The report “Less greenhouse gas emissions from a notched detached than a passive” drawn conclusions based on a highly questionable basis, says SINTEF Building Research.
Also read: Laft greener than passive
Missing Data
Chief researcher has gone over comparison of building types and found a number of errors. In an article in Byggeindustrien explains Andresen some of them:
“This paper shows the results of a greenhouse gas accounting for an existing notched detached located in Lom, compared with a theoretical detached listed in passive house standard. Greenhouse gas emissions are given in kg CO 2 equivalent per year, per square meter, averaged over a 60 year life cycle. It says nothing about what is meant by square meter, but usually it is heated BRA used, so I suppose it is this which is also used here. “
” There is no description of structures or technical installations in the two houses, but it is mentioned that both houses have a heat pump. It is also not shown any drawings of the two houses. “
” For passive house is given a built-up area of 137 square meters, a gross area of 345 square meters and a floor space of 124 square meters basement. For cogged house there is available a few spaces, “writes chief scientist.
Comparison of greenhouse gas emissions?
Andresen also find errors in the calculation of greenhouse gas emissions from energy use in the production phase. These are based on different assumptions for the two dwellings.
“For a log house is it based on measurement data for 2.5 years from January 2013 to April 2015. It stated no source for these data, but it can well believed that it is based on meter readings from the energy company. “
” The energy use of passive house is based on a theoretical calculation, since this house is not listed. It says nothing about what are the prerequisites for these calculations, ie what is placed by use times and operating conditions, ventilation airflow, indoor temperature, lighting and equipment. But out of the estimated total annual energy requirement, which is 86 kWh / square meter per year, one can assume that the calculation is based on standardized values acc. Norwegian Standard 3031, “writes Andresen.
This is like comparing apples and pears, explains Andresen.
-” We know from several measurement projects, including from Eble project that energy consumption can vary greatly even though the homes are built on entirely similar manner and in the same position. This applies to all types of buildings, ie both passive, low-energy buildings and other buildings, writes researcher. “
Comparison of greenhouse gas emissions
The big difference according to Cultural Heritage report lay in emissions from the production of byggematrialene .
– “The calculation of greenhouse gas emissions from the use of materials for the two buildings appears to me like comparing apples and pears. For example, the accounts show that greenhouse gas emissions from soil and foundations are 2.16 kg CO 2 eq / square meter per year for passive house, while it is only 0.95 for cogged-house. This is the largest and most important record in the greenhouse gas accounts for materials, and constitute 45 percent of emissions for passive house and 40 percent for cogged house. If one looks at material lists attached, one sees that this is largely due to the concrete amount used for passive house is twice as high as in cogged house (about 100 tons of passive house and 50 tons of cogged-house).
This is a very strange comparison, when it is not given that a passive house is more concrete in ground and foundation than a building logs together, “writes Andresen.
Useriøst
The researcher stated that the Directorate has exited with calculations on such a basis, and believes in his article that she “could have taken up a number of weaknesses as those discussed above. But the conclusion is that this note certainly can not be used to draw any conclusions about the woodworkers Ahus has less greenhouse gas emissions than passive. “
It is disappointing that Riksantikvaren go out with a so-eyed message based on such a small through work basic document, concludes Andresen before she adds that she “hope we do more such facile statements and that we also can get a fruitful and knowledge-based discussion based on thorough research that shows how we can reduce greenhouse gas emissions from all types of buildings.”
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