Reusing HVAC is possible - anyone who wants it can do it
HVAC - The hidden climate giant
Reuse of pipes
Photo: Hoëgh Eiendom
"We want 100% reuse" was the start of an exciting journey for the committed project team. The statement came from Line Karlsen at Høegh Eiendom and concerned the upgrade of Glynitveien 33 with new ventilation. The project started on April 18, 2023 and was to be completed as early as July 3 of the same year. In the preliminary project, the client set guidelines that they wanted the most realistic project economics possible.
- We wanted to see what could be realized in a "normal" project, in a project size that we have a lot of, says Line.
In the preliminary project, Multiconsult was attached as RIV, and later added to the ventilation contract. Earlier than usual, a first model draft and a simplified quantity take-off were made.
- We made a simplified materials list early on and defined minimum requirements for ventilation units and other components. With this, the project team could start the search for the right reusable products, says Anders Liaøy, who was RIV on the project.
The project was included in the research project Grønn VVS, and four research partners were involved. In addition to Høegh Eiendom and Multiconsult, GK was chosen as the ventilation contractor. Swegon was hired to assist with the reuse of the unit, which in turn was sourced from a fifth partner - KLP and their donor building in Trondheim.
Photo: Höegh Eiendom
How was reuse implemented in practice?
Project manager Lars Jørgen at GK took on the challenge. A reuse survey had previously been carried out and what could be preserved was considered. For Lars Jørgen, an obvious next step was therefore to use unused products on other construction sites that would otherwise have been thrown away. He found ducts, VAV dampers, silencers and valves that could be used in the project.
The project also looked for good, used products with a remaining life. The most important find for Lars Jørgen was a 9-year-old Swegon Gold unit that was no longer to be used in a KLP building in Trondheim. The unit was reviewed and found suitable in terms of air flow, pressure drop, energy efficiency and geometry. An important question was whether components and automation needed to be upgraded before reuse.
Swegon reviewed the unit and upgraded the software so that the ventilation unit had the same quality and life as a new unit. Swegon offers an upgrade kit that enables the reuse of all existing Gold units with remaining service life. The certainty that future replacement of wear parts and upgrades are possible was crucial for Höegh Eiendom to find reuse justified.
- Investing in well-documented quality products with responsible manufacturers is important for later reuse, says Mads Mysen in GK.
Logistics and warranty are recurring issues
Unloading and transporting the unit proved to be more challenging than expected. Some of this was due to flooding and closed roads, but the transport company also made mistakes, and everything had to be followed up and corrected by Lars Jørgen. Such challenges do not occur when ordering through established supplier channels, and in practice mean additional work and follow-up by the contractor when components are to be reused. Responsibility for damage during transport must also be taken care of when reusing in a different way than when ordering directly from the supplier.
Warranty and complaint liability had to be handled, since this is no longer taken care of by the supplier. In this project, Høegh Eiendom accepted the risk of reused products without warranty or complaint options. The industry will need to work on this barrier further, and several players are already working to find solutions for sharing risk.
The current calculation method is not set up for reuse
Greenhouse gas calculations for reuse also presented challenges. A 50-year calculation period for the building must be used (TEK §17-1), while the product's lifespan can, for example, be stated in the environmental declaration. In the case of reuse, one approach can be to subtract the useful life, so that the product has a remaining lifespan into the reuse project.
In practice, this means that an extra component can be replaced, with the consequence that the total calculated greenhouse gas emissions increase when reusing, compared to using new products. Here, LCA methodology can quickly become anti-reuse without that being the intention. For example, a supplier states a lifespan of 50 years for new ventilation ducts. For reused ducts, some of the service life has been used up, so that one replacement is made during the calculation period.
New ducts, on the other hand, have a service life as long as the calculation period, and thus theoretically have no replacement over the life of the building. In practice, ventilation ducts are almost never replaced because they are worn out and exhausted.
What was the result?
Despite a short implementation time of 2.5 months, the project managed to deliver a ventilation system with a large proportion of reused components, even though the ambition of 100 percent was not reached. The reused components are shown in green in Figure 2. This resulted in a calculated greenhouse gas reduction of 36% compared to a reference system with new products.
The savings are based on GK's greenhouse gas calculation over the life of the building. The choice of methodology greatly affects the result you come up with, and Grønn VVS sees a great need for a unified method. In any case, the project achieved major environmental savings. This was made possible by a climate-ambitious developer at Høegh Eiendom, a forward-thinking project team and a project manager at GK who took on the challenge head on.
Did it cost more?
Reusing valves and dampers was profitable compared to new products in this project. The unit cost with dismantling and transport was significantly lower than new, but a new unit would have been more compact and easier to connect to existing systems. Ducts, sound traps and other parts were somewhat more expensive than new due to extra transport and sorting.
Lars Jørgen estimates that he has spent about twice as many hours on project management than on a new system and this additional work is difficult to predict. All in all, we believe that reusing was less expensive than a completely new ventilation system would have been.
Photo: Multiconsult
What can your company do?
Glynitveien 33 is an example of how easy it is to achieve a significant environmental improvement in HVAC if you think “a little outside the box”, and here all actors can contribute. Policy makers can start by demanding a reuse share and rethinking warranty and complaint liability. This will give reused products greater value and create commercial framework conditions for reuse actors.
Advisors can describe reuse and map needs early. Suppliers can consider control, upgrading and resale of reused products as new business areas, as Swegon and also research partner Armaturjonsson are now doing. Technical contractors can offer solutions that use reused products in whole or in part, as GK did. Building owners can dismantle reusable products, ensure that as much as possible is used in their own projects, and make the rest available in market arenas for reuse.
The time has come for action
The goal is a sustainable future, and that future must consist of much more reuse than today. This provides opportunities for all players in our industry who are innovative and environmentally ambitious. Environmental improvement is not achieved with speeches, but through concrete actions. We hope more players will take the initiative and say like Høegh Eiendom - "We want 100% reuse".
This article is one of three that deals with reuse in the article series from FoU Grønn VVS.
Further information about Green HVAC
Green Plumbing is an Innovation Project in the business sector, supported by the Research Council of Norway. The project was carried out in the period September 2021 to March 2025.
Project objectives: Building competence, developing new services and sharing knowledge. Showing the way to a 50% reduction in greenhouse gas emissions from HVAC installations in model projects
The project manager is Multiconsult. Partners in the project are Höegh Eiendom, GK, Armaturjonsson, Swegon, KLP Eiendom and Pipelife. R&D supplier is OsloMet. The reference group consists of VKE and FutureBuilt.
