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HVAC Load Calculator for Oil to Gas Conversion Suggestions?

PilotPat24
PilotPat24 Member Posts: 22
Hi Guys,

I am looking to convert a house on Long Island, NY from Hydronic Baseboard Oil to Gas. Does anyone have a recommendation of a Free HVAC Load Calculator to determine to BTU requirement?

Thanks,

Pat

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 18,699
    Are you replacing the boiler? Or installing a gas conversion burner in the existing boiler? Very different projects.

    You have two load conditions -- one is what the capacity of your existing radiation -- the baseboards -- is. The other is what the house needs. Whichever is less limits the maximum size of the boiler wanted -- most likely the house load. That can be calculated with the Slant/Fin calculator, here: https://www.slantfin.com/slantfin-heat-loss-calculator/
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    In_New_England
  • STEVEusaPA
    STEVEusaPA Member Posts: 5,671
    edited May 11
    How many gallons did you burn in the last 12 months?
    What equipment do you currently have, make/model #, and do you use your boiler for domestic hot water?
    steve
  • PilotPat24
    PilotPat24 Member Posts: 22

    How many gallons did you burn in the last 12 months?
    What equipment do you currently have, make/model #, and do you use your boiler for domestic hot water?

    Hey Steve,

    2021 - I had 665 Gallons Delivered
    2022 - I had 375 Gallons Delivered so far. In the fall, I'm sure I would have another 225 gallons delivered which would be about 600 gallons for this year.

    Thanks,

    Pat
  • PilotPat24
    PilotPat24 Member Posts: 22

    Are you replacing the boiler? Or installing a gas conversion burner in the existing boiler? Very different projects.

    You have two load conditions -- one is what the capacity of your existing radiation -- the baseboards -- is. The other is what the house needs. Whichever is less limits the maximum size of the boiler wanted -- most likely the house load. That can be calculated with the Slant/Fin calculator, here: https://www.slantfin.com/slantfin-heat-loss-calculator/

    Hi Jamie,

    I am not sure what I want to do yet. I currently have in this house a Peerless WBV boiler that has to be about 25 years old. Your thoughts?

    Thanks,

    Pat
  • Steamhead
    Steamhead Member Posts: 15,263
    Those are good boilers. If that were mine, I'd clean it out thoroughly, install new firebox refractory, replace the oil burner with a Carlin EZ-Gas burner matched to the boiler and the oil barometric with a gas one, and add a blocked-flue switch. It's not unreasonable to expect this setup to last another couple decades.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
    rick in Alaska
  • Hot_water_fan
    Hot_water_fan Member Posts: 436
    I like using usage:

    https://www.greenbuildingadvisor.com/article/replacing-a-furnace-or-boiler

    That's probably placing your heat load around 40,000 btu/h without DHW and 30,000 btu/h with DHW, which is probably about half of your current capacity.
  • STEVEusaPA
    STEVEusaPA Member Posts: 5,671

    steve
  • PilotPat24
    PilotPat24 Member Posts: 22
    I like using usage: https://www.greenbuildingadvisor.com/article/replacing-a-furnace-or-boiler That's probably placing your heat load around 40,000 btu/h without DHW and 30,000 btu/h with DHW, which is probably about half of your current capacity.
    Well the boiler only supplies baseboard heat which is 102,000 BTU's.  I have a Toyotomi on demand HWH for hot water.  I am sure the boiler is way oversized.  It's a 2000 ft/sq house.  

    I'm guessing people's thoughts is that I should stick with oil?  Would it be worth it for me to have a properly sized system?

    Pat


  • Jamie Hall
    Jamie Hall Member Posts: 18,699
    Before I even began to consider switching from oil to gas, I'd ask what the relative cost is going to be. First question, obviously, is do you already have natural gas run to the house? Is the service big enough? If you do, what is the cost of gas per BTU vs. the cost of oil per BTU? But even then, with that low an oil usage, what can you really save? Would it pay for a new boiler in the 10 years or so a new boiler would last (the saying "they don't make 'em like they used to" comes to mind). Probably not -- but it might pay for the conversion burner which @Steamhead suggested.

    Eventually that Peerless will give up, but with any care at all it will be a while -- and by then the choices and reasons for them will have changed.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • In_New_England
    In_New_England Member Posts: 49
    edited May 11
    I used the Weil McLain worksheet.

    The slant/fin app looks great, but a bit complicated.

    I also looked at my oil consumption for Jan/Feb (150 gal) and got a rough estimate of my average BTU during that period. There is a way of working out the heat demand more precisely using outdoor temperature charts for that period.

    I also used the slant/fin baseboard charts to estimate my baseboard output. A quick rule of thumb is 580 BTU/hr x feet of baseboard if it is driven at 180F.
  • STEVEusaPA
    STEVEusaPA Member Posts: 5,671

    I used the Weil McLain worksheet.

