Better and Best: Energy Efficiency at Armory Park del Sol

More technologies used in the Zero Energy House
May 31, 2003
Typical Armory Park del Sol Home $333,000 for 1717 square feet
The Zero Energy Home $376,000 for 1717 square feet ($43,000 additional*)
User notes
Photovoltaic panels
1 kWh
3.5 kWh
BP Solar through Dankoff Solar and The Solar Store; SMA America (inverters)
Additional PV power accounts for most of the additional cost in the ZEH.
HVAC Equipment
Heat pump with 12 SEER cooling, 7.5 HSPF
An 18-SEER, 2-speed air conditioning system with variable speed air handler
The high-efficiency air conditioner in the ZEH takes ½ the usual energy to run; very quiet. Sized to run at low speed most of the time.
Water/space heating
A solar water heater only (with back-up provided by on-demand tankless water heater)
An innovative, integrated solar water and space heating system (with back-up provided by on-demand tankless water heater )
SunEarth Inc. (solar collectors); Seisco (tankless water heaters)
Of all the energy features in ZEH, the biggest additional installation cost. System is sized to provide all water and 80% of space heating needs.
Plumbing system for hot water supply
Copper plumbing supply buried in concrete slab
PEX plumbing lines for hot water supply
Manifold provided by Sioux Chief Manufacturing
Hot water lines run in conditioned space in ZEH.
Plumbing vents
Conventional through-the-roof plumbing vents
Air admittance vents (AAV)
Studor (AAV)
A break-even on cost: more for the AAV, but less on labor and roof vents. The elimination of roof penetrations is advantageous for the solar installation.
High efficiency windows
Double pane, low-e, vinyl, with argon (Windows have a low solar heat gain coefficient)
Double pane, low-e, vinyl, with argon
NAHB Research Center simulations showed Miller’s typical windows were compatible with ZEH requirements.
Roof decking
Standard OSB
Radiant barrier roof decking
Radiant barrier technology is advantageous in cooling climate.
Lamps and permanent fluorescent lighting fixtures
Incandescent lamps and ceiling fans. Permanent fluorescents in garage and kitchen.
Permanent fluorescent lighting used throughout house. Two-lamp fixtures provide half-dimming.
Nora Lighting; Osram Sylvania (lamps); Sun Lighting (supplier)
Super energy efficient bulbs and fixtures run an extra $2,800. Saves on cooling as well as running the lights.

In the ZEH, when possible, decorative lights were fitted with CFLs or supplied with dimmer switch.

Ceiling fans
Ceiling fans with light kits
Energy efficient ceiling fans without light kits
Emerson Fans
Fans without light kits may reduce inadvertent lighting energy use.
High efficiency appliances
ENERGY STAR qualified dishwasher, range and microwave/ ventilating hood combination
Additional ENERGY STAR® qualified appliances (refrigerator, washer, dryer)
The Duet front-loading washer will use about 1/3 of the water and energy of conventional washers
Bath fans
Standard efficiency fans
ENERGY STAR® qualified bath fans
High efficiency fans offer quieter operation as well as cost savings.

* Additional cost for a Zero Energy Home is based on aplan built with typical APdS specs. Cost does not reflect homeowner's Sunshare rebate of $5,000 for additional photovoltaics. Pricing reflects upgrade package (appliances, surfaces, fixtures, etc.).