It cost about $2400 to tent our house when we bought it, but it's bigger, so yours might be cheaper.
We didn't do the gas treatment, though. for about the same price, we found a company that does heat treatment. It's a little more hassle, since you have to remove from the house anything that's going to suffer damage at 150 degrees (all small electronics, all candles, certain foods). What some folks do is rent a UHaul overnight to stash all those items in.
The big advantages:
* Kills termites, dust mites, and certain other bugs just as effectively as the gas.
* No poison!
* You can move back in about 6 *hours* after treatment starts. The treatment itself takes about an hour, but you have to let the walls and floors cool off. ;-) (With the gas, you have to let it air out for 72 hours after the treatment is over, and it takes most of a day.)
If you have a full, but unfinished, attic, you can do an orange oil or borax-based treatment instead... we only have a crawlspace, though, so you can't get to the tops of all our walls. It's superior to both gas and heat treatment, in that it remains in the walls and *keeps* killing the termites for 2-5 years. Both the conventional gas treatment and the heat treatment kill everything when they happen, but go away as soon as you're done. The thing about the orange or borax treatments is that they can miss spots. Best of both worlds is to do heat treatment, and *then* the non-toxic chemical treatment.
If you have subterranean termites, it's a whole other deal, but usually you can address that by remediating leaks and drainage issues that cause damp earth under your house. You also need to break their little tunnels.
UC Davis has a really awesome website about integrated pest management. I read everything they had to say about termites when deciding how to address the problem here. That's how I knew to look for the alternative treatments.
