The average installed system cost is $6,600 to $9,000
before any federal, state or local incentives.
But depending on where you live, incentives
can offset a large fraction of the cost.
SOLaR WateR-HeatINg SySteMS By tyPe
Common Name (type)
Working Fluid Number of Pumps
Heat exchanger
Freeze tolerance
integrated collector storage (1)
city water
None
None
No Hard Freeze
Open Loop drain down ( 4)
water
One Pump, Low Pressure
None
mild; must Use Power
closed Loop ( 6, 7, 8, 9)
antifreeze
One, Low Pressure
double wall in tank
Very Hard Freeze
drain back closed Loop ( 5)
water
One, High Pressure
None
moderate Freeze
integrated thermosiphon ( 2, 3)
city water
None
None
Hard Freeze; dole Valve
spills water
closed Loop ( 10)
antifreeze
two Pumps, Low Pressure
double wall
Outside tank
Very Hard
Pressure Relief /Vacuum Recovery
Valve (Auto Radiator Cap) Radiator
Overflow
Flat Plate
Solar
Collectors
Sensor
P Pressure
Gauge
Flo w Gauge
Glycol Fill
Check Valve Sensor
Glycol
Drain
Glycol
Pump
Glycol Solution in Loop
Differential
Controller Coldin
from House
Cold in
Shut Off
T&P Hotout
to
Valve House
Mixing
Valve
VALVE KEY
GlycolLoop Open Drain Conventional
Water Heater
Closed
closed Loop Low Pressure, 16 psi,
internal “screw-in” Heat exchanger
T&P
Valve
Sensor
Drain
Solar Storage
Tank
external wraparound
Pressure Relief /Vacuum Recovery
Valve (Auto Radiator Cap) Radiator
Overflow
Flat Plate
Solar
Collectors
Sensor
Glycol Solution in Loop
Differential
Controller Coldin
from House
Cold in
Shut Off
T&P Hotout
Valve to House
Mixing
Valve
P Pressure
Gauge
Flo w Gauge
Glycol Fill
Check Valve Sensor
Glycol
Drain
Glycol
Pump
DHW Pump
VALVE KEY
GlycolLoop Drain Conventional
Open Water Heater
Closed
closed Loop Low Pressure, 16 psi,
Pumped external heat exchanger, 1 tank
