Consider Options Before Changing Oil-Fired Furnace

HOME CLINIC: I am considering replacing the oil-fired furnace in my home with an electric or gas unit because the cost of fuel oil is increasing so rapidly. Will this be a good investment?

- D.S., Seattle

DEAR D.S.: The best time to consider fuel conversion is when your existing heating system is in need of major repair or replacement. Replacing your furnace strictly in reaction to fluctuating fuel prices is rarely cost effective. Regardless of how you heat your home, the easiest and the most cost-effective way of reducing your fuel bill is to keep your heating system well-tuned and to install insulation, storm windows, weatherstripping and caulking.

After taking energy-conservation steps, direct your attention to your furnace. Have a qualified technician tune up your furnace and test the combustion efficiency. Combustion efficiencies for typical oil-fired furnaces should be 70 percent to 80 percent. If you find that your oil furnace is not operating at top efficiency, here are options to consider:

Oil heating options

First, determine the age of your furnace. If it was built before 1970, you may want to replace the furnace entirely rather than retrofit it with a gas conversion or flame-retention burner. Replacing a pre-1970 furnace with a new oil-fired unit with a combustion efficiency of 80 percent to 85 percent can reduce your consumption by as much as 30 percent. The cost of a new oil furnace can range from

$1,800 to $2,500.

In the early 1970s, most oil-furnace manufacturers were switching to flame-retention burners on new units. If your furnace was built in this period but does not have this type of burner, the most cost-effective method of reducing oil consumption is to retrofit your existing system with a flame-retention burner. This simple device can save 15 percent on heating-oil use. New burners cost around $700 and rebuilt burners are available for $350.

For more information on how to improve the efficiency of your oil heating system contact Ed Besch at the Oil Heat Institute, 548-1500.

Natural-gas options

Installing a gas conversion burner on your existing oil furnace will cost around $1,000, but will have little or no impact on the efficiency of the unit. A gas conversion burner also may be leased from the gas company for $4.20 per month. Any dollar savings achieved will be the result of the difference in fuel costs per BTU required to heat your home. Refer to the chart accompanying this column for cost comparisons of various heating fuels.

Replacing your existing system with a natural-gas furnace with an 80 percent to 85 percent combustion efficiency will cost between $1,500 and $2,300 for the furnace and installation. Washington Natural Gas is one company that finances gas installations for heating and hot water systems. Through their guarantee program, they require no down payment and offer up to 5 years financing upon credit approval. Interest rates range between 9 percent and 13 percent depending on how many appliances are being converted to natural gas. Inquire from your particular dealer about similar programs.

High-efficiency condensing furnaces with combustion efficiencies higher than 90 percent are available for an additional $1,000 to $1,200 more than the cost of a standard furnace. In addition to being cheaper to operate because of the increased efficiency, they have the advantage of using outside air for combustion, which seals the combustion process from the house and eliminates back-drafting. Because of the corrosive nature of condensed flue gases, the life span of the heat exchanger in a high-efficiency condensing furnace can be as short as 10 years. Consider this type of furnace only if the heat exchanger has a lifetime guarantee.

Other costs

If you replace your oil furnace with a gas unit, there will be additional costs and considerations. First, because natural gas does not burn as hot as fuel oil, the temperature of the air coming from your registers will be about 15 degrees lower. While the BTUs required to heat your home remain the same, the gas furnace takes a little longer to supply the heat and will run about 20 percent more. Second, you should consider the additional cost of installing gas piping to your furnace. With the added expense of gas piping, the installed cost of a gas furnace is about the same as an oil unit. Third, don't forget the expense of removing or decommissioning your underground oil storage tank.

Requirements for unused oil tanks vary considerably depending on where you live in Western Washington. The Uniform Fire Code states that fire marshals have two options: They may require you to remove the tank, or pump it out and fill it with sand. In most areas of King County, you are required to remove the old tank if it will not be used for a period of one year or more. For requirements in your area, contact your local fire marshal. Permits are necessary to remove oil tanks and permit costs vary from no charge to $130, again, depending on your area.

Removal of a typical 300-gallon tank can cost from $600 to $2,800 depending on site conditions and contractor. It is a good idea to obtain several bids before selecting a contractor. You can find contractors that do this type of work in the Yellow Pages of the telephone book under Tanks or Waste Disposal - Hazardous.

For a free fact sheet on comparing the cost of home-heating fuels write Home Clinic, c/o The Seattle Times, P.O. Box 70, Seattle, WA 98111. Enclose a legal-sized, self-addressed stamped envelope marked ``Comparing.''

Home Clinic answers questions about home maintenance, repair and energy conservation. It is prepared by the Energy Extension Service, a division of the Washington State Energy Office. It appears Sundays in the Home/Real Estate section of The Times.

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COMPARATIVE HEATING COSTS

Comparative costs of one million BTU's of delivered heat, which is enough to heat a 1,000-square-foot house with average insulation for 75 to 100 house. It does not include the cost of heat loss through heating ducts. Actual figures could vary depending on use.

(Source: Washington State Energy Office.)

TYPE

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Oil furnace . . . .

Upgrade to flame- . . . .

retention burner . $8.50-12.50 . $550-650 . $50-75 .

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New unit . $7.50-11.50 . $1.500-2,100 . same .

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Natural gas . $5.75-6.25 . $1,500-1,950 . $50-75 .

. . . (as needed) .

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Electric furnace . $13.50-15.00 . $1,050-1,450 . $60-70 .

. . . (as needed) .

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Electric heat pumps . $6.50-7.50 . $4,000-6,000 . $70-120 .

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Certified woodstove . . . .

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Buy cordwood . $7-8 . $1,000-2,800 . $50-75 .

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Harvest cordwood . $1-3 . same . same .

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Buy pellets . $10-11 . same . same .

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