Solar Water Heating for Multifamily and Commercial

Lewis Family Apartments Case Study

"Residents like the solar system – they never run out of hot water."

– Jeff Lewis, property owner

Solar Thermal by the Numbers

San Diego Apartment Uses Solar Hot Water to Save on Property Natural Gas Bill

Like most apartment building owners, the Lewises supplied their tenants with hot water for personal use and the shared laundry room as part of their lease agreements. Then they heard that a solar thermal system could provide savings on their property’s natural gas bill.

They were able to take advantage of California Solar Initiative – Thermal program rebates, federal tax credits and accelerated depreciation to decrease system installation costs and reduce on-site energy consumption.

Installation of the solar thermal system on the Lewis property included insulation of exposed piping, low flow aerators and shower heads installed in all units, and expansion tanks added to the hot water heaters. Building tenants appreciate reliable hot water, and the property owners are able to market the environmental aspects of their apartment complex when leasing vacant units.

The systems have an anticipated lifetime of 25 years and provide an annual energy cost savings of more than $2,500. As an added benefit, the energy saved reduces the property’s annual greenhouse gas emissions by 75%.

Property Profile

System Owner: Jeffrey and Marsha Lewis Trust

Location: San Diego, CA

Site and System:

  • 10 Units
  • 6 Solar Thermal Collectors (339 sq. ft.)
  • Year Installed: 2011
  • Contractor: Arnold Solar

Project Savings:

System cost: $35,520
Rebates: $12,641
1603 Grant: $10,655
Total out of pocket: $12,224
Annual energy savings ($1.14/therm): $2,410
Simple payback: 5 years