Energy Usage Visualized with Thermal Imaging

Thermal cameras have come down enough in price that a consumer can purchase one for about the price of a mid-range personal computer. In my case, I chose the Flir E4 infrared camera. Up to this point in the article, I’ve been using the camera to take a variety of infrared pictures.

Professionals use thermal imagers for more useful purposes -- usually around energy usage and energy conservation.

Power Vampires

A surprisingly large number of household electronic devices consume power even when turned off. One of the causes is that power supplies are often located before the device’s power switch. Thus, the power supply is converting household voltage to low voltage for the device, even when the device is not in use.

For example, here is an old Nintendo 64 game console that sits unplayed in the family room. The thermal image clearly shows that power is being used even when the device is turned off.

Nintendo 64 powered off infrared Nintendo 64 powered off visible

Nintendo 64 powered off (infrared and visible)

Individually, each device consumes very little power. However, a country full of idle electronics wastes a lot of energy in total.

The U.S. Department of Energy created the Energy Star program to drive the industry to better practices. One of the pushes led to more power supplies based on switching technology, rather than the old transformer bricks. In the thermal image below, two separate 5-volt 1-amp power supplies are plugged into an outlet strip but not plugged into any equipment. Notice the hot spot is in the obsolete power brick.

Power adapters infrared Power adapters visible

Power adapters (infrared and visible)

In any case, I suppose the best advice is to unplug devices or turn off the power strip to which they are connected when not in use.

That won’t solve all of the problems. Some household electronic devices are active all the time. For example, the LED alarm clock in our house is an instantly-obvious hot spot in the bedroom.

LED alarm clock infrared LED alarm clock visible

LED alarm clock (infrared and visible)

A more surprising source of energy consumption is the wireless receiver on the garage door opener. LiftMaster, must it really use this much energy when idle?

Garage door opener infrared Garage door opener visible

Garage door opener (infrared and visible)

But that wasn’t the most surprising of all! I was amazed to discover how much power usage a GFCI (ground-fault circuit interrupter) electrical outlet consumes when nothing is plugged in.

GFCI electrical outlet infrared GFCI electrical outlet visible

GFCI electrical outlet (infrared and visible)

The power outlet caused me to consider another household wiring device. Anyone who has touched a room-lighting dimmer switch after a long dinner knows how hot they can get. The newer ones are much better. This switch temperature is not exceedingly more than the room, and heating only occurs when the lighting is turned on.

Modern dimmer switch full on infrared Modern dimmer switch full on visible

Modern dimmer switch full on (infrared and visible)

Cooling and Heating

A thermal imaging camera is often used to located leaks or inadequate insulation. This is an example of where the camera can pay for itself in a relatively short period of time.

When the air conditioning is turned on, the vents on the first floor should be closed to channel the cold air to the second floor. Unfortunately, sometimes it is difficult to determine which vents are the air returns and which vents are actually closed. The thermal camera quickly indicates dark areas where cold air is coming out.

Air conditioning vent infrared Air conditioning vent visible

Air conditioning vent (infrared and visible)

There is a quote about ceiling fans, “They cool people, not rooms”. Here is a thermal image of a ceiling fan running on high in an empty room. Notice the amount of heat the motor is producing.

Ceiling fan on hi in empty room

Ceiling fan on hi in empty room (visible)

My wife insists that we close the closet doors when the central air conditioning is enabled. I mentally dismissed the notion, based on the eventual cooling of the entire thermal mass over time. This thermal image shows that the walls of closets that abut exterior walls (or attic space in this case) can indeed leak heat or cooling. So, she is right that we can save money and increase comfort by closing the closet doors.

Closet near outside wall poorly insulated infrared Closet near outside wall poorly insulated visible

Closet near outside wall poorly insulated infrared (infrared and visible)

Depending on the internal/external temperature difference and the type of construction in your home, you may be able to view the framing. In this case, the wood beams are more thermally conductive than the insulation between the beams. This difference is enough to be noticeable with a thermal imager.

Wood beams infrared Wood beams visible
Wood beams in sloped ceiling infrared Wood beams in sloped ceiling visible

Wood beams in sloped ceiling (infrared and visible)

Thinner portions of doors show a similar effect.

Modern door lets heat through infrared Modern door lets heat through visible

Modern door lets heat through (infrared and visible)

Temperatures vary significantly around a home water heater. The basement is cool (58.8°F), the incoming water pipe is cool, the outgoing water pipe is hot, the tank is hot (116°F), and the gas exhaust is somewhere in-between (75.6°F).

Home water heater infrared Home water heater visible

Home water heater (infrared and visible)

Finally, let’s find a way to take close-up infrared shots and videos.