Residential Multizone Air Distribution — An Energy Savings Opportunity?

CARD webinar

March 22, 2022 | 11 a.m. to noon

Online

Host
Minnesota Department of Commerce, Division of Energy Resources
Event Description

Join this webinar to learn more about these results and whether and how multizone systems might be utilized in Minnesota to save energy and improve comfort.

Unlike commercial buildings in which heating and cooling is often optimized by zone, most Minnesota homes have forced air distribution systems with constant flows to all branches or zones. The entire house is heated or cooled based on the needs of the space where the thermostat is located. Nonuniform solar gains, internal gains, and air infiltration loads that vary throughout a day or season result in areas of the house that are over- or under-heated and cooled. This can result in uncomfortable conditions and potentially wasted energy. Residential multizone systems are available to address these concerns but have not been widely installed.

In this webinar, Dave Bohac, PE, from Center for Energy and Environment (CEE) will discuss results from a recent CARD project that assessed the energy savings opportunities for residential multizone air distribution systems. Dave will present findings from interviews with equipment distributors, HVAC contractors, and utilities. He will discuss the results from building energy simulation models of one- and two-story houses with single-zone and multizone distribution systems. The models helped evaluate the impact of over- and under-heated and cooled areas on annual energy use. They also estimated the potential energy savings that multizone systems can achieve with more strategic temperature setbacks for individual zones.

Stakeholder interviews found that almost all major HVAC manufacturers have pre-packaged multizone systems for furnaces and heat pumps. In Minnesota, the systems are primarily installed in larger, new homes for improved comfort. Improved energy efficiency could be another benefit, but no Minnesota or U.S. utilities currently offer energy efficiency incentives for multizone systems. The energy modeling indicated that a multizone system could reduce space heating energy use by almost 10% for a two-story house with an over-heated basement and second floor. A significant setback of the basement temperature could also reduce energy use by over 10%. On the other hand, a house with a single-zone system that has under-heated areas would have improved comfort but up to 15% more energy use if updated to a multizone system. Multizone system percent savings are greater for space cooling but have less impact on annual energy costs in Minnesota’s heating dominated climate. Field studies will be needed to better estimate the energy impact of installed multizone systems, but the modeling results from this study provide a starting point.

Cost
Free
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