I switched to a Pellett stove from woodstove last Febuary. Here are some of the thoughts that went into my decisions.
My wood supply was free, but that would not last forever on my small property other than the occasional blowdown. It certainly was not going to be enough to meet all my needs in the future. Once you factor in the price and time to process it, there is a cost to "free' wood anyway. If you are buying wood, in addition to the cash, it still costs you a bit of time to process it(stack in woodshed, split to size). I figured if I was going to buy wood, I might as well purchase wood that was already processed. Moves easilly, no real mess in the house, no bugs, ect... Factoring in all things, including the extra electricity, I think I am about even using pellets without the physical effort of processing the wood.
The pellet heats pretty well, but it isn't the deep radiant heat that the woodstove gave. There is also the noise to consider. These stoves typically have 2 blowers and a auger motor. Some are quieter than others so this is an important point to look at when deciding.
Power was also a concern. Woodstove didn't need it so power failures were never a big issue to me other than keeping the food cold. Typical pellet stove uses about 450 Watts under normal operation(700-900 watts during automatic startup). That would require a VERY large UPS to run any length of time. I have a 500VA(watt) UPS on my woodstove and it is only good for about 5 minutes of normal runtime. Enough to carry over and protect the controller from a small power hit or give me enough time to perform a normal shutdown if the power goes out completely. Also most modern UPS's won't startup unless they have valid 120VAC input power, even if their batteries are fully charged, so comming home to a dark cold house and starting up the pellett on the UPS is not an option. A better option might be an inverter, but that way also has issues. 450 Watts is a current draw of 3.75 amps at 120VAC. Using a 12VDC-120VAC Inverter, that is in excess of 40 amps of current draw from the 12VDC source, once you factor in the inverter efficiency. A typical car battery will net you about 40-50 Amp hours of capacity so in theory you are only going to run that stove for an hour on a fully charged car battery. Unfortunatly, a 40 amp draw is way in excess of the standard amp/hour rateing which is based on a draw over a 20 hour time period(2-2.5A) so you will lose a lot of energy to internal resistance of the battery(battery will generate heat). The high draw also shortens battery life. How you going to recharge the battery in an hour? There are some stoves out there that run on 12VDC motors and use a 120VAC power supply to feed this need when comm power is available. They are more easilly and more efficiently configured for 12VDC backup operation. If your power supply is in doubt, probably best to have a small genset on tap. This has the added benefit of giving you some light as well as some other creature comforts during a power failure(such as keeping the food cold).
