Building Electrification Expansion

Moving the Residential Building Sector to Expand Electrification

Christie Amero is an Associate at Cadmus specializing in building electrification. We took a few minutes to talk to Christie about her team’s current project-a one of the first of its kind to analyze the actual heating season utilization, grid impacts, and performance of cold climate air source heat pump (ccASHP) systems designed for whole-home heating in the Northeast-and what drives her to look for new insights and opportunities through that work.

Christie, why is building electrification such an interesting focus for your work right now?

Building electrification of the residential sector in particular is really critical to decarbonizing our economy and reducing our greenhouse gas emissions and there’s a huge opportunity to move the majority of that sector to be fully electric. In the United States, the areas of the Northeast, Midwest, and Northwest may struggle during the coldest periods of the year to use currently available ccASHP systems to meet their full heating needs, but heat pump technology and performance is constantly improving and this study will provide valuable insights to improve understanding and increase adoption in the market.

What really drives me in this work is the prospect of shifting away from fossil fuel-based sources like gas, propane, and oil to electricity which can eventually be powered by renewable sources like wind and solar. As an engineer, I love numbers and data and this current ccASHP study we’re working on is very data based. It’s been great to see how these systems are performing and being utilized in the field (in a real New England winter) collecting that performance data, and then analyzing it and coming up with conclusions. We’re also starting to explore other related research areas, such as the impact of high global warming potential refrigerants that are used in many of the ccASHP systems and potential alternatives.

How do you respond to skepticism about residential building electrification and a major market transformation?

Yes, there is a lot of skepticism and for good reason. While there is a lot of opportunity for building electrification in the residential sector, two key challenges to widespread market adoption continue to be education around selecting the right type of heat pump system for a home and improving the cost-effectiveness of replacing existing natural gas boilers or furnaces.

There are many different heat pump system types available and a lot more work needs to be done to train contractors and customers to better understand how the systems are intended to work, what systems are best suited to particular homes, and how the customer actually plans to use the system. In some cases for this current study, we were under the impression from the contractor’s information that these systems were designed to be the primary source of heating for the home. But when we spoke to the customers, they only planned to use their ccASHP system when it was above 20°F and then switch over to their traditional heating system. In that situation, the ccASHP system can end up being oversized for the customer’s load and they likely won’t get optimal performance.

Regarding the cost-effectiveness, until we put a carbon tax on natural gas systems it’s going to be really difficult to ask homeowners with gas heat to switch to heat pumps without any sort of incentive from a local utility. Another challenge is that a lot of homes, especially in the Northeast, are more than 100 years old and while they may have had upgrades over the years, heat pump systems really work best in homes that are well insulated. So, when we’re thinking about home building electrification, we need to consider programs that couple a heat pump installation or retrofit with energy efficiency upgrades such as weatherization and improved insulation.

Will the current policy environment facilitate more opportunities to overcome those challenges?

Recently the Biden Administration increased funding for the Department of Energy to do more R&D on ccASHPs, so we’re expecting to see more utilities offering programs focused on heating electrification using heat pumps. However, there is still a lot of concern over customers not using the systems as intended. In our research, we’ve received some anecdotal feedback from utilities that have tried to offer these programs, but then have found the systems are only used for cooling, which is still pretty common especially in the Northeast.

We also heard from some customers that the contractor had told them that they should switch from the ccASHP to their backup heating system at a certain temperature. So even the contractor had doubts about its performance at low temperatures. The increased attention and funding from the current Administration is great, but if utilities are going to pursue more whole-home electrification programs, we really need a combination of contractor and customer education about the different types of systems and how to use them.

Can you tell us more about your current project and how you are drawing insights from the data you’ve collected?

Our team did a very intensive whole-home ccASHP metering study of 43 homes across MA and NY over the past heating season. One of the challenges to analyzing the performance of heat pump systems has been the lack of really detailed data on how different systems have performed under a variety of real-world conditions. To address this, we worked with Cadmus’ Data Analytics team to design a flexible data framework that we could use to aggregate the different data sources needed to do an effective analysis. Although this is a small sample size, we can apply calculations across sites and system types to pull out more high-level conclusions and trends that can be applicable to future efforts.

What’s really unique about this study is that we looked at more than just ccASHP system power and were able to calculate the heating load and performance on a granular level. Because we collected metered data for an entire heating season, and not just a couple of weeks like a typical evaluation study, we could see actual utilization for multiple system types. We also compared the measured heating loads to expected loads to better understand whether heat pump systems are being properly sized for various home types.

Another interesting element of the study is that a lot of people who participated had onsite solar. For homes that receive the vast majority of their electricity from onsite solar, they are barely paying anything for heating in a New England winter, which is pretty amazing. If we’re able to start coupling ccASHP installations with sites that have onsite solar or incentivizing them in conjunction that can dramatically improve cost effectiveness of the installations.

Where do you go from here? Is there an opportunity to broaden the dataset? 

Yes, going forward there seem to be numerous opportunities to expand our data set and understanding of heat pump performance. We are looking to include data from other existing studies that may have been done in the Midwest or Northwest and use additional primary data collection to fill in some of the gaps for the rest of the country. Right now, we’re focused on residential homes in the northern section of the country. We already know heat pumps perform well at 30°F or 40°F for the southern portion of the country, but we need more insight into these extreme cold periods, especially the -10°F and -20°F temperatures they get in the Midwest. Taken together, all these insights will help drive utilization of ccASHP technology in the marketplace and greatly improve our understanding of how to accelerate market adoption of this exciting technology.

Christie, can you tell us a little about yourself and what brought you to Cadmus?

I studied mechanical engineering at Northeastern and was able to work at a couple of different companies through their co-op program. One of my rotations was a gasification company where they were designing a system that would take waste materials and use them in a combined heat and power plant to generate energy. That’s when things really clicked for me and I realized that I wanted to use my degree to do good things in the world. I was really interested in thinking about how we could reduce our impact on the planet. I worked in the Boston area in energy efficiency for several years before moving out to Boulder, CO, and starting my career at Cadmus. I have a strong connection to nature and I love being able to say that my career is having a positive impact on the planet and the places that I enjoy every day.