In addition to those required by law, the inspectors at Regal Home Inspections, LLC also carry other tools that are helpful, informative (for the inspector and buyer) and provide for a more comprehensive inspection. One such tool is a thermal image (TI) camera that allows the inspector to, “see” in the infrared light spectrum. The human eye can’t see in the infrared light spectrum but a thermal image camera can.
Thermal imaging is used to help confirm the operation of radiant floor heat and can help identify areas of a wall or ceiling missing insulation and even help identify leaks. The tool uses temperature differences to help identify problems. For example, a section of exterior wall that may have missing insulation will radiate the heat or cold (Depending on the season) into the house differently than a section of the wall that does have insulation. The thermal image camera can detect those small temperature differences and give us an image that identifies the areas in question. Radiant heat in the floor has heating coils that provide a very subtle heat that can’t be seen by the naked eye and can’t be felt by your bare feet or if you put your hand on the floor. An example might be to compare radiant heat to a forced hot air heating system. When the forced hot air furnace is on, you can feel the warm air at the air supply registers and you know that it’s working. The air coming out of the air supply register may be 85 – 110 degrees and you can usually feel the heat with your hand and you can feel the air coming out which is how you can verify that the furnace is working. With radiant heat, if you want the room to be 72 degrees, the radiant floor heating system may make the floor 74 degrees. That’s not a big difference and hard to detect with your hand or foot.
However, a thermal image camera can easily see that small and subtle heat difference.
In this first example, I simply placed the palm of my hand flat on a wall for about 10 seconds. In those few seconds heat from my hand went into the wall. One of nature’s laws is that heat moves toward cold. So, heat from my hand (warmer than the wall) moved into the wall. And the thermal image camera could see the residual heat left, on the wall, from my hand.
During a home inspection, differences in heat on a surface can be of the utmost value. For example, a toilet that leaks on the 2nd floor of the house may cause water to get into the drywall of the ceiling below. Now, without getting too technical, another concept that makes understating thermal imaging a little easier is the concept of Thermal Mass. Everyone knows that it’s easier to heat a cubic foot of air than it is to heat a cubic foot of rock or even wood for that matter. They have different thermal masses. A material (Let’s use drywall for example) that is dry has a different thermal mass than the same material that’s soaking wet. In floor tile, as a radiant floor heating system starts to heat the tiles the heat moves into the tile slowly and if viewed at the right time, one can see the heating coils in the floor. If left on for an hour, for example, eventually the entire floor should reach the same temperature but for a period of time the floor has areas of different temperatures. That’s where the thermal image camera can identify the areas where the coils are and the heat if radiating from. So just like the other tools in a home inspector’s tool bag, the infrared camera helps with the gathering of information, good or bad, in the home inspection process.
Is a thermal image camera always used? No, it’s not. In the training for the use of a TI camera, the National Association of Home Inspectors classes say that the TI is sometimes step 1 and, for example, a moisture meter, is step 2 to positively identify a moisture condition. Sometimes, the signs of a moisture problem are visible to the eye and I go straight to step 2 which is identify the elevated moisture condition with a moisture meter. It’s a judgement call based on the facts as they present themselves and the situation.
On a related note the inspectors at Regal Home Inspections have also added a laser level to the tool kit. A laser level is very valuable in identifying floors that are not level and quantifying (Measuring) the amount of slope that a floor may have. Again, in the preparation of a home inspection report, the addition of good information and data points are valuable to providing facts, not just opinions.