Most projector bulbs are warranted for either 90 days or one year, but most also have usage-based warranty periods. If the lamp is used heavily, perhaps as a home TV that's on six hours a day, the warranty could expire on usage after only one or two months. With projector lamps typically selling in a range of $300 to $450 each, this is a significant consideration in terms of warranty.

If the lamp is used only one or two hours per day, the warranty might expire on the calendar alone, but as a worst case -- with the lamp consistently burning out on day 91 -- this could involve a materials cost of $150 a month in quarterly bulb replacements. Even if a $300 bulb lasts six months, that would mean the operating cost could top $50 a month. Even if the lamp is replaced only once a year, this cost is significant compared to the typical $1,500 selling price of the projector itself. So with this product type, we're going to list lamp warranties as a third metric, alongside the overall parts and labor warranties.

Unlike other consumer electronics categories that use a year's parts warranty and a 90-day labor warranty to discourage the pursuit of warranty claims late in the year, most front projectors have identical parts and labor warranty periods. With projector lamps, however, the shorter warranty actually encourages replacements, and the customer usually does the replacing themselves.

With printers, neither the paper nor the ink carries an express warranty (although clearly defective toner cartridges would be replaced). So while there may be a significant ongoing operating cost in consumables, and while the ongoing replacement of ink and paper is a given, this has no bearing on the hardware warranty. With televisions, especially flat screens, the glass usually has a separate and shorter warranty, but it's not ordinarily considered replaceable. So a cracked screen is usually a total loss, especially with CRTs, and the shorter warranty on the screen encourages disposal.

With rear projection units, both the screen and the bulb usually have shorter warranties than the electronics inside, and like these front projectors listed below, the bulbs tend to wear out over time. So perhaps this metric deserves scrutiny too? If so, we may need to go back and revisit the list in the Sept. 7 column. But the replacement bulbs for these units are priced closer to $200 to $250, and they don't burn as bright or as fast as front projection lamps. Replacements are to be expected every three to five years.

Epson warrants most of its projectors for two years, but the projector's lamp is warranted for only 90 days. Even on models with three-year warranties, the projector's lamp is warranted for only 90 days. Optoma does likewise, giving the basic unit either a two- or three-year warranty period, but the bulb is warranted for only 90 days.

InFocus grants either a 90-day or a 180-day warranty on the projector bulb, depending upon the model.

Hitachi warrants its projector lamps for 90 days or 180 hours of use, whichever comes first. NEC warrants its projector lamps for one year or 500 hours.

Mitsubishi warrants most of its lamps for 90 days or 300 hours of use, while the lamps in some models such as the ES100U and the XD490U carry a one-year/1,000-hour warranty. All bulb warranties are parts-only, meaning that the customer must replace the bulb themselves or pay for a technician to do so.

On some models, Panasonic caps both its projectors and its lamps with usage limits. For instance, the PT-AE900U projector is warranted for one year or 2,000 hours, whichever comes first, while the lamp is warranted for 90 days or 500 hours. The projector warranties cover both parts and labor, while the lamps are parts only (customer replaceable units).