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Laser Thermometers


KY Ted
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They do not give you the air temperature, but rather the register or the duct work. You need a good digital thermometer. The IR thermometers are good tools; I use one to test ceilings and walls for insulation among a few other things. I have a four year old Raytex, which I paid dearly for back then. I think you can pick a good up for around $200 or less. The more expensive the smaller the measurement area. I think my Raytex reads 6" at 10'.

As for buying one I would try Ebay at first and if you have a Grangers or similar store near you I would try them and then I would try the various gadget guys (Professional Equipment, Etc).

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Originally posted by KY Ted

TY guys, but do they measure air temp or not? How do you use them on appliances? say a stove?

I appreciate your input!

Ted[:-banghead]

No, they don't measure air temp; they measure the temperature of the object that the conditioned air is contacting. That isn't going to give you the air temp.

Use them for measuring temperature of just about everything other than air.

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They measure the surface temperature of whatever they hit. They do not measure air temperatures. For example, if you use your IR thermometer to measure the temp at a AC supply register you're measuring the temp of the grill or the ductwork behind the grill (or, if you're not careful the surfaces around the register).

Hope this helps!

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Originally posted by allspec33351

I have to respectfully disagree. The temperture of the surface of a object is a direct coralation to the surronding air temp. All things being equal. So if I want to know the temp of the air I shoot the object that would give me the best response. [:-banghead]

Therefor I get the air temp within a degree or two.

Yes, there is a correlation, albeit one that cannot be trusted or confirmed w/out testing the air temp. Whether or not it is actually within a degree or two requires testing the air temp. This would be fine if "close enough" was what one needed; in many instances, it would be fine.

There are lots of ways that laser thermometers can be a great help, & there are a few ways that they can mislead and/or misinterpret results. If you want to know air temp, a $4 thermometer will tell you.

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you turn the stove and oven or broiler on and then you have a choice; touch it and say "Damn, that's hot! [:-jump]or use the raytek and say well this appearers to be functioning.[:-graduate]

As for the air vs. surface it measures the surface. The surface temp will eventually reach the air temp (Within a degree or two) but, many times I have not gotten the temp split at the registers but when I check the duct 4 feet on each side of the unit with my old probe style thermometers I get the proper split. Many times the temp changes in the duct work depending on the location and length of the run.

I do use it to determine if I have conditioned air in each room.

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Yes, there is a correlation, albeit one that cannot be trusted or confirmed w/out testing the air temp. Whether or not it is actually within a degree or two requires testing the air temp. This would be fine if "close enough" was what one needed; in many instances, it would be fine.

There are lots of ways that laser thermometers can be a great help, & there are a few ways that they can mislead and/or misinterpret results. If you want to know air temp, a $4 thermometer will tell you.

Kurt

You are getting to sound just like your good buddy Jerry.[:-bigeyes]

And I'm not going to ask you where I should put this 4 buck thermometer.[:-bulb]

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Originally posted by allspec33351

Kurt,

You are getting to sound just like your good buddy Jerry.[:-bigeyes]

Oh Boy!! If we were in a bar, all of the chairs would be shooting back right now so people could get out of the way! Thems' fight'n words pardner! [:-fight]

Brian G.

Gittin' Out of the Way [:-bigeyes2] [:-cowboy]

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I think Scott is right w/ his analogy; the surface temp of various objects can be different than the ambient. In many cases, it may not matter.

I can think of two instances where the trusty old Raytek didn't tell me what I needed to know. I was shooting registers to verify function; the sucker was hot, I thought it was OK. What I wasn't checking was volume of air flow; heck, just stand in the door, shoot the register, move on to the next room. I got to pay for an additional air return on that job, since the room was not heating adequately. The other instance was taking temp splits on an AC; I shot the metal grill above the AC condenser instead of measuring air temp. Maybe it was the sun on the grill, maybe it was me, I don't know. What I do know is that I had a bad measurement, & a resulting inaccurate assessment of the condition.

The longer I inspect, the larger the bag of unused fancy tools gets.

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KY Ted:

Very good question but the answer is not a quick one. In 2002 & 2003 I spent about 100 hours reseaching non-contact infrared thermometers (IRT) and comparing 6 different models. From that research I wrote a 10 page, 2 part article for the NAHIforum that included more than you'd ever want to know on the subject. I also presented an hour and a half seminar on IRTs at the National Association of Home Inpsector's (NAHI) National Education Conference in Clearwater Beach, FL, in Feb 2003.

If I can work out the details with Mike I will try to make the written articles available to you here on TIJ.

The best advise I can give you in two sentences is: When you point and shoot, what the IRT is not telling you is more important than what it is telling you. Don't wave it around Clients until you sure you know the difference.

But it is a very handy tool. I own four. I use two regularly.

