How to Maintain a Furnace | Ask This Old House

Ask This Old House heating and plumbing expert Richard Trethewey explains the best practices for keeping your furnace up and running during the winter. (See below for a shopping list and steps.)

SUBSCRIBE to This Old House:

Richard walks through the finer points of maintaining a furnace to keep it running all winter long.

Shopping List for How to Maintain a Furnace:
– Replacement filter

Steps for How to Maintain a Furnace:
1. A homeowner should replace the furnace filter at least once per heating season, or more frequently in houses with pets. Remove the old filter, note the size, and replace with an identically sized filter.
2. A professional technician can check the efficiency of your furnace. This will tell how much fuel that you’re paying for is being used to heat your home. An older furnace should be around 80-percent, while a newer one may be as high as 97-percent.
3. A professional will also check and clean the combustion area and all safety devices that ensure the furnace will safely turn off in an emergency.

A homeowner should be replace furnace filters at least once a season, and more often in homes with pets. Replacement filters can be purchased at home centers.

Annual furnace servicing that checks safety devices and efficiency should be performed by a professional HVAC technician.

Expert assistance with this project was provided by Caron Electric [].

About Ask This Old House TV:
Homeowners have a virtual truckload of questions for us on smaller projects, and we’re ready to answer. Ask This Old House solves the steady stream of home improvement problems faced by our viewers—and we make house calls! Ask This Old House features some familiar faces from This Old House, including Kevin O’Connor, general contractor Tom Silva, plumbing and heating expert Richard Trethewey, and landscape contractor Roger Cook.

Looking for more step by step guidance on how to complete projects around the house? Join This Old House INSIDER to stream over 1,000 episodes commercial-free:

Plus, download our FREE app for full-episode streaming to your connected TV, phone or tablet:

Follow This Old House and Ask This Old House:

For more on This Old House and Ask This Old House, visit us at:

How to Maintain a Furnace | Ask This Old House