Karsten John Hjarsø

Member hos Danish Business Angels - DanBAN

📍 Denmark🔄 Updated September 2026💼 10 investments📅 2 years investing🗓 Last invested Jul 2026
VC🌍 DenmarkInvested this quarter
10
Total investments
1
Early stage
4
Mid stage
3
Late stage
2y
Years active

Portfolio

10 investments · sorted by recency
All investments
Early stage
Mid stage
Late stage
Investor
Jul 2026
SmartBrønd monitorerer og styrer regnvand i de tætte byzoner. Vi benytter innovativ IoT-data til revolutionere håndteringen af regnvand. Vores mission er at gøre det muligt at optimere, kontrollere og genanvende opsamlet regnvand på en nem og overskuelig måde. Følg med her for at se vores nyeste projekter og forbedringer af byens klimatilpasningsprojekter.
Investor
Jul 2026
Leading the way in moisture detection 🌧️ | Formerly Woodsense, now Tector Real-time alerts, AI-powered insights & effortless integration | Trusted by contractors, architects & sustainability leaders | #BuildBetter #ProTected Tector helps construction and real estate professionals prevent costly moisture damage before it happens. Our intelligent sensors and AI-driven analysis provide real-time insights for timber structures and flat roofs, reducing material waste, CO₂-heavy repairs, and operational disruptions. Why proactive moisture monitoring matters: ✔ Prevent damage early – Detect and localise moisture issues before they escalate. ✔ Cut costs & CO₂ – Reduce material waste, dry-out expenses, and environmental impact. ✔ Extend building lifespan – Protect structural integrity and ensure long-term durability. ✔ Enhance compliance – Align with sustainability goals and ISO standards. With the Tector application, you get real-time alerts, historical data, and automated reports tailored to your project needs. Need seamless integration? Our API connects with your existing construction tech stack. Let’s build smarter, more resilient structures—together.
late stageConstruction
Investor
May 2026
We believe in shoes that feel amazing on your feet and are kind to the planet. https://wollow-official.com/ Visit us at our flagship store at Elmegade 30, 2200 Copenhagen
Seed Investor
May 2026
Aparta is Europe’s leading co-ownership infrastructure for residential real estate. Trusted by consumers, banks, developers, and investors, we bring greater flexibility to homeownership by managing the legal, financial, and administrative complexities. Our infrastructure supports the full housing journey: entering the market, purchasing a home, or selling a share of an existing property. By connecting homeowners seeking more flexible ownership with investors looking for exposure to residential real estate, Aparta has built the first platform of its kind in Europe. We are currently established in Norway, Sweden, Denmark, and Iceland, with plans for further expansion across Europe. If you are interested in exploring investment opportunities in Aparta, please reach out to our Founder and CEO, Eilin Schjetne (es@aparta.com).
Investor
Jan 2025
Gismap er et nature tech startup med en B2B SaaS-platform til måling, analyse og rapportering af biodiversitet. Vi revolutionerer ejendomsselskabers indsigt i biodiversitetspåvirkning ved hjælp af avanceret AI og dataanalyse, hvilket muliggør præcis ESG-rapportering på biodiversitet.
Investor
Apr 2024
Buildcode is a software engineering company, with a background in the construction industry, we are specialized in developing systems for optimizing quality assurance and progress management on construction sites. Our solution is based on day-to-day registrations done with the use of drone and scanning technologies for recording and processing the data related to building informatics that enable to: - minimize errors and deficiencies on the construction site, - improve communication during the construction process, - enhance the overall quality of the building. Using drones and scanners for delivering accurate and objective registrations of larger areas is one of the most effective ways of quality assurance of buildings. As a result, more errors and deficiencies can be found before they lead to failure. Our system boost overall efficiency on the construction site hence is an effective digital tool for project management helping to stay align with project budget and follow work schedule.
Investor
Apr 2024
Estabild is a modern cloud-based software for construction project budgeting and reporting to management stakeholders. Our software streamlines and automates business processes to ensure predictable outcomes and project delivery. With Estabild stakeholders get a complete overview of their development projects, efficiently manage project funding, drawdowns & payment requests, and consolidate all key data in a single source of truth. Were focusing on delivering three core values to our clients: predictability, transparency, and connectivity. These values combined improve the level of trust between stakeholders and their capital investments, to help reduce the risk of undesired outcomes such as cost overruns and schedule delays. Estabild enables stakeholders such as real estate financiers, developers, owners inspectors, and asset managers to: • Get a complete overview of development projects. • Keep track of financials, schedule, scope of work, and development risks in real-time, to replace static and outdated reports. • Share project progress updates. • Have all project documentation securely stored in the cloud. • Consolidate and streamline information from different sources in one place. • Collaborate with key internal and external stakeholders involved during the project development. • Get a centralized overview of portfolio projects to analyze data and auto-generate reports.
