Regular Guest
I have been doing research on the possibility to replace my current oil boiler to a gas boiler. I have steam heating and two zones with hot water baseboard.
Some calculators online say that for my consumption (previous owner last year used 1,200 gallons) I would be saving about $1,000 to $1,500.
My concern is the fact that efficiency wise my system would not get much of an upgrade. Or so it seems. My current efficiency, according to the Oil company maintenance guy is 81%. (not sure how old is the system, but my guess is 25 yrs).
Gas steam boilers are also in the 85% efficiency rating.
Last year the owners paid about $3,000 for heating on oil. However, few houses down, I have a neighbor who has a almost exact house as mine and he paid around $1,500 to heat his house. Very similar windows, no insulation, same sq. footage, etc.
Where would the savings come from if I switch to gas? Just the price itself that gas is cheaper, or will I gain some on efficiency because a 81% efficiency on a 25 yr old boiler is not the same as 85% efficiency on a brand new steam boiler?
My current estimate is that my payback would be around 5-6 years or so if I make the switch. Because switching to gas would also include switching the hot water heater to gas or tankless, and re-lining the chimney, plus removal of the oil tank.
Regular Guest
The cost savings, if any, are calculated based on the cost of the fuel, the btu value of the fuel, and the efficiency of the furnace/boiler/heat pump etc.
What is your delivered price for oil (in $$ per gallon)?
What is your delivered price for natural gas (in $$ per therm, or $$ per ccf)?
Professional Member
Old steam systems usually have gobs of room for improvement beyond the burner efficiency itself.
Size matters.
http://steamheating.googlepages.com/home
Regular Guest
Originally Posted by gary_g
$81.55 per 100 therm for gas (85% efficient unit)
$2.30 per gallon for oil (say (81% efficient unit)
Regular Guest
If I understand correctly, this means that the newer system would have other improveements in addition to the burner efficiency?
How come the federal credit $1,500 is for 95% efficient unit, when those are so so rare?
Also, can you just replace the burner and not the boiler?
Regular Guest
Compare the cost of 1 million btu's of heat.
Oil at $2.30 per gallon, 81% AFUE
(1,000,000 / 139,000 btu per gallon) x 2.3 / .81
= $20.24
Gas at $.8155 per therm, 85% AFUE
(1,000,000 / 100,000 btu per therm) x .8155 / .85
= $9.59
In this example, gas is 53% cheaper than oil for the same 1 million btu's.
Take care.
Regular Guest
Fed Tax Credit for a boiler is 90% AFUE.
Fed Tax Credit for a gas furnace is 95% AFUE.
http://www.energystar.gov/index.cfm?...edits.tx_index
Take care.
Professional Member
They are trying to get rid of steam systems and trying to promote EFFICIENT designs in delivery systems.
Imagine if you have about 6 piping problems and a perfectly tuned oil burner, and you yank the burner out and put in a gas burner on the same failed delivery system.
Imagine who is at fault if you ask for a new burner and all you get is a new burner and the system still works exactly the same....
Professional Member*
They are not rare at all, for hydronic boilers.
Steam boilers are a different story, you will not be able to condense the flue gas and reclaim the latent heat from the water produced during combustion. If you can get 85% AFUE with a steam boiler you are doing great.
The theoretical efficiency is higher with oil than with gas on a steam boiler (non condensing), but, as already mentioned, the cost per btu of NG is typically half or a third that of the cost per btu of oil.
Another thing to consider is the prssure at which the system operates. Go as low as you can.
Professional Member
long term pas prices
Natural gas prices have dropped dramatically this year and should stay down in the future.
The committee that caculates the ammount of natural gas availiable in the united states DOUBLED their projections in April. The explation was given that new drillling techniques make it possible to access shale gas deposits that previously were not cost effective.
These "new" supplies should bring stability to gas pricing
God Speed, Jim. We'll miss you - 2-26-23
Does your neighbor have steam heat also.
Are the steam pipes in your basement insulated?
Global Moderator
Your old boiler may have a combustion efficiency of 81% but the "annual" efficiency is likely MUCH less. The reading is taken with the boiler fully warmed up and burning at its peak. In reality, figuring standby losses and startup inefficiencies, the oldie is probably more like 60% vs 80-85% for the new gas boiler.
As the others say, piping issues can kill steam boiler efficiency so you would need to find the best steam man you can to size the boiler right, install it right and fix any piping and venting issues.
Regular Guest
Yes he has steam.
No the pipes are not insulated. They were last year when the owner used 1200 gallons, but asbestos was removed recently. Any suggestion for insulation material?
Professional Member*
Fiberglass is a start. Get them insulated! Uninsulated pipes can make a big difference in steam system performance! Any hammering with the uninsulated pipe?
Regular Guest
I hear some pops at the second floor radiators, but no hammering on the pipe, which is a nice surprise.
God Speed, Jim. We'll miss you - 2-26-23
Get some estimates on insulating those pipes.
And get ready for sticker shock.
The proper insulation is not cheap. But, can save you a lot on your heating bill.
Regular Guest
In terms of insulation. Is fiberglass, 1 inch the norm? How about reflectix?
I just have this feeling that in 20 years people will say fiberglass is what asbest is today.
What about the joints. What can I use to insulate the joints?
Professional Member*
I have been doing research on the possibility to replace my current oil boiler to a gas boiler. I have steam heating and two zones with hot water baseboard.
Some calculators online say that for my consumption (previous owner last year used 1,200 gallons) I would be saving about $1,000 to $1,500.
My concern is the fact that efficiency wise my system would not get much of an upgrade. Or so it seems. My current efficiency, according to the Oil company maintenance guy is 81%. (not sure how old is the system, but my guess is 25 yrs).
Gas steam boilers are also in the 85% efficiency rating.
Last year the owners paid about $3,000 for heating on oil. However, few houses down, I have a neighbor who has a almost exact house as mine and he paid around $1,500 to heat his house. Very similar windows, no insulation, same sq. footage, etc.
Where would the savings come from if I switch to gas? Just the price itself that gas is cheaper, or will I gain some on efficiency because a 81% efficiency on a 25 yr old boiler is not the same as 85% efficiency on a brand new steam boiler?
My current estimate is that my payback would be around 5-6 years or so if I make the switch. Because switching to gas would also include switching the hot water heater to gas or tankless, and re-lining the chimney, plus removal of the oil tank.
Steam systems are all about the piping and radiation. Most systems were over sized in there day. Fuel was cheap and "warm customers were happy customers". Replacement boilers are most often sized off the existing radiation. No heat loss calculations done. Get an accurate heat loss done on your home and compare the result to the capacity of your current system. Look at the piping capacity and the boiler output seperately. You may be shocked at what you find.
Good luck.
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