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Really unequal heat in 2-family

My husband and I have a two-family house in Boston built in 1902. Bought it in 2001, live on the second floor, and have had two long-term tenants on the the first floor. There are two oil burners in the basement, and the heat is forced hot water radiator heat in both units.

Here's the thing. The first floor stays at 65 with less than half the amount of oil required for the second floor to stay at 65. I bleed all the radiators every year, and have had the burners cleaned every year. There's no real difference in the number of windows/doors in each unit. We have an attic above us; tenants have a basement below them.

Why do we use three tanks full of oil for every one they use downstairs when our thermostats are set at the same temperature? Must this be an insulation issue, or could the pipes somehow be distributing our heat to their radiators?

Re: Really unequal heat in 2-family


Three tanks to one of theirs---that's quite a difference.

Lack of insulation on the 2nd floor could be a big factor, but there are others---you'll have to do some detective work to get closer to the actual cause.

It's unlikely the piping is switched & the 2nd floor is heating the first---the way to check that is to try & trace the plumbing as it exits the basement---if the 1st floor is empty anytime during the week, try turning up your boiler & see if any of the 1st floor rads heat up.

Also check the name tag on each boiler to see what the INPUT and OUTPUT is of each boiler---you'll see something on the tag/label saying something like "INPUT 60,000 btu/hr//OUTPUT 50,000 btu/hr---the upstairs boiler may be considerably larger in heat output than the 1st floor.

There may even be a relatively simple difference where the NOZZLES on the boilers are different---if the upstairs nozzle is rated at say 1.20 gph (gallons per hour) and the downstairs nozzle is rated at .75 gph, then the upstairs nozzle is burning almost twice as much oil---you would have to check with your service person to see if they know---if you know how to get open access to each oil burner, the nozzle is a 1" brass object on the end of the burner that has the gallon-per-hour oil usage stamped on the front of its housing & would say 1.20 (for 1.2 gallons per hour oil flow) or .75 (for 3/4 gallon per hour oil flow), etc.,etc.

By all means check the upstairs insulation---you should have at least R19 in the exterior walls and R40 in the attic---you can check the wall insulation by unscrewing the faceplates of the electrical receptacles & shining a flashlight in to see if you can see any insulation---it's best to temporarily shut off the juice to the circuit & also remove the steel/plastic box inside the wall & unravel a steel coat hanger & run it up the hole----if it clatters around as you shake it, there is probably no insulation in the exterior walls---hook one end of the hanger with a pliers & see if you can "snag" any pieces of insulation.

If you DO need insulation, it is a rather inexpensive project to have cellulose insulation blown in (Yellow Pages: Insulation) by a local company---they loosen a shingle or piece of siding here & there, do all the work from the outside & usually do it within one day.

Check the total square footage of both apartments to make sure they're the same---check items like number & condition of windows/double pane/storm windows, etc.---check to see that the height of the ceilings in both apts. are close to the same---an infrared heat survey may be a good idea to see if there is a lot of weak spots in the upstairs envelope where heat is escaping.

If the domestic hot water is connected to each boiler, check the gallon per week usage in both apts---if it's considerably higher on the 2nd, this could account for the oil usage difference.

If the oil tanks are buried outside, the 2nd floor one may have a leak.

Re: Really unequal heat in 2-family

Thanks! I will get on these items and let you know how it turns out!

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