Compliance with NYC heating laws & resident comfort: send heat all day, or only when code requires?
We have a high rise multifamily coop apartment building with 2-pipe steam heat (district steam; NO BOILER.) 1960s brick building, minimal insulation, decent dual pane windows. Our goal is to lower overall steam usage and maintain or improve resident comfort.
NYC code says:
From 6am-10pm we must maintain a minimum indoor temperature of 68F when it is below 55F outside.
From 10pm-6am we must maintain a minimum indoor temperature of 62F regardless of outdoor temperature.
We have an outdoor thermometer and thermometers in 25% of our units sending indoor temps back to the central controller. We have our setpoint temperatures MUCH higher than code requires; our setpoint is 75F during the day and 74F at night.
When outdoor temperatures are hovering at or above 55F during the daytime, we send no heat, so indoor temperatures will tend to drop during the day. Then we send heat starting at 10pm.
This doesn't seem optimal for resident comfort. I think we ought to send heat when indoor temp drops below setpoint, regardless of what the outdoor temperature is. That way, residents have a predictable temperature all day and night, and the system doesn't have to work as hard to "catch up" at 10pm nightly. (Note, with district steam, we get steam instantly on demand; there's no boiler to fire.)
My hope is that if we maintain constant indoor temperatures all day and night, we could lower our setpoints to something like 72F or 73F and save on steam usage.
My concern is that we will be using a lot more steam to maintain temps during the day, and the steam usage will not be offset by less steam use overnight.
What do you think? We do not have good heat loss measurements for our apartments; I think the only way we'll find out what works is to try it experimentally and measure results.
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If you have it set up according to the requirements currently you may reach out to some long standing residents to find out if they have any issues with the current set up before you make a change.
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Oh, our residents reach out to us OFTEN. With 420 units, we have people running electric resistance heaters during the day and night (even though our setpoints are high!) and other people opening windows to cool down their apartments. We'll never satisfy everyone, my goal is to find a happy medium where most people don't feel the need to run electric heat or open windows so much.
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dschwarz, The first thing that you should do is identify the apartments on each side of your building that have the highest heat load. These are the units that you must legally satisfy. Place your thermometers [I assume wireless] in these units. This change will give you a better guide for providing heat. The second thing is to change your controller or the way it operates. The more you rely on timing or outdoor temperature to supply steam, the less comfortable your residents will be. That is assuming your system is reasonably balanced. I had this issue in my Coop and had to build a controller. I intend to cover this in another discussion.
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@dschwarz I agree it will be trial and error. You will probably never get it perfect but holding a more steady temperature will reduce complaints and maybe reduce fuel usage…..no guarantee.
To large of a temp set back can be counterproductive.
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@dschartz, You should also get a data logger if you do not have one to measure the time the steam actuator turns the steam on, the out door temperature and the mains temperature of the end of the longest mains run. Then place data loggers in the coldest apartments. I assume you are in Manhattan so they would be in apartments on the Eastern, Southern and Western windowed apartments. This is because of the effect of sunlight. This arrangement will allow you to measure any improvements in your system. Example: comparing a daylong period with an average temperature of 45 F to another period later in the year with the same average temperature. [the sunlight and wind which can found from the weather service]
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Are there separate electric meters for each unit?
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We have temp sensors throughout the building on all risers. It's a 20fl building and we have 5 temp sensors per riser, so 1/4 of the apartments on the North, South, East, and West sides are all being logged. We had PEPCO install a Delta Controls control system and have access to logged data via enteliWEB.
I think we may have some balance issues particularly on the lowest floors, trying to get reliable info on that using our sensors.
The building electrical system is master metered with no submetering, so that won't help us determine which apartments are running heaters and when. I can see them on the data charts; anytime the system is not sending steam for hours and the apartment temp is WELL above our setpoint, that's a sure sign they're running a heater.
Likewise if an apartment is continually below our setpoint, even when sending heat, we know they have windows open.
If I had full access to the sensor data I could write some Python code using heuristics to detect heater-on and window-open scenarios. I don't have that yet.
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dschwartz, the heaters you are referred to. Are they portable heaters?
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Yes
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dschwarz, The reason I asked is 4 years ago I contacted the DOB to see if I could make my own boiler control. They and my insurance company mentioned UL approval so I modified an existing UL approved device. The DOB sent me an unsolicited statement in the building code:
MC309 Interior spaces intended for human occupancy shall be provided with active or passive space-heating systems capable of maintaining an indoor temperature of not less than 68°F (20°C) at a point 3 feet (914.4 mm) above floor on the design heating day. The installation of portable space heaters shall not be used to achieve compliance with this section. Refer to Section 1204 of the New York City Building Code.
