Good news: a European Standard for heat load testing has been released. I hope it will lead to more research that measures the performance gap (if any) between the heating load predicted by design stage energy modelling and as-built performance. Heat load testing is also known as co-heating testing, it’s a measure of a building’s thermal performance. The standard uses a simplified test but it’s the best option available for New Zealand’s design and construction industry to swing behind.
Heat load testing is very expensive and while I’d love it to happen much more often, it’s typically a one-off research project. An agreed standard everyone can reference will hopefully mean more testing—which should in turn reduce the cost and encourage more testing.
Sustainable Engineering Ltd was heavily involved with FMI’s Zero House. We reviewed the heat load testing results, which matched the modelled results quite well as the graph below shows. You can see the full details in the FMI Fenestration Volume 7. This testing used a proprietary method and included tracer gas sampling to measure the actual infiltration during the test. It’s superior to these new standards but way more expensive.
FMI Fenestration Volume 7
I strongly recommend you budget for a heat load test to these new standards if you are building a research or demonstration building.
References
EN 17887 1:2024: Thermal performance of buildings — In situ testing of completed buildings — Part 1: Data collection for aggregate heat loss test.
EN 17887 2:2024: Thermal performance of buildings — In situ testing of completed buildings — Part 2: Steady-state data analysis for aggregate heat loss test.
“These new standards were developed through a collaborative effort led by Professor David Johnston at Leeds Beckett University and Professor Richard Fitton from Energy House Labs, with valuable contributions from experts across Europe. They will be implemented by national standardisation bodies in 34 countries, including major European nations and the UK.” https://energyhouselabs.salford.ac.uk/2024/06/21/issue-15-june-2024/
20240812 Edited for clarity thanks Kara – added Aggregate (Coheating) Heat Load … in title.
For even more clarity this in an in situ test and similar to a blower door test to ISO9972 which measures the as-built in situ air tightness of a completed building, this test measures the as-built in situ heat loss from a building. Effectively you heat the building up to 25C constant temperature for 15 days and correct for solar gains to determine the buildings aggregate heat loss. Again similar to the airtightness testing this allows you to see the real as-built aggregate heat loss including any defects in the construction etc.
This test standard runs for a minimum of 15 days and includes the data during the daytime (ie solar gain) which is corrected out using measured irradiance and a statistical technique. This means testing is best done only in winter where solar gain is minimized.