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HVAC Retrofits for Older Buildings

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Many older homes are a popular target for remodeling by homeowners who seek dwellings with vintage charm but demand 21st century amenities. Older commercial buildings are also finding new life, often being repurposed as multi-use commercial and residential developments, a process known as adaptive reuse. Adaptive reuse is just one factor behind retrofitting older buildings. In other cases, older commercial buildings are that are still being used for their original purpose must be adapted for the 21st century.

Ductwork or Ductless?

Many older buildings have handsome architectural features such as crown molding, chair rails and wainscoting that add charm to their interiors. In such buildings, ductwork for HVAC retrofits can often be hidden in attics, behind walls or in other unobtrusive spaces. However, many times such buildings lack sufficient attic or basement space to install necessary ductwork for a central HVAC system. However, homeowners and commercial building owners need not be resigned to sweating out the summer months – or living with loud, unsightly window mounted units.

For such buildings, ductless mini split systems often represent an excellent solution. Like conventional central air units, mini splits are powered by a large compressor, usually installed outside the building. Thin refrigerant lines connect the compressor to unobtrusive units mounted in individual rooms. High velocity systems that use narrow insulated air supply tubing to force cooled air into designated areas represent another alternative for buildings that lack sufficient clearance for ductwork associated with conventional central air conditioning systems.

Electrical Issues

Insufficient electrical capacity is another issue that must be considered, especially when retrofitting HVAC systems into individual homes. Many old homes are only wired for 110 volt- 60 amp service. That’s not nearly enough to power central air conditioning units, which frequently run on 230 volts and 20 to 50 amps. In such cases, an electrician must upgrade all the wiring before a central air conditioning system can be installed in an older home.

Landmarked Buildings

Private homes and commercial buildings that bear local landmark or national registry status present special challenges, specifically in the form of restrictions governing allowed changes to the building. Obtaining the necessary permits frequently also involves obtaining the go-ahead from the landmark agency or registry. However, landmark restrictions are frequently not as restrictive as they might appear at first glance. Specifically, these restrictions typically only cover certain aspects of the building. As a result, the ultimate impact on the ability to retrofit the building with a modern HVAC system is minimal.

For instance, Preservation Chicago cites a number of limitations that are imposed on landmarked buildings, all relating to changes made to the exterior that are visible from the street. In most cases, that means that landmark restrictions are only limited to the front of the house; however, houses located on corner lots may be restricted in changes made to the front and to the side of the house exposed to the street. Preservation Chicago does not impose restrictions on additions to the back of the house. There are also no restrictions on exterior paint color. What this means is that a compressor can usually be installed on the side or in the rear of a landmarked home without colliding with landmark restrictions.

Changes to the interior of the home, including HVAC retrofits, are generally not restricted by landmark regulations – assuming that the installation process is not detrimental to period elements of the home. Specifically, homeowners that wish to take advantage of tax freezes and other incentives associated with landmarked buildings must frequently retain elements such as period ornamentation or fireplaces. Likewise, drafty windows may be replaced with windows that are more energy efficient. However, windows facing the front of the house (and the side of the house on a corner lot) must conform to landmark requirements.

The Bottom Line

Whether an older building is being repurposed, remodeled or simply updated, adding HVAC is not always as simple as installing an appropriate system in new built construction would be. There are practical and potential legal consequences involved with such jobs. Contractors who take on these projects should be aware of the possible complications before taking on such projects, as well as accounting for potential additional costs in their estimates to minimize the risk of taking a financial loss.

Audrey Henderson

Posted In: Residential Buildings

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