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Rensair
Founded 2020 · 29 employees on LinkedIn · 3 known investors
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Rensair provides air filtration technology and works to improve commercial building HVAC systems to reduce energy use and carbon emissions while improving indoor air quality. It serves commercial building owners and operators across sectors such as offices, hospitals, and universities.
Also known as Rensair · Rensair Limited · Rensair Ltd · Respired Group · Respired Limited
Founders & leadership
Rensair was founded in 2020 by Christian Hendriksen and Henrik Hendriksen.
Investors · 3
Company profile
researched Aug 2026Respired (trading as Rensair) develops air purification hardware and connected software aimed at improving indoor air quality and reducing the energy consumption of existing commercial HVAC systems. The company positions its offering as an "air quality ecosystem" combining filtration units with monitoring and cloud software, marketed under the theme of "hacking" existing HVAC rather than replacing it, so that buildings can lower running costs and carbon output without large capital replacement projects.
The product line includes the Core and Core i air purifiers, a Compact unit, the AirBubbl, Rensair Cloud and the Rensair Air Monitor, together with replacement filter kits. The company states its HEPA filter and light-based technology removes 99.97% of pollutants, listing viruses, bacterial spores, pollen, mould spores, fungi, vehicle particulates, dust mite allergens, pet dander, odours, tobacco smoke, household dust and staphylococcus. It also offers HVAC commissioning and demand-controlled ventilation (SDCV) approaches, and publishes case studies covering an insurance company office estate, a university and ambulance services. [0]
Corporate materials identify the operating structure as the Respired Group, with Respired Limited (UK company number 12586496) registered at Lincoln House, 296-302 High Holborn, Floor 6, London WC1V 7JH acting as data controller for the website, alongside group companies Rensair Limited (UK and rest of world), Rensair LLC (US and Canada) and Rensair BV (EU). [1]
Business model
The company sells air purification hardware (Core, Core i, Compact, AirBubbl) plus consumable replacement filter kits, alongside connected software and monitoring products (Rensair Cloud, Rensair Air Monitor) and services such as HVAC commissioning, addressing commercial building operators directly. [0][1]
Latest developments
The RENSAIR trademark, applied for in Canada on 2020-09-14 with a UK priority filing of 2020-06-15, was approved on 2024-11-18, advertised on 2024-12-11 and registered on 2025-03-03 under registration number TMA1294394, with an expiry date of 2035-03-03. [2]
▸Full profile — market position, technology, go-to-market, geography
Market position
Rensair describes over two decades of activity in commercial air filtration and frames its current focus as energy-efficient ventilation retrofit, arguing indoor air quality can be up to five times worse than outdoor air and that its approach could contribute to a 6.5% reduction in global carbon emissions. [0]
The company emphasises retrofitting and optimising existing HVAC installations rather than replacing them, combining filtration hardware with connected monitoring and cloud software to target both indoor air quality and energy/carbon reduction in a single offering. [0]
Technology
HEPA filtration combined with light-based (ultraviolet) treatment, stated to remove 99.97% of pollutants, packaged in portable and installed air purification units and paired with cloud software and air quality monitoring. The company also applies demand-controlled ventilation (SDCV) and HVAC commissioning to reduce energy use in existing mechanical ventilation systems. Its trademark filings cover ultraviolet air purification devices, UV lamps and filters, industrial and commercial air purifiers, air cleaning units, ionizers and exchangers, and HVAC systems for buildings, vehicles, cleanrooms and hospital isolation rooms, plus engineering and consulting services for air purification and HVAC design. [0][2]
Go-to-market
Direct engagement through the company website with sector-specific solution pages (senior living, offices, universities, hospitals and healthcare, transport), contact-led sales, published case studies, certifications pages and editorial content on topics such as mould, portable air purifiers, dust and HEPA filters. [0]
Commercial and institutional building owners and operators, specifically senior living owners and operators, offices and corporate real estate, hospitals and healthcare providers, universities, and transport operators including ambulance services. [0]
Geography
Headquartered in London, United Kingdom, with group entities covering distinct territories: Rensair Limited for the UK and rest of world, Rensair LLC for the US and Canada, and Rensair BV for the EU. The RENSAIR mark is also registered in Canada. [1][2]
Compiled by commissioned research from 13 cited public sources — announcements, filings, and press listed under research sources below.
Key figures
latest reportedCompany-reported or press-reported figures, each dated to when it was claimed — not independently audited.
Timeline · 4
launches, deals, and filingsCanadian Intellectual Property Office registered the RENSAIR standard-character trademark to Respired Limited of London, UK, under registration number TMA1294394. The application (2051393) was filed 2020-09-14 with a UK priority filing date of 2020-06-15, approved 2024-11-18 and advertised 2024-12-11; registration expires 2035-03-03.
Rensair raised $7 million in a Series A round that began in December 2021 and closed on 3 May 2022. Hoxton Ventures led and provided approximately half of the round; the remainder came from high net worth strategic investors with real estate backgrounds. Proceeds were earmarked for North American expansion, 10-20 new hires globally over the following year, and IoT-oriented product development.
$7M source ↗
Rensair acquired AirLabs, an air quality monitoring and air cleaning company, adding about 10 employees as part of its product expansion.
Co-founder Frederik Hendriksen relocated to New York roughly two years into the business to lead North American expansion, with the US identified as the company's largest expansion opportunity after an initial UK and European focus.
Dated company events from announcements, filings, and press; legal rows summarize public dockets and regulator releases.
Companies House · registry record
View on Companies House ↗- Registered name
- RESPIRED LIMITED
- Company number
- 12586496
- Status
- Active
- Company type
- Private limited company
- Incorporated
- 5 May 2020
- Registered office
- Third Floor, 20 Old Bailey, London, United Kingdom, EC4M 7AN
- Nature of business (SIC)
- 28250 — Manufacture of non-domestic cooling and ventilation equipment71129 — Other engineering activities
- Accounts
- last made up to 31 Dec 2024 · next due 30 Sept 2026
- Confirmation statement
- last made up to 27 Oct 2025 · next due 10 Nov 2026
Current officers · 5
- Christian Hendriksen — director, appointed 5 May 2020
- Frederik Hendriksen — director, appointed 25 Nov 2020
- Hussein Kanji — director, appointed 4 May 2022
- Mark Kendall — director, appointed 7 Feb 2025
- William Kourakos — director, appointed 18 May 2022
Source: Companies House public register · retrieved 30 Aug 2026. Contains public sector information licensed under the Open Government Licence v3.0.
▸Research sources · 13
primary sources listed
- Respiredrensair.com · web
- PITCH DECK: Rensair Raises $7 Million Series a Round - Business Insiderbusinessinsider.com · web
13 public sources were cited for this profile; the first-party ones are listed here.
Frequently asked questions
- What does Rensair do?
- Rensair builds connected air purification and HVAC efficiency technology for commercial buildings.
- Who founded Rensair?
- Rensair was founded by Christian Hendriksen, Henrik Hendriksen in 2020.
- Who are Rensair's investors?
- Rensair's investors include Alumni Ventures, Hoxton Ventures, Second Century Ventures.