The house I am living in now is over 30 years old, and after many years small gaps have started to in spots letting cold air in during the winter and humid hot air during the summer. Its hard to visualize these leaky spots just with your hands, or by using an infrared thermometer. But by using a thermal camera can that actually see heat loss it all becomes quite apparent. It was in the 20s Fahrenheit when I took these pictures, so the coldness outside was doing its best to enter and would show well on the camera.
I replaced the windows and doors on the basement level a few years back, and we can see how well the glass blocks the cold. Being double paned it helps to block the cold air outside. But it would seem the framing around the window may need some attention.
Taking a look at the door that was replaced we can see the same, the door itself is quite insulated but the framing around seems to have some small areas where its not as energy efficient.
Going back to the new windows we can see the spot right under the frame that may need some attention. The molding will need to be removed to see what's going on.
A few spots seem to have some draft issues, so in the future I will have my handyman 
Another spot that has some leakage is where there used to be a large sliding door. It has been walled off though it would seem where the seams meet some air is finding its way through.
Seems its mostly the bottom and the corners at the top.
Taking a look in my office the windows have been replaced there too, and they are doing quite well, just the gaps between the window frames we can see some heat loss.
I walk back where the windows with the leaks below were seen. I take a picture a little more further away so we can see more of what's going in that room.
Interestingly the cats have always been curious about that window frame, sticking their nose in it and even clawing at it. I guess they can smell the outside through it.
The door lock is quite cold too as its exposed to cold air on the outside of the door.
A crack in the door frame we can see heat escaping.
Now we go upstairs and check out some windows that are very possibly original to the home. They are quite drafty and need attention. We can see how the entire glass is allowing heat loss, compared to my previous windows where only the framing around them show heat loss. The bottom of the window has the most loss, as its where the frame meets with window seal. Over the years the frames have warped along with the windows allowing cold air to enter the bottom of the window frame.
Its quite apparent seen here, maybe adding foam while open and then closing the window will help.
We check out another door that is quite leaky too. Where the lock is air seems to be getting through along with the bottom of the door. Hello kitty!
Closer we can see the bottom right corner has some leak, maybe weather sealing with help.
We had a pet door installed and its a major source of heat loss.
Looking at some larger windows we can see the top pane is quite leaky, just being a single pane of glass it does not stop much of the cold.
Some more leaking, we can also see the heater vent glowing as the heat is running to keep these drafty windows and doors at bay.
The front door needs some attention as well, leaking from the bottom.
Also where the door lock meets the frame we can see some loss.
One of the rooms with a bunch of windows has the most loss. They are double paned, but have failed and now are not working so well. Warped doors and frames are not helping as well.
The windows are leaking where they latch.
At the top too as the rails are old and have gaps in them.
The bottom of the door needs some weather stripping.
Same with this window, maybe foam will help. Otherwise the entire window need to be replaced.
Pretty much every room on this level has leaky doors and windows and this causes our heater bill to be higher than it needs to be.
Glad I broke out the thermal camera and walked around to find major sources of heat loss. Its good to see my new windows and doors are well insulated but as for the framing around they may need some attention. And as for the old doors and windows, it was to be expected and now seeing exactly where the loss is. I can go in there with foam and other weather stripping materials to try to seal off the cold.
