Yes, there are regulations on using wood stoves, particularly concerning emissions and installation standards. The Environmental Protection Agency (EPA) sets emission limits for wood stoves to ensure they burn cleaner and more efficiently. Additionally, local building codes may have specific requirements for installation and venting, so it's essential to check with local authorities before installing or upgrading your stove.

The timeframe for a gas fireplace installation typically ranges from 1 to 7 days, depending on the complexity of the project. A basic installation with gas line connections and venting may take 1-3 days, whereas a more involved project that includes framing and masonry work can take 3-7 days.

Both wood-burning stoves and fireplaces can emit smoke and other combustion gases that are harmful to human health. According to the American Lung Association, wood smoke can lead to coughing and wheezing as well as long-term health impacts like increased risks for heart attacks and stroke. 

Newer models meet the modern efficiency standards set in 2020 by the Environmental Protection Agency for cleaner burning, more efficient wood stoves. Regular maintenance can also minimize smoke.

Shiplap can be safe for a gas fireplace, but you should consult with a fireplace installation pro before proceeding. You need to make sure your project meets building and safety codes since shiplap is made from flammable wood. You may need to install another non-combustible material, like stone or brick, around the fireplace for a certain amount of space before you can add shiplap.