Answer
May 06, 2020 - 11:33 AM
The most straightforward way to tell is by looking inside your walls. Unfortunately, that can also be destructive. Regardless, if you have a drill and can drill a ~1/2" hole in the wall of a closet or other such space, you can look and feel what's on the far side. If you find shredded newspaper material or fiberglass insulation, then your walls are insulated. This method has the advantage that you can do it during any season. That's what a MassSave energy assessor will do during his or her visit to your home.
During the winter, you can get an indication of your level of insulation if you have a way to measure the temperature of your walls. If the wall temperature is substantially below the nominal air temperature in the room (e.g., if your walls are 60 degrees with the thermostat set to 68), then you likely don't have insulation, or at least not much. You can measure wall temperature using an infrared thermometer, which costs about $25-$40 (and is useful for checking refrigerator and oven temperatures, too!).
If you don't have insulation, then MassSave will likely give you an excellent deal to fill them with densely packed cellulose (shredded newspaper, essentially).
If you are planning to replace siding on your house, it is an opportunity to consider installing rigid foam insulation underneath the new siding. You should discuss it with a siding contractor, paying careful attention to whether he/she is very familiar with installing such foam insulation. Poorly installed insulation may damage the house by accumulating moisture inside the walls.
