How to Add or Replace Heating and Cooling Systems in Old Houses

Upgrading heating and cooling systems in an old house can be a challenge because these buildings aren’t designed to accommodate modern HVAC systems. In this blog, local HVAC company Schmitt shares an overview of the best ways to heat and cool old houses.

Air Conditioning

Old houses don’t have existing ductwork, and adding it may not be the most practical choice. Fortunately, there are options designed to work in these conditions that require minimal changes to be made to the home. High-velocity HVAC systems, for example, feature efficient cooling through a compact duct system. It’s equipped with insulated fiberglass and aluminum tubes that are routed through the drywall and ceiling, replacing standard ductwork. High-velocity air movement makes up for the small duct size.

Ductless mini-split HVAC systems, as the name implies, eschew ducts altogether by splitting the HVAC unit into two: the compressor unit, which is installed outdoors, along with the condenser and blower, which are installed indoors. Instead of drilling large holes for ducts, only a small hole is needed to accommodate the supply lines between the two units. HVAC contractors recommend ductless systems for average-sized rooms and small houses. For big, old houses, you may need to have several mini-split units installed.


Heat pumps are essentially reversible air conditioners. When the flow of the refrigerant’s evaporation-condensation cycle is reversed, heat can be generated by the same system instead of cool air. A reversible mini-split system is perfect for old homes that don’t have existing HVAC systems of any kind, as it can be used for both heating and air conditioning.

Existing radiators can be upgraded to more efficient ones. You should consider this if the house still has a fairly efficient boiler. A capable HVAC contractor can help you determine which parts of the boiler/radiator system need to be upgraded, as well as calculate its cost, efficiency and expected life span. Modulating-condensing boilers offer better efficiency by only heating the water as needed, as opposed to heating all of the contents of the tank before circulating it. With these cooling and heating options, you can be perfectly comfortable in an old house.

Call Schmitt for All Your Heating and Cooling Needs

Schmitt is your leading provider of residential and commercial HVAC repair services. Give us a call at (415) 522-0966 or fill out our contact form. We serve customers in San Francisco.