Switching to natural gas (many questions)

[Jaugust124]

As the title states I may be switching over from oil to natural gas sometime before the next heating season. I have been hard at work trying to get our local utility company to bring natural gas to my neighborhood and I have a few questions that I thought maybe some of you could assist me with.

The utility company is offering to provide service to the house and I would be responsible for everything inside the house. They are offering substantial rebates on new equipment up to $1000 (I think) depending on the efficiency. They stated that a conversion could cost the homeowner $7000-$8000.
They even offer a service that will take care of everything, oil tank removal installation, etc. I do not have to call anyone. They will set up the entire conversion and even process the rebates.

My current set up is a Dunkirk Empire II oil fired boiler with a coil for domestic hot water. The unit was installed by previous owner in 2006. It has the Energy Star rating and the efficiency is somewhere in the 85% range +or-.

1) Can I just switch out the oil burner for gas and not replace the entire boiler? This would be a much less expensive option. Looking around on the Internet has given me mixed results, mostly stating that efficiency would drop.

2) I have about 300 gallons or so currently in my oil tank. By the time the next heating season rolls around I should be down to about 250 gallons. That's nearly $1000 worth of oil! Will the oil company buy back the oil? I doubt it. So, the real question is... What do I do with the oil? I hate to see it get pumped out and disposed of. If I had realized this sooner I would have stopped automatic delivery.

3) If I do end up replacing the entire boiler should I go with another tankless system or get a separate hot water heater? We have had problems running out of hot water in the winter with our current system. This is a separate problem to be resolved. We literally run out after 2 minutes in the shower and it takes another 2-3 minutes to get hot again. We do not have a high demand. Just the wife and I and we shower about 30-45 minutes apart. So, I am a bit bias against the coil system.

4) If I did get a separate hot water heater should I go with the gas or a hybrid electric? Electric runs about 16 cents per kwh.

5) Anyone out there with natural gas and still burning wood?

Thanks in advance for all your help.

 

[woodgeek]

Personally, I would not retro the oil boiler.....that unit has a cast iron heat exchanger, so you will have to run the burner and exhaust hot enough to avoid condensation/corrosion. Since there is more H2 in NG than oil, that means the exhaust will need to be even hotter than it is now, lowering your eff % (as you point out). While your DHW coil can prob be fixed (by adjusting the aquastat and tempering valve), I am also not a big fan of those systems.

More to the point condensing NG boilers (with SS exchangers) are eff, easy to vent, and pretty standard mature tech.

A key issue is knowing your design heating load....a lot of those oil boilers are way oversized, getting a smaller NG unit could save $$ relative to getting the same BTU output you have now. I would start by totaling your winter oil usage and dividing by your heating degree days for that season to get oil per HDD. Then figure out the HDD and oil usage that would correspond to the coldest temp you might experience, say 10 below. IF you then figure 110 kBTU/gallon, you can get your daily and hourly max BTU demand.

For the oil, I would try craigslist, and sell it at a discount. Or call the guys that pull out boilers/tanks...they all have a way of burning dreg oil.

As for DHW, the choice is whether to integrate it with the boiler, or to get a separate heater. Hard to say much not knowing your design load. If you want to have two showers at the same time (e.g. kids in the future), then you will likely want a storage system of some sort. I like HPWHs, but in your climate a NG fired system would be lower operating cost.

 

[nate379]

You can put a natural gas gun in most oil burners. It won't be as "ideal" as a gas boiler, but all depends on what you want to spend. A 6 year old burner has plenty of life left in it.

As far as the oil. If the oil company won't buy it back, could use it in vehicles. If you don't have anything diesel (darn shame!), put it up on Craig's List, $2/gal. It'll be gone in under a day.

 

[peakbagger]

Put up a ad on Craiglist selling the oil to whomever wants to haul it off. I have a friend with a couple 55 gallon drums and drill pump that heats his house emptying oil from tanks folks dont want.

 

[Jaugust124]

Thank you all for the advice.
As far as selling the oil, I saw ads on Craigslist of people offering to purchase the oil for $1.50/gallon. I wonder if I would be better off donating it and getting a hefty tax write off. Selling approximately 250 gallons at $1.50 nets me $375. Better than nothing. Could try to get $2.00 or so. Might be worth a try.
Same goes for the boiler. I hate to see a 7 year old boiler go to the scrap heap. Maybe I'll keep it and see what I can get for it or again donate it to Habitat for Humanity or something.

Woodgeek, I will try to do the calculations to figure out my boiler size. Looking at my current set up it looks like its a 150,000 btu capacity with a max input of 175,000 btu.

Thanks again everybody.

 

[velvetfoot]

Geez, I wish I had your issues. We'll never get natural gas lines where we live.

 

[EatenByLimestone]

When I did my conversion my utility put the line in for free as long as I promise to use NG for a few years. In addition to the conversion burner I had an indirect water tank put in. My boiler heats the tank. I did this for a few reasons. The mfg code on the water heater said August of '78 on it. It was much closer to the end of its life than the beginning. I guess they don't make them like they used to? I chose the indirect tank over other options because I have the wife and a 3yo little girl here. Eventually she will follow in her mother's footsteps and take long showers. I know I would not have any hot water if I went with a traditional system when she reaches teenager years. I thought of a gas water heater and did not want to add another flue. The indirect tank gives me limitless hot water as far as I can tell and only one ignition source. It should make the boiler last longer also since it fires daily and any condensation is driven off. I played with my standby and water temp a little, but my aquastat will not let me bring it below 160 or 170. I can't remember. One last selling point for me on the indirect tank is the stainless steel tank inside of it. I don't think I'll need to replace it... ever... or at least for a long time.

The total cost was around $4500. I also had a primary/secondary system installed on the recommendation of a HVAC guy from Canada. My primary is about 1 1/2 inch copper and forms a loop. Off it I had them plumb one zone for the indirect tank and another for the ground floor. I had them put in stubs for another zone that I used for the attic when I finished it off. The zones are not operated by valves but by separate pumps.

It's too bad you can't burn that oil Can you have them hook up the NG for something like a clothes dryer and then have somebody come back and install the new boiler/conversion boiler when the oil is about gone? I'd hate to take such a big loss on the oil. I let myself run out the last winter I was on it and then used a 5 g gas can to put kero in it once and then diesel in it the 2nd time it ran dry. There wasn't much for them to get out of the tank.

Run the price on NG and electricity per btu. I did this when my dryer went and electricity came out to be 2.5X the cost of NG per btu. It only cost my about $100 and a couple hours to run the black pipe for the dryer. The wife loves her new dryer.

I have a few cords of wood still in the back yard, but only burn on the real cold nights. It really doesn't pay to. Heating costs me between 100 and 130 a month. If I bought my wood (I scrounged) it would be half a cord. If I was on oil it would be 25-30 gallons? That wouldn't go far. My electricity is about the same as yours. I haven't calculated it in a while.

 

[velvetfoot]

"I have a few cords of wood still in the back yard, but only burn on the real cold nights. It really doesn't pay to. Heating costs me between 100 and 130 a month."
Blah, blah, blah ......

 

[EatenByLimestone]

If it makes you feel better I still have a wife that complains she's cold. Then again I've walked into a 90 degree room and caught her under a blanket.

Women are just odd.

Matt