With October drawing to a close and cooler temperatures on the way, many buildings are about to turn on their heating for the first time. This month's Green Building Tip highlights three simple methods to reduce heating costs over the winter.   

According to the Urban Green Council, leaving an uncovered window AC unit in over the winter is roughly equivalent to leaving a 7.6 square inch hole in your wall, and costs a typical homeowner between $32-45 a year in unnecesary heating consumption per unit.  

While the ideal solution is to remove the unit entirely when not in use, a variety of cover solutions are available if this is not feasible. Many of these options feature two part covers to seal both the indoor and outdoor portions of the unit. 

Instead of simply switching the thermostat switch from "Cool" to "Heat", you should also consider reducing the temperature setpoint to 68°F. Humans adapt to the conditions of the climate around us, so cooler indoor setpoints are acceptable when the exterior temperatures are low and vice versa. Harvard's official temperature policy allows a winter heating setpoint range of 68°-71°F and a summer range of 74°-76°F

One simple solution for making steam or hot water radiators more effective is to place a reflective metal foil between the wall and the heating coils.  While pre-made products are now available for this specific purpose, DIY aluminum foil secured to either styrofoam, cardboard, or balsa wood could work as well. The 'shiny' side of the foil should face the interior of the room, and it's important to maintain a gap between the barrier and the radiator itself to maintain proper airflow over the coil.

The foil acts a radiant barrier, preventing heat energy from being absorbed in the wall and instead reflects it back into the space you're trying to heat.