When building a new home, it pays off to think about energy efficiency, as many construction details done incorrectly or missed altogether can leave a lasting effect on a home’s energy consumption. Yet armed with knowledge, some easy-to-come-by materials, and a little elbow grease, an existing home can be made more energy efficient. Indeed, “weatherizing” a home has become a popular way to save money in the face of rising energy costs. This fall, a handful of Deltec employees are getting together to tackle easy opportunities to weatherize each others’ homes.
Last Sunday we took on the home of our Director of Engineering, where, even having only one weekend morning to work, we found and corrected two all-too-common energy efficiency shortfalls:
1. Leaky Band Joist
This basement, like many basements, is built of cinder block walls. The wooden components of the house above; the floor joints and wall framing, sit directly on top of these concrete walls, often with nothing at all installed between wood and concrete. This makes for a junction that is far from airtight, and in many places we could see light from outside through the gap between wood and cinder block. Not only was this gap allowing cold air into the basement in the winter, making downstairs TV watching far more chilly than necessary, it was letting in that cold draft right underneath the floor of the house upstairs. The homeowner had commented that the floors near outside walls sure were cold in winter!
The fix was relatively simple: we sealed the gap between wood and concrete around the entire perimeter of the basement with silicone caulk.
2. Leaking Air Ducts
Duct-work is designed to bring warmed or cooled air from your mechanical unit and into the living spaces of your home. You would think duct-work would be extremely air-tight, the better to deliver as much warmth or coldness as it can. In reality, most duct-work is anything but airtight, leaking as much as 25%–one quarter–of the air it carries. Most of these leaks occur at joints in the sheet metal that make up ducts.
In this house, we covered these seams with a special kind of fiberglass tape–NOT duct tape, which loses it’s stickiness throughout several seasons of temperature swings–and painted over the tape with a good thick layer of duct mastic. Duct mastic comes in a tub at a home improvement store and looks and feels like putty–but dries into a tough but flexible air-tight material.
Stay tuned for more home energy efficiency projects we will do for each other.