This Bitcoin Boiler Pays for Itself in 2 Years

Elmeri Suomi runs a heating company that happens to mine Bitcoin. His product, the SunBit Bitcoin Boiler, drops one or two hydro-cooled ASICs into a water tank, heats a house to 60°C, and lets the mining revenue pay the power bill — in the best case leaving the homeowner in profit on their heating. He started in water-to-air heat pump sales, began mining as a hobby in 2020, and founded SunBit in 2023 once the two worlds clicked.

In this episode we get into the economics that make consumer-scale mining work at 7–12¢/kWh power: not fat mining margins, but offsetting an oil bill that can run 3,500 litres a year at €1.80/litre. Elmeri walks through the ROI (two years best case, five years worst), why he explains everything in cents per kWh instead of hashprice, and how spot-price optimisation and solar over-production feed into the tank.

We also cover why he abandoned immersion after too much grey hair — dissolved cooling paste, dead S21s and oil everywhere — and landed on hydro; why the boxes are Antminers, not Whatsminers (60°C is all you need once you're past Legionella at 52–55°C); the 3×25A wiring that lets it fit a normal Finnish home; the first installs in Kotka and Nokia plus the first international job in the Netherlands; and the pre-seed raise now funding a 100 kW industrial version.

Guest: Elmeri Suomi, CEO & Founder of SunBit Oy

SunBit: https://sunbit.fi/en

SunBit on X: https://x.com/SunbitOy

SunBit on LinkedIn: https://www.linkedin.com/company/sunbit-oy/

Timestamps:

0:00 Intro: a heating company that mines Bitcoin

4:30 Where the savings really come from — offsetting the oil bill

11:00 Explaining hashprice vs cents per kWh, pool and Lightning

17:30 Skepticism, "is this legal?" and the remote-managed mini-PC

23:00 Why hydro beat immersion — the grey-hair story

29:00 First installs, the total market and the pre-seed raise

Sponsored by:

Luxor. Mining pool, firmware, hardware trading and hashrate tools

https://luxor.tech/

Altair Technology. ASIC hardware, replacement parts and mining infrastructure

Code: HASHRATEUP

https://altairtech.io/aff/125/

HashrateUp Hardware Deals: https://t.me/hashrateup

Free 5-Day Bitcoin Mining Course: https://hashrateup.com/newsletter-sign-up/

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