GRADES HERS Index Targets
Energy Star - 5 Star+, Indoor Air Plus V3.0 <64-79*
1. ROSE BASE LEVELS <60
- ROSE Construction Method Building Envelope w/HRV
- 95% efficient, fuel-fired, heating plant and hot water systems
- Rough-ins for possible (future) geothermal, solar thermal, and solar PV additions
1a. ROSE Construction Method Building Envelope w/HRV <45
- 95% efficient, fuel-fired, hot water tank w/built-in heat exchanger
- Solar thermal panels (limited to domestic hot water needs)
- Air-Air Heat pump(s) or equivalent
1b. ROSE Construction Method Building Envelope+ w/HRV <30
- E-Max Hybrid™ whole house geothermal-solar system using:
- Water-Water or Water-Air Heat pump(s) or equivalent
- Solar thermal panels with dedicated solar storage tank and on-demand
(peaking) water heater
2. NEAR ZERO NET ENERGY
- ROSE Construction Method Building Envelope+ w/HRV <15
- E-Max Hybrid™ whole house geothermal-solar system using:
- Water-Water or Water-Air Heat pump(s) or equivalent
- Solar thermal panels w/solar storage tank, and on-demand (peaking) water heater
- Solar PV or other renewable power source for partial electrical offset
3. ZERO NET ENERGY
- ROSE Construction Method Building Envelope+ w/HRV < 0
- E-Max Hybrid™ whole house geothermal-solar system using:
- Water-Water or Water-Air Heat pump(s) or equivalent
- Solar thermal panels w/solar storage tank and on-demand (peaking) water heater
- Solar PV or other renewable power for total electric annual (zero net metering) offset
4. OFF-GRID OPERATION
- ROSE Construction Method Building Envelope+w/HRV <<0
- E-Max Hybrid™ whole house geothermal system w/expanded solar and thermal storage
- Water-Water or Water-Air Heat pump(s) or equivalent
- Expanded PV solar and/or other renewable power generation w/battery storage and back-up power generator
*Based on a published sample of 10 homes in climate zones 2, 3, and 4