Adding Forced Air Heat to NYC Condo with Central Air

kriskoeller

Hello,

We live in a 100-year-old, pre-war building in NYC. Last summer we remodeled the condo and updated the unit's central air conditioning ducting and installed a new thermostat. The central system is cooling only, and is powered by an in-unit air handler attached to a common cooling tower on the building's roof. (Forgive me if I'm getting the terminology incorrect).

Heat is supplied by the building's central boiler that produces steam that travels to two, wall-mounted radiators. These radiators have all the features and issues you would expect: uneven heating, noise, drying the air, unpredictable performance, etc. They are also unattractive and take up space. The steam heat is included in my monthly HOA/maintenance fees, so I don't pay additional costs to operate that.

Question: I would like to remove the radiators as part of Phase II of our remodel, and add a centralized heating source to leverage the new ducting from last summer's Phase I. My question is what type of unit I should be looking at. The air handler/AC unit is 20 years and need of replacement (the previous owner never performed any maintenance on any of the critical systems). I'd like to find a new, quieter more efficient AC unit that can also produce heat. Since its inside the condo, I would presume the heat source would either be electric, or perhaps water-heated from the building's boiler. Seeking suggestions on what to look for.

We also intend to add a steam humidifier and perhaps some advanced air filtering.

Thanks in advance.

Kris

RJ_4

1 option would be to replace the entire system to a splt system heat pump. This would require roof access and ability get equipment to the roof, and run refrig. lines and electrical to the roof. (electrical service would need to be adequate ) . You would need to replace the AHU ( air handling unit ) and some duct, install a condensing unit and provide electrical service for supplemental heat. option 2 would be to replace the AHU with a condensing furnace, This would require a natural gas service to your unit. It would require installing a furnace in existing duct and running a pvc intake/exhaust, to the roof. some codes require stainless pipe. Most cities I have worked in don't allow all electric furnaces, if they did you would have to increase your electric service. Using the bldgs. steam system would require some type of steam coil for the AHU. There are humidifiers available that mount on the duct and use domestic hot water. just some ideas. In any case you should contact a reputable HVAC contractor and a mechanical engineer to look at the possibilities. The bldg. owner or homeowners group would need to ok any work









. a Honeywell or aprilair style humidifier could be installed on duct by AHU

SWEI

Several options there, including a steam coil air handler or some hybrid of radiant and air. I would call John Cataneo and arrange for a consult http://www.72fllc.com/

STEVEusaPA

Keep in mine you'll have to let the building super know you are removing the steam radiators for 2 reasons:
1. It may affect performance of the other units or entire building.
2. They probably want to save those in case they ever need to replace one in another unit.

The other option is maybe the steam system needs an expert who can evaluate/fix the system so everyone has great, even heat, and saves the building (you included) a lot of money.

Jamie Hall

kriskoeller said:

Hello,

...steam that travels to two, wall-mounted radiators. These radiators have all the features and issues you would expect: uneven heating, noise, drying the air, unpredictable performance, etc. ...

Kris

None of those are issues you should expect. They are not characteristic of a well-maintained steam system, which should be even, quiet and predictable.

As to drying the air, heating the air -- by whatever means you choose to do it -- will dry it. No heating system is much better or worse; it's pure physics and you can't change it.

You -- and your whole condo -- would be much better advised, and financially better off, if that really matters, to get the steam system properly maintained and adjusted.

KC_Jones

Just some food for thought. You are paying an HOA in that building to basically NOT maintain your steam system. Now you are talking about spending more of your money to take that out and put in a completely new system AND continue to pay the HOA to NOT maintain the system that you are then not using. If it was me, I would be complaining about them sucking money out of me and NOT doing their job. I get paid to work at my job not sit around with my thumb shoved in my hind quarters, but apparently in your building everyone thinks that is ok? It seriously sounds like you need to get a steam expert into the building to actually get the system working the way it was designed which is quietly evenly and efficiently. Your description shouldn't be considered typical it should be considered wrong.....period.

jumper

More info. Is steam heating one pipe or two pipe? How tall is the building? How big is your condo? Number of rooms and square feet? Are windows original or modern? Generally radiators are far more satisfactory than central air. Especially if ducting is primarily for cooling.

ChrisJ

kriskoeller said:

Hello,


Heat is supplied by the building's central boiler that produces steam that travels to two, wall-mounted radiators. These radiators have all the features and issues you would expect: uneven heating, noise, drying the air, unpredictable performance, etc. They are also unattractive and take up space. The steam heat is included in my monthly HOA/maintenance fees, so I don't pay additional costs to operate that.

Strangly enough these features are what most expect from a forced air system. Especially the noise and drying the air part.

However as was already said, all system dry the air.

Get the steam system fixed and working properly and use a separate portable humidifier. Steam systems when working properly produce extremely even heating and no noise.

