Historic Savings: Insulating an Old House for Energy-Efficiency

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Adrienne Bashista and one of her 25 chickens.
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Adrienne Bashista’s historic 1915 farmhouse needed many energy-efficiency upgrades to make it through the cold North Carolina winter. To make the home more efficient, Bashista and her husband got a home energy audit, added insulation to the attic and under the floor, and caulked all cracks they could find in their old farmhouse.
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To improve efficiency in her old farmhouse, writer Adrienne Bashista caulked the gaps between each individual board in her 1915 kitchen’s beadboard walls and ceiling.

In the early 2000s, my husband and I started a business renovating historic properties in central North Carolina. These homes were beautiful, fascinating, full of history–and filled with leaks. They weren’t built to be heated and cooled with central heat and air-conditioning. We dedicated ourselves to finding ways to remain true to these houses’ beautiful historical nature while also providing modern conveniences. Today, our company focuses on renovating historic homes by making them more livable and energy-efficient. By insulating an old house, we preserve its beauty and historical significance as well as its energy costs.

The evolution of our family business from historic property renovators to residential energy-efficiency experts began with our home, a 1915 farmhouse in the heart of central North Carolina. The day we saw this sweet, rustic fixer-upper, we knew we would buy it. The seller knew it was a sure thing when she saw my husband zip up his coveralls to crawl under the house, then climb a ladder to inspect the original metal shingles–water-tight as the day they were installed. We knew quality and charm when we saw it. After all, this was what we did for a living! But, as we soon discovered, thoughtfully renovating an old home to maintain its historic charm was quite different from actually living comfortably in it, especially when it came to heating and cooling.

We thought our house’s interior needed only basic cosmetic work: The original beadboard walls and ceilings begged for a simpler touch than the decorative paint the previous owner had used. The floors needed refinishing, the bathrooms updating. Structurally, the house was sound. The only big improvement needed was to install central heat and air. We were puzzled by the lack of air-conditioning in a climate that regularly sees weeks of 95-degree days, and we thought the individual propane heaters in each room were too complicated and took up too much space. Central heat and air was a no-brainer–until fall turned to winter and we discovered the economics of pumping hot air into a space originally intended to be heated by fireplaces and cooled only by the shade from a deep porch and the blessing of a mid-day breeze.

The first winter we owned our 2,300-square-foot farmhouse, we spent more than $4,000 on heating, and our family wasn’t even living there. The thermostat was set to 55–just warm enough so my husband and his subcontractors could work on the house. The reality of the appealing beadboard walls hit home: Where each individual board touched was a place air could leak out and in, and leaking air meant leaking energy, which translated into lots of money floating out the walls. We must have heated the western half of our small town that winter! Something had to change. So instead of new kitchen cabinets, we switched gears and spent our remaining money and time making our home more energy-efficient. Although our specific house is an extreme case, the lessons we learned about insulating an old house can be applied to all homes, historic or not. Here’s what we did:

Got a home energy audit.

This is our family business now, but at that time the idea was new to us. A professional auditor came to our house, inspected it and made suggestions to make the house more energy-efficient. In an older, inefficient home, a professional energy audit should always be the first step.

Made friends with caulk guns.

Where every individual board of the walls touched, we caulked the resulting leak. I spent two weeks on the kitchen ceiling alone, and when it was time to move to the second floor, we hosted a caulking party where we outfitted our friends with caulk guns and provided pizza and beer to all who’d donate a few hours. We also sealed all the other places air might leak in, including around plumbing and doors, next to the five fireplaces, and in the spaces between electrical outlets and switch plates and the walls. Each of these leaks might have been very small, but together they added up. Even now, five years later, when winter comes and the wood shrinks, we spend a couple of hours caulking cracks in the wall. (Read more about identifying and sealing leaks in Sealing Air Leaks in the Winter Home.)

Added insulation to the attic.

The house had insulation, but it was ancient. In most homes, you can simply add insulation without removing the existing insulation. But in our nearly 100-year-old house, the insulation had been home to a variety of creatures over the years and had gotten dirty and wet. If this happens, it becomes a health hazard and needs to be completely replaced. When insulating old homes, always seal off areas where you’ll be working with old insulation, and wear a breathing mask. We sealed the attic floor with caulk, then we removed the old, dirty insulation and added 10 inches of new cellulose insulation.

Installed spray foam under our floor.

Foam insulation is controversial when it comes to insulating an old house because it can trap in moisture if installed incorrectly and make future repairs more difficult, but adding it made a huge difference in stopping the unrestricted air flow that was coming from under the house. Our floors are made of beautiful, solid, wide pine planks, but that’s all–there is no subfloor beneath the wood. It’s just boards. So, much like the walls, the space between each individual board offered the possibility of a leak, and we had to do something radical to stop the air (not to mention spiders, bugs, moisture and dust) from coming in.

Examined our ductwork.

Our HVAC system was newly installed by a licensed installer, and we assumed it had been put in correctly and leak-free, but we were wrong. The lesson? Even new ductwork can be leaky. Older ductwork is nearly certain to be leaky. Industry statistics say the average American home loses 20 to 30 percent of its conditioned air through leaky ducts–meaning you’re paying to heat air that leaks out before it even reaches your living space! Sealing our ducts made a huge difference.

Installed custom storm windows over the original windows.

We are proud that every window in our house is original. The glass is wavy, the frames are crooked, and they are beautiful. Of course, those beautiful windows were very leaky. Because the house is so old, we had to have custom storm windows made. They sit inside the window frames, blocking air flow, saving money and providing an unrestricted view.

The detective work required to figure out all of these energy-efficiency upgrades paid off: Within a year, we’d reduced our heating and cooling bills by half, and they’ve gone down every year since as we’ve continued to work on our house. Working on this puzzle of insulating an old house also led to a new career. When renovation work became hard to come by in the troubled real estate market, we shifted gears and began focusing on making other North Carolina homes as energy-efficient as ours.

Adrienne Bashista and her husband, Mark, own Home Performance NC, an energy auditing and home weatherization contracting company. Visit their website and read her blog at Home Performance NC.