My dear reader,
You've read right: if you live on the edge of a thermal vent - or a volcano - you can now get heat-pumps that shift that warm, warm geothermic air straight to the inside of your house (absent offensive gasses)!
No, not really: 'geothermal' is a bit of a misnomer; what the 'geothermal' heat-pump does is move heat from below the ground to the inside of your house.
So, how's this different to the average heat-pump? Well, not by much, really: heat-pumps 'shift' heat from the outside to the inside of the house (or from the inside to the outside), which allows them to be really efficient since they have the effect of generating more energy than what they use up.
This, of course, relies on it not becoming too cold (since the absence of outside heat would make it harder to shift it inside).
The good thing about shifting heat from the ground is that the ground tends to stay a pretty even temperature (15 degrees, according to the link at the end of the paragraph), so the 'geothermal' heat-pump wouldn't be affected by sudden shifts in air temperature. You can find out about it here.
Question: how much will it cost?
Answer: around $42,000 (excluding GST), based on their estimates. However, they reckon that the running cost is about $400 per year, which amounts to an average of $33 per month. So, if the Energywise website is anything to go by, we would spend an average of $58 per month, if we had a power bill of $200 per month.
This would amount to savings of $25 per month; so, if we were going on the amount saved alone, it would take 140 years to pay for itself.
140 years! Better to go on other factors, like what heats the best, and what has a longer lifetime, methinks.
Any words of caution? Yes: this stuff could be seriously damaged in an earthquake; but, then again, what wouldn't? Make sure you talk to your insurers to see what they're offering in regards to that.