"Why does smoke puff into the house?"
The reasons vary from home to home. It can be one reason, but often it is a combination of several. A cold chimney is sluggish until warmed. Pre-warm by lighting single sheets of 'unwrinkled' newspaper, one after another. Then crack open a window. Make up air MUST enter the house for every bit expelled out. Other appliances such as dryers, exhaust fans, and furnaces all increase the demand for make up air. This increases the likelihood the weakened draft or even a reverse flow. Chimneys are often built a bit short, and sluggish to vent. Sometimes they're restricted with soot. Moisture in wood creates 10 times the smoke, and not enough heat to induce a strong draft…a bad combination. Blowing wind is never the sole cause. Usually, smoke issues are mix of two or more factors, in varying degrees.

"Where can I get seasoned wood?" Answer- Nowhere. You must get the best you can and hold onto it for the next heating season. What was considered seasoned for past stove technology is no longer acceptable. One year seasoned wood is usually 4 to 8 months old, and it sat uncovered and un-split. One additional year split and covered removes the extra pint or two from each 12 pound log. With the water removed, the smoke burning feature is functioning.

Using the new definition of seasoned wood, you will insure the following*:

Much less wood consumption. (Water keeps smoke fuel from burning.)
Much less wood toting, ash removal, and mess.
Much longer burn times that also help the heat to spread out more evenly.
Long burns allow fewer restarts, and the furnace turns on less.
Much faster heating and heat larger areas.
Cost of wood is less when bought a year in advance.(inflation)
Lighter wood to carry and load. Much easier start-ups.
Cleaner environment and happier neighbors.
Safe and economical 'stay clean' chimney.
Allows the new air wash system to keep the class clean.

* You lose all these benefits also if you bought a cheap quality new stove, that due to over firing or poor maintenance, is now not tight enough to pull down secondary combustion air.

"Can I tap a wood stove into a flue being used by my furnace?"
Many do it to save the expense of a new chimney, with no problem. Building code says you can't primarily because soot can block the shared flue. If new stoves are operated properly, there should be no smoke, let alone a creosote blockage. New chimneys installed are almost all stainless steel, and cost between $1200 and $3000 installed.