Hawaii First State to Require Solar Hot Water in New Homes

As of January 2010, new single-family homes in Hawaii must be equipped with solar thermal water heating in order to receive a building permit.

When this law was passed in 2008, roughly 25% of Hawaiians were using the sun to heat their domestic hot water (see EBN Aug. 2008). Tax credits of 35% and a $1,000 rebate were available while the systems were voluntary, but those incentives were phased out last month.

As of January 2010, new single-family homes in Hawaii must be equipped with solar thermal water heating in order to receive a building permit.

When this law was passed in 2008, roughly 25% of Hawaiians were using the sun to heat their domestic hot water (see EBN Aug. 2008). Tax credits of 35% and a $1,000 rebate were available while the systems were voluntary, but those incentives were phased out last month.

Critics take issue with the many exemptions that are available—in cases where solar access is limited, where the payback period would be longer than 15 years, where other renewables are used for water heating, or where a gas-fired tankless water heater plus one other gas-fired appliance are installed. That last exemption is expected to be monitored closely by environmental and solar thermal advocacy groups to guard against the possibility that it will lead to a rise in gas-fired tankless water heating.

– Andrea Ward