Home has crawl space?...I will assume boiler for radiator heating....what fuel?...is nat gas available to your home?...

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NY is hard to price because it is so expensive. Radiator heat is very nice and comfortable. The radiators are unsightly to some persons. If not a problem for you, then you might consider a high eff nat gas boiler. But only after your radiator system is thoroughly checked. You would still need a ductwork system regardless and I assume your basement has the room for this. Otherwise a small furnace and AC system. If no obstacles or other issues, I would use a budget figure of $10-12K. Shop around.

IMO

Is this a single or two story home? Do you currently have a single pipe steam system?

I think it is impractical to rip out out all the radiators and replace them with a forced hot air heating and cooling system. You could leave the radiators and install duct work just for cooling. Installing the duct work in the basement could work, but it is going to be difficult if you have a second story.

Another option is to install mini splits to provide cooling. They can also provide heating, but that would mean high heating cost due to the NY electric rates. The current boiler could be replaced with a gas fired model. That can be done at a later date if there are budget constraints.

The price is going to dependent on the options you choose and the level of difficulty in the installation. I think a budget of $10-12K is at the low end.

A mini split would not be my first choice either. However trying to run duct work in a 1940 house with high ceilings and plaster walls is challenging.

There is nothing wrong with an oil fired boiler other than the cost of fuel oil. Oil prices are rising again, so high efficiency, proper size, and lower fuel cost would make the return on investment in a conversion to an gas fired boiler relatively short.

Look at a high-velocity air conditioning system. This way you can keep your heating system.

That's a good idea, I will look into high-velocity AC systems

I have a similar sized 2 story house in Virginia, outside DC, and we upgraded both heat and A/C. IIRC it was about $8300 to install a new medium efficiency Buderus gas boiler and remove the old oil tank, and close the oil pipes with cement to prevent someone trying to fill the tank. The gas line already ran to the water heater in the same room, so changes in the gas line were minimal. We later installed central A/C in the attic, with vents running to the 1st and 2nd floors (none in the basement). IIRC, that cost about $10,000.

Installation of A/C in the attic works well because there is better air flow to the 2nd floor than the 1st, so the 2nd floor is actually a little cooler than the 1st. My highest gas bill in the winter has been about $200/month, but I have a gas boiler, gas water heater, gas dryer and gas range, and my wife loves to run the gas fireplace insert when the weather is cold. The old cast iron radiators provide very even heat.

Bruce

Although New York City may be and expensive place to live
and install central air, most of the State is not any more expensive than many
other parts of the country. Check into the NYSERDA program. The need for
cooling varies a lot between the humid and relatively warm costal plain and
inland mountains in the North. Lots of
choices to be made and if you make them before contacting contractors, you can
get a better comparison.

If the OP could be happy with the cooling performance of
good quality window units, then mini splits could work quite well. I really don’t like the idea of outdoor
ducts, whether they be in the vented attic or crawlspace. In a home that size, you might be able to get
away with a minimally-ducted mini split and a wall unit or two, or two of the
former. The minimally ducted units can
be installed by sacrificing the upper reaches of a closet or two, or in the
upper space of a basement stairway. One
AHU can supply directly at least two rooms that way and often three or four. IMHO, mini splits are a made to fit solution
to adding cooking to a fine hydronic heating system.

How is the domestic hot water supplied right now?

Assuming that you don’t have steam, if you decide to stick
with hydronic heat, please get someone that knows what they are doing or do
your own research. Plugging a modern,
low mass modulating boiler into an old system can be tricky. If it is not done right, you will get less
than optimal comfort, no payback from a more expensive boiler that could have
saved you money, and a broken down boiler before its time. If you have all the original radiators and
have (or will) improved air sealing and insulation in the house, you are a long
way towards a situation that can take advantage of an efficient boiler. That is
because you can get sufficient heat out of excess radiation, especially cast
iron radiation, at relatively low water temperature.

In a home that size, I’d consider installing a Westinghouse WGR050NG076
water heater as your boiler. They
modulate 3:1. They are efficient. They are inexpensive; the appliance can be
had for about 2 kilobucks. You don’t
have to be rocket scientist to install them in place of a high mass boiler
because they are high mass boilers. Little or no modification of your current piping would be needed.

