19 Dec 2009

Thermal Imaging Houses project to cut heat loss

I previously mentioned my uncle's involvement in a project looking at Thermal Imaging (see here) as a way of raising awareness about heat loss - well below are some of the notes he has gained from experiences of five communities (not in Gloucestershire). Big thanks to him for sharing them here.

Photos: Pics from appendix A below of the report - see there for more details - apols for quality - I couldn't get them to reproduce in a jpeg so ended up photographing the photos on the screen - hence the terrible quality!!
Picture one is south elevation and front of a village hall - you can see radiators (red) have been heating the uninsulated wall. Picture two - north elevation shows insulated extension compared with poorly insulated main walls and roof - lower windows and doors double glazes but it was warmer inside there. Picture three - south elevation with heat escaping from open door - the white spot is a direct view of the hall radiator.

This Thermal Imaging Project is an exciting and very visual way to highlight heat loss - seeing the results are a clear way to motivate behaviour change - but it isn't easy as the report shows. Indeed behaviour change is tough stuff - there are those motivated to change - and projects like the energy monitors in libraries locally (see here) are great for that - but then how do we engage wider populations? This is the challenge.

A recent tenants energy group at the District Council couldn't get enough members to keep going and a local Transition Stroud Carbon Reduction Action Group (CRAG) folded due to not enough interest.....even free insulation often isn't enough to make people accept it - changing behaviours is hard - but clearly rising fuel prices will impact and encourage change - Ofgem say we can see 60% fuel price rises within next 5 years - some say they could be higher.

For me there are very real concerns re fuel poverty - and of course climate change - as noted before I am chairing a District Council inquiry into funding of this issue - we only just started but a report should be out by our February Scrutiny meeting - I completed the first draft earlier this week - yet without serious investment we cannot hope to tackle these issues. Anyhow I'll leave you for mo with this report....

Thermal Imaging Houses – Some Conclusions

Based on experiences of 5 communities using infra-red photos to highlight houses’ heat loss.

The Good News & the Bad News

The Bad News
- Thermal imaging is not so easy.
- Interpreting results needs training, care & experience.
- Normally it needs to be done in cold weather when neither the sun
nor rain has fallen on the house being imaged. This and the need for discussion with householders mean that it takes more time than one expects to image a number of properties.

The Good News

- It fulfils its main function in being absolutely intriguing, raising interest and awareness.
- It makes people think they should do something to save energy.
- Householders are pleased and enjoy having it done. They can recognize and confirm what they see in the images.

Gathering initial support & involvement

It was important to advertise the project beforehand and seek committed team members and individuals interested in having their properties imaged. This can be done via personal contact and suitable local publications.

It is necessary to made clear that no images will be taken of properties without the householders’ permission.

The Team

Team structure and the choice of committed individuals is important. Obviously the choice can be approached in different ways, but certain key characteristics are required:-

Someone to set out & coordinate the imaging program (i.e. Project Director / Leader).

Someone with good contacts & knowledge of the community is needed to facilitate communication & identification of individuals.

Imagers who have training / experience specifically in operating the infrared camera. Experience with normal digital photography is useful but not enough.

Those downloading the digital thermal image data onto computers, processing it and probably printing it will need suitable computer skills.

Someone, presumably one of those involved above, to keep track of the rather large amounts of data collected.

Camera Use

Thermal imaging is different to normal digital photography. Using the camera & putting in the appropriate settings is not straightforward. Training, practising & understanding beforehand is essential.

Imaging glass windows can be affected by reflection. Even the heat from the imager’s body can be reflected. So the angle and what might be reflected needs care in image taking & interpretation. For example, shiny surfaces and roofs imaged at an angle can give distorted temperature readings.

Other equipment

Although not essential, a tripod & thermometer can be useful. For image interpretation it helps to know the temperatures inside & outside the property being imaged. The camera itself does measure ambient temperature, but takes some time to respond. Some hand held thermometers are quicker.


A temperature differential between inside & outside of at least 10ºC is needed for good results.

