How House Wrap Affects Fireplace Efficiency

Modern home building has an increased focus on energy efficiency. Building codes now enforce different kinds of insulation to reduce air from getting in or out of the home. Poly based house wraps are one of the most common ways to create an energy-efficient home.

While that may be good for saving on energy bills and reducing heat loss, it doesn't allow for natural airflow to occur and aid in combustion for your fireplace. This can actually lead to a lot of issues if you install a vent free or B-vent fireplace and are unaware of how they operate.

A fireplace has to have cool inside air sucked into its firebox so it can oxygenate the wood or gas burning inside it. This process is called combustion. Normally, air sneaks in through cracks in windows and doors and provides a steady flow of air to continue that process.

As the air is heated, much of it goes up through the chimney and is exhausted outside. Other portions are pushed into the house through vents in the appliance.

When a house is heavily insulated, this disrupts the natural flow of air that comes through the outside, into the fireplace and out through the exhaust pipe. So, in an effort to try and balance itself, a vented wood burning or B-vent fireplace, which has an open firebox, will suck air back down through the chimney, pulling exhaust smoke and fumes into your home. Vent free fireplaces can simply shut off due to lack of available oxygen.

This problem can be increased by bathroom fans, range hoods or other devices in your home designed to remove or redirect air.

The best option to aid this issue is to not install a B-vent or vent free fireplace in your home if it is heavily insulated. An electric or direct vent fireplace is the best option because electric fireplaces don't need combustion to operate and direct vent fireplaces have a closed firebox so exhaust fumes will never push back into your home.

If you like the look of a real wood burning fireplace or stove, that is also an option as long as you attach it to an outside air kit. We discussed outside air kits more in detail in another article that you can view here.

If you have any other questions on this, please don't hesitate to call us at 800.203.1642.