8.5   Combustion Space Heater Replacement

Space heaters are inherently more efficient than central heaters, because they have no ducts or distribution pipes.

Weatherization agencies replace space heaters as an energy-con­servation measure or for health and safety reasons. Choose a sealed-combustion space heater. Inspect existing space heaters for health and safety problems.

✓     If power outages are common, select a space heater that operates without electricity.

✓     Follow manufacturer’s venting instructions precisely.

✓     Don’t vent sealed-combustion or induced-draft space heaters into naturally drafting chimneys.

✓     Verify that flue-gas oxygen and temperature are within the ranges specified in Table 8-4 on page 275. 

✓     If the space heater sits on a carpeted floor, install a fire-rated floor protector.

✓     Install the space heater with adequate clearance from traf­fic, draperies, and furniture.

✓     Provide the space heater with a correctly grounded duplex receptacle for its electrical connection.

8.5.1   Space Heater Operation

Inform the customer of the following operating instructions.

✓     Don’t store any objects near the space heater that would restrict airflow around it.

✓     Don’t use the space heater to dry clothes or for any pur­pose other than heating the home.

✓     Don’t allow anyone to lean or sit on the space heater.

✓     Don’t spray aerosols near the space heater. Many aerosols are flammable or can cause corrosion to the space heater’s heat exchanger.

8.5.2   Unvented Space Heaters

Unvented space heaters include ventless gas fireplaces and gas logs installed in fireplaces previously designed for wood-burn­ing or coal-burning. The unvented space heaters and fireplaces create indoor air pollution because they deliver all their com­bustion byproducts to the indoors.

Unvented space heaters aren’t safe. Replace them with vented space heaters or electric space heaters if at all possible.

DOE forbids unvented space heaters as primary heating units in weatherized homes and mobile homes. However, unvented space heaters may be used as secondary heaters, under these requirements.

1.      The heater must have an input rating less than 40,000 BTUH.

2.      If located in a bedroom, the heater must have an input rating of less than 10,000 BTUH.

3.      If located in a bathroom, the heater must have an input rating of less than 6,000 BTUH.

4.      The heater must be equipped with an oxygen-depletion sensing shut-off system.

5.      The room containing the heater must have adequate combustion air.

6.      The ambient air CO level shouldn’t exceed 9 ppm con­tinuously or 35 ppm during peak heating periods.

7.      Home must have adequate ventilation: See “ASHRAE Standard 62.2–2016 Ventilation” on page 397.