New York is a historic city, settled by the Dutch in the 1600’s. There are actually quite a few structures dating back to the mid-17th century. As a result, we have many unique and beautiful historic buildings mixed in with the glass and concrete high-rises throughout the city. Many of those older buildings are protected by law and must be renovated according to strict rules for historic buildings conservation. That impacts an HVAC retrofit or replacement that’s typically needed to restore a historic space to a condition that works for a business or even a luxury residence.
Here at Arista, we have been working on historic building renovations for decades (no, not since the 1600’s but we’ve been at this for a long time!). So we’ve learned a thing or two about the unique requirements of historic spaces for HVAC.
Last week, we shared the first article in a two-part series about some of the issues you need to address with an HVAC retrofit or replacement for historic buildings. In part 1, we began with a list of 9 DOs when installing HVAC solutions in a historic space.
In case you missed it: HVAC Solutions: DOs and DON’Ts for Historic Building Preservation
Today, we’ll reveal the all-important HVAC DON’Ts for historic buildings conservation in part 2.
HVAC retrofit or replacement: DON’Ts for historic buildings conservation
1. DON’T install a new system unless you need to
Even when you’re making structural fixes or cosmetic changes to meet the needs of a new commercial tenant, it’s possible that the existing HVAC system, or components of it, can be salvaged for the sake of historic buildings preservation. That’s especially true of the heating system. For example, you may be able to keep the old radiators and replace the old boiler with a new one. Or, consider an HVAC retrofit to add AC to parts of the building not cooled by an existing system.
There are some situations where a repair or an HVAC retrofit may be a viable option for historic buildings conservation. There’s one caveat to be aware of, though: think carefully about keeping AC systems that use the old R-22 refrigerant. That refrigerant is currently being phased out due to the environmental impacts, and getting R-22 is becoming more difficult and expensive every day. That means you may need to consider a replacement system that uses one of the newer refrigerants.
2. DON’T forget to consider modern HVAC options for historic buildings conservation
If an HVAC retrofit will not meet your needs, don’t assume you have to replace an older system with the same type of older system! There are newer HVAC technologies that have significant benefits for historic buildings.
A variable refrigerant flow (or VRF) system is one such option. For one thing, these system don’t typically require ductwork, which can be a boon when you’re trying not to damage existing walls, ceilings and building structures. Also, the system consists of multiple air handlers which are smaller and take up less space.
What’s more, these new systems are extremely quiet, energy efficient and customizable for zoned operation.
3. DON’T cut through exterior walls
In many buildings, it’s standard practice to cut holes through exterior walls to install what’s called “through the wall” HVAC units. This is usually forbidden by building regulations for historic buildings conservation. That means an HVAC retrofit to add a small unit onto an existing system might not be an option.
In some cases, you’ll have to get creative using existing penetrations through exterior walls, and consider ductless systems.
Related article: Ducted vs. Ductless Air Conditioning? How to Choose
4. DON’T alter historic architecture
Just like you have to be creative to avoid cutting through the exterior, it takes some expertise to find solutions that avoid altering architecture in a historic buildings conservation project.
Here are some of the things you should avoid doing whenever possible: avoid dropping ceilings, covering window openings, masking historic features or altering spaces to make room for HVAC equipment. If you are creative, there is usually a way to do it without destroying original architecture.
We could tell you so many stories to illustrate that point! Take a look at this previous blog to see what we mean: Residential HVAC Services: Innovation Improves Cooling in NYC Luxury Homes.
5. DON’T make condensing units or vents an eyesore
Aesthetics is a primary concern for historic buildings conservation. That includes both the interior and exterior of the space. Whether you are completely replacing the HVAC systems or only doing an HVAC retrofit, placement of equipment is extremely important.
That means, don’t put condensing (outdoor) AC units on a visible part of the roof. Don’t add vent pipes that ruin the asthetics of the roof line. If you must put a condenser in a visible area outside, at least use some creativity to hide the unit.
Read this related article for some great ideas: 15 Creative Ways to Hide Your Outside Air Conditioner
6. DON’T introduce moisture that can damage older structures
An HVAC retrofit or replacement, done as part of a historic buildings conservation project, requires the expertise of trained HVAC professionals. Be sure you choose a company that is experienced with older buildings, because if you’re not careful with the installation you could end up with condensation damaging the historic building structure.
Water leaks can stain walls and ceilings, and uncontrolled humidity can damage woodwork and expensive finishes.
7. DON’T skip regular preventative maintenance!
As we stressed in our part 1 article, investing in HVAC preventative maintenance is a smart move for any business, but it’s a must for those located in historic buildings. Not only are the consequences higher when something breaks (see the previously cited article about water leaks!) but the costs for repairs can be higher because it’s harder to access equipment and ventilation systems without harming building finishes.
Imagine the repair costs and building damage that you could face if a blocked drain causes a slow water leak that spreads mold through the walls before anyone notices?
That’s just one reason that our last DON’T may be the most important of all.