Today, we are not pinching nickels, but degrees.
I mentioned in the last post that it took us until November 17 before we turned the heat on, whereas other Chicagoans fired up their furnaces in early October. Why were we still comfortable several weeks into the cold weather?
Waste heat!
Boiling the kettle, cooking dinner, baking banana bread … Then add in all the electrical appliances that produce waste heat: running the fridge, TV, laptop and desktop computers, having the lights on … all this and more produce some level of waste heat which is welcome during this season. Not so much during the dog days of summer, though.
But wait! There’s more. Let’s not ignore the four critters occupying the space. Two of them two legged, and the other two four legged. Believe me, they all have a healthy metabolism going, based on the heat they throw off! Seriously, body heat from building occupants is not to be ignored – not in the context of a deep energy retrofit.
Let’s think of these heat sources as miniature radiators. Individually, they don’t do much. But cumulatively they begin to matter, if – and this is a big IF – the building is well insulated and as good as airtight. Because now this waste heat doesn’t escape. It lingers around and keeps the building interior at a comfortable temperature when others have long reached for their thermostats.
In this context, your furnishing and the actual interior of your building begins to act as a heat sink – it becomes thermal mass. Your oak dresser, your hardwood floors, your drywall, your bathroom tiles, you name it – they all store heat to some degree, which adds to the comfort.
Another gadget that helps us to delay the start of the heating season in the Energy Recovery Ventilator (ERV). It delivers fresh air into our airtight building envelope, but does so with the help of a heat exchanger. This allow us to recover most of the precious waste heat and yet still get fresh air.