Fireplace Inserts That Turn an Open Hearth Into Heat

An open masonry fireplace gives atmosphere far more than it gives heat. Most of its warmth goes up the chimney, and once the fire dies down it keeps pulling warm room air up the flue until the damper is closed. An insert fixes that by putting a sealed, glass-fronted steel firebox inside the old opening. The fire burns slower and hotter, the heat is pushed into the room, and you load wood far less often.

New Jersey's older suburbs are full of fireplaces that could take one. Essex and Union counties have some of the oldest housing in the state, and many of those homes have deep masonry fireboxes under tall chimneys. The insert has to fit the opening and the flue, though, so we measure both before recommending a size, and every wood insert we fit gets stainless liner to the top of the chimney.

Signs you need this

• The room is colder after a fire than before it
• You burn a lot of wood for very little heat
• Drafts from the fireplace when it is not in use
• Cracked firebox or damper you were going to repair anyway
• You want wood heat without building a new chimney

How we do it

1. Measure the fireplace and flueAt the free visit we take the width, height and depth of the opening, the hearth size and the flue height, and check the firebox and chimney condition.
2. Choose the insertWe help you pick an insert that fits and suits the space you want to heat, then give you a written price for the whole install.
3. Line the chimneyA stainless liner runs from the insert's outlet to the top of the chimney, finished with a top plate and cap. The damper is removed or fixed open.
4. Set, seal and testThe insert slides in, the surround panel closes the gap, and we test-fire it and walk you through the controls.

Why does an insert need a full liner?

The insert's outlet is far smaller than the old fireplace flue. Venting a small, controlled fire into a large, cold masonry flue lets the smoke cool, which slows the draft and builds creosote fast. A stainless liner sized to the insert keeps the exhaust hot and moving and gives a smooth surface that is easy to sweep.

It is also how inspectors expect to see it. The liner's make, listing, material and size are part of the paperwork that goes with the permit.

What does a fireplace insert cost in New Jersey?

Expect $3,000 to $7,000 for a wood insert fitted with stainless liner. The insert model, the chimney height and any firebox or smoke chamber repairs needed first move the number. We write the price down after measuring, before anything is ordered.

If you would rather not handle wood, a sealed gas insert is an option. See our gas inserts page for how those vent and what they cost.

Do I need a permit for an insert?

New stoves and inserts generally go through your town's construction office in New Jersey, and the state's F-370 chimney verification form has a section for solid fuel appliances and fireplaces. We file for the permit when your town requires it.

Once the insert is in, you have a fuel-burning appliance in the house, so CO alarms near the sleeping areas are required under the state fire code.