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Thermal Imagery - Frequently Asked Questions

 
  • What is Thermal Imagery?
  • How was the survey done?
  • Why have we done this?
  • How much has it cost? 
  • Why are we doing this now?
  • When was the survey carried out?
  • How do I find my property's thermal imaging results?
  • How is the heat loss value calculated?
  • What do the different colours mean?
  • What do the values mean?
  • What should I do if my house shows an poor/high heat loss?
  • What are the limitations with the thermal survey?
  • I've installed insulation recently, why hasn't my home changed colour?
  • What should I do if my business premise is poorly insulated?
  • Can I remove my properties thermal value from the website?

What is Thermal Imaging?

Thermal imaging uses infrared technology to view heat levels.

We have used this to help identify relative levels of heat loss from buildings in the borough.

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How was the survey done?

The survey involved using a light aircraft with special thermal imaging cameras that mapped the amount of heat escaping from properties across the borough.  The aircraft flew at a height of 3,000 feet above Poole and collected the images which were then laid over a map of the borough. 
Each property was given a colour-coded rating based on their relative level of heat loss. 

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Why have we done this?

Poole is committed to reducing its own CO2 emissions by 25% by 2013 and this aerial study provided a snap-shot of energy efficiency using thermal maps so people can see how much energy is lost from their homes and businesses.

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How much has it cost? 

The project was funded by the Energy Saving Trust and has cost £17,500.

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Why are we doing this now?

The Council is committed to reducing its own CO2 emissions by 25% by 2012.  This will take time and so we need to have a clear picture of our energy efficiency now so we can check progress in the follow up survey in 2011.

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When was the survey carried out?

The survey was carried out on the 17th and 26th December 2008.   A clear, cold night without snow is needed to get the best picture for the thermal imaging cameras and to ensure households are more likely to have their heating turned up high.

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How do I find my property's thermal imaging results?

1)    Go to our online mapping system 'Your Poole' ;

2)    Click on the 'New Property Search' Button;

3)    Enter your address details and click on 'Search'. Your address will appear below. Click on your address and the map will update and relocate to your property;

4)    On the left hand side is a menu option called Interactive Mapping - Click on this button to reveal a number of overlays that can be clicked on and off.  The first layer is called Thermal Heat Loss

6)    Tick the box next to the name and the Thermal information for your property should now be visible.

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How is the heat loss calculated?

The value is calculated by using a thermal camera to measure the amount of infra red being emitted by surfaces - the emissivity, which can be interpreted as the amount of heat being given out. An average emissivity value was calculated for each building, relative to the rest of the area surveyed and this was then translated into a colour on the map and separated into the three heat loss values.

The following factors can influence the readings picked up by the thermal camera:

  • Building construction and materials directly affect the thermal values of a roof, as some materials are capable of absorbing more heat and / or retaining heat for longer. For example a slate roof may appear to give out less heat than a concrete tiled roof.
  • Surface colour can affect the actual temperature: dark surfaces tend to absorb and retain more heat than lighter coloured ones.
  • Heat sources such as flues and chimneys can increase the average temperature of a roof if they were being used to remove hot exhaust gases when the survey was carried out.
  • Surface moisture and standing water on surfaces increases the values picked up by the thermal sensor, showing the roof to be warmer.
  • High levels of dirt or large amounts of mould growth may give a higher reading than a clean surface, making the roof appear warmer than it is.
  • The amount of heat emanating from roofs may be affected by nearby tree canopies or vegetation, as moisture contained in them will emit higher values, increasing the average temperature of a roof structure.

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What do the different colours mean?

The colour is used to represent the average heat recorded for the area of the coloured block.  The actual aerial thermal image is based on the "greyscale" of black through to white.  Subtle variations are difficult to interpret by eye.  Different colours have been used to show relative heat loss and make it easier for people to understand the information.

  • Red represents - Poor/High heat loss
  • Yellow represents - Average heat loss
  • Green represents - Good/Low heat loss

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What do the values mean?

Poor/High Heat Loss
The premise has high heat loss, which means a large proportion of heat from the building is escaping through the roof of you property. Money can be saved on fuel bills by making improvements on energy efficiency measures, such as cavity wall insulation, loft insulation and even simple draught proofing measures.

Average Heat Loss
The premise has moderate heat loss, which means some heat is escaping through the roof. You may have installed some insulation within the property, however, there are additional measures which can be taken to reduce your energy bill. For instance, you may need the insulation in your loft topping up, or re-programming your heating controls may also help reduce your energy bills.

Good/Low Heat Loss
The premise has low heat loss, which is an indication that the building is well insulated with minimal heat loss. In some cases, the building may have been vacant during the time of the survey with no heating on, or the building may have little heating on. There may still be some improvements you can make on saving energy within your property, for instance, turning lights off when not required or reducing the temperature of the building. 

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What should I do if my house shows an average or poor/high heat loss?

It is worth checking to see that you have the recommended depth of loft insulation (270mm / 11in) and, where appropriate, cavity wall insulation. By insulating your property you can increase its thermal comfort and reduce your fuel bills by up to 30%. You may qualify for free or discounted loft and cavity wall insulation, depending on your personal circumstances and a suitability check on your property.

Further information and advice, including grants for insulation, condensing boilers and renewable energy systems can be obtained from the Energy Saving Trust .

Tenants in social rented accommodation should contact their landlord for details of any assistance they may be able to provide.

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What are the limitations with the thermal survey?

The survey has been useful as it has provided information which would otherwise be very difficult to obtain. However, there are some limitations to the data, which include:

  • The image is a snapshot at one moment in time of how much heat a property was losing from the roof.
  • The outcome of the survey is affected by certain factors (for instance how many people were at home on the night of the survey, whether the heating was on, the building materials used in constructing the property, level of insulation, commercial premises with residential above or vice versa).
  • During the survey, the aircraft completing the survey would have been subjected to variations in pitch, yaw and roll movement caused by forward inertia and cross winds during the flight. These factors can also affect the output.  

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I have recently installed insulation - why hasn't my home image changed colour?

The survey was completed in December 2008 and shows heat loss at that time.  If you have improved your energy efficiency since then, it will not be reflected on the map.

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What can I do to improve my energy efficiency and reduce my heating bills?

For free advice and information on subsidised insulation and heating systems telephone 0800 975 0166 or visit Dorset Energy Advice Centre website.

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How will we know if it's working?

A further flight is scheduled in 2011 to chart the progress made in improving energy efficiency

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What should I do if my business premise is poorly insulated?

Help and support is available to business on energy saving initiatives which will contribute to reducing your energy bills.

Business Link and Carbon Trust provide practical ways in helping you to reduce your energy bill. For further information see:

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I don't want to be involved - can I remove my property?

Yes. If you are not happy with your property being included within this thermal survey we are able to remove your data from the online system. Please e-mail your address to GIS@poole.gov.uk and we will proceed with your request.

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