the only non-destructive way i know of would be to use an infrared camera to see the hot/cold spots onthe walls. it won't tell you just how much insulation is there, but if the wall shows real cold you know it is not enough!

The only thing I can think of ,that is non-evasive is using thermal imaging to find the heat leaks. Best way is to find a home inspection service that does this.

anggi821,

Using caution! You can remove receptacle and switch plate covers on an outside wall. Maybe there is already a gap between the electrical wall box where you can see into the wall cavity. You may be able to make a small hole in the wall board/plaster, just above the wall box where the cover plate (When reinstalled) will cover. Kill the power at the electrical panel main before trying this.

Take Care,

Dan Martyn

Check with your electric company to see if they will do a heat-loss inspection. There were freebies for a number of years in the DC area.

Although my present house was built 1940's, when we remodeled the kitchen we discovered that neither subflooring nor flooring extended more than a few inches beneath the cabinets! Yikes, no wonder that floor was cold! Friends with 60's era houses have found the same thing, so that may be common practice.

I live in the Cleveland area. 1961 was right at the front end of the mmmm lets add more insulation erra... My house only has r 7 in the side walls. ( buit in 1967 ) So when I reside I will add more then or take out the old and foam.

Be brave DRILL A DARN HOLE. Drill it low ( not eye level)
Drill a few so that you have a good idea of what you measured. If you use a 1 or 2 inch hole saw you can replace the plug and fill it in with spackling and paint.

I replaced the furnace with 95.5% eff cut the bills in half.

Scott

Remove the outlet covers and probe a metal coat hanger between the box and the drywall or plaster. Move it up and down and feel if you have any resistance. Put some honey or sticky stickum on it and probe again to see if anything sticks to it. Most time you can see between the box and plaster with a good flashlight. Paper insulation can compress over time. So if you find paper then you will have to bust a hole higher up in the wall and see how high it remains. Spray in foam insulation for existing walls is available and is very efficient insulator as well as expensive.
Get a Raytec Minitemp lazer temperature gun and check the wall temperatures. If it's 2-3 degrees below the room temperature then you likely don't have insulated walls. The Raytec will also help you find cold spots and warm air leaking out of the house.
I have no insulated walls. They read 61 to 65 at eye level.
The outside air is 33. Right now my room thermometer at the 5 foot level says 69 degrees. The ceiling temp is 64 to 75 degrees in my 550 square foot work area. (Above an unheated and uninsulated basement that reads 41 degrees warm.
The attic is Insulated with cellulose.)
The floor and bottom of the walls have readings of 58 to 70. The 70 is right below my ceiling fan, which I just cut on high speed. Two insulated doors read the same as the walls but at the space between the doors and trim it's 54 in the low areas. The higher speed fan blowing more warm air down is helping things feel warmer here now plus I refilled the water in the empty humidifier. I got cold earlier before I noticed the humidity had gone down to 36 percent. It took a couple or three hours to get it up to 50 percent but now it's toasty.
Find the leaks and check your humidity.

"Put some honey or"

DO NOT put honey or any food food inside your walls. That's a great
way to attract insects or other vermin into your home.

Regards
Chris