Back in 2019, before the Climate Mobilization Act went into effect, we started work at a co-op building that was using Con Edison steam for heating and cooling. A lot of the equipment had been installed when the building was constructed in the 60s and was at the end of its operating life. There were problems with the distribution piping for pushing water through the building. There were leaks as well as water condensation when the air conditioning system was running, which caused a lot of damage to apartments. The board, which was paying around $300,000 a year for Con Ed steam, also knew that it was the most expensive form of heating and cooling. The board wanted to reduce costs for shareholders and set the building up in terms of energy efficiency for the next 50 years.
Looking at alternatives. We did a feasibility analysis to see how we could get the building off Con Ed steam and came up with a plan to connect to natural gas and put in high-efficiency, small-module boilers to provide heat and hot water. On the cooling side, we looked at potentially upgrading the steam chiller or using gas for cooling, but determined that putting in small electric-module equipment would eliminate a lot of the construction costs that might have been required to hoist a large piece of equipment up on the roof. The goal was to keep things cost effective by maximizing the use of the existing infrastructure.
Spying an opening. The building had a steam line running from the basement all the way up to the Con Ed heat exchanger and steam chiller in the mechanical room on the roof. We had to find a way to bring in a new electric line and gas line in order to power the boilers and chiller. Fortunately, the building had an open-well staircase — the kind where you can look down to the ground floor from the top. We designed an enclosed fireproof pillar and put the gas and electric lines and the control wiring for both systems inside it. As for the distribution piping, the old pipes didn’t always line up with what the original drawings showed. There was definitely piping that was not where it was supposed to be, so we had to design around that and reroute the new piping. In addition to all that, the work began before the pandemic and the job had to be shut down, which created a lot of turmoil. We restarted a year and a half later, but the job got done.
Savings at a glance. The co-op has reduced its heating and cooling costs by at least 50%, from around $300,000 to below $150,000. Looking at the building’s 2016 energy efficiency data, the co-op would have been facing a $66,000 a year penalty starting in 2030 under the Climate Mobilization Act. Now they’re not going to have any penalties through 2034.
Taking the long view. This board chose to go from steam to gas for heating and to electric for cooling before the Climate Mobilization Act, but buildings with similar configurations that are now considering switching away from Con Edison steam to meet their carbon emissions reduction goals should know that there is no one-size-fits-all solution. On the cooling side, switching to electric chillers is definitely much more economical and does help meet those requirements.
As for heating, you want to evaluate what your building’s carbon emissions will be and how far off you are from your target, and then determine whether it’s more cost effective to go from steam to gas or from steam to electric. At many older bldgs, including this one, natural gas definitely was more economical. But there are plenty of buildings where it would be better to switch to electric heating as well as cooling. It depends on your energy usage, how efficiently your current systems are operating, and what infrastructure is already in place.