HVAC is the home’s heating and cooling system. In a forced-air heating system, the furnace feeds a main supply duct. This branches off to other ducts that lead to the various rooms of the house. Other ducts circulate cold air back to the furnace. Ducts that service the upper floors of a house usually rise straight up through the cavities of wall studs.

Some homes use a passive heating system, one that does not employ the use of a fan. A hydronic system, for instance, uses hot water or steam and a network of pipes to circulate heated water from a boiler to heaters located throughout the house; whether baseboard, convectors, or radiators.

When renovation projects alter the plumbing, wiring, or HVAC system in any way, it is important to accurately map out each of these systems when still in the planning stage. This can be a complex process, as investigation of the course of pipes, wires, cables, and ducts can be difficult to chart. Yet, knowing exactly what is behind the surface of walls, floors, and ceilings – before work begins – is essential.

Key points to remember before beginning any project that will alter your house’s plumbing, electrical wiring, HVAC system, or structure in any way:

• Accurately assess the structure and system of your house, and draw up a detailed diagram.
• Draw up a detailed plan of your home renovation project.
• Show your plans to a local building inspector for approval.
• Obtain all necessary permits that may be required before work begins.

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The Comprehensive Guide to Home Renovations