I've had a woodstove for nine years and I love it.
Factors in determining if you will get the heat you need from wood for your home:
1) Size of your home vs stove/insert firebox size
2) Air sealing your home
3) Insulating your home
4) Properly seasoning firewood
Obviously outside temps matter too.
1) When choosing an insert or woodstove look at the fire box size. This is the biggest factor in determining heat output, I think. Unless your home is under 1000 sq ft, you should go with a minimum of 2.0 cubic feet firebox. Look at what manufacturer says you can heat with that stove. If company X says their stove/insert would heat 2,000 sq ft, assume that is for a really tight new construction with code level insulation done properly, all margins taped, proper air sealing, etc. If you live in a drafty old house, cut the number in half. Thus 2,000 sq ft would be 1,000 sq ft. Then resolve your self to get insulation under control. If house is "typical" assume stove would heat 2/3 of the claim is a safe bet.
2) Air seal your home. Go look for leakings in basement, around windows, etc. Use caulking or canned spray foam (plan ahead with spray foam - it is messy and you usually can't reuse the can). If you can feel cool air coming into your house through a hole, imagine all the heat you are losing. I have a 1920 built home. Over the years I have probably used a couple of standard sized window surface area worth of caulk and foam. If you can afford it - hire a pro to spray foam the sill plate where the basement meets the first floor. Lots of older homes lose a lot of heat here.
Another cheap fix is unscrewing light switch and outlet plates on outer walls and putting in foam pads under plate. Will reduce air flow through the plate and they cost like 19 cents each.
3) Insulate to code. This is especially helpful if you have not sized your stove properly. This will make your family way more comfortable. After air sealing, do celing, then walls. Plenty of posts here about insulation.
4) Often overlooked. Use seasoned wood. Stack off ground and cover top in place that ideally gets sun and wind. Most wood needs 1 yr to season properly. Oak-sugar maple-hickory and other dense woods need 2-3 yrs, but you could get away with one.
Plan ahead. Start getting wood NOW to season. If you buy from someone, assume it is not seasoned even when they tell you it is. Then stack it for a year if possible. Seasoned wood has lots of checks and cracks in it, is lighter, and often grays. You could also get your own wood. Neighbors lose trees, maybe you have a wooded lot, etc. Cutting up pallets otherwise disposed of from box/haardware stores can be good as well. Stay away if pallets treated with chemicals. Don't load stove only with pallet wood as its usually kiln dried and will burn very hot. You don't want to overfire your stove. and cause damage.
Finally I would advise on getting the installation and chimney liner (if you need one) inspected. Piece of mind that your house won't flood with smoke or burn down is nice.
Good luck.
Lots of people new to wood burning ger