How to measure heat leakage from a building.

jms698 · 06-06-2009, 03:41 PM

I'm trying to find out where in a newly built house heat is leaking out due to poorly constructed walls or windows. My plan is to use some kind of infrared camera to find those spots on the house that are hottest during the night. I'm wondering if an infrared filter like this, might allow me to use my K20d for this purpose.

What do you think? Will that work? How long would I need to explose the picture with such a filter attached? Does anyone have any experience?

UPDATE: it seems that a filter won't do the job. So, my question turns into: what kind of device or technique would I use to measure the heat leakage from a building?

*khardur* · 06-06-2009, 04:17 PM

I don't think that would work for the type of use you are looking for. Basically the sensor on a standard digital camera doesn't pick up infrared well enough to do thermal imaging. It works for reflected infrared light, but the kind you're talking about requires a much more sensitive device.
You're looking for something like a thermal imaging camera, it may be better off hiring someone who has this sort of device to do a survey of your home, or if possible rent one?

Also your digital camera isn't going to give much color variation to the different "temperatures" like a real thermal imaging camera would, and that's even if it did pick up enough infrared from your house to show an image.

*Ex Finn.* · 06-06-2009, 05:13 PM

No, the filters will not do it.
Hiring a company to do a survey is the way to go. You can rent one but correctly interpreting what you see is the tricky part.
A good thermal imaging camera is very expensive. We have FLIR systems cam. at work, think it cost just a hair under $ 100k.

.FLIR Thermal Imaging Infrared Cameras

Cheers. Mike.

jct us101 · 06-06-2009, 06:11 PM

The filter just removes the red channel from the image I believe, and doesn't have any effect on finding things such as heat.

Here's an example of an infrared photo:

alohadave · 06-06-2009, 09:54 PM

Originally Posted by jct us101

The filter just removes the red channel from the image I believe, and doesn't have any effect on finding things such as heat.

Here's an example of an infrared photo:

No, what it does is block most visible light, and passes IR frequencies and some visible red freqs.

The image you linked most likely swapped the red and blue channels.

mithrandir · 06-06-2009, 10:12 PM

Harbor Freight has some rather inexpensive electronic thermometers that you can aim at a wall for spot temperature readings. I've seen them on sale, depending on the model, from about $10 and up. You could take a series of readings where you believe there is a heat leak and find the hot spots pretty quickly.

jct us101 · 06-07-2009, 03:42 AM

Oh...shows how much I know about infrared photography.

*Ex Finn.* · 06-07-2009, 07:20 AM

Here is one taken with R-72, desaturated and tweaked levels some.

Cheers. Mike.

Bactman · 06-08-2009, 06:55 AM

The only method I know of to measure heat loss involves a thermal imaging system (typically a FLIR camera) and a large turbo fan. The tests are usually conducted in the evening or night time to take advantage of the cooler outside air compared to inside. The fan is set up in a door so that the exhaust is directed from inside the house to the outside environment, thus creating a negative pressure within the residence. The IR camera can then be used to detect penetration of cool air into the structure (as the negative pressure will draw air into the house from outside), such as around windows, through electrical outlets, between baseboards, etc. When the different penetration sites have been identified, you can implement corrective actions to halt the air movement. These may include caulking around windows, installing insulated face plates, and making sure the exterior is weathersealed.

I have tried to use an IR camera around my own home to see where thermal bridges or cool spots are, but it can be difficult to really determine what is occurring. For example, is the thermal contrast missing insulation, or just a shaded spot of the house?

*jem* · 06-08-2009, 08:58 AM

Cool! Three different recs for the company I work for - my group builds some of our camera models. Nice to see we have brand recognition. Thanks!

To the OP: You might try contacting the New Zealand FLIR rep here. The rep might be able to point you to a local firm who does thermal building analysis or where a rental camera might be available for 'do-it-yourself' applications. FLIR also offers thermography classes world-wide (including New Zealand in July) though the cost may be a bit more than you want to spend if you are not looking for professional certification.

*reeftool* · 06-08-2009, 09:17 AM

For starters, look in your attic and make sure there is even coverage of insulation. Detecting a sloppy job can be difficult. Heat loss through the roof can be easily seen after a fresh snowfall as the snow will melt rapidly but areas in the walls are hard to detect. In a former home many years ago, on a cold night (15-20 below 0F) there would be frost spots on the inside walls but I don't know if it gets that cold or if your place is that poorly insulated. I found areas above the doors and windows that had no insulation at all. My method? I pulled the walls down, shimmed them out 2 inches and re-insulated.

Bactman · 06-08-2009, 12:27 PM

In older homes I have surveyed with an IR camera, there will be sometimes voids in insulation within the perimeter wall assembly. I've seen where entire stud channels were devoid of insulation or where the insulation had sagged and compressed enough to allow for a 3' gap at the top of the stud bay. If it is a newer home, you will likely have the former compared to the latter.

alohadave · 06-08-2009, 03:20 PM

Originally Posted by jem

Cool! Three different recs for the company I work for - my group builds some of our camera models. Nice to see we have brand recognition. Thanks!

To the OP: You might try contacting the New Zealand FLIR rep here. The rep might be able to point you to a local firm who does thermal building analysis or where a rental camera might be available for 'do-it-yourself' applications. FLIR also offers thermography classes world-wide (including New Zealand in July) though the cost may be a bit more than you want to spend if you are not looking for professional certification.

FLIR is pretty cool. When I was in the Navy, we were doing marine interdiction in the Persian Gulf. One night, the helo crew put the footage to Hell's Bells by AC/DC. It was great watching the people on the ship moving around in the dark with the music building up.