"My old boiler uses too much oil"
Column #833 02/12/2011
On The Level
Q. We have an older house with an equally older boiler. It think it is the original. It also used to have a hot water coil in it. I see pipes for it but they have been cut. My question is do you know how this thing operates? This thing likes fuel-- a lot. It seems to heat water whenever it wants and when the thermostat calls for heat it sends hot water to the baseboards and radiators. Even if it’s not being called by the thermostat for hot water, it still seems to heat up. My guess is it’s holding water hot just in case it’s needed. Is that true? The size is about 4 feet long, 3 feet wide and almost 5 feet tall. It’s been a cold winter and my oil bills are high. I usually shut if off during the day at the emergency switch near the basement steps. The house stays pretty warm.
A. What you have is called boiler fed hydronic heat and your boiler is truly an antique. A new one of the same output in Btus would be about half the size of that one. I think that the domestic hot water coil that once provided the home’s boundless hot water, known as a “Summer/Winter hook-up”, was terminated so the boiler could be shut down in summer. That was done a lot to those old boilers when the cost of oil shot up. Your domestic water heating costs now show up in your electric bill from an electric water heater. However, who ever did that probably didn’t know how to alter the controls and this type of boiler likes to maintain a core temperature between 160ºF to 180ºF all the time. That’s why you hear it cycling on, pumping oil into the burn chamber and exhaust up that eight inch flue pipe to the atmosphere, even when the thermostat is not calling for heat. Another reason your ancient boiler likes to stay in one warm temperature range is a repetitious cooling and heating of the metals as the boiler would alternately fire and cool would stress the joints and gaskets to eventual leakage.
I realize that replacing the boiler might be a stretch for an out of pocket purchase for you now but it’s a case of you almost can’t afford not to replace this boiler-- it will eat you out of house and home as you are learning. You might be able to squeeze a little bit of efficiency out of this beast by having a truly gifted old-time boiler technician tweak the controls and add baffles to the burn chamber but it would be like putting new tires and two-barrel carburetor onto an old car to see if you could get a mile per gallon more out of it. The old car just wasn’t built for it. Finding parts for boilers built before 1990 is getting harder and harder to do.
Boilers generally last between 40 to 60 years. A lot of boiler technological advances have been made in the last 60 years. Yours is ready for replacement based on age and technology if nothing else. Cost of operation savings will pay for it over a period I’d guess to be about six to ten years. I can’t predict fuel prices just levels of consumption. The guru of hydronic heat in this country is a fellow named Dan Holohan from New York whose books I use for reference. You can find him on the web at www.heatinghelp.com.
If this boiler is in a house that is the age of the boiler then you need to do an extensive inventory of heat loss areas that may have been built into this structure. Do your own energy audit. If the house was built in the 40’s, or even before WW2 it may have no sidewall insulation or attic insulation whatsoever. Attic insulation will be easier to install than sidewall insulation if you have little or none. There was a booming business in the 1950s of pumping loose insulation into exterior walls of homes that didn’t have any and covering the access holes by residing the house in aluminum or asbestos/cement shingles. Doing that today would involve a more modern insulation and siding material. Check the windows and doors. How leaky are they? Check the door bottoms and thresholds as well as the jamb sides for air leakage and weatherstrip as needed. Every little bit counts and every tiny bit of air leakage you can stop makes the house feel warmer and you’ll burn less oil.
Keep the mail coming. If you've got a question, tip, or comment let me know. Write "On The Level," c/o The Capital, P.O. Box 3407, Annapolis, MD 21403 or e-mail me at firstname.lastname@example.org or email@example.com.