Which Multifamily Buildings Should Be Electrified First?
While some small buildings have taken to electrification retrofits, large multifamily buildings have been a harder nut to crack. Seeing “virtually no progress in this sector” in New York City, the Urban Green Council studied the reasons why and released a report detailing the existing multifamily building type that could benefit the most from electrification and that would be presented with the fewest challenges.
“Going Electric” first details some of the real and perceived challenges of electrifying large residential buildings and teases out the true barriers. The arguments analyzed in the report are summarized below:
1. All-electric systems will cost more.
Response: Not compared to one-pipe steam heat systems that use fuel oil, district steam, or electrical resistance
Based on 11 proposals over the past 10 years, replacing existing steam-heat systems with unitary mini-split retrofits or a centralized variable-refrigerant-flow (VRF) heat pump system tended to be less expensive than upgrading the old steam system and replacing boilers and cooling towers. However, even the least expensive and most efficient cold-climate heat pumps can’t currently compete with the lifetime costs of natural gas systems, because the cost of electricity is roughly five times as much as natural gas per unit of energy.
2. Heat pump refrigerants bring regulatory risks.
Response: Maybe, though new regulations for refrigerants typically grandfather in existing systems
Some refrigerants have 2,000 times the global warming potential (GWP) of carbon dioxide, which makes them subject to evolving regulation. Yet methane emissions from the U.S. oil and gas industry currently contribute more to global warming than refrigerant leaks on an annual basis, according to the report. And building owners are unlikely to be forced to retrofit refrigerant systems while systems are still operational, making high-GWP refrigerants “an issue to overcome [through proper management and monitoring], rather than a reason to rule out a heat pump installation,” according to the report.
3. Most multifamily buildings may need electrical upgrades to support additional electrical demand.
Response: Unclear. Many may, but there is no way to know how many.
Wiring for 40 amp-capacity—common in pre-war multifamily buildings—would likely need to be upgraded to accommodate unitary heat pumps. But there is no current inventory of how many buildings in New York City have 40-amp electrical capacity.
4. Landlords may shift the costs of heating to tenants without reducing rent.
Response: True. New York City needs policies that protect tenants without deterring landlords from pursuing heat pump systems.
Unlike steam radiators, heat pump systems enable landlords to track heating use by unit and bill tenants for actual heating consumption. Current laws aim to protect tenants by requiring comparable rent reductions when landlords shift the costs of heating to tenants. However, protections are only in place for metering through unitary heat pumps; there are none for central heat pump systems.
5. Heat pumps will not actually reduce greenhouse gas emissions because the electricity is still generated from dirty sources.
Response: False. Replacing almost any fuel heating system with an industry-standard heat pump will reduce emissions.
Emissions savings vary depending on the efficiency of the new heat pump system, the efficiency of the system being replaced, and the evolving makeup of the electric grid. The report found that even when New York’s electric grid becomes more carbon intensive because of the Indian Point Nuclear Facility’s closure, heat pumps with a coefficient of performance (COP) of 2.0 will always be responsible for fewer carbon emissions than a fossil-fuel system. The most common retrofit scenario will be a steam-heat system that’s about 75% efficient, according to the report, in which case the heat-pump system need only perform at a COP of 1.5 to reduce the building’s carbon footprint. (Note that this analysis did not account for refrigerant leaks.)
After analyzing these challenges, the report concludes that currently the best candidates for heat-pump conversions are owner-occupied buildings with one-pipe steam heat systems that use expensive fuels. Buildings that fit the bill represent approximately only 3% of New York City’s building stock, or 480 properties.
To make electric heat pumps attractive to a broader base of building types, the report lays out a series of recommendations, including harnessing Local Law 97 (New York’s law that sets carbon caps for existing buildings) to spur electrification, lowering electrical rates in expectation of higher demand, and surveying electrical infrastructure needs.
For more information:
Urban Green Council
Pearson, C. (2020, June 19). Which Multifamily Buildings Should Be Electrified First?. Retrieved from https://www.buildinggreen.com/newsbrief/which-multifamily-buildings-should-be-electrified-first