Let me just give this tidbit of information; my friend is having to replace their HVAC in a home that everything is already in place, just replacing the old with a new system. It is going to cost them over $8000 for a new Lennox system for a house that's 1500 sq ft. This is not a top of the line system either, just a mid range system. It is FREAKIN' EXPENSIVE!!!!!!!

I got bids about 6 years ago in New Orleans. The first did not include any work on the ducts and was for 4 tons and actually removed cooling from a utility room that was supplied by a crawl space duct that originated in the attic and ran down from the attic through a chase. I was looking at getting rid of that disaster.

SEER 13 $6290

SEER 14.5 $6630

SEER 18 $9530

The second was 4 tons, 16 SEER: $12054

The third was 2 stage, 16 SEER for $13,000. That included new ducts. At the same time, he ball parked a mini split installment (7 indoor units, 3 compressors/outdoor) at $11k. Later he settled on on $14,288 which is obviously a lot higher than 11, but competitive with his ducted system. He also offered a ducted system + one mini split (to abandon the duct in the open crawl). That was $13,894 for a Reem 16 SEER and 13 EER.

I went with the higher bidding guy. He was the most knowledgable and careful. He was recommended by an energy rater with no skin in this particular game. Despite the fact that he teaches at a local building trades school going back decades, he had not much or any practical experience with mini splits. He brought on a trusted colleague with more experience to share the contract. I think that he was looking at it as a necessary learning experience to upgrade his skills for his students. (He said that when he is done working in the field, he is done teaching.) In retrospect, I probably should have given the third alternative more consideration for operational reasons.

Unfortunately, it is imposible to give you an estimated because of the cost of installing ductwork, which will be specific to your home. Best bet is to get 3-5 estimates and choose based on cost and how comfortable you are with the contractor.

arkansas,

If it's not too late, persuade your friend to avoid the Lennox and take a look at Carrier options.

I think radiators give you the most comfortable heat and forced air the least. If you want to add AC, either install new ductwork or use mini-split(s). If your mini-splits are heat pumps and provide pleasant heat, you can use them as your primary heat source and the radiators for when the heat pumps are inadequate.

Hardly anyone can justify building a home or doing a down to the studs reno and installing both ducts and hydronic because the love the hydronic so much. (People do love it. I would say, however, that radiant floor heat is really the top!) It is just too expensive to install and maintain two systems. That's one reason that I think that mini splits are a natural for retrofitting hydronic heat homes with some level of cooing in areas with low cooling demand. You still have two systems to maintain, but it can cut the up front costs. Basically, if a couple of window units would do it for you, the same number of mini splits will do it better and you don't need to go through all that is involved with finding places to hide long duct runs.

Adding ducts can go well in some cases. It depends a lot on the layout of the home. I live in a home that had forced air (heat and cooling) added in the 50s. Originally, it was done quite well with a ceiling central return in the main hallway and the ceiling in that hall was dropped from 9 to 8 feet for supply ducts. (I'd say that dropping that ceiling was pleasing from the architectural standpoint.) Later, with additions to the house, attic and crawlspace ducts were added. Things got ugly....

You make some good point, Marc. For the sake of complete information, I'll point out a few things. Some people don't like a modern look preferring a generally older look or maybe a particular era. This particular OP might like the '40s look.

Window units are certainly inferior to mini split in their varied forms and old-fashioned central, ducted systems. They are, however, much better than they used to be and getting better all the time -- lighter, quieter more efficient and easier to use. After the Katrina and the Corps of Engineers' faulty flood wall designs took my home, DW and I were fortunate enough to rent a decent 1 Br apartment early on. The owner wanted to get it up in a hurry and put two window unit heat pumps in place so that specialize feature is available in window units, going back over a decade and a half, all in one user-friendly unit.

Where window units are not inferior is cost. Some people who have lived their entire lives in predominantly cooling environments may not understand this. In areas where people love their comfortable radiant heat and use it over 8 or 9 months yearly, it is pretty tough to justify installing central air for use over a few weeks.