An infrared point-and-shoot thermometer can help you get a thorough understanding of where your home is losing heat in cold weather, or gaining it in summer. The more you know about where heat is entering or leaving your house, the more effective you'll be at controlling energy waste.
With an infrared point-and-shoot thermometer, you just move about the inside and outside of your home on a hot summer day or a cold winter evening, and point and shoot at windows, outside doors, walls, and other places where heat may leak through. The device helps you get a detailed picture of problems with insulation, sealing, or windows in need of an upgrade.
Professional energy efficiency inspectors often use infrared imaging to show you where you're gaining or losing heat, but thermal imaging devices are expensive and the audit itself can run over $200. An infrared heat gun doesn't give you the same colorful printout, but they sell for about $50, so they put this detailed information within reach of the average person.
Most infrared heat detectors come with a beam ratio of 1:12, which means that if you point the gun at a wall 12 feet away, then take a reading, you'll get a temperature reading for a one square foot area of the wall. These guns also come with a laser beam so you can see exactly what spot the reading was done from.
I suggest beginning your thermal leak audit from outside. Standing 12 feet back, take a series of readings with your infrared gun to figure out what the reference temperature is. You are looking for the coldest temperature in winter, or the hottest in summer when the AC is on.
Don't take readings on a sunlit wall, because it can mess up your results. Rather, wait for cloud cover, or for the sun to move.
Note each reading on a sketch of the wall or in ordinary notes. Pay particular attention to window temperatures, as these are major sources of thermal loss both in hot and cold weather. You may want an inside helper to close shades and curtains after your first measurement so you can then note the impact of such window coverings on cutting thermal leaks.
Where readings are considerably worse than your baseline (hotter in cold weather, colder in summer), take more measurements close by, to pinpoint the boundaries of the thermal leak. You may have gaps in, or settled insulation, cracks in the wall, or a broken seal in a window or door.
Next do an indoor thermal audit of the outward-facing walls, floor, and ceiling of each room. Choose an interior wall as your baseline; exterior wall readings should be cooler than the baseline in cold weather, or warmer in hot weather. Again, you are after thermal leaks on window glass, around windows and doors, through ceiling light fixtures, in cracks in drywall or plaster, or anywhere that is touching an exterior wall. Take close-up measurements of any wall outlets or light switches that are close to the outside, even if they are on an interior wall.
Take readings of top floor ceilings, as insulation, especially blown in insulation, can get pressed or matted down in leaky attics. For hot weather measurements, do your ceiling readings twice: once early in the morning before the sun has heated the attic space, and again in the early evening when the attic is hot, so you can see how much of that attic heat leaks into your living areas.
You will probably find that windows without their window coverings will be your biggest heat leaks, as even the most efficient windows have a much lower thermal barrier capability than walls or ceilings. You can either upgrade old windows with new efficient ones, add thermal curtains or shades, or apply thermal barrier window film to the window pane itself.
You will also probably find drafts in walls, particularly at light fixtures or where wires or pipes exit the home. You should seal these as best you can, as drafts can be major contributors to home energy costs. Seal around the edges of window frames; use wall outlet insulating foam to prevent air from flowing through the outlets. Your bricks may need tuck pointing, or you may have a more severe problem: settled blown-in insulation between wall studs, in which case the only remedy is to gut the room from within and put in new insulation and drywall. If the walls have no insulation at all you may just be able to inject foam insulation, which costs less than a complete gut and reno.
You should consider doing your own mini-audit with your infrared point-and-shoot thermometer first, and call the contractors later. If you know where your thermal leaks are, you'll be able to ask each contractor what solutions they recommend to your problem. Inviting a contractor over and just telling them the house gets too cold in winter, or too hot in hot weather, means inviting major repairs that may not help at all.
You can use an infrared point-and-shoot thermometer for countless other measurements around the house, such as reading hot water pipe temperature before and after adding pipe wrap; reading the temperature coming out of forced air registers and going into the air return register, if you have central air conditioning, to gauge air conditioner efficiency; measuring frying temperatures on your stove; or finding the best location in your basement for a wine cellar.
Whatever model infrared heat detector you choose, you will doubtless get many hours of use out of it, locating the hotspots and cold spots in your walls, floors and ceilings, your garage, your fridge, freezer, your car engine - anywhere you want to know the surface temperature. You can even use it to measure the temperature of your compost bin - without getting your hands dirty!
By: Robin from Green Energy Efficient Homes
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