SunEarth Empire collectors are the brand\'s value-engineered flat-plate solar thermal collector lineup. Empire collectors deliver competitive solar performance at slightly lower cost than premium options, making them well-suited for budget-conscious residential solar water heating installations.
Empire collector specifications
- Empire EP-32: 4-foot x 8-foot collector, ~32 sq ft absorber area, daily heat output 25,000-35,000 BTU in good sun
- Empire EP-40: 4-foot x 10-foot, ~40 sq ft absorber area, daily heat output 32,000-45,000 BTU
Sizing matches household demand: EP-32 for 1-2 person residences, two EP-40 collectors for typical 4-person households.
Construction features
- Selective surface absorber plate: high-absorptivity black coating maximizes solar heat capture
- Copper riser tubes: efficient heat transfer from absorber to circulating fluid
- Tempered low-iron glass cover: high solar transmission, hail-resistant
- Aluminum frame: corrosion-resistant, robust mounting
- EPDM gasket seals: long-life weather sealing
- Mineral wool insulation: reduces back-of-collector heat loss to ambient
Empire vs SunEarth ThermoRay (premium tier)
SunEarth offers two flat-plate collector tiers:
- Empire (value tier): standard absorber plate efficiency, competitive pricing
- ThermoRay (premium tier): higher-performance absorber, optimized geometry, premium pricing
Performance difference is meaningful but not dramatic — Empire delivers 85-90% of ThermoRay performance at typically 15-25% lower cost. For most residential solar DHW installations, Empire is the cost-effective choice.
Empire vs Heliodyne Gobi
The two dominant US flat-plate collector brands. Comparison:
- Empire: SunEarth\'s value-tier collector, slightly broader US distribution
- Gobi: Heliodyne\'s flagship collector, slight efficiency edge in independent testing
Both are credible US-manufactured collectors at similar warranty terms. Choose by local installer preference and dealer availability — these are commodity products at the residential solar thermal tier.
Mounting and orientation
Optimal Empire collector orientation:
- Azimuth: due south (within ±30 degrees acceptable)
- Tilt angle: latitude angle (35° in San Francisco, 40° in Denver)
- Mounting: roof rack, ground rack, or pole mounts per site conditions
- Shading verification: no shading during midday sun hours (10 AM - 4 PM)
SunEarth provides mounting hardware for various roof types. Professional installation strongly recommended for roof mounting — improper flashing causes leaks that exceed any solar savings.
Pairing with SunEarth storage tanks and controllers
Empire collectors pair with SunEarth solar storage tanks and differential controllers in complete SR-Series pre-engineered systems. Compatible with other brand solar storage tanks (Vaughn SS, Heliodyne, Wessels) if controller and pump sizing are properly matched.
Performance expectations
A typical residential solar DHW system (two Empire EP-40 collectors + 80-gallon solar storage tank) provides:
- 60-80% of annual residential hot water in good solar locations (Arizona, southern California, Florida, southern Texas)
- 40-60% solar fraction in northern climates (Pacific Northwest, New England, Great Lakes)
- 20-40% solar fraction in worst-case scenarios (heavily-shaded sites, persistently cloudy regions)
Glycol system maintenance
Closed-loop Empire installations use propylene glycol antifreeze in the collector loop:
- Glycol degrades over time (typically 5-8 years), losing freeze-protection capability
- Schedule glycol replacement every 5 years
- Verify glycol concentration and pH at least annually
- Acidic byproducts from glycol degradation can corrode pipes and pump components
Lifespan
Empire collectors carry 10-year manufacturer warranty and typically last 20-30+ years in service with proper maintenance. Common failure modes after year 15:
- Gasket degradation (allowing water entry into collector housing)
- Glass damage from severe hail or impact
- Absorber plate degradation (rare with proper glycol maintenance)
Pre-engineered system option
Empire collectors are commonly sold as part of SunEarth\'s SR-Series pre-engineered solar DHW kits. Buying as a complete system simplifies design and installation vs assembling components individually. For most residential installations, the SR-Series kit is the practical choice.
Federal tax incentive
Empire collector solar DHW systems qualify for the federal 25D Residential Clean Energy Credit — 30% of total installed cost through 2032. For a $5,500 installed Empire-based system, the credit returns $1,650 — effectively lowering the system cost to $3,850. Many states and utilities offer additional rebates.
Honest assessment
Empire collectors deliver competent residential solar thermal performance at value pricing. They\'re not exceptional — ThermoRay or Gobi collectors deliver slightly more energy per square foot — but the performance-per-dollar pencils out well for most residential installations. For homeowners prioritizing maximum solar capture in space-constrained roof areas, the premium options pay back; for everyone else, Empire is the practical choice.
Service and warranty
Empire collector warranty service routes through SunEarth direct or authorized solar installers. The collector itself rarely needs service during typical lifespan — most service events relate to the broader system (controller, pump, glycol, expansion tank) rather than the collector.