If the kids left the door ajar with the air-conditioning running, you’d close it. If the windows were open and it grew too chilly, you’d shut them. If a tree crashed through your roof, you’d get it fixed.
But, if you’re like me, you’re probably ignoring the reality that your home has hundreds or even thousands of hardly visible points of ingress and egress where air flows in or out. All those tiny spaces make most homes, even new ones, one-and-one-half to four times as leaky as they should be.
That’s what I learned when I finally scheduled our home energy audit and trained technicians scoured the house for cracks, gaps and all sorts of inefficiencies, pinpointing where your heating, cooling and electricity dollars are going to waste.
My home, they told me, was behaving like a giant fan, pulling in air from below and expelling it above, robbing me of 30 to 40 percent of any heated or cooled air.
The Unseen Culprit
Every home has a point of neutral pressure. Below that point, cooler air will be drawn in any gaps. Above the neutral point, warmer air escapes through any openings in a process called conductive looping. Turning up the thermostat makes it worse, for increasing the flow of warm air is like turning a fan to high.
Nor will more insulation do the trick, because insulation doesn’t stop air.
The solution is to stop air going out and air coming in.
A batt of fiberglass insulation peeled from the attic floor revealed the evidence of rampant airflow. Where the fiberglass overlapped the framing from the walls below, the underside was plastered with dirt and dust. Yuck!
Another source: Cavities between the studs in a wall and the joists of a floor act as natural ducts, channeling air from below up to the top.
To dramatize the airflow, my technician attached a red-cowled blower to the front door. Having sealed the house as tightly as possible, he fired up the fan. In a house perfectly sealed, our ears would have popped in the vacuum. They didn’t.
That imperfection is good in another way, too. Houses need to breathe, and so do people. A healthy house exchanges 35 percent of its air each hour.
The blower fan allows energy auditors to extrapolate how much airflow a sealed house allows. Standing before a closed door, I felt a strong flow of air coming from within. At the top of the basement stairs, air came at me as if a fan were directed my way. Even around some door and window frames, I could feel a stirring.
By the time the fan powered down, I was not surprised to learn that my house was allowing almost three times the ideal airflow.
Getting It Right
How to stop the airflow? The process is a pretty straightforward matter of caulk, spray foam and weather stripping that could be undertaken by a fairly capable weekend warrior.
Once the leaks are sealed, comes the harder job: beefing up the insulation anywhere an inside surface of the house comes into contact with the outside.
What surprised me most was the problem of the attic.
Think of that unfinished space as the outside, I was told. Seal it off from below and blow in insulation to more than double the present depth. Then close it off for good.
If I could give up that space, I’d be shrinking the space needing heating and cooling. Better yet, with all that insulation, I would be isolating the attic’s extreme temperature swings and keeping that conductive energy from affecting the living space. Without enough insulation, an attic in summer is a giant radiator.
A final report spelled out my home’s shortcomings, often with accompanying photos, along with the steps to correct the faults. At the end, these suggestions were broken into three differently priced packages, from fixing everything — under $15,000 — to focusing on only the most egregious problems — around $8,000 — to something in between. All three bids qualified for a tax credits or rebates. Depending on the work done, my energy savings would amount to between 10 and 20 percent.
My home energy audit cost only $100, about the same you can expect to pay. The rest of the cost — about $300 for homes up to 3000 square feet — is subsidized through Maryland’s Home Performance with ENERGY STAR program. Utilities are the middleman, certifying contractors to make energy audits and suggest specific improvements and their energy savings. The work itself is eligible for rebates up to $7,500.
When you add in the rebates and the point-of-service installations, you might think the program was free. But in truth, you and I and every other person with an electric bill in Maryland is already paying for it. As part of the Empower Maryland legislation to reduce energy consumption, every utility bill in Maryland includes an eight- or nine-cent monthly surcharge to underwrite the cost of home audits.
Start your home energy audit with your utility:
• BGE customers: www.bgesmartenergy.com/residential/home-performance-energy-star
• SMECO customers: www.smeco.coop/save-energy-and-money/home-performance.