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Thermocill Ltd
Case Study

Thermocill

The wall of warm air generated by Thermocill is claimed to reduce the amount of heat loss through the window, reducing the home’s heating demand.

Challenge

Windows can be one of the least energy efficient components in building design, contributing to heat loss. Thermocill Ltd developed an innovative energy efficiency product called Thermocill, which replaces the standard window board with a device that redirects warm air from a radiator underneath a window, up towards the windowpane. The device is placed underneath a window in a home and creates a wall of warm air adjacent to the double-glazed window, without using any energy.

The wall of warm air generated by Thermocill is claimed to reduce the amount of heat loss through windows, reducing a home’s heating demand. Raising the temperature around the window frames is also claimed to reduce problems associated with condensation and moisture.

Action

Thermocill requested product performance verification from Energy Saving Trust, based on submitted evidence that their product provided financial, carbon and energy savings for customers as well as reduced condensation within the home, which can provide health benefits.

Energy Saving Trust reviewed the experimental work carried out at the Salford Energy House and numerical studies from the University of Manchester. Several changes were identified within the analysis method that would allow for more accurate savings to be calculated.

“Working with Energy Saving Trust was amazing – no stone was unturned. The experience was very practical, highly informative and very thorough by a professional and skilled team.”

Keith Rimmer, CEO of Thermocill

Result

After Energy Saving Trust’s product verification report, the following energy saving claims were amended and then tested to the correct standards.

  • Claim: The energy required to heat a room is reduced by up to 14% with the addition of a Thermocill unit to a window above a radiator. 1
  • Claim: The time taken for a room to heat up is reduced by up to 19% by the addition of a Thermocill unit to a window above a radiator. 2
  • Claim: The addition of a Thermocill unit to a window above a radiator can significantly reduce the likelihood of condensation at the bottom of the window. 3
  • Claim: Customers could reduce their total space heating demand by up to 8% per year by adding Thermocill to their existing radiators/windows. 4
  • Claim: Customers could save up to 150 kg CO2e per year by adding Thermocill to their existing radiators/windows. 5

Thermocill is now free to use its verified and accurate energy saving claims and the Verified brandmark from Energy Saving Trust. Manufactured in the UK and made from 100% recycled materials, you can now find the Thermocill product on the Energy Saving Trust Register.

Learn more

Visit the Thermocill Ltd website or follow them on Twitter / LinkedIn

Caveats

  1. The values are based on a 9-hour heating cycle from experimental work carried out at the Salford Energy House on the original Thermocill design. This assumes a room with double glazed windows, a typical external brick wall construction and a temperature set point of 21°C. Different temperatures and configurations may produce higher or lower savings.
  1. The values are based on experimental work carried out at the Salford Energy House on the original Thermocill design. This assumes a room with double glazed windows, a typical external brick wall construction and a temperature set point of 21°C. Different temperatures and configurations may produce higher or lower savings.
  1. Based on numerical studies, the addition of a Thermocill unit increases the temperature around the bottom of the window which produces a higher vapour pressure and therefore reduces the risk of condensation.
  1. These savings are based on modelling carried out using the EnergyPlus software for a typical 3-bedroom semi-detached property with double glazed windows and an annual gas usage of 12,500 kWh before Thermocill is installed. Thermocill is installed in the 3 bedrooms and the living room, all of which are assumed to have radiators beneath the window. This reduces the space heating energy by 14% in each of these rooms, based on experimental work carried out at Salford Energy House on the original Thermocill design. A heating set point of 21°C and a setback temperature of 16°C are assumed for the modelling. Other temperatures may result in different savings values.
  2. These savings are based on modelling carried out using the EnergyPlus software for a typical 3-bedroom semi-detached property with double glazed windows and an annual gas usage of 12,500 kWh before Thermocill is installed. Thermocill is installed in the 3 bedrooms and the living room, all of which are assumed to have radiators beneath the window. This reduces the space heating energy by 14% in each of these rooms, based on experimental work carried out at Salford Energy House. A heating set point of 21°C and a setback temperature of 16°C are assumed for the modelling. Other temperatures may result in different savings values. An average GB gas CO2 factor of 0.208 kgCO2e/kWh is used for the savings.

Last updated: January 8th, 2021