Subscribe or Renew Membership Subscribe Renew

propane vs oil fired boiler

jroy's picture

My hvac contractor is recommending a new hi eff propane boiler versus an oil fired version. I realize that the propane version will be more efficient...but is propane worth the higher fuel cost associated with propane (vs oil) as well as the lower btu output? It seems that when oil prices rise so too does propane. I dont have a natural gas line to tap into so my choice is limited to either oil or lpg.

You can compare the relative (post #184846, reply #1 of 11)

You can compare the relative costs, but you need the fuel costs and the efficiencies of the units. If one costs less to operate, but costs more to buy, you can estimate "payback" with HDD (heating degree days) for your area.

What reason does the contractor give for his recommendation? There are some very nice, very efficient oil boilers out there (i.e. Viessman). What type of system do you have, hot water or steam? With a steam system, the process limits the efficiency no matter the fuel.

Personally, I prefer LPG. Not really affected by temperature, not as messy, tank is outside. thousands of NG products that can be easily converted to LPG.

There is no number at which (post #184846, reply #2 of 11)

There is no number at which propane works out. '

a gas furnace should be cheaper up front, but will cost more in the long run.


I just installed a 92 percent Buderus oil, so I have done the math.


I too wish I had gas in the street....


>>There is no number at which (post #184846, reply #3 of 11)

>>There is no number at which propane works out. '

It depends on where you are - for the OP, SE Mass is likely stay oil=centric for a long time to come.  In many parts of the country, I believe residential oil is no longer cost competitive

>>a gas furnace should be cheaper up front, but will cost mre in the long run.

Including maintenance?

E.g., One never has to replace jets on a gas combustion device


Including life expectancy?

Including producing hot water?


IS there a reason far more parts of the country use gas rather than oil?

I don't know the answers to these questions, but think they are worth considering.

======================================== "Man's capacity for justice makes democracy possible, but man's inclination to injustice makes democracy necessary." Reinhold Niebuhr: 'The Children of Light and the Children of Darkness' ========================================

Gas yes, propane (post #184846, reply #4 of 11)

Gas yes, propane no



just do the math

Oil fired!  They make oil (post #184846, reply #5 of 11)

Oil fired! 

They make oil fired burners that can burn various oils from Kerosene to used motor oil, and they burn clean. This is just a sample link so you can see what I mean.

If you could get an oil change place to give you their waste oil, you may not even have a heating bill, well not the bill for fuel anyway. Waste vegtable oil works too.

I'm trying to build one from scratch, (Not recommended), it has a learning curve to it. :-)


Hi, You can calculate which (post #184846, reply #6 of 11)


You can calculate which is cheaper easily using this calculator:

We use propane -- the price around here for propane is very volatile.  It was 80 cents a gallon when we started 10 years ago and is not about $2.20. 

Spend your money on more insulation :)



Hi Jroy,   up here in (post #184846, reply #7 of 11)

Hi Jroy,


up here in maine, oil and propane are close to the same cost per gallon.  oil has about 160kBTUs/gallon and propane has about 90kBTUs/gallon.

propane will easily run 20% more efficiently, real world, in a sealed combustion/modulating unit than any oil unit on the market in america will.    that's easily:  the AFUE may not show that, but with modulating operation and sealed combustion operation, we've seen it time and again.

I know there is a "92%" efficient oil boiler out there and hey, maybe I'm wrong, but I think it's still a high mass cast iron unit and unless they have very radically changed the design and control of the beast in more than just the nozzle design I'd have to be pretty skeptical you're ever going to see that out of oil.  for now I'll ignore that boiler at any rate.

but even 20% more efficiently isn't so great.  If you assume 95% vs 75%, for example, that's still 86kBTUs vs 123kBTUs... oil still delivers the same heat in 2 gallons that propane will in 3. 

so propane will probably never close that gap.

that said, it also does not require a chimney, fires quieter and cleaner too.  those count for something.  how much?  depends on you.  In my case I had a powervent on oil that stunk up my screen porch on domestic calls.  it was worth a lot to get rid of that.


