Lower supply water temperatures and stable ground temps push COP higher. [Point 2] (Source: Energy gov Heat Pump Tips)
Seasonal performance depends on loop sizing, ground conditions, and controls. Oversized systems can short cycle and lower efficiency. Proper commissioning ensures flow rates and controls deliver design COP across seasons.
What COP and performance numbers are typical?
Most well-designed GSHP systems show seasonal COPs from 3.0 to 4.5 under real loads. In good soil and with proper loop length, some systems approach COP 5.0 in moderate climates. COP is heat output divided by electrical input.
Keep in mind that COP varies hourly with load and ground temps. Design focus is on maximizing average seasonal COP rather than peak numbers. Ask installers for modeled seasonal performance based on your Manual J.
What maintenance keeps efficiency high?
Annual service keeps heat pumps running near rated efficiency. Have a qualified tech check refrigerant charge, electrical connections, and compressor health. Verify pumps, flow rates, and manifold operation each season.
Inspect loop fluid for correct freeze point and check for pressure drift. Clean or replace filters and strainers on circulators. Keep a log of maintenance and commissioning reports to track trends over years.
How to choose a contractor?
Pick a contractor with specific GSHP and radiant experience. Look for IGSHPA training or NATE certification and recent project photos. Ask for written references and commissioning reports from similar installs.
Get at least two detailed bids and compare itemized costs. Ask that bids include loop design assumptions, expected COP, and a commissioning plan. Avoid very low bids that lack clear design or warranty details.
What questions should I ask installers?
Start by asking how they size the loop and heat pump. Request expected seasonal COP and a sample Manual J load. Ask which equipment models they prefer and why, and which warranty terms apply.
Also ask who will handle permits, which subcontractors they use, and how they document commissioning. Clear answers about timeline, payment schedule, and service response times reduce surprises.
How to compare bids fairly?
Make sure bids use the same design basis and equipment specs. Request itemized costs for loops, heat pump, manifolds, pumps, controls, permits, and restoration. Confirm assumptions on bore depth and soil conductivity. [Point 3] (Source: Energy gov Heat Pump Tips)
Compare value instead of price alone. A higher bid with a clear design and long warranty often saves money over time. Ask bidders to include modeled energy savings and expected payback years.
What warranties and guarantees matter?
Look for multi-year warranties on compressors and heat exchangers. Manufacturer warranties often cover core components while contractors cover labor for a specific time. Get everything in writing.
Clarify who is responsible for loop failure, drilling damage, or missed performance targets. A commissioning report tied to warranty acceptance helps protect you if issues arise after install.
How to verify system commissioning?
A full commissioning report shows measured flow rates, supply and return temps, refrigerant charge, and measured COP during test runs. It confirms control logic, zone operation, and safety interlocks. Insist on a report before final payment.
Testing should include flow verification for each loop and zone, plus a check of mixing valves and thermostats. Save the report with warranty docs. A good report makes future service and resale simpler and safer.
How long does installation take and what disruption should I expect?
Most residential installs take from two to six weeks once permits are in place. Horizontal trenching and radiant pours can be done in days, while vertical drilling may take several days per bore plus mobilization time. Commissioning adds a few days at the end.
Expect yard disruption during trenching or drilling and some heavy equipment on site. Contractors should give a clear schedule and restore surfaces after work. Plan interior work around slab pours or overlay installs.
How to maintain and troubleshoot systems?
Routine checks prevent big failures. Inspect manifolds, pumps, and valves for leaks. Confirm loop pressure and antifreeze concentration annually. Track energy use and room temperatures to spot drops in COP early.
If a room stays cold, check thermostat settings and zone flows first. Look for pump noise, trapped air, or faulty zone valves. Electrical anomalies or rising energy use may signal compressor or refrigerant issues that need a pro.
Ready to start?
If you live in Las Vegas, Henderson, or North Las Vegas, call The Cooling Company at 17029308411 for a GSHP and radiant floor consultation. They perform site surveys, Manual J loads, loop coordination, and full radiant installs. Ask for local references and a detailed commissioning report.
Outside the Las Vegas area, look for contractors with IGSHPA training or NATE certification. Find NATE at natex.org to verify credentials. If you plan a project in our area, The Cooling Company handles permits, installation, and warranty work in Las Vegas, Henderson, and North Las Vegas.
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About The Cooling Company
- Phone: 17029308411
References
- U.S. Department of Energy (Energy.gov) (accessed 2025-12-29)
- U.S. Environmental Protection Agency (EPA) (accessed 2025-12-29)
- ASHRAE (Standards and guidance) (accessed 2025-12-29)
- ENERGY STAR (Heating & cooling) (accessed 2025-12-29)