Insulating Your Old Home

By Lisa Hassler on January 25, 2019

As the Cape and the rest of the northeast wades knee deep through winter, homeowners, and in particular historic home owners, are making sure their homes are prepared for the cold weather too. Old houses, despite their beauty, have the tendency to be drafty. If your house hasn’t been completely remodeled to contemporary standards, your windows are likely single-paned, your plaster walls are uninsulated, and let’s face it: the overall construction of your home is just old. There is bound to be a crack somewhere. So where does one begin? Let’s start with windows.

Original double-hung window in an 18th century Connecticut cape

Single-paned windows featuring the original glass are treasures to hold. I personally would sacrifice comfort (along with my wallet) to preserve them if I had no other choice. Luckily, historic homeowners have many options to retain their original windows without sacrificing anything. Start with detecting any drafts your window might have. The easiest and most effective way to do this is by blowing smoke against the corners of the glass. Cigarettes aren’t necessary; incense, a smoke pencil puffer stick, or even a home inspector’s draft detector will do the job. Once you pin point where the drafts are coming from, reseal them and add weather-strips to increase the insulation.

Interior aluminum storm window in my bedroom

After the drafts have been taken care of, it’s time to consider storm windows. They’re nothing new; storm windows have been around for centuries and many old houses today already have them. My house, built in 1830, has the old aluminum storm windows from the 70s which are not so pleasing to the eye, but do the trick. Other homes are lucky to still have the original wooden storm windows from the 19th century that tend to blend in with the exterior of the home more and are only slightly noticeable. In recent times, many preservationists have opted to use interior storm windows which are nearly invisible and a fabulous choice for those who do not want to compromise the historic authenticity of their home. With various options to choose from, like glass, acrylic or polycarbonate glazing, interior storm windows are easy to install and remove and are surprisingly cost effective. Whichever type of storm window you choose, make sure each panel is functioning properly, and they’ll be sure to block those icy drafts that gust right through your single-paned glass. 

Installing batts in the underside of a roof (Photo by

Moving on from the windows, arguably the most important place in an old home to insulate is in the attic. Statistically, 30-40% of heat is lost through the roof. Heat rises, so increasing the insulation within your attic is crucial for conserving the heat within your home. Fortunately, attics are the easiest room in the house to insulate. They’re usually unfinished, so adding batts (fiberglass insulation that comes in rolls) to the underside of the roof or to the attic floor is incredibly effective and simple to install. The only thing to keep in mind is ventilation. Make sure your attic has at least one source of ventilation (i.e. traditional gable vents or another type of vent) to prevent moisture from being trapped inside and creating wood rot.

A hidden treat discovered while restoring the plaster walls of an 18th century tavern in Long Island, NY.

Many people ask about insulating the plaster walls of an old house. My advice to them is to leave them alone. You might ask why and I’ll assure you that you will do more damage to your home than good by drilling holes into the plaster and blowing in insulation. Plaster walls were constructed without a vapor barrier the way sheetrock walls are built today. When moisture clings to plaster walls and enters through hairline cracks, outlets, etc., the foam insulation will trap the incoming moisture, eventually causing dry rot and mold. This excess moisture can also attract termites, and even cause exterior paint failure on wood siding. If that isn’t bad enough, the pressure from the insulation foam can expand and crack the walls, and in particularly bad cases cause structural damage to the entire house! All that being said, it is best to leave the walls as they were built two hundred years ago and focus on the alternative methods.

This fireplace heats the entire first floor of my half cape

Historic homeowners are a special breed. Instead of striving for flawlessness, we embrace our home’s quirks and imperfections: squeaky floorboards, crooked walls, and yes, a little draftiness. It’s all part of the character. That still doesn’t mean you need to go broke and freeze this winter! As you see, there are many ways to add some extra insulation to your home without compromising its historical integrity. Let’s also not forget those fireplaces of ours serve more than an aesthetic purpose– they create warmth! So, as we curl up with a cup of cocoa and watch the snow fall this winter, turn down the heat and throw a log on the fire. You and your home will be toasty in no time.