Almost every home has one: the bonus room over the garage, the finished basement or the addition that never feels as warm as the rest of the house. The good news is that most cold rooms have a clear cause and a practical fix. Here is a simple guide from First Mate Heating & Cooling for Lee's Summit homeowners, from Downtown Lee's Summit to Lakewood and Raintree Lake.

1. Why some rooms stay cold

• Bonus rooms over garages often have outside air on several sides, including the floor, and sit at the end of a long duct run.
• Finished basements may have only a few supply registers and little or no return air.
• Additions, sunrooms and converted garages were sometimes built without extending the ductwork, or with a duct run too small for the space.
• Rooms far from the thermostat can run cold because the thermostat is happy with the temperature where it hangs, not where you are sitting.

2. Start with simple airflow checks

• Open every supply register in the cold room and make sure furniture, rugs and curtains are not blocking supply or return grilles.
• Change a dirty furnace filter. A clogged filter cuts airflow to the rooms at the end of the line first.
• Keep doors open when you can, so air has a path back to the return.
• In a two-story home or a home with a finished basement, look for adjustable dampers on the ducts near the furnace. Some homes have marked summer and winter settings.
• Close blinds and curtains at night in rooms with a lot of glass.

3. When the ductwork needs attention

If simple checks don't help, a technician can look at the system as a whole:

• Airflow balancing sends more warm air to the rooms that need it.
• Sealing and insulating ducts that run through a garage ceiling, crawlspace or attic keeps heat from escaping before it reaches the room.
• Adding a return or upsizing a duct run can help a room that is starved for air.
• A furnace and blower check confirms the system is moving enough air for the whole house.

4. When a ductless mini split makes sense

Some spaces are hard to reach with ducts at all. A ductless mini split pairs a small outdoor unit with a quiet indoor unit mounted on the wall, and it both heats and cools. Each indoor unit has its own temperature setting, so the cold room can finally match the rest of the house.

Ductless mini splits work well for:

• Additions and sunrooms with no ductwork
• Bonus rooms and attic rooms at the end of a long duct run
• Converted garages, home offices and workshops
• Finished basements that stay chilly while the main floor is comfortable

As an Amana and Daikin dealer, First Mate can help you choose the right ductless system for the room, and our licensed technicians will size it and place it for even comfort. Learn more about ductless mini split installation in Lee's Summit.

5. Use space heaters safely in the meantime

A portable space heater can take the chill off while you sort out a long-term fix. Follow these safety tips from the National Fire Protection Association and the U.S. Fire Administration:

• Keep the heater at least 3 feet away from anything that can burn, including bedding, curtains and furniture.
• Plug it directly into a wall outlet. Never use an extension cord or power strip.
• Choose a heater with a recognized testing laboratory label, overheat protection and an automatic shut-off if it tips over.
• Set it on a solid, flat surface, out of walkways and away from children and pets.
• Turn it off and unplug it when you leave the room or go to bed.
• Never use an oven or stovetop to heat your home.

Common questions

Why is my bonus room over the garage always cold?

A bonus room over a garage usually has outside air above, below and on several sides, and it often sits at the end of the longest duct run. Airflow balancing, duct sealing and insulation, or a ductless mini split can fix it.

Should I close vents in rooms I don't use to push heat to cold rooms?

Usually not. Closing a lot of registers can reduce airflow through the whole system and make your furnace work harder. Balancing the airflow is a better way to send more heat where you need it.

Can a ductless mini split heat a room through a Missouri winter?

Yes. Most ductless mini splits are heat pumps built to heat as well as cool. A technician will size the system for the room and let you know if backup heat makes sense for the coldest nights.

Are space heaters safe to use?

They can be when used carefully. Keep them 3 feet from anything that can burn, plug them straight into a wall outlet, and turn them off when you leave the room or go to sleep.

Does First Mate fix cold rooms in Lee's Summit?

Yes. Our shop is right here in Lee's Summit, and we help Lee's Summit homeowners with airflow problems, ductwork and ductless mini splits, with 24/7 emergency service when the heat goes out.

About First Mate Heating & Cooling

First Mate Heating & Cooling is a family-owned heating and air conditioning company that has kept Kansas City area homes comfortable since 1971. Our licensed technicians repair, maintain and install furnaces, heat pumps, air conditioners and ductless mini splits, and we are an Amana and Daikin dealer. We answer 24/7 for no-heat emergencies, offer free estimates on new system replacements and installs, and back our work with warranties. We proudly serve Lee's Summit, Blue Springs, Raymore, Greenwood, Grain Valley and Leawood.

First Mate Heating & Cooling, 1800 SW Market Street, Lee's Summit, MO 64082. Learn more at callfirstmate.com.