Do Not Replace That Steam Boiler!

I have rarely recommended replacing a steam boiler. With climate change now looming as an ever-larger threat, I have stopped recommending steam boiler replacement altogether. Here’s why.

A few years ago, New York City adopted a plan called “80 x 50,” which is shorthand for “reduce greenhouse gas emissions 80 percent by the year 2050.” It’s a tall order, and many entrenched interests are doing everything they can to make sure the effort fails. But as the city’s 522 miles of coastline start slipping under water, more and more New Yorkers will begin to grasp that 80 x 50 is actually a very good idea, and they’ll start to take steps to meet its goals.

When this happens – and I hope it happens well before 2049 – most multifamily and commercial buildings in the five boroughs will change their heating system from steam, hot water, or resistance electric to heat pumps as part of a larger process called electrification. (Resistance electric heating occurs when an electric current is passed through a resistor, creating heat, as in a space heater.) The idea behind electrification is that if we convert all heating, cooling, transportation, and other energy-intensive tasks to electricity – and then produce that electricity without burning fossil fuels – then we have a chance to blunt the impact of climate change and keep our city above water.

What does this have to do with my steam boiler today?

Quite a lot, actually. Even in New York City, where many boilers are poorly installed and maintained, a typical steam boiler can easily last 30 years or more. And if they are properly installed and maintained, they can literally last a century. The year 2050 is just over 30 years away, which means that if you replace your steam boiler any time between now and then and take proper care of it, you are going to be extremely reluctant to fork over the funds necessary to convert to heat pumps. I can hear the anguished cries: “Why didn’t someone tell us about this? We spent all this money! The boiler is working fine – and now the city wants us to spend even more!”

To avoid this scenario, I am telling you now so you are not blindsided. New steam boilers are very expensive, and they are generally no more efficient than the ones they replace. Few pay for themselves in fuel savings. So you are much better off taking good care of what you have now, paying for occasional repairs, and saving up to install high-efficiency heat pumps in the not-too-distant future.

Today’s high-efficiency heat pumps are great – a huge improvement over heat pumps of the 1970s and 1980s. They are roughly six to eight times as efficient as a steam system, and they have a lot of other advantages as well:

•    No distribution losses through riser pipes or standby losses in the boiler.
•    Room-by-room individual control and no over- or under-heating.
•    More efficient cooling than even the best window AC units.
•    Much less maintenance.
•    No banging steam pipes or baseboard expansion noise.
•    Easily metered so you pay only for the energy you use.
•    If one apartment’s system should fail, no other apartment is affected.
•    No oil soot or odor, or carbon monoxide danger.
•    No need for chimney relining – or a chimney, for that matter.
Are heat pumps a panacea?

No. The technology is well-proven and is used in hundreds of thousands of buildings around the world, but as a retrofit in an occupied building it must be carefully designed and installed. And it may require additional energy-saving measures, such as air-sealing and some exterior insulation, if energy use is to be reduced the full 80 percent.

In New York City today, where electricity is relatively expensive and natural gas is relatively cheap, it’s unclear how much energy costs will go down even if energy use plummets. But it would be a mistake to let fuel cost considerations sway your decision-making, because one thing is certain: 80 x 50 is a dead letter – and much of an unbearably sweltering city will be under water – if we don’t start installing high-efficiency heat pumps…yesterday.

Tom Sahagian is a consultant, teacher, and writer on energy efficiency.