Speakers for screen porch not exposed to rain?

Hi, Thanks for your help. I have a summer house which has a screen porch 11x22. The room is pre wired for the speakers to be up high on the wall at the cieling line.(8ft) This location is totally not exposed to weather but is of course exposed to summer heat and somewhat cold at night(across the lake from Chicago). I want to upgrade my 7 yr old Cambridge outdoor speakers. While shopping I have noticed the large price difference between bookshelves and outdoor speakers, also that there are no used outdoor speakers for sale. As the outdoor speakers are usually not ported, I'm thinking of buying a good used bookshelf and bringing it indoors promptly when the weather starts to change. I'm prepared for a shorter life span if it's not too drastic. Thoughts? John-- Thanks. [email protected]
If you mount speakers at ceiling level, you've leargely defeated the point of having a conventional high-end speaker, which is designed to put the tweeters at ear level. Plus, as you note, they won't be completely shielded from the elements. I've never even looked at outdoor speakers, so I've no idea what the options are, but my suggestion would be to not invest a lot of money in any case. You're buying for background music in this location, not critical listening. So I guess my first choice would be an inexpensive outdoor speaker, and my second choice would be an inexpensive indoor speaker that I was prepared to replace more often than is typical.
get a pair of JBL indoor/outdoor speakers with the mounting brackets included, front ported bass to 75hz, great little porch speaker for around 200 bucks per pair.
Try the Niles outdoor models. They are excellent indoor speakers also.
You might want to check these out, http://www.polkaudio.com/homeaudio/specs/multiapplication/atrium60/

We've got them on the boat (inside the cabin) and they sound very good for the application, ie., non-critical listening. Shop around, they can be had for less than list.
I kept EV-40's outside permanently in Pittsburgh. Nothing stopped them. They were not even under cover, just angled down a little. They may not be as sonically nice as a great indoor speaker but the "built like a tank" quality and the fact that it is your porch will make up for that fact.
Bag the speakers. Open the windows and crank it!