Who will install the projectors
Internal team, dealer/integrators? I am not recommending one over the other, but some choices in projectors will raise the costs. For example a wall mounted above the screen ultra-short throw projector needs less cabling, less installation time than a traditional ceiling mount. When you are contracting with a dealer, the difference can be a lot. If you have school tech teams doing the work, then the hours change a bit, but the costs are less likely to blow out your budget.
Who will maintain them
Virtually every LCD projector on the market has at least one filter. A few don't need filters changed for a couple thousand hours or more, some only when the lamp gets changed, but most LCD projectors will, at some point require a filter change.
DLP projectors mostly lack filters, and when they do, they will normally not need changing in less than a thousand hours or two, of use. That brings us to one aspect of cost of ownership, maintaining the projectors.
If you have a lot of projectors, filter cleaning can become a tiresome, labor intensive chore, if those filters need frequent, rather than infequent changing. For a projector or three, that's not a big deal. If you are managing 500 projectors spread across 20 schools and you have projectors that want lamps cleaned every 250 or even 500 hours, you now have a logistical and cost headache. If you have to touch the filter every 1000 or couple thousand hours, then it shouldn't be near as significant of a factor. In this report, one of the Epson projectors claims the filter gets changed every 5000 hours, which means just change it out when a new lamp is needed. That's ideal. All of the projectors in this report can be ceiling (or for the ultra short throws, wall mounted), except for the pocket projectors. A fewl of these projectors must be detached from the ceiling or wall mount, to get to the lamp door. Trust me, that's a pain, it makes lamp replacement take many times longer.
A fast lamp replacement, if a projector is already cool, should take 5-10 minutes and that is including: Moving chairs or desks to gain access, opening a ladder, climbing it. Using a screwdriver to remove two to six screws, removing the door (it might be hinged), removing the lamp, sliding in the new one, replacing the door and screws. Then: Clean the lens and check the focus and image on the screen (it's easy enough to accidently change the focus or slightly change the angle of the projector...)
If you have to unmount the projector from the ceiling or wall mount, the 2-5 minutes needed above, can stretch to 20 minutes 30 minutes or a lot longer. And I can tell you, it's a real pain in the you know what!
The Interactive Projector - Big Time
Ahh something new, sort of. As a projector dealer, my old company had sold SmartBoards since the mid '90s. Smart Boards, especially in conjunction with a projector, makes a rather powerful tool. If you aren't familiar with SmartBoards and competing products, check'm out. No time to get deep into it here.
You just want to know this: Most of the core features of a combination of SmartBoard and projector, plus many additional ones, are appearing from projector manufacturers, moving into Smart's "space". Last year, the Epson Brightlink 450wi was the first one we saw. This year, we are reviewing the updated, 455wi. Last year that was the only interactive projector shipping at the time of our report, but this year we have four and there are several others on the market.
May I recommend you read Tony's review about the Epson Brightlink, Then, you might want to check out the Smart site as well so you can get a handle on the incredible wealth of abilities possible with a projector + SmartBoard, or an Interactive Projector. In the case of the Epson, no need for any type of "smartboard", just the projector and a standard whiteboard. Impressive stuff. I think the most amazing thing though is how these new interactive projectors dramatically reduce the cost compared to projector + SmartBoard. You don't get all the features, but you may be able to buy 3 inteactives for the price of 2, or buy 5 for the price of 3 (projector + smart board). That's huge!