Lawrence Berkeley National Laboratory

Direct Heating Equipment (DHE) is a category of ductless space heating appliances that supply heat directly to the space where they are installed. While DHE is the primary or secondary heating source in a non-negligible proportion of California households, its performance, installation, and operational characteristics remain poorly understood, as do the main barriers to adopting efficient DHE in the state. Inefficient DHE increases household energy costs, greenhouse gas emissions, and safety and health risks to users. We surveyed households with DHE in California. Results demonstrate that both homeowners and tenants are willing to invest in a new DHE unit to improve their thermal comfort and indoor air quality and reduce fuel costs and environmental impacts. It further shows that the primary barrier to more efficient DHE is their additional cost compared to baseline models. Monetary incentives and building codes that are more stringent can contribute to increasing the adoption of high-efficiency DHE in the state, increasing safety, reducing energy costs for consumers, and reducing greenhouse gas emissions in California.