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Converting from oil to gas heat

Hi. We live in an approximately 80 year old brick home a block from the ocean in South Jersey. We have oil heat and have a tight utility room that houses the boiler and hot water heater as well as washer/dryer. There are only 2 people living in the house most of the time, but as many as 8 a few times a year. The house is brick and approximately 2000+ sq. feet. There are 3 1/2 bathrooms.

We want to switch from oil to gas to reduce the monthly bill and so we can get a gas stove. There is no problem getting gas to the house, and we presently have an above ground oil tank after having 2 underground tanks removed. The question is what to get instead of the present setup. We have received 3 quotes. 2 of them proposed a combination boiler/tankless water heater. We like the idea of that because it minimizes how much space the units will take up. One proposed a Bosch combination heat and domestic hot water wall hung high efficiency boiler with a capacity of 151,000 btus and AFUE rating up to 95% for $14,425. The other proposed a Quietside S-Line series with a capacity of 160,000 btus and AFUE rating up to 92% for $12,700. Those quotes included removal of the oil tank and all labor, materials, and permits.

The quote we received today suggested a Weil McLain boiler with 125,000 btus and AFUE rating up to 97% with a separate tankless Rinnai 7.5 gpm for $8,995. This quote came from someone who was not sold on the combo units and did not want us to be a guinea pig. His charge did not include removal of the oil tank.

We want to maximize the space in the utility room so we can add some storage. We do not want to do that at the expense of getting a lousy setup though. What we like about the current setup is that we can have all the showers, the dishwasher, and washing machine going at the same time and still have plenty of hot water. We understand that will not be possible, at least with the combination units. I would appreciate any feedback on the combination units versus separate tankless water heater and boiler. If we did decide to go with the combination unit, any thoughts or experiences with the Bosch versus the Quietside for the proposed prices would be helpful.

Thank you.

Re: Converting from oil to gas heat

Multiple guests plus a tankless WH in the winter in Jersey may be a rough combo. Look into what tankless WH other neighbors have to see if it fits their needs.

Re: Converting from oil to gas heat


I agree with function; first of all congratulations on obtaining natural gas service, I think you will find quite a $$$ savings over #2 oil, which is costly & keeps going up in price.

There are 3 basic categories of hot water heating systems being installed in homes:

Category 1: -- condensing boilers (95% eff.) combined with a tankless hw heater
Category 2: -- standard boilers (85% eff.) combined with an indirect hw heater
Category 3: -- using the boiler you have now, just change the oil gun to a gas gun.

First of all, get a lot more quotes by consulting the Yellow Pages under "Heating" and look at the display ads to find those heating contractors who install forced hot water heating systems---I'm not a big fan of so-called "high efficiency" condensing boilers and "tankless heaters" that are often sold to homeowners, often because they are smaller, lighter units that can be installed easily (less work for the heating contractor installer), but can present a lot of problems with automatic resets and insufficient domestic hot water production (dhw) (hw for dishes, showers, clothes washer, etc.).

Some of the problems with Category 1 have been mentioned; it is often necesssary to have a much larger gas service entry pipeline installed (more cost) so that the tankless dhw unit can be fired---& as function noted, hw usage by multiple occupants can cause supply problems.

I would recommend you also get 2 or 3 quotes for a "standard" gas-fired boiler (85% efficiency) by Peerless, Buderus, Burnham, Dunkirk, Slant/Fin & Crown which would be combined with AN INDIRECT HWH by Lochinvor, TFI Everhot, Triangle Tube, HTP Superstor, or Weil McLain G0LD Plus.

An indirect hwh (usually 40 gallon capacity) is a stand-alone tank that sits next to the boiler & heats all the dhw needs by a circulating tube connected to the boiler----these are very efficient, supply loads of hw & last for decades without any problems because there are no moving parts to wear out.

If your present boiler is not too old, the heating installer can simply change the oil-firing gun for a gas-firing gun & leave the rest of the original boiler & all its piping in place--this costs lots less, & should be considered if you don't intend to own the house much longer.

Insist that any future heating contractors do a HEAT LOSS CALCULATION (simple arithmetic) that calculates how big/or small in capacity the new boiler should be--often the present boiler is much too big (too much capacity/burns too much oil/gas) for the needs of the house---you may be able to get by with a 70,000 btu/hr or 80,000 btu/hr boiler & save lots of $$$ on fuel usage---it's beyond me where the previous boiler size quotes are 151k & 160k for a house your size.

Therefore, when you greet any future heating contractors into your home for a quote, ask them directly---"Wouldn't it be better to install an 85% efficiency standard boiler with a 40 gallon or 50 gallon indirect hot water heater ????"---the installation cost should be lots less than $14,000, and you'll end up with a more reliable system.

In some areas the local gas co. charges close to $1k to run a gas line from the street to the house, if there is presently no line in place.

Google "oil to gas conversion" to get millions of hits on this topic.

Also check out dedicated heating sites below:


Re: Converting from oil to gas heat

Continue to get bids. Even your lowest bid so far is too high. In NJ you can find installers who do only this type of work, some of them are so efficient and their prices are so reasonable. And BTW, summer is the time to do it.

My friend who lives in NJ had one of those guys (licensed and all) come in and out in one day. The oil was pumped out by a different crew, for free (but they kept the oil) and the tank was left in the ground.

Re: Converting from oil to gas heat

Oil tanks can be "Freecycled" or placed in the "free" section of Craigslist as there always seems to be somebody needing one. I have a local contact here who takes old heating oil and uses it in his farm equipment. He takes my tanks too, but only because he gets all the oil I come across for free. I get him an average of 50-75 gallons of fuel a year and that's well worth his time plus it helps me too since I don't have to deal with anything more than my telephone!


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