Rockport Mechanical

HVAC Design and Installation in beautiful Rockport Maine

Thanks for all the thoughts (post #184846, reply #8 of 11)

Thanks for all the thoughts on this subject as Ive decided to stick to oil for heating.  My hvac guy has suggested using a Biasi B10-5 w/Superstore s.s indirect water tank for a replacement heater.  I like the Buderus BE125, but the price is too steep.

The reason Im looking to switch (from a furnace) is two fold...I cant run ductwork into parts of my new addition & my furnace is over 25yrs old, oil fired water heater 12yrs old.  I have a air handler in the attic which runs off the water heater to provide heat to the bedrooms and Ive never liked having it run off the water heater.  So changing to a boiler will allow me to use the air handler for the bedrooms, run hydro air in the ductwork I have (along w a/c)and run baseboard to the areas of the addition where duct work isnt practicle.

I would appreciate your thoughts on a good quality, efficient boiler that is reasonably priced.




There are a host of other considerations in switching to propane (post #184846, reply #9 of 11)

Courses should be offered regarding the host of considerations when switching from oil-fired boiler to propane.  However, when you contact a qualified, known contractor, and they do not disclose everything you should have known prior to installation, what recourse is there, unless you have $10,000 laying around to switch it back.

Oil is so much more straightforard.  It is what it is.  It is far less likely to explode.  I'm sure that oil burns much more cleanly than this mercaptan-scented propane.  The sole reason for the switch was that the furnace cracked, and every contractor brought in swore that there was no way to get another oil-fired furnace, and holding tank inside the house.  (And, I'm in your neck of the world).  So now?  The money is gone, and I've got some kind of eye/neuro problem I did not have... It is highly likely that the flue vent to the outside was placed too close to a window, and that the tanks themselves, placed directly under a window, is a very bad thing.  But do you think the company - the highly-reputable company will do anything about this.  If it wasn't freezing, I'd shut the entire operation down in a second, and I surely will do so the moment the weather is warm again.

I hadn't known I would have eye/neuro irritation, nor that the "vapor" - such a benign-sounding word, isn't it? - would be so effusive, and, I'm thinking it will warp the side wall shingles.. I did not know that the tanks should not be directly underneath a window...

I mean, I'm considering that I now shouldn't mow anywhere near the propane tanks, for fear of sparks from hitting a stone.  I've had rather severe eye irriation in one section on the first floor of this small old house, since the installation.  The vapor vent to the outside produces remarkable amounts of vapor, and I have to wonder if I'm being exposed to Carbon Monoxide gas in that area of the house.  But I'm not even close to being an expert in chemistry, or physics, or HVAC functioning.  Nonetheless, I'm having a rapid-blinking response, even though my eyes are overly moist.

Then, there is the entire retrofit problem should, down the line, one want to switch to something else.  All the copper piping would have to be tossed.  And the expense which in no manner will compensate for any alleged "energy savings" - not that that is why this boiler-condenser was purchaed. 

Frankly, I feel like there ought to be a way to have the purchase refunded and the entire mess removed on the basis of insufficient information being provided by the experts, and, quite likely, improper placement.  Fat chance.

We had propane in this house (post #184846, reply #10 of 11)

We had propane in this house for two years, before natural gas came available again.  (There was a moratorium on NG connectrions in 1976.)  Never caused a problem, once I fixed the gas leak.  (You could smell gas whenever you got close to the furnace room.  The leak was a tiny spot in one joint -- a quarter turn with a pipe wrench fixed it right up.)

I would suspect you have a leak.

Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

aha Easter time again early, (post #184846, reply #11 of 11)

aha Easter time again early, -- aka another ressurection

OP HVAC guy must be a fossil fuel fossil,

Unless yu are in the froen north, mini-split HP cheaper both purchse and opertional,  you can diy jmini-split