Capitol Hill Restoration Society

HVAC & Insulation – Preservation Cafe

Posted on October 22nd, 2016

Patrick Murphy Murphy of Harvey Hottel HVAC/Energy Solutions led the October 20, 2016 Preservation Café on “HVAC and Insulation – Comfort Solutions for Historic Rowhouses”.Patrick has many years of experience in the HVAC business,
as an installer, sales representative and energy modeler. The company focuses on designing and installing HVAC systems as well as spray foam installations of renovations and additions to historic homes.
The presentation focused on the many HVAC and insulation choices that can be used on Capitol Hill homes.

The exterior envelope of a house is made up of several components: the walls, roof, slab/crawlspace and their openings (doors, windows, skylights). The key to a comfortable interior is to seal the exterior, unconditioned air from penetrating into the interior of the house (air sealing). One way to do so in an older home is via spray foam insulation. Spray foam application is recommended in tight and hard to reach places, such as the rear portions of attic spaces under a low-slope roof or at furring against a brick wall, where no insulation existed before and interior oor space loss needs to be minimized. Of the two types of spray foam, open-cell is recommended over closed-cell when encapsulating an attic space, since it lets water through in case of a leak and is more cost-effective.

Examples of HVAC systems discussed by Patrick included:

Split system. The most common forced-air system found on Capitol Hill, the ideal split-system has gas heat and electric cooling. The air handler should be located in a conditioned space (encapsulated attic or an interior closet) while the condenser can be located on the roof. The two parts are connected by refrigerant lines.

Rooftop package units. These systems are completely outdoors, so they save on interior oorspace. The exterior ductwork needs to be insulated.

Mini-split systems. These electric-based systems are great in small areas due to lack of ductwork. The interior units condition each space they are installed in, creating a multi-zoned system that is energy efficient.

Gas boiler with radiators. A traditional heating system found in many Capitol Hill homes, the radiators heat rooms e ciently without introducing dry air in the wintertime. New radiator systems are more compact than older boiler-fed systems.

Glad to answer any HVAC or insulation questions, Patrick can be reached at (240) 449-8589 or