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Here's what you need to know about installing central AC in your NYC townhouse

The recessed ceiling cassette by Mitsubishi is one type of mini-split system that doesn't require a lot of ductwork in the installation. 

Mitsubishi Electric Trane HVAC 

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Spending the summer in the city? If you own a multi-family townhome, you may well be considering installing central air conditioning for both you and your tenants. Knowing your options will help determine if it’s worth the investment. 

Facts are facts: New Yorkers are traveling less and staying home more as a result of the Coronavirus pandemic. Making your house cool and comfortable with central air conditioning could certainly help ease that shift, which might very well be the new normal. Adding central AC is also a way to attract or keep tenants in pricier rentals—key in today's slowing market, which is seeing the vacancy rate tick up.

“Anything you do to entice people to lease your property is an advantage in this quiet market,” says Soozy Katzen, leasing director for Fox Residential. “Adding air conditioning will make the rental more competitive with newer developments. You can’t give them a swimming pool but you can give them this value-added amenity.”

It’s also a way to help your property stand out in the white-hot townhouse rental market. Nadine Adamson, broker for Brown Harris Stevens (who leases the garden floor of her own townhouse), says brownstones are—for once—winning the race against larger developments. “Because of Covid-19 safety concerns, it makes so much sense to be in a small building. Now is an especially good time to spend money toward attracting qualified candidates.” (She should know—she owns the townhouse catty-corner to hers and rents that as a duplex.)

Which of the two basic AC options you choose will depend on the usage as well as the budget. Traditional split systems (what people think of as "true" central AC) involve a big air handler inside that branches out through the heavy use of ductwork, requiring hefty construction work to hide all the mechanicals. Wall-hung units (aka mini splits) are easier and quicker to install—no ductwork required—and therefore less expensive, though by no means cheap. These also provide heat. Both rely on outside condensers. 

George Wong, owner of Mr. Air NYC, a HVAC contractor, says many townhouse owners do a mix—traditional (ducted) in your own residence for the clean design and wall-hung units (ductless) for rentals. 

Brick Underground spoke to these and other experts about the ins and outs of installing air-conditioning in your NYC townhouse. 

Ducted vs. ductless central AC? 

The differences mostly boil down to installation and aesthetics. With traditional split systems, there’s simply no getting around ripping open the walls to run the ductwork. 

For that reason, Adam Meshberg, founder of Meshberg Group, an interior design and architecture firm, advises doing these projects as part of a larger renovation. “Once you are doing sheetrock work, you may as well do it properly to hide the ductwork and avoid ending up with soffits anywhere.” 

On the other hand, mini-splits are much easier and quicker to install—no ductwork required (though it can be optional; see more on that below). That's why these less-invasive options are the default for tenant apartments. But they are also catching on with landlords, who may not want the hassle and dust. Brands include Mitsubishi (the contractor favorite), Daiken, and LG (top pick of the engineers Meshberg works with). 

Adamson for example went with wall-hung units in the rental as well as her own residence, where she didn't want to disturb the original plaster details. She put two units on the upper two floors with the bedrooms, which also keep the parlor floor cool (since warm air rises). “I don’t love seeing the boxes but I love how great they work.” 

There's a solution for that: Mitsubishi offers a low-profile, ducted unit that can go above the ceiling or under the floor as well as a recessed ceiling cassette.

Meshberg usually recommends installing these kinds of mini-splits in a dropped ceiling in a closet or pantry or bathroom and then run some ductwork through the joists to keep the ceilings elsewhere nice and high. "You only need about four inches for mini-splits compared to eight inches for regular splits, and you won't end up with a big box along the side of the room."

Vinnie Croce, owner of Cool Tech HVAC, says ducted mini-splits now account for about 90 percent of all his jobs. He too puts them in the ceiling of a closet or other space and says it will be enough to cool three to four other rooms, all with minimal ductwork. "It works well and is very quiet."

