Using Hydronic Radiant Floor Heating with a Water-to-Water Geothermal Heat Pump

Water-to-water geothermal heat pumps work great with correctly designed hydronic radiant floor systems. The temperature of the air in the home will be warmer at the floor, and cooler as you rise toward the ceiling, which is unmatched for heating comfort. This also reduces the heat loss through the ceiling and upper walls. Because of this lower heat loss, and because a water-to-water geothermal heat pump has lower operating temperatures, these systems have the highest efficiencies and energy savings of any active heating system. The only drawback to these systems is their higher cost of installation.

Many people ask us if they can replace their fossil fuel-fired boiler with a water-to-water geothermal heat pump. This can be done, but only if the existing piping or radiator system is designed for it. Most hydronic systems are sized for the very high water temperatures of a fossil fuel boiler (typically between 140 and 180°F), meaning they have a relatively small amount of surface area in the piping or radiators. A water-to-water geothermal heat pump operates at much lower temperatures (between 90 to 120°F). This makes it more efficient (COPs are often over 5), but requires more heat transfer surface area. If a geothermal hydronic heating system is not designed right, it will be unable to fully heat your home during the coldest parts of the heating season. To prevent this problem, your boiler system must be evaluated correctly to determine if it can be used with a water-to-water geothermal heat pump.

Water-to-water geothermal heat pump systems also need certain parts that are usually lacking in fossil fuel-fired boiler systems. Buffer tanks, certain types of controls, and air handlers might need to be added, for proper operation with a water-to-water geothermal heat pump. If you install an air handler with your water-to-water heat pump, you can also cool your home in the summer months, using the same geothermal heat pump.

Hydronic / Radiant Design includes:

• Size and length of your radiant heat circuits, including manifolds and locations, with LoopCAD pipe layout drawings.


• Radiant mechanical panel and piping drawings (with layout optimized to save space), including geothermal load pump and buffer tank type and sizing, pipe sizing, zone pump and zone valve selection, air eliminator and expansion tanks, shutoffs and drains for flushing, and all other parts for proper operation of a radiant heat system.
  Cooling designs include air handler units, pumps, and piping design.


• Radiant system wiring schematics, including geothermal low-voltage controls, geothermal load pumps, aquastat controller, zone pumps, zone controls, and thermostats.
  Cooling designs include all wiring for air handlers and relays for seasonal changeover.


• Programming instructions for your aquastat controller, geothermal heat pumps, and thermostats, for maximum efficiency using outdoor reset and correct differentials.


• Links to online sellers for all specialty parts, including pumps, valves, controls, and air handlers.


• Installation instructions and support by email and phone as with our other design packages.

We can correctly design every part of a hydronic radiant system for any application, whether you are upgrading an existing system, adding a system, or designing a system for your new home. Most heating-only radiant designs with up to six zones will cost $2,600.00 USD. Let us know what you'd like to build and we'll confirm a quote!