Monitoring and QuickScan show that Energiesprong works

Net zero energy homes in the Netherlands put to the test both on technical performance and customer satisfaction

Energiesprong net zero retrofits make great promises but do they deliver? The performance insights from monitoring over 900 net zero energy retrofits in the Netherlands confirm that, yes, the retrofit and new built approach does perform. Apart from teething problems in the pilot projects, such as a chaotic building process or insufficient airtightness, in general the houses perform as promised and tenants are satisfied with their renovated home. Some homes even perform above expectations and are energy positive whilst tenants of the social housing properties are proud of their new deep window sills and renewed exterior, saying it feels like living in an owner-occupied property.

Results of extensive monitoring

In the Netherlands, independent researchers have monitored over 613 homes. All homes were monitored on the execution and delivery of the refurbishment and 154 homes were monitored over 1 year of usage.

The monitoring results show that, in general, the energy performance of net zero homes matches the design and performance specifications, meaning that in practice the net zero energy houses function according to the agreements in the performance guarantee. Of course, there were some teething problems.

Issues like insufficient airtightness were a quite common defect in early projects. In response, a blower door test has now become part of the delivery protocol for Energiesprong homes. Such issues were explained by the builders needing to install new products for the first time. These issues can be (and mostly have been) quickly addressed through the monitoring process, allowing subsequent projects to benefit from improved design and instalment.

Tenant behaviour can also influence energy use (and practical performance). Some tenants wear a warm sweater and use less energy whilst others heat their house more than average or shower a lot.

The advantage of live monitoring is that these patterns are typically quickly identified, and residents can be educated to avoid higher energy bills in the future. Or they choose to keep using more than the provided energy plan or allowance/bundle allows for and pay some more at the end of the year. Like they do in the old situation.

Reed the full report

Happy tenants

In addition to this research another 19 projects including a total of 900 houses have been assessed under a project commissioned by the Dutch ministry of interior (housing). The QuickScan done by consultancy firm Atrivé shows that tenants in the Netherlands are happy with their net zero energy retrofitted homes. They are satisfied with the comfort inside the house and in particular they are pretty excited about the new façade. Furthermore the energy plan[1] turns out to work better than expected. People don´t have to pay extra. However, it appears that understanding the energy service plan mechanism is quite difficult for many tenants. Tenants also appreciate that the insulation and most installations are placed on the outside, so that the living space does not become smaller.

A small group of tenants experiences disadvantages inherent to the concept (controllability of temperature and lack of radiant heat). This may be a matter of habituation or further fine-tuning of the product. The potential benefits on lower intrusion effects of modular (prefab) renovation compared to traditional renovation still have to prove themselves in practice. In projects that are being implemented in 2017 or are under preparation, more experience is being gained with renovations applying improved installation approaches. This is helping to increase customer satisfaction.

Important lessons

One of the lessons learned is that it really works well to have the same dedicated team of workmen doing the work on a home. In this way tenants always know who to expect and who to turn to when they have questions.

Another important lesson is to do the retrofit when other home improvements also need to be done.

Furthermore there must be a home available during the retrofit for vulnerable residents and at peak times in the work it´s wise to offer a short-term stay elsewhere for tenants.

Read the whole report (in Dutch)

Overall conclusions

Apart from some problems starting the pilot projects, Energiesprong homes generally perform as promised and tenants are satisfied with their renovated homes. Some construction companies have struggled to get the quality up to standard, especially in the early projects. With the support of NOM Keur (a Dutch industry standard which requires the retrofits to meet certain standards on energy performance, indoor climate and consumer satisfaction)

the market is weeding out low quality products quickly: either they improve, or they don’t get contracts in the future. When compared to the traditional way of retrofitting (without a performance guarantee) the quality of retrofits where monitoring is mandatory has improved significantly. Both builder and tenant profit from the direct feedback on technical performance and behaviour. Although both parties have to get used to this new way of working and living, the energy usage statistics in the first year speak for themselves.

Read the full report with statistics

Read the QuickScan done by consultancy firm Atrivé (Dutch)

[1] An Energiesprong/net zero energy renovation is financed in two ways: through energy cost savings from tenants and by reduced maintenance and repairs costs for housing associations. Both are part of the business case. The objective is that tenants have the same monthly expenses – they pay the housing association an energy service plan instead of the bill of the energy supplier. The housing association can now use this new income stream to pay for the renovation. In most markets legislation needs to allow the conversion of the monthly energy bill into a so-called energy plan for the housing association. In the Netherlands they did. The energy plan (EPV) is now arranged by law and brought into practice the first of September 2016. The energy plan can only be used for net zero energy make-overs (or new build) that come with a 30 year performance warranty and fit certain standards. Read also
















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