Noise Control for Building Interior Heating, Ventilation and Air Conditioning Equipment Guidance Sheet (PDF)Sticking outside in all their boxy metallic ugliness, dripping onto passers-by, and blocking light and views indoors, window mounted air conditioners are as ubiquitous a feature of NYC apartment life as fire escapes and water towers.  (For more info, check out BrickUnderground's guide to all things window a/c).PTACs are usually installed when a building is constructed and hooked up to a building’s hot-water system.  Hot water produced by the boiler flows into the PTAC, and circulates the resulting heat into the apartment.  The PTAC has a separate chamber containing coolant that produces cool air.  They are vented to the outside through a cutout below the window typically covered with a metal grill, similar to a through-wall a/c, says Gary Cottam of Cottam Heating & Air Conditioning. 2. Choosing the right through-wall unitFriedrich, LG, GE, Amana, and Frigidaire are the most popular brands. 

There are standard calculations  to determine the number of BTUs you need--room size, ceiling height, amount of sunlight, number of occupants, and proximity to the kitchen.central ac cost per hourAnd don’t forget to jot down the voltage and amperage of the electrical plug, along with the capacity of the outlet the a/c will use.  average cost of replacing an air conditioning unitIf you’re buying a unit that requires more electrical power than your existing outlet can handle, you’re going to need an electrician to upgrade your wiring.  used rv ac unitAnd that will require lots of permits along with permission from your landlord, or co-op or condo board.3. Installing a through-wall a/c where none has gone beforeAlthough cutting an opening through the masonry of an exterior wall is physically a relatively simple undertaking that costs around $2,000, like most things connected with New York City real estate you’ll have to get the requisite building and construction permits, permission from your landlord, co-op, or condo board, and maybe even an architect

,  says Ranjit Singh, president of Cool Air Inc.Arline Kob, a principal at Key Real Estate Associates, which manages co-ops in New York, says that she’s “never known a co-op board to allow the installation of a through-the-wall unit where none exists.”  The board would be concerned about façade uniformity and breaking the seal of the building’s exterior. If your board is through-wall-friendly, you will be expected to install an exterior grille that matches existing ones and lines up to them, says property manager Michael Wolfe of Midboro Management.  The grilles will also need to be flush with the building's facade and the building's architect or engineer will need to review the proposed installation.In addition, says Kob, "the resident and future buyers, not the co-op, would be responsible for maintaining the newly installed sleeve and the wall into which it was cut.  That includes damage to surrounding apartments that may result.”If you live in a landmarked building or district you’ll have to get the go ahead from the Landmarks Preservation Commission too. 

Good luck with that, especially if the altered wall will be visible from the street.  “Landmarks would never allow it,” says Kob.Because a PTAC is hooked up to the building’s water, the units need to be rigorously maintained to get rid of clogs that can cause leaks. These can go unnoticed for long periods of time, causing floors and walls to buckle and often damaging apartments below the one in which it’s housed. Damage from PTAC units is, in fact, among the most common apartment insurance claims in New York City, says Jeff Schneider of Gotham Brokerage, with an average claim size of $5,000.In addition, PTAC units are prone to the musty, mildew-y odor known as 'dirty sock syndrome', which is generally thought to be caused by bacteria and mold accumulating on heat pumps.  The PTAC’s dual heating and cooling functions make them susceptible to it. Frequent professional cleaning can help sometimes, but the problem has no good solution; the very nature of the PTAC unit makes it susceptible.  

Summer's coming: Here's what you need to know as a/c season nearsThe Appliance Doctor: Quick fixes for impatient New Yorkers in a high-end appliance worldIs spending $350 to get your a/c cleaned worth it?Care for some mold with that a/c?Dear Ms. Demeanor: Irreconcilable air-conditioning differences3 ways to get around a/c-unfriendly window barsAsk an Expert: Best apartments for central a/c?The cost of cool: Tipping advice for a/c seasonWhy you mite not want to use your a/c just yetYou can temporarily lift this restriction by proving that you're human:Noise is unwanted sound and needs to be considered when designing HVAC equipment. Air conditioner noise is unavoidable but it can be minimized with the use of insulator, rubber and other noise absorber materials. Good equipment design plays a big factor in the air conditioner noise emitted by the unit.In mini split system, the typical sources of noise is the condenser which is located outside the house and the evaporator which is inside the house.

The typical air-cooled condenser consists of the compressor, fan, coil and expansion valve. The compressor emits the highest sound pressure and the sound pressure increases over time due to the wearing off of the vibration pads that are used to mount the compressor to the metal casing. Other factors include the wearing off of the components in the compressor such as the motor, valve and other mechanical component.There are not much you can do to a hermetic compressor as you will not be able to access the internal mechanical parts. If the noise comes from the mounting problem, this can be solved else you will need to replace the compressor for good.Sometimes, the noise can come from the leaves and other material that block the fan blades from rotating properly. Check also the bearings of the fan motor which can cause imbalance to the fan.The indoor unit or evaporator consists of electronic control, cooling coil, air filters and blower. The noise usually comes from the fan. Over time, dirt and other materials may block the movement of the fan blades and the air. 

Hence it is always a good practise to clean the air filters regularly. Internal parts that are not easily accessible should be cleaned by qualified technicians. Check also the bearings of the fan motor.Sound waves are generated due to a changing of air pressure and travels in all directions. The strength of the sound decrease with the distance from the source. The measurement of the sound pressure is usually taken from about 3 feet from the source. For most people, the sound frequencies from 1kHz to 4kHz are the easiest to hear.The typical sound pressure is as shown in the table below. The human ear hears the same loudness for sound pressure even though with different decibels for different frequencies. For example, the loudness at 93dB(50 Hz) is the same as 87dB(5 kHz).The measurement unit usually used is dBA instead of dB. The dBA unit means that the sound pressure is measured using a standard "A" filter that has been placed in the microphone. This filter decreases the amplitude of the low frequencies but letting the higher frequencies pass through.