Investor
Feb 2024
The purpose of the fund is to invest in proptech start-ups, primarily in the Nordic countries. Focus is on start-ups in the pre-seed and seed stage, and to create value through active management and engagement. Proptechfonden is established by a group of DanBAN business angels and Realdania.
Investor
Jan 2024
I CLIMAID mener vi at alle skal arbejde i godt indeklima og at man ikke skal blive syg eller føle ubehag heraf når man går på arbejde. CLIMAID er stiftet og drivers af indeklima-nørder, men vi ved at det ikke er alle der går lige så meget op i det som os, derfor ser vi det som vores vigtigste mission at udvikle løsninger der gør det nemt for virksomheden og dens medarbejdere at opretholde et godt indeklima.
Investor
Jan 2024
Waitly was created to provide a simpler solution for both the cooperative housing and rental markets. We have personally experienced the difficulties of navigating waitlists as home seekers (and admins), never knowing our position or when we might be offered a housing opportunity. When Tim Myhrvold, CEO of Waitly, became the chairman of a cooperative housing association, he saw firsthand the administrative challenges of managing waitlists and the significant amount of time volunteers on the board spend on this task. What DocuSign managed to do for digital signature, is what Waitly wish to be for digital waiting list.
Experience · 22 entries
All (22)
Investments (10)
2026
Investor
Jul 2026
SmartBrønd monitorerer og styrer regnvand i de tætte byzoner. Vi benytter innovativ IoT-data til revolutionere håndteringen af regnvand. Vores mission er at gøre det muligt at optimere, kontrollere og genanvende opsamlet regnvand på en nem og overskuelig måde. Følg med her for at se vores nyeste projekter og forbedringer af byens klimatilpasningsprojekter.
Investor
Jul 2026
Leading the way in moisture detection 🌧️ | Formerly Woodsense, now Tector Real-time alerts, AI-powered insights & effortless integration | Trusted by contractors, architects & sustainability leaders | #BuildBetter #ProTected Tector helps construction and real estate professionals prevent costly moisture damage before it happens. Our intelligent sensors and AI-driven analysis provide real-time insights for timber structures and flat roofs, reducing material waste, CO₂-heavy repairs, and operational disruptions. Why proactive moisture monitoring matters: ✔ Prevent damage early – Detect and localise moisture issues before they escalate. ✔ Cut costs & CO₂ – Reduce material waste, dry-out expenses, and environmental impact. ✔ Extend building lifespan – Protect structural integrity and ensure long-term durability. ✔ Enhance compliance – Align with sustainability goals and ISO standards. With the Tector application, you get real-time alerts, historical data, and automated reports tailored to your project needs. Need seamless integration? Our API connects with your existing construction tech stack. Let’s build smarter, more resilient structures—together.
late stageConstruction
Investor
May 2026
We believe in shoes that feel amazing on your feet and are kind to the planet. https://wollow-official.com/ Visit us at our flagship store at Elmegade 30, 2200 Copenhagen
Seed Investor
May 2026
Aparta is Europe’s leading co-ownership infrastructure for residential real estate. Trusted by consumers, banks, developers, and investors, we bring greater flexibility to homeownership by managing the legal, financial, and administrative complexities. Our infrastructure supports the full housing journey: entering the market, purchasing a home, or selling a share of an existing property. By connecting homeowners seeking more flexible ownership with investors looking for exposure to residential real estate, Aparta has built the first platform of its kind in Europe. We are currently established in Norway, Sweden, Denmark, and Iceland, with plans for further expansion across Europe. If you are interested in exploring investment opportunities in Aparta, please reach out to our Founder and CEO, Eilin Schjetne (es@aparta.com).
2025
Investor
Jan 2025
Gismap er et nature tech startup med en B2B SaaS-platform til måling, analyse og rapportering af biodiversitet. Vi revolutionerer ejendomsselskabers indsigt i biodiversitetspåvirkning ved hjælp af avanceret AI og dataanalyse, hvilket muliggør præcis ESG-rapportering på biodiversitet.
Show all 22 entries ↓
Investment activity
2024–2026 · 10 investments
202452025120264
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