Fred

Whatever you install will likely eat some floor space, probably more than those two radiators. The air handler is consuming some space, maybe a closet? I have a steam system, in a large house and I installed two central air systems, 25 years ago, along with forced air furnaces since the incremental cost, compared to air handlers was minimal. My thought was I'd have a back-up to the steam system if/when it failed. In those 25 years, I've used the forced heat exactly 2 days and couldn't wait to get the steam back on for the comfort it provides. I'm not trying to change your mind but I do want you to be aware that getting the building management to address your steam issues would be a far better use of your time. You are already spending the money for that. I'm not sure what type of radiators you have but there are a multitude of design options out there, from antique to new. I'm sure you can find a couple that will fit nicely with your decor.

kriskoeller

Hello,

Firstly, what an amazing community. I posted this question figuring I would check back in a few months to see if there were any responses, so I was pleasantly surprised by all the answers and insights. Genuinely appreciated.

I don't see a way to respond to individual comments, so I'll attempt to respond here.

1. A heat pump has come up, but I think it would unlikely to be allowed/able to run any access lines to the roof, etc. Its a chilled liquid AC system with a shared cooling tower, to clarify the current installation. Curious on your comment about NYC not allowing electric furnaces; I had not heard that before. The steam humidifier I'm looking at is the Aprilaire.

2. I've also thought about radiant, as in installing a radiant heat floor when we re-do the floors later this year. Due to the limitations living in a condo, it would have to be an electric radiant heat floor, which I reckon is costly to operate, but I do know that radiant heat flooring is quite comfortable.

3. The super is aware and has already offered to take the existing radiators. He also indicated we could cap the line and not affect other units.

4. The state of repairs and maintenance of the steam system has been the subject of much HOA angst long before I arrived. The consensus seems to be that while not great, it works well enough for most who are happy to suit up in layers during the cold months. While I could get involved and try to achieve an outcome, I'd rather take charge of my own heating with a system I control, even if it costs a bit more. The HOA fees are not expensive, so I'm not too beat up about missing out on the "free" steam heat.

5. Understood that a well-functioning, well-maintained steam system should not have the issues I've experienced.

6. Lastly, and I should have pointed this out initially, the condo is a 1,600 square foot rectangle with the two radiators at one end, the master bedroom and master bath at the other end, and a living room and kitchen in between. When the system is behaving, the heat rarely makes its way to the back of the house in a way that's comfortable, and doesn't require over-heating the front rooms. Its not really feasible to add additional steam heat to the back room, so we resort to wheeling out a space heater when it gets really cold, which can be dangerous and costly to run. The ducting, which is new, supplies all areas of the home pretty evenly, so I see that as an advantage.

7. Lastly, my other option, as indicated, would be to install radiant heat flooring. My personal experience with these systems is positive, once you overcome the initial installation cost.

I appreciate everyone's inputs and insights; I've not yet decided what to do, but will report back once we have a plan.

Thanks again.

KC_Jones

Something else to think about, when you had the ducting replaced was it sized for AC AND heat or just for AC? This can make a difference.

John Mills_5

If you have a chilled water fan coil, about the only thing I can think of is replacing with a fan coil with electric heat. I have heard in rare cases, that isn't allowed. Also between the electric furnace and the steam humidifier, you will need plenty of juice so a main service & panel upgrade may be likely.

KC_Jones

kriskoeller said:

3. The super is aware and has already offered to take the existing radiators. He also indicated we could cap the line and not affect other units.

This isn't exactly true. Yes the other units will still get steam, but it will impact the function of the system. How much it effects it is a function of how big the system is. If it already isn't working well this probably won't help matters much. Definitely points to the lack of knowledge with respect to the steam system. Also 2 radiators for 1600 sq ft. I am guessing the building had significant floor plan changes over the years with little or no regard for properly heating it?

kriskoeller

Couple of things:

1. During Phase I of the reno, we upgraded the electric service to 200 amps in anticipation of these upgrades, and some new kitchen appliances.

2. The building was built in 1922 as a commercial building (Wells Fargo built it to be a fur vault, since this part of NYC was the Fur District) and was converted to condo in 2001, so residential heat was never really part of the master plan. I supposed that could have been addressed during the conversion, but it wasn't so this is what we have to work with.

3. A question was asked if the ducting was specced for heat and cooling; I believe so, but I'll need to confirm.

Thanks again, everyone.

jumper

You can use the steam allotted to you to generate heating hot water. Quite compact heat exchangers are available.

Also it is possible to extend steam heat during renovation. Go to STEAM section here and look for Igor Zhadanovsky. He does that with small diameter flexible tubing. That is my suggestion.

SWEI

Call John. Really.
http://www.72fllc.com/
http://www.gatewayplumbing.com/

tim smith

If it is a central chiller, you could order a dual coil air handler from someone like First company, Install a small steam to water heat exchanger and feed the hot side coil of air handler with this. Use a small pressurized feed tank (like Axiom) for water supply to heat exchanger to limit liability of a water leak? Pretty simple system. Ideally it would be a water source heat pump but don't think you have the central system to support it. Just some food for thought. T