Exception: Interior spaces where the primary purpose is not associated with human comfort
You might want to make sure no one tells the city that space heaters are in use. Apparently the cities heating requirements are not met by space heaters. Also, note that they as do I measure the heat 3 ft above the floor. I also place sensors 6 to 8 ft from any radiators or windows.
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Hello from the future - 5 months later, I have set up a server and built a screen-scraper daemon to pull all the heating data from the proprietary server every 5 minutes, 24/7. That, plus a dashboard and some Python based analytics, are giving me better information on the system than I ever had before. FIndings:
- Heat is surprisingly well distributed throughout the building; we don't seem to have big differences by exposure or height, except on the 20th floor. (And I have found that we are not using portable heaters, they are part of Wallmaster heat pump units.
- Our nighttime setback to 74F, morning boost to 76F, daytime setpoint of 75F was overheating the building and spiking our peak steam demand precisely during the ConEd 6am-11am penalty period. I set the building to run at 74F day and night, no more morning peaks, no complaints so far.
- The building is still running about 1F higher than setpoint at all times, so I'm considering dropping our setpoint to 73F all day.
- Despite the lack of insulation, the building is so thermally massive, we can shut off the heat for 12 hours for repairs on a cold day and still remain within legal temperatures.
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@dschwarz I don't envy your position. I know you need to keep the coolest apartments warm enough and with a 74-76F set point some apartments are going to be "just right" and others are going to be screaming hot.
I like things on the cool side. Murphy's law dictates that if I lived in that building I would have the hottest apartment, at 80F+. I'd be running window air conditioners in January!
Good luck on your trials and keep us posted! 😎
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I have to ask if TRV's have been considered?
Is a TRV on each radiator allowed with NYC plumbing code when the steam is supplied by the utility?
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I do not recommend the use of TRVs for dschwartz. TRVs are known to not be effective for 5 story buildings and higher. Also, there are things the management can do with the heating service that would cost less and be more effective and less intrusive. You might talk to Con Edison about them,
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The condition of TRVs being ineffective for 5 story buildings is not "known" to me. Please advise or expand on this.
@leonz There is no restriction or requirement regarding the use of TRVs and municipal steam in NYC.
Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
Consulting & Troubleshooting
Heating in NYC or NJ.
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Hello and good morning to you JohnNY, I agree with you, I could in no way picture that TRV's would not be effective for any multistory building fed with steam for heating.
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Gentlemen, I will look into TRV effectiveness. I am a bit busy. I will say that as a person who manages a Coop who has consulted others who manage buildings of more than 4 stories at $140 per radiator [one pipe] and getting access to each apartment, it is not a practical and financially good option. It is difficult enough just to get into an apartment to do an inspection.
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I am a bit pressed for time, You might look into a posting by Hollahan on TRVs. I do not remember it but I know there was one.
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You said they're known to not be effective.
That's entirely different than not being able to gain access to install them, or them being cost prohibitive.
@JohnNY Would be my go to when it comes to TRVs being used in larger buildings. I suspect he's been there done that a few times.
Single pipe 392sqft system with an EG-40 rated for 325sqft and it's silent and balanced at all times.
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I've built from out of the ground, worked in and consulted in NYC High rise residential & office bldgs for decades. I have found that building height has no bearing on the efficacy of TRVs. The issue that I encounter over and over is gross overuse of TRVs.
TRVs should be used sparingly. The biggest issue is TRV envy: Mrs Goldberg has one on all her radiators so Mrs. Antonucci tells the Super she wants them too! Then, Mrs. Murphy, who is playing Bridge with the ladies sees them and gets TRV envy......and on and on until every radiator in every apartment has them. Mad Dog
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I do not have the time to took into analysis of TRVs, I think they are in an old computer. Please look into the posting by Holahan. [excuse the misspelling of his name].
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I’m sorry, @ARobertson13 but are you busier than the rest of us? Back up your claim, please. “Look into the posting by Holahan” is not a mechanically sound reply and you’re speaking to mechanics here. I routinely recommend these products to my customers in NYC buildings of all sizes and commonly witness and enjoy their benefits and purely positive results.
They absolutely have their limitations and are often misapplied in an effort to resolve issues not related to their functionality. TRVs are easily defeated by over pressurized steam systems and require a significant differential to allow them to open and close in a hydronic application. But none of that speaks directly to support a claim they don’t work in tall buildings. It just means an installer and specifier needs to know what they’re doing.
Best to all,John Cataneo, Master Plumber
Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
Consulting & Troubleshooting
Heating in NYC or NJ.
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@ARobertson13 A week ago you won't accept test results from a fellow member because they lack a specialized industrial metering device but now we are just supposed to take your word for it? Seems like a double standard. Inform us, since you make it a point to always have the proper tool to back up claims surely you have done testing with your very own vortex flow meter and can back up these claims.
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