That said, sometimes the ceiling is just too low even for that. In those cases, Meshberg says the console-type mini-splits (at only eight inches deep) are great for putting on the floor in front of a window. He usually builds out a custom bench to house it. "It's like the package you see in a new apartment building, only much smaller and quieter. We do this a lot in garden-level spaces." 

In some rare cases, you may be able to retrofit your existing heating ducts to accommodate a new split system, drastically reducing the installation work. 

Ravi Kantha, partner and director of Brooklyn sales for Leslie J. Garfield, a real estate firm that focuses on townhouses, is currently installing central AC in his own townhome. He says one client, a townhouse owner, was able to do this on two out of three floors and then use ductless units on the other floor. Adamson reports a similar situation with one of her clients. So it's worth investigating in your own situation, just in case. 

How much does installing central AC cost? 

Costs vary, as no two townhouses are alike and there are so many variables at play. Croce puts the average cost to cool a four-story townhouse between $40,000 and $50,000. 

Wong says it would cost about $60,000 for a four-story duplex with ducted units in the owner-occupied half and ductless in the rental half. But the costs can quickly spiral up if you plan to put condensers on the roof, which is by far the more common occurrence. "You can mount one in the backyard or hang it from the rear but not two," Croce says. Both must go on the roof in a historic district. 

Rooftop installations could add $8,000 to $10,000 in filing fees from the Department of Buildings; $5,000 to $20,000 for steel dunnage (or support); $1,000 to $2,000 for a crane to hoist it all up; plus other costs to meet fire department code standards. 

Case in point: Meshberg says installing AC was going to cost between $80,000 and $100,000, including electrical wiring but not necessarily all the rooftop expensees, for a four-story, 20-foot-wide townhouse on the Upper East Side. "You can't cover the whole floor of a big footprint with just one handler. The more zones you have, the more handlers and condensers you will need, and the more construction work is required."

Score one more advantage for the Mitsubishi mini-splits: Wong and Croce say you can run as many as eight different units on just one outside condenser (more like five or six for other brands), each with its own zone. The condensers are usually smaller too. "That makes it easier to get by landmarks," Meshberg says. 

You can even hide a ground-floor condenser behind a cool facade.

Wong hid a condenser behind one of his own custom cedar fences. 

Mr. Air NYC

Is putting central AC in a rental worth the investment? 

The answer appears to be yes, especially in the current market that has landlords competing for tenants.

Kantha has seen potential high-end renters shun apartments when there's no upgraded AC, especially in larger spaces where you'd need two or three window units per room. “Tenant who are spending anywhere from $5,000 to $20,000 a month expect to have a functional air conditioning they can control on a thermostat.” 

So he recommends an HVAC upgrade to all his landlord clients, minimizing expenses by putting AC only where the tenant needs it and going with mini-splits, “People can look beyond the boxes, so the added expense of installing ducted AC is not going to be worth it in terms of rental value.” 

Adamson points to another benefit: Having mini-splits makes it easier to charge tenants for their electricity, since each system is clearly earmarked (the same goes for heat). “It gives the tenant individual control over the thermostat and then they can eat the cost should they crank it up and leave town.” (Though she herself would encourage a more energy-saving ethos.)

And according to Energy Saver, the U.S. Department of Energy's consumer resource on saving energy and using renewable energy technologies at home, ductless units are as much as 30 percent more efficient than central systems.  

What about installing a new heating system? 

According to those interviewed here, most people prefer to stick with their existing radiators and just spend money on air conditioning. But mini-splits provide both cooling and heating. "There's a special valve that closes up in the winter and then the build-in heat pump produces heat," Croce says. 

Wong says this allows you to do away with a traditional mechanical room, cutting out the boiler and using these as the sole source of heat. "Some models can go down to -13 degrees Fahrenheit, so plenty of heat." 

At the very least he recommends relying on these for all but the most frigid months, so maybe you only have to ignite the boiler for February and March. "It's more economical because you are only heating the zones you are in rather than the entire building," he says. You'll also be reducing your carbon footprint and using less fossil fuel. 

Meshberg agrees: "The cost for the additional heating will be minimal. You'll end up with forced hot air plus radiators, which can be pretty good for a cold house."