Solar gain is another problem. Sun on one side of a building, even hours earlier, can seriously distort the thermal imaging results.

A wet surface, such a brick after rain, can also be a problem.

Thus winter evenings after overcast skies without rain give the best results.

A local weather forecasting website, such as www.metcheck.com, can help in organizing imaging dates.

Time needed

Imaging a number of properties takes longer than expected. This is largely due to weather uncertainties and the establishment of coincident availability dates for householders & imagers. Contacting householders & imagers and programming imaging dates is essential.

Good organisation is key! One community was assigned the camera for only a short time and yet thermally imaged 18 properties in only 4 evenings. This is the best time performance to date from any of our communities.

Having the camera allocated for an extended period seems good but a shorter period a say of ~2 weeks can concentrate the mind and give better use of time if well organised (& given suitable weather). Also imaging sessions seem better fitted in after evening meals rather than before.


The team organisation needs to be set up beforehand with individual roles defined. Once the camera collection date is known, a date for training the team members needs to be established. Training needs adequate time, and more than one training session may be needed.

The most usual operating teams consist of 2 ‘imagers’ one of whom concentrates on operating the camera and the other on the essential note taking. A third, a director/‘imager’ may be added to help coordination.

Note taking

Image interpretation is not straightforward. One cannot stress enough the need for careful notes of the weather, building structures & any anomalies found.

Anomalies to keep an eye open for are unexpected colours / temperatures in the image. Then it’s best to try to establish & note the possible explanation. The householder’s explanation / opinion is likely to help. Knowing the weather conditions & building structure (e.g. insulation already installed etc.) helps with image interpretation.

Field Note Taking is helped by having pre prepared forms for the imagers to complete on site whilst out imaging.

Downloading, Processing Images & Producing Reports

This can take longer per property than the imaging itself. But for maximum impact the results should be fed back to the householder fairly quickly, say within a month.

Before starting report production it is necessary to decide the nature of the reports to be produced, the colour palette for the images, the software to use (this can be camera software alone or in combination with other software e.g. JPEG & MS Word), and how they will be conveyed to householders.

Some opt for reports of several pages using camera software, incorporating not only Red-Blue palette thermal images, but added normal digital images of the properties as well.

Some used the camera software to process the thermal images, but produced their 1 or 2 page reports with JPEG images using MS Word (see example Appendix A below).

One community opted to save paper by circulating images via email and only printing images for householders without computers.

All the communities managed to get example results in village & local publications & on display boards at local events, all of which helps to convey the message.


Our community projects have been well received. Thermal imaging is fascinating. People were very interested to see the results and pleased to have the images and analyses. Sometimes it did not tell them much they did not suspect or know, but it emphasised their energy loss and added to motivation.

As with most motivational projects continued follow-up & varied approaches are needed.
Perhaps the most difficult aspect is getting people to act on the information received and to spend their hard earned cash on energy saving improvements.

One suggestion is for a suitable member of the team to return to the householder say about one or not more than two weeks after they have received the thermal image results to discuss possibilities. For this it is helpful to have details / publications on energy saving and its costs & returns produced by organisations such as the local Energy Centre and the Energy Saving Trust.

However, energy prices are going to rise further and people will start to see an even stronger need for making the necessary savings in the home.


Good - Planning, Organisation, Team Selection, Training, Communication & Commitment are the keys to success.

APPENDIX A: Thermal Imaging Study

Date: 8.3.08 Time: 10.00
Inside: 10 º C Temperatures: Outside: 7 º C
Build Date: c1871
Householder: The Village
Image Address: Village Hall
Wall Structures: Solid brick main building & cavity in extensions
Window Types: Upper single glazed & double glazed in extensions
Roof: Tile non insulated.

Photos: see above for a brief description of each of the pics.


Greg Dance said...

It is highly important to mention that measures taken to lower fuel use can be undone by rebound effects. i.e energy customers save money and then spend it on other consumption which counters the CO2 saved by the initial efforts.

Andy said...

Totally agree with the last comment but I reckon this thermal imaging will persuade some of the hardest people to reach.