How to get the best out of a thermal imaging visit
I have a contractor coming around in a few days to do thermal imaging on our house with and without a blower. He’s going to visit at 6am so we should have at least 10C difference between inside and outside and no direct sun since the day before.
I was wondering if anyone might have some advice on how to get the best out of the visit. Our house was built in 1930, it’s what we call locally Spanish Mission style, single-storey double brick, on stumps, with insulation underfloor (about R10 American, I think) and in the ceiling (about R25). The roof is terracotta tiles on timber trusses. The windows are all timber frame and single glazed. We have drapes on some windows
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Wow, I've rarely had a client agree to a 6 AM inspection, even though it's sometimes best. It sounds like your person knows that a 10 degree Celsius delta T is needed and direct sun is problematic. To that I would add, windy conditions are not helpful and I cancel if I get up in the morning and it's blowing.
It's good if there has been recent rain and wind. Up until recently, we had many weeks in a row of hot, dry conditions, and I had to push off a couple of moisture inspections. Now that we've had a bit of nasty weather I've done the first of those, and found at least one leak that might not have been evident during a dry spell.
As far as preparing, one of the things you can do is move stuff away from the walls. Assuming you are looking for energy and/or moisture issues, a lot of the inspection is of the exterior walls, and if they're covered with dressers and bookcases, those areas get skipped. The easiest inspections are houses that have little or no furniture.
Make sure your woodstove or fireplace is not burning, and if you have baseboard or wall heaters, turn those off before the inspection, as they make hot stripes on the walls and take more time to sort out. Forced air that hits the wall can do the same thing.
If you have vermiculite insulation or any other possible asbestos, make sure the inspector knows that. Same goes for any areas you know have mold/mildew/fungus, or anything else nasty that could get airborne.
I'm curious... did your inspector not have some specific requests?
Thanks for your comments, David.
Thermal energy efficiency imaging for homes is not used widely in Australia. Energy has traditionally been cheap here and we generally have a mild climate. So housing energy efficiency has not had the same focus as in Europe and North America. There is increasing interest in energy saving as energy prices have been rising recently.
I'm going to be writing up the visit for a few local magazines. So this effort is a bit of a joint effort in some ways although I am paying for it.
Hence I'm not fussed about getting up early ... but I did have to check with my wife :)
You've probably already seen this article -- but in case you didn't, here is a link to an article that may interest you: An Introduction to Thermal Imaging.
I had seen your article some time ago, Martin. It was a very useful introduction to the technique. After reading it I suggested to the thermal imaging guy that we should take the shots first thing on a cooler morning.
GBA is a great site. So much useful stuff
We did the thermal imaging over the weekend early on a crisp Spring morning. Absolutely fascinating. Confirmed some leaks etc that I knew about and revealed lots of other information. I've attached a few images. These are:
Leak Through Floor Boards
Roof space manhole
Leak under partly open drape
We did the imaging with and without a blower. The blower definitely helped to make some air leaks more visible.
David (or anyone else who might know),
Why weren't the drapes fully opened during the testing/imaging?
I wanted to show the difference made by drapes and a partly open drape. I guess we could have done another shot with the drapes completely open. The windows are 80 years old and leaky single-paned so not expecting any great thermal performance from them
Now that you've had this testing/imaging done, do you have any plans to upgrade/retrofit?
A house I'm working on just had a batch of new honeycomb shades installed. One of them was defective and so one window is missing its shade. I was surprised at the difference in temperature between the covered windows and the uncovered window.
In this shot, it's cool outside and very warm inside, no wind, no sun on the exterior. The windows are older aluminum units with insulated glass, which has a minimal airspace, probably 1/4".
The obvious candidates are:
a/ Doing something about the leak between the floorboards. We had underfloor insulation installed a few years ago but I think some remedial work may be in order. Bit cramped and dusty under there.
b/ Replastering some cracks.
c/ Insulating the roof space manhole cover. There's been a couple of helpful articles on GBA about this.
d/ Caulking the skirting boards.
e/ Weatherstripping the windows and possibly putting in some double-glazing.
f/ Investigating a couple of anomalies that have popped up.
g/ Big draught finding its way from behind the dishwasher. Will have to pull the unit out to fix this up, unfortunately.
h/ Weatherstripping external doors. Possibly replacing the two front-doors with solid wood with smaller glass area.
i/ We have ventilation grilles (small rectangular cement grille openings) in the house. These are very common in Australian homes. I guess we should look at blocking these.
Then I guess do the measurements again to see how the thermal performance has improved.
David, if you have an attic and a crawl space, a number of the air leakage solutions are fairly standard, and just involve getting into both spaces and sealing all the leaks. It is helpful to have a blower door during this, but run it in reverse so it blows air into the house that leaks into the attic and crawl.
Did your inspector have other air leakage images?
Hi David M,
We have about 40 images all up. I think it would be useful to do more images of the same house component with and without the blower to pick up increased airflow through particularly leaky bits. I've attached images of the bathroom fan with and without. No prizes for guessing which is which. With the blower even though this was located a hallway and several rooms away from the bathroom the fan was literally humming. Some work needed there.
Any suggestions on how we might seal the floorboard cracks? We want something that's not visually intrusive but gives a much better seal. The underfloor insulation obviously isn't producing an air seal.
On a related note its interesting to see the reaction to these images here and overseas. There's been quite a bit of interest here from a number of groups. I also sent them to a friend in Austria who has recently moved into the straw-bale house he built. He replied matter of factly that they had just had -5C at night with some snow as winter arrives in the northern hemisphere and that he needed to get on with doing some thermal imaging. I was in regional Finland earlier this year where it had been nearly -35C a week or two before I arrived. As I write at 2pm it's around 30C here - which is warm for this time of year. So you can see the different emphasis.
But of course blocking up the leaks will help with summer comfort as well as winter.
All good stuff!
Here's one that's an absolute cracker. This is a picture of the water storage tank connected to our solar hot water system. The bright spot is the hot water outlet of the tank. A very nice example of a thermal bridge! A local group - the Alternative Technology Association - sells a cosy for these outlets to help reduce the thermal loss.
I've been using the outlet as a vernacular temperature indicator of how warm the water in the tank is getting. (With care during summer; it's get pretty warm.) We've been pleasantly surprised at how good the performance has been over winter. I think we might bling the tank up a bit with a temperature output and do some insulation around the hot water outlet