A wood insert installed to its manual in MetroWest

Clearances measured from the insert body

Each insert manual carries a clearance table for combustible materials around the unit. The Pacific Insert guide measures from the insert body and gives separate minimums for an adjacent sidewall, a mantel, top facing and side facing, with a drawing of each.

Those numbers apply to your chosen model only, which is why we never quote an installation from a general rule. At the inspection we measure every combustible surface near the opening and compare it with the table, and anything that falls short appears in the estimate with the fix we propose.

• Wood mantel shelf above the opening
• Wood or painted trim at the sides
• A wall that meets the fireplace at a corner
• Shelving or cabinets built beside the hearth

The hearth in front of an insert

Insert manuals set the noncombustible hearth required in front of the fireplace opening. The Pacific guide asks for a hearth raised above an adjacent combustible floor and extending 16 inches in front of the opening and 8 inches past each side, and allows a flush hearth only if it reaches further forward.

Many fireplaces already have a hearth that meets the manual, and some do not. We measure yours against the model you choose, and if it falls short, the extension and its material are written into the estimate before work begins.

Room air and a surround left unsealed

The second route in the Pacific guide uses room air. The insert is installed as described, and the surround is deliberately not sealed to the fireplace, so enough air can enter the fireplace cavity and reach the insert. An air cover can also be removed for more supply.

Which route applies depends on the model and on the fireplace. We follow the one the manual names for your setup and explain why, so a later handyman does not caulk a gap that was left open on purpose.

Why the air control is not left on high

Running a wood heater flat out is not the goal. Pacific reserves the high air setting for starting and preheating fresh loads, and warns against overfiring, which it says can permanently damage the heater and the chimney.

We point out the markings on your air control and explain what each range is for. Most evenings the right setting sits well below full once a good bed of coals has formed, and the insert then gives steady heat with a clean flame instead of a roar.