Yes, you can install a wood burning insert in a prefab fireplace, but it's not recommended. Prefab fireplaces are not made to withstand the heat and smoke from a wood burning insert, so there is a risk of fire. In addition, the flue in a prefab fireplace is typically too small for a wood burning insert, which could cause problems with draft.

It depends on the prefab fireplace. Some prefab fireplaces are designed to hold a wood burning insert, while others are not. If you're not sure whether your prefab fireplace can accommodate a wood burning insert, it's best to consult with the manufacturer or a fireplace professional. If your prefab fireplace is not designed to hold a wood burning insert, you may be able to have one custom-built. However, this will likely be more expensive than purchasing an off-the-shelf model. Additionally, if you have a gas fireplace, it's important to note that converting it to a wood burning fireplace may not be legal in your area.