Several ways to improve the comfort of cold rooms without replacing your heating system.
No matter how well designed or installed a heating, ventilation, and air conditioning (HVAC) system is, there are always locations that may feel uncomfortable, especially during cold winter temperatures. You can warm up a room without using a plug-in electric heater which can become safety hazards if it remains on for extended periods or if it is left unattended. Space heaters can be dangerous with children or pets in the house, as well as being an eyesore and larger models may overload electrical circuits.
If at all possible you should attempt to correct your existing HVAC system to correct any zones that are too cold. Properly sealed ductwork and balancing can improve the comfort level of colder rooms at little to no additional cost. If you are still experiencing colder than normal temperatures you may want to consider a permanent option such as radiant floor or ceiling heating, duct booster fans, toe-kick heaters, and other devices described below.
Electric or Hydronic toe-kick heaters
Toe-kick heaters, also called kick space heaters, are practically invisible and they are installed in the bottom of kitchen cabinets, bathroom vanities, or even stair treads that are controlled by a thermostat that mounts on a nearby wall. You can install a toe-kick heater under an existing cabinet by prying off the toe-kick.
Most toe-kick heaters require a dedicated electrical circuit from your main electrical panel. While most models utilize a thermostat, some have an option for a timer or a regular light switch, but you will be better off getting a model with some type of temperature control. Powerful units can blow enough hot air to soften vinyl flooring. Look for units that produce the least amount of noise.
If you have hot water baseboard heat, hydronic toe-kick heaters can be easily connected to the hot water heating system, however they will still need an electrical connection for the blower.
If you have a forced air system and you have a cold spot in your kitchen you can also install a toe-kick register to get warm air where it is needed most. A special duct transition piece can be purchased and installed under the cabinet and connected to your existing ductwork.
Toe-kick register adapter
Duct booster fans
Duct booster fans can be used when you have a forced-air heating system where there is limited airflow to a particular room. Duct booster fans can be installed in the duct or at the register in the room.
In-line duct booster fans fit inside standard-size metal ducts, but they can be adapted to fit various sizes with transition pieces of ductwork. Some units have a built-in sensor that senses air pressure from the furnace when the blower comes on and turns on the booster fan automatically. Some in-line duct boosters simply plug into an available outlet, while other models are hard-wired. See my article discussing in-line duct booster fans here: knoji.com/how-to-install-an-air-duct-booster-fan/
An alternative to in-line duct booster fans are register booster fans. Depending on the model, it either sits on top of or replaces a floor or wall register grille, and plugs into an outlet. A built-in thermostat switches on when the furnace operates. Register fans cost $40 to $70.
Cove heaters are radiant heaters mounted along the ceiling. Cove heaters are silent since they are radiant panels. Cove heaters emit heat downward to warm people and objects directly instead of heating the air. Because they are installed high in the room, they don’t take up valuable floor space and they are out of the way of children and pets. They work well in rooms where heavy drapes and furniture make baseboard heaters impractical.
Cove heater installed just below the ceiling.
To power a cove heater, you'll have to run a new circuit from your main electrical panel and install a thermostat. A larger unit will require a 240-volt circuit rather than a standard 120-volt circuit. Cove heaters range in length from 34 in. to 132 in. and cost $85 to $300.
Electric floor heat
This can be a great choice for a small-scale retrofit project like heating a mudroom or kitchen, or warming up a cold bathroom. Under-tile radiant systems are still the most common, but many companies offer systems that work equally well beneath laminate, carpet and engineered floors. There are two basic types of systems: “loose wires” that you run across the floor and “mat” systems, with the wires prearranged inside a mesh or fabric mat. Some manufacturers have systems that can be stapled to the underside of the subfloor which eliminates the need to remove existing flooring. zmesh.com/floorheating.html
Adding electric radiant floor heat for a typical bathroom when you install a new floor adds about $200 to $300 to the cost of the project. The electrical connections can be handled by the average do it yourselfer. Since these systems generally draw only 10 to 15 watts per square foot, you can usually connect them to an existing circuit to heat a typical bathroom.
Heating cables on an electrical floor heating system
Radiant ceiling panels
Radiant panels work best for spot heating certain areas of a room such as seating areas. Like cove heaters, radiant ceiling panels heat the occupants of a room from above. The panels mount on the ceiling and can be an energy efficient option in a room where you want to heat people in a specific area. The panels are made of a thick slab of gypsum that is mounted over the existing drywall ceiling or in an existing suspended ceiling grid. They can heat to 150 degrees F within five minutes of being switched on, and they cool down just as quickly.
The panels range from 1 x 2 ft. to 4 x 8 ft. and the electrical lead and thermostat can be installed in a standard junction box. Power from an existing circuit can supply a single panel. Larger panels require separate 120- or 240-volt circuits. The panels are textured and some can be painted. Panels designed specifically for bathrooms include a built-in exhaust fan, light and night-light. The panels cost from $200 to $500 depending on the size.
Radiant ceiling panels installed in a kitchen between recessed lighting.
Note: It is important to follow the manufacturer’s installation instructions and be carefully not to install any fasteners through the sheet except where noted. Electrical shock or fire could result if the panel is damaged of altered in any way.
Ceiling fan heater
The Reiker Room Conditioner is a ceiling fan with a built-in heating unit and the fan circulates the warm air around the room. This type of heater fan installs just like a regular ceiling fan and provides fast, even heat over a large area. This ceiling fan produces warm air at around 230 degrees F through the ceiling-mounted heater and the fan blades circulate it throughout the room. During the summer, the unit functions as a conventional ceiling fan and the fan can be installed with a light kit also.
It's available in manual and remote control units, and can be wired to an existing circuit. The standard models cost around $270, and remote-controlled units cost $330 to $370, depending on the finish.
If you have a room with a wood burning stove or fireplace that can become too warm, you may be able to distribute the heated air with a room to room ventilator.
These types of ventilator fans use the space between stud walls to move warm air in the winter, or cool air in the summer, from one room to another. The ventilator uses an intake blower that draws air into an open stud cavity and a diffuser that mounts near the ceiling or floor on the opposite side of the wall to distribute the air. There are also ventilators that distribute air between floors.
Ventilator fans can be installed as a plug-in type with the power switch on the unit itself and a hard-wired type controlled by a wall switch or thermostat. The prices range from about $50 to $200.
Room-to-room ventilation system