Remodeling for Energy Efficiency
Can a 150-year-old house approach net-zero energy use? Three case studies point the way from the 19th to the 21st century.
Synopsis: Building a new house with state-of-the-art energy-efficient techniques isn’t so hard to do. Remodeling a old house to make it energy smart is a much more difficult task, but it can be done. Building-science specialist Betsy Pettit offers insights on how to update an old house for energy efficiency based on lessons she learned in three projects she worked on, with the long-term goal of renovating for net-zero energy use. In addition to details for three case studies, this article includes sidebars on the seven steps to net-zero energy use and one about the amount of insulation a house needs.
Magazine extra: Read Flashing Replacement Windows for a step-by-step guide to preventing future leaks.
In America, there are around 58 million houses that were built before the last energy crisis. Because these pre-1970s houses have little or no insulation, they are all ripe for energy-efficiency improvements. Houses eat up 20% of the energy used in this country and account for 21% of the carbon dioxide that contributes to global warming. This adds up to a huge opportunity.
America’s old houses can be made much tighter and can even approach net-zero energy use. Here, I’ll highlight three houses that my company, Building Science Corp., has renovated. Each house had different limitations and learning curves. I share one of the houses with my husband and business partner, Joe Lstiburek, and two of them have been used as our office space.
Renovating an old house is an expensive process. It’s also a delicate process because the end product must retain its charm. Most old houses are still around because people love their timeless form, floor plan, trim, details, and historical significance. Renovating an old house is a surprising and challenging process because many of them have undergone numerous renovations over the years. You never know exactly what you’ll find.
In old houses, most systems are at the end of their useful life
A hundred years can take its toll on infrastructure, and this is often the case with old houses. The water line from the street, electrical wiring, plumbing, mechanical systems — all are often nearing the end of their life. It would be foolish to renovate a house without replacing these basic systems. Windows often no longer function as intended, either. Their ventilation properties are hindered by layers of paint, or they simply became swollen shut years ago. If neglected, siding can need repair or replacement, too.
And while the shape, floor plan, and details of an old house allow it to endure, people often think they need an addition to provide another bathroom, bedroom, office, or better views. Then they spend money building an addition, only to spend all their time in this new space because the rest of the house is uncomfortable. They don’t really get more space in this deal; they get a smaller space that’s comfortable.
Energy upgrades are cheaper than you think
While the cost of fixing wet basements and adding bathrooms can add up quickly, energy upgrades don’t have to put things out of reach. In fact, they don’t really cost that much more because they’re integral to the decisions and choices made in the renovation process.
If you consider a renovation as a whole system, you might find that you can add modern conveniences (such as an extra bathroom, bedroom, or office space) and comfort without building an addition, and reduce your energy costs in the process. The basement and attic are already built; you just need to use them. By adding rooms in the basement and attic, you often can reconfigure the floor plan to accommodate an extra bathroom, a larger kitchen, or a master suite.
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