The roofs are alive with the sound of HVACs

August 10, 2017 7:32 PM

What will residents living in a group of houses (25' tall, 1200 sq. ft) have to endure sound-wise if a nearby apartment development places their HVAC system 45' up on the roof of their structure?

A large proposed development (48,000 sq. ft) of 150 apartments may be built about 200' away from a group of neighboring small houses 25' high? The developers plan to place their HVAC equipment on their roof above the 45' roofline. How noisy is this HVAC equipment likely to be for houses in a setting that is currently very quiet?

posted by Elsie to Home & Garden (5 answers total)

Given the 200' horizontal distance and the 45' vertical difference, I think it's highly unlikely you would hear anything at all when inside the existing homes with the windows closed. When outside or with windows open, it's possible that you'd hear a whir, but I think it's unlikely to be a substantial amount of noise. Keep in mind that the HVAC equipment will be serving a new block of apartments that would be rather less desirable if the drone of loud equipment were omnipresent.
posted by EKStickland at 7:46 PM on August 10, 2017 [5 favorites]

Honestly, I wouldn't expect this to be a problem. The external portion of a residential HVAC system consists primarily of a refrigerant compressor and a fan, neither of which is known to be especially loud. On top of that, one of the advantages of a rooftop unit is reduced noise, since it is both physically farther away and much of the noise travels up rather than along the ground reflected by building walls. You already likely have dozens of the same sort of sound making equipment far closer to your home in the form of your neighbor's air conditioners. You'd probably have a hard time hearing the sound they make from 200' away.

Personally I'd be more concerned with other loud noises an apartment complex can bring, 150 units is a lot of people introduced into the area, so I wouldn't be surprised to hear loud music, cars coming and going, kids playing, etc etc.
posted by Mr.Encyclopedia at 7:50 PM on August 10, 2017 [4 favorites]

Do the houses also have air conditioning (and so leave their windows closed on hot days).

Depending on how much city / road / air traffic is nearby, it shouldn't be too noticeable, and most small HVAC units are designed to be quiet. Putting them up high (and even better, with walls or the roof detail covering them), means most of the acoustic noise points straight up.
posted by nickggully at 7:51 PM on August 10, 2017 [1 favorite]

I spent 3 years in Facilities at a university, and was on the roof with several HVAC units like what would be in this building. You can't hear anything until you're right up there, there's no real chance of hearing it from the ground.
posted by deezil at 8:02 PM on August 10, 2017 [1 favorite]

Unless the HVAC people are utterly incompetent, this will not be a problem. You'll know if they're incompetent as shortly after you hear anything you'll see their roof catch fire.

...however, if you're genuinely concerned (enough to spend $), hire someone to do a before-and-after sound survey. A professional -- having some kid stand around with a Harbor Freight sound meter will not suffice. If the existing residents find themselves disturbed by the new noise, that sound survey will be very important -- just also understand that the sound survey is very likely to find their concerns are not valid.
posted by aramaic at 9:42 PM on August 10, 2017 [1 favorite]