Earlier in this series we saw that data center waste heat is low in temperature, and that heat from air-cooled data centers in particular is hard to reuse. So can data center waste heat really warm people’s homes?
In Odense, Denmark, it already does. Heat pumps lift the lukewarm heat from Meta’s data center to warm about 11,000 homes. This post looks at how Odense uses data center waste heat for district heating, and how the project has grown.
The Odense data center waste heat project
| Item | Details |
|---|---|
| Data center | Meta’s Odense data center (Denmark) |
| Heat taken by | Odense district heating (Fjernvarme Fyn) |
| Heat supply since | 2020 |
| Heat pump output | About 45MW |
| Supply temperature | 70–75°C |
| Homes warmed | About 11,000 (as of January 2025) |
Collecting heat from an air-cooled data center
Meta’s Odense data center is air-cooled, meaning it cools its servers with outdoor air. The air leaving an air-cooled data center is only lukewarm and hard to use as it is, so in Odense the heat is first transferred to water and then raised in temperature by heat pumps.
※ Air cooling: cooling servers by blowing cool air over them
※ Liquid cooling: cooling servers with a liquid such as water
Fjernvarme Fyn invested in and operates the heat pump plant, and the heat pumps run on renewable electricity.
The original plan and today
When Meta announced the plan in 2018, it expected to recover 100,000MWh of heat a year, enough to warm 6,900 homes. Heat supply began in 2020, and in the same year Odense’s district heating company began planning to expand the plant.
As of January 2025, waste heat from Meta’s data center alone supplies district heating to about 11,000 homes, well beyond the original plan.
The bottom line
Odense shows that even lukewarm heat from an air-cooled data center can heat a city once heat pumps raise its temperature. A heat supply first planned for 6,900 homes now warms about 11,000.
Heat that was once thrown away can warm a city when it is matched with the right place and the right way to use it. GIGAette’s IsoTES® is a constant-temperature thermal storage system that charges from whichever heat source fits — waste heat, renewable electricity or grid power — and releases the stored heat at a steady temperature.
If you would like to work out where the heat from your facility could be used, request a technical meeting.
Sources
- Odense Data Center — Meta Engineering (2018-04-26) — cooled with outdoor air, heat recovered by passing server-warmed air over water coils, heat pumps running on renewable electricity raise the temperature further, plan of 100,000MWh a year for 6,900 homes, wind power
- Meta: surplus heat to district heating — Ramboll — energy center ready to operate in late 2019, heat output of about 45MW, electric ammonia heat pumps to 70–75°C, Fjernvarme Fyn began expansion planning in 2020, Meta representative: “100% wind-powered, from running the servers to supplying the heat”
- Waste heat from Odense data center to warm local community — Alfa Laval (2026-01-08) — cooled with outdoor air, warmed air heats water in water coils, cooling water piped between the data center and the heat pump plant, Fjernvarme Fyn invested in and operates the heat pumps, ammonia heat pumps
- Heat Reuse, Sustainable Data Centers Roadmap — Innovation for Cool Earth Forum (ICEF) (2025-10) — Meta began sending heat from its Odense data center to Fjernvarme Fyn in 2020, temperature raised by heat pumps
- Stor sejr for fjernvarmekunder — Fjernvarme Fyn press release (2025-01-17) — waste heat from Meta’s data center alone supplies district heating to about 11,000 homes
- Cover image: AI-generated (colour-adjusted)