Dual-Fuel HVAC Solutions for Homes

Think of a dual-fuel HVAC system as an equivalent to a hybrid car – a more energy-efficient alternative, yet one that may leave you stranded. The equivalent to not having a charging station available is not having sufficient backup heat for an electric heat pump on a subzero winter night. These are the calls no contractor wants. Nor do they want unhappy clients who are facing high electricity bills when temperatures drop or when cooling in markets with time-of-use electrical rates. Simply put, a dual-fuel HVAC solution makes sense for contractors who are basing their business model on delivering building performance and quality.

By “dual-fuel” we typically mean an integrated system consisting of two different appliances using two different fuels. All of these systems are using an electric heat pump that is integrated … or installed in parallel .. with a propane or gas-burning appliance

A lot of HVAC contractors still believe heat pumps are ill-suited to cold climates. But as engineer John Siegenthaler, who operates Appropriate Designs, a building systems engineering firm in Holland Patent, N.Y. explains, much of that thinking is left over from experiences with first-generation heat pumps that have been displaced for almost two decades ago by better technology. Specifically, heat pumps using  variable-speed (aka inverter-drive) compressors and enhanced vapor-injection have extended the range for efficient heat output, and this newer technology has become standard in many cold-climate markets for both air-to-air and air-to-water heat pumps. Even with these advanced systems, output will drop off when outdoor temperatures drop below 0 degrees F. And no matter where you live in North America, it’s likely that over  the next decade, as electric utilities transition to a higher capacity grid necessary to meeting increasing electricity demand, dual-fuel HVAC won’t just be nice-to-have; it will be a must-have for contractors who want to deliver better performance and resilience to their customers.

In this Building Session, Editor-in-Chief Clayton DeKorne sits down with John Siegenthaler and Armistead Mauck, a consultant with Propane Education & Research Council (PERC) to explore the why and how of implementing hybrid, or dual-fuel, HVAC in homes. The discussion offers practical guidance on

• When and why dual-fuel HVAC makes sense for contractors concerned with delivering comfort to homeowners
• How today’s electric utility pricing is affecting heating and cooling costs
• Selecting heat pumps for cold climates and low-load homes
• Practical and low-cost applications for retrofitting dual-fuel systems into homes
• How to set customer expectations for the cost and performance of dual-fuel systems
• Recognize electric-grid vulnerabilities and the need for resetting timelines for state and municipal energy policies
• Realizing cost efficiencies from switching fuel-types (seasonally and daily, depending on utility price structures)

This JLC Building Session is underwritten by Propane Energy and Research Council (PERC).