Sustainable solutions for climate systems are often aimed to be integrated into newly build residences. For existing systems, retrofitting poses challenges. However, it’s important to adapt solutions so they can more easily be integrated into existing households too.
Climate systems in Dutch residences are primarily powered by gas-boilers, although all electric heat-pump systems are steadily on the rise. Just like other solutions, they pose their own set of challenges for retrofitting. This thesis aims to make retrofitting more attractive by finding areas in climate systems that can be improved, making the system more efficient, comfortable and/or healthy.

“Develop a controlled decentralized addition for Joule Technologies' new system to be integrated into existing Dutch Households. 'Future-proofing' them to be more sustainable through smart features.”

This thesis is done in cooperation with Joule Technologies and will focus on making it easier/more attractive to retrofit residences with Joule technology’s new ventilation heat-pump BEN.

In insulated residences ventilation is responsible for ≈43% of the climate system’s energy loss. During the project the importance and possible impact of increased ventilation control was found to be important. For modern systems this exists, but the required infrastructure and cost to apply such a system to existing residences does not make it attractive.

This project begins by analysing where climate systems are installed, how users interact with climate systems, what problems are encountered during retrofitting and analyses current solutions available on the market. It then explores the problem space to find areas improvement areas, of which one is chosen, analysed and improved by a system addition. This is then further developed into a product and analysed to see if the solution is viable and interesting enough for Joule technologies to add to their BEN line-up.

This process provided a prototype for the dynamic valve. Valves are placed on the ends of the ventilation system to distribute flow to the right areas. Dynamic valves do the same, but can measure the status of air, adapt the air distribution and communicate with the ventilation heat-pump how much ventilation is required. Providing more precise control over area-specific climates in the residence.

Simple communication is lacking in the HVAC market as users often are only provided with the current temperature and a target temperature. The influence of changes on their system is not shown, sometimes causing confusion or misunderstanding. As dynamic valves take over the user’s ventilation control it’s important to inform the user. The visual movement in dynamic valves communicates to users what the ventilation system does.


Venting only when required reduces the total flow of vented air, saving energy by reducing required heating/cooling of incoming air. For insulated residences, this allows BEN to save ≈11-14% on the occupant’s energy bill for climate control, whilst making their climate healthier and more comfortable.

Each dynamic valve costs ≈€33-53 to produce, depending on the CO₂ sensor type and power source.

The concept is promising, but the solution needs further development before implementation.

The following steps are required to reach TRL 7:
1.Eliminate whistling noise
2.Replace the seal with legs and foam
3.Test a VOC CO₂ sensor for accuracy
4.Build an automated prototype with sensors
5.Conduct a full-scale system/pressure test
6.Adapt and test product look and feel

After these steps a better evaluation can be made on the value of dynamic valves as addition to the BEN environment.