Your older or historic building operates differently than a modern building, so you should take deliberate steps to improve its conditions.

First and foremost, make sure you investigate the many low-cost and minimally invasive passive heating strategies before opting for an entire new system. Service your furnace each fall and be sure to change out filters regularly to maximize airflow and the efficiency of your heater. Or consider a zoned heating system with separate controls for spaces. Installing a programmable thermostat is another way to keep your home warm when you're there and cooler while you're away. Also, close your damper when your fireplace is not in use to avoid a major source of heat loss.

Useful Links

• National Park Service guides to energy-efficient HVAC systems. 
• A guide to mechanical systems in historic houses from the National Trust for Historic Preservation.