Status of Solar Heating/Cooling and Solar Buildings - 2012

Status of the Market for Solar Thermal Systems

Market Size and Trends

The market size for solar water heaters (SWHs) in the U.S. is about 1% of the total residential and commercial water heating market. The size of the SWH market has been growing, and the compound annual growth rate between 1992 and 2008 was 6%. Recently, due to incentives in states like California, North Carolina, and Massachusetts, the installation of commercial SWH systems has been increasing. The market is expected to continue to grow at least through 2016, when the 30% federal tax credit is set to expire.

Typical Applications and Products

The main residential applications are domestic hot water and pool heating. Pool heating makes up about 85% of the market (by collector area), and the remaining market is made up of domestic hot water systems. By number of systems, domestic hot water makes up about 55% of installed systems, and pool heating makes up ~45%. The most typical domestic hot water system is a pumped, indirect system that uses glycol. A typical residential system is about 4.6 m2 and has a 300l tank.

Main Market Drivers

The main market driver is incentives. In the 1970s and 1980s, the U.S. saw a significant national market for SWHs, partly in response to the energy crises and partly because of a 40% federal income tax credit coupled with individual state incentives. Sales peaked at about 180,000 SWH systems in 1984, just before the end of federal tax credits, representing almost 2% of the total number of WHs installed that year. In 2006, a federal investment tax credit was passed, and sales have recently increased again. The key barriers in the U.S. are the cost of an installed system, the relatively low price of natural gas, and lack of consumer awareness.


There is a domestic manufacturing base, but the number of imports has increased over the past few years. Imports make up ~25% of SWH shipments and exports make up about 10%. Most systems are marketed using a three-tiered structure: to wholesalers, who sell to installers, who sell to consumers.


In 2010, the National Solar Jobs Census found that the solar industry supported 100,000 jobs in the U.S. This includes the solar heating/cooling section, but also includes the PV sector.


The cost of installing a domestic SWH ranges from $5,000 to $10,000, depending on system type and size.

Other Key Topics

The aesthetics of the collector is a key issue in the U.S. Roof mounted collectors are expected to blend well with the roof and look aesthetically pleasing. Freeze and overheat protection are also key issues. Almost all of the continental U.S. has a high likelihood of experiencing freeze conditions at some point during the system lifetime, and since system reliability is a requirement for SWH systems in the U.S., freeze protection is important. Overheat caused by stagnation conditions can also impact system reliability. Therefore, overheat protection is another key issue in system design.

Status of the Market for Solar Buildings


Energy efficiency is a focus for buildings in the U.S., which is evident in popular home rating certifications such as LEED and ENERGY STAR homes. Solar is a piece of the energy-efficiency puzzle, but is not usually the main component. Passive homes do exist, but in a niche market. Daylighting is recognized as important in the commercial sector, but is less of a focus on the residential side. Photovoltaics are the focus of major cost cutting efforts and are expected to become a competitive solution in the near future.

Market Size and Trends

The market for new homes is on target to be 373,000 for 2012. This is up from 2011, which was the worst year on record with 307,000 new homes built. New home sales are expected to rise in the coming years as the U.S. economy continues to recover. The new home sales in a healthy economy are ~700,000.

Main Market Drivers

The main driver for energy-efficient homes is reduced operational cost. Although energy prices are reasonable right now, it is generally believed that fuel prices will rise in the near future. Buying a home that uses less energy to operate is therefore an appealing idea to homebuyers. Low awareness is an issue, but energy efficiency in homes is becoming more wide-spread and is generally looked upon favourably by homebuyers.


All solar related jobs are rolled into the 100,000 jobs number previously mentioned.


Passive solar homes are estimated to cost between 6% -12% more than a conventional home.

Other Key Topics


R&D Activities

R&D Infrastructure

R&D Institutions
Institution Type of Institution Relevant Research Areas IEA SHC Involvement Website
NREL Research Institute Solar Heating & Cooling Task 43 , Task 39
NREL Research Institute Building America Program No
FSEC Research Institute Solar Thermal Technologies Task 43

Actual Innovations

The U.S. has introduced various flat-plate, ICS, and pool heater designs. Current innovations are focused on low-cost SWHs made of polymer thin-films, storage in the form of liquid desiccants, and combining solar with heat pump water heater technologies.

Support Framework


The United States Department of Energy (DOE) has goals and strategies that are directly related to energy, renewables, energy efficiency, and climate change and are relevant to solar thermal. Specifically, energy savings from solar thermal technologies will directly contribute to DOE’s strategic goal to “catalyze the timely, material, and efficient transformation of the nation’s energy system and secure U.S. leadership in clean energy technologies.” SWHs will also help DOE reach their target to “reduce energy-related greenhouse gas emissions by 17% by 2020 and 83% by 2050, from a 2005 baseline” (taken from DOE’s strategic plan, released in May 2011).

Government Agencies Responsible for Solar Thermal, for Solar Building Activities

The main agency is the U.S. Department of Energy.

Most Important Public Support Measure(s) for Solar Thermal and for Solar Buildings

The U.S. has both federal and local incentives for solar thermal technologies. The federal tax credit for solar thermal is 30% and is set to expire at the end of 2016. Local incentives vary by state, but include state run loan and rebate programs, utility run loan and rebate programs, financing options, and other incentive programs.

Currently, there is no regulation that requires the use of solar in new buildings.

Information Resources

National Solar Associations (industry and non-industry)

American Solar Energy Society (ASES) -

Solar Electric Power Association (SEPA) -

Solar Energy Industries Association (SEIA) -

National Associations on Green/Solar/Sustainable Buildings

American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) -

U.S. Green Building Council (USGBC) -

National Association of Home Builders (NAHC) -

Most Important Media for Solar Thermal and Solar Buildings

Utility Solar Water Heating Initiative (USH2O) -

Solar Thermal Advantage --