John Wells

www.hs1.biz

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Originally posted by house-smart

KY Ted:

Very good question but the answer is not a quick one. In 2002 & 2003 I spent about 100 hours reseaching non-contact infrared thermometers (IRT) and comparing 6 different models. From that research I wrote a 10 page, 2 part article for the NAHIforum that included more than you'd ever want to know on the subject. I also presented an hour and a half seminar on IRTs at the National Association of Home Inpsector's (NAHI) National Education Conference in Clearwater Beach, FL, in Feb 2003.

If I can work out the details with Mike I will try to make the written articles available to you here on TIJ.

The best advise I can give you in two sentences is: When you point and shoot, what the IRT is not telling you is more important than what it is telling you. Don't wave it around Clients until you sure you know the difference.

But it is a very handy tool. I own four. I use two regularly.

John Wells

www.hs1.biz

I like your statement "what it isn't telling you is more important than what it is telling you".

I am looking forward to reading your articles. The use of "fancy tools" is of constant concern to me; I own too many, & have discovered w/ many of them that they lead me down paths that shouldn't have been gone down.

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Knowing that the IRT measures surface temps, I still use it to "guesstimate" AC D/T. I just make sure the AC has been running 30 minutes or more to bring surface temps close to the air temp.

I also check every register in the house. It's amazing how often I come up with 8, 10, 12 even 15 degree differences between rooms and even registers in the same room. I write it up as poor air distribution. This has worked well for me. I can't recall ever being questioned about my AC calls.

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Here's a couple non inspector uses.

I bought mine (and use it for) an extremely fast way to isolate a non firing cylinder in both gasoline and diesel applications. I just shoot each exhaust outlet at the manifold and then go to work on the cold one. This technique sometimes shows things that 100 grand worth of scopes and computers miss. It's especially helpful on older diesels w/o computer controls and mechanical injectors.

I use it on my boilers out-put and return lines when I want to know if I can add a circuit.

I check brake rotor temps to do a simple equalization evaluation.

Isolate squeaking belts. They squeak because they're slipping and the cause of slippage can be determined (hottest pulley) and estimated w/o any disassembly.

My list goes on and on, but it's a handy gadget.

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Originally posted by Chad Fabry

Here's a couple non inspector uses.

I bought mine (and use it for) an extremely fast way to isolate a non firing cylinder in both gasoline and diesel applications. I just shoot each exhaust outlet at the manifold and then go to work on the cold one. This technique sometimes shows things that 100 grand worth of scopes and computers miss. It's especially helpful on older diesels w/o computer controls and mechanical injectors.

I use it on my boilers out-put and return lines when I want to know if I can add a circuit.

I check brake rotor temps to do a simple equalization evaluation.

Isolate squeaking belts. They squeak because they're slipping and the cause of slippage can be determined (hottest pulley) and estimated w/o any disassembly.

My list goes on and on, but it's a handy gadget.

Now those are some useful tips. I'm gonna use it on my squeaky fan belt on the work truck. I'm a lousy mechanic (I hate working on cars), so any little insights I can gain before I succumb to my local wrench is valuable.

I have used them to figure out the proliferation of radiant floor heating systems I'm now seeing; shooting the floor temps is a decent way to begin understanding the distribution pattern.

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I don't use them for AC split, mostly for simple distribution problems. I rely on my eyes for supply-return issues like Kurt mentioned. Be careful in these new shacks with cathedral ceilinged bathrooms, bedrooms. It can be tricky.

But for your standard Cape, ranch or colonial or condo, a lot of this is not tricky.

It's the 'contemporary' with funky open plans, lack of returns, supplies, that can get you in trouble. I guess the Raytek is really most useful in determining if a grille is a supply or a return. Like I said, a hell of a laser pointer and 'pretty useful' but not 'the end all' if you know what I mean.

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KY Ted and Kurt and All:

Okay the technical paper on Infrared Thermometer Use and Misuse is ready and online at my website. http://www.h-s.bz/images/Infrared_Therm ... ok_PDF.pdf

It's an Adobe Acrobate PDF and at almost 4MB it may take a while for you dial-up guys to download, but I think it's worth the wait. The paper is 30 pages of text, photos, graphics, and charts. Hope it is useful to you. Please let me know if you have another use that I didn't cover. Sorry Chad I didn't put in anything about engine analysis (you're covered the subject very well), but I do use one for that too.

One note if you intend to do engine analysis with an infrared thermometer in addition to home inspection, you may want one that has a higher measuring range. The Raytek MT4, the most popular model for home inspectors, only reads to 525 degrees F. When the engine is much above idle the exhaust manifold is hotter than 525. In addition to an MT4 I also have a Raytek Ranger ST60 which reads up to 1100 degrees and combined with its very narrow field of view it is quite useful for the analysis technicques that Chad described.

John Wells

HOUSE-SMART Inc.___We're Smarter About Houses [:-graduate]

www.h-s.bz

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