For now yes, Hohm is targeted at US single-family households. Sure, it’s possible to use it for multi-family homes, but some of the assumptions start to break down. Over time we’ll extend the models to support other countries. In the meantime, if you want to try out the site, the US models generally apply if you pick a zip code that climatically matches your own (and has comparable energy prices).
There is a known issue with browser language settings that we’re actively addressing as I write this and we expect to roll out a hotfix soon. To get around this problem you can simply switch your browser to use en-US as the default locale. And no, we don’t really think your annual energy costs are in the US $1b range. That’s a bug. It’s a beta.
If I might ask a favor as well – if you use the site, please send us your feedback via the feedback links. We’re still in beta and we’re listening to everything our customers are saying. Thanks.
[Edit 8 Jul 9:45am] We released a hotfix yesterday which should address the browser language setting. It was a mistake on our part and it was fixed. The huge energy cost problem, as one might imagine, was related to the language fix and shouldn't appear from now on.
[Edit 8 Jul 11:10am] Ok, so we didn't roll out the hotfix yesterday. We decided at the last minute to take one additional fix. I'll update when the us-EN assumption is fixed. Sorry.