TFA:

To be eligible for the eRadiator, your home has to have... "an external wall" ... and the external wall is needed for venting (if you "turn off" the eRadiator, the servers don't actually turn off; the heat is just pushed outside).

Admittedly, without active refrigeration this is unlikely to work too well when the temperature outside is over 35 C.

EDIT: they don't mention separate electric supplies, so presumably the unit has a way of tracking its power usage and reimbursing the homeowner. Otherwise this is just a scam, because far more efficient electrical [EDIT: thanks 'votingprawn!] heat pumps are available for less initial cost. However, the non-scam scenario seems only to make sense as a business in cold locations.