    The slant/fin app looks great, but a bit complicated.

    Too many 'rules of thumb' in the calculations, I'd think it might oversize. Actual usage would seem to be more accurate, and much easier.
    steve
    Hot_water_fan
  • Dave Carpentier
    Dave Carpentier Member Posts: 109
    I found the SlantFin app for the phone to be pretty cool. You still have to measure and define things of course, but the app was well designed for even an amateur to use.
    30+ yrs in telecom outside plant.
    Currently in building maintenance.
  • Jamie Hall
    Jamie Hall Member Posts: 18,699
    I have heard people say the Slant/Fin app is too complicated. It's not. You do, however, need to exercise enough to get reasonable inputs. With reasonable inputs, it gives reasonable results -- and they are almost as accurate as a full scale Manual J. Actual usage can also be reasonably accurate -- no better and no worse -- but you again need the correct inputs. Without them, it's worse than useless.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • PilotPat24
    PilotPat24 Member Posts: 22

    Before I even began to consider switching from oil to gas, I'd ask what the relative cost is going to be. First question, obviously, is do you already have natural gas run to the house? Is the service big enough? If you do, what is the cost of gas per BTU vs. the cost of oil per BTU? But even then, with that low an oil usage, what can you really save? Would it pay for a new boiler in the 10 years or so a new boiler would last (the saying "they don't make 'em like they used to" comes to mind). Probably not -- but it might pay for the conversion burner which @Steamhead suggested.

    Eventually that Peerless will give up, but with any care at all it will be a while -- and by then the choices and reasons for them will have changed.

    I do not have natural gas currently at the house. It is currently in the street and National Grid would run it to the house providing I switch one of the appliances over to gas.

    I will take a couple of pictures of my current configuration and see if anyone has any recommendations to improve anything the way it is currently set up.

    Thanks,

    Pat
  • ChrisJ
    ChrisJ Member Posts: 12,657
    You're going to find there's a few on here that are against natural gas no matter what.

    I converted from oil in 2011 and I'd never go back.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • PilotPat24
    PilotPat24 Member Posts: 22
    This house is a rental and I pay for the heat. I'm just trying to figure out what fuel would be cheapest to heat the house with and if it would be worth it to switch over to gas over the long term.

    Pat
  • pecmsg
    pecmsg Member Posts: 2,813
    Cost per BTU/h between Oil and Gas is always fluctuating always changing. Some years Oil is cheaper some Gas. I highly doubt you'll ever see a return on investment converting, it's more a personal choice.

    Tightning the envelope and properly sizing the equipment WILL give you a return-on-investment year after year.
  • PilotPat24
    PilotPat24 Member Posts: 22
    pecmsg said:

    Cost per BTU/h between Oil and Gas is always fluctuating always changing. Some years Oil is cheaper some Gas. I highly doubt you'll ever see a return on investment converting, it's more a personal choice.

    Tightning the envelope and properly sizing the equipment WILL give you a return-on-investment year after year.

    Understood. I will begin to gather all of the specs on my house and my system I currently have.
  • PilotPat24
    PilotPat24 Member Posts: 22
    pecmsg said:

    Cost per BTU/h between Oil and Gas is always fluctuating always changing. Some years Oil is cheaper some Gas. I highly doubt you'll ever see a return on investment converting, it's more a personal choice.

    Tightning the envelope and properly sizing the equipment WILL give you a return-on-investment year after year.

    You don't think it would be worth converting to Natural Gas with Fuel Oil Prices being $5.50+/gallon? I don't see fuel oil prices coming down anytime soon.
  • Jamie Hall
    Jamie Hall Member Posts: 18,699
    Natural gas spot prices are going up, too. Unless artificial controls are established, I believe that you will see the various fuel prices per BTU even out again, but at a much higher level than before. Fuel oil prices are more volatile, as the level of government control is less.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • ChrisJ
    ChrisJ Member Posts: 12,657

    Natural gas spot prices are going up, too. Unless artificial controls are established, I believe that you will see the various fuel prices per BTU even out again, but at a much higher level than before. Fuel oil prices are more volatile, as the level of government control is less.


    So.
    That's a bad thing, no?

    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • Jamie Hall
    Jamie Hall Member Posts: 18,699
    edited May 14
    ChrisJ said:

    Natural gas spot prices are going up, too. Unless artificial controls are established, I believe that you will see the various fuel prices per BTU even out again, but at a much higher level than before. Fuel oil prices are more volatile, as the level of government control is less.


    So.
    That's a bad thing, no?

    That is a political question... not going there.

    It is worth noting, though -- without getting off into the weeds too far -- that natural gas (and town or manufactured before that) is what the economists call a "natural monopoly" -- one where a single entity controls the market in an area naturally, since installing competing infrastructure is excessively costly. Other natural monpolies include electric power, cable television, hard wired phones... that sort of thing. Fuel oil or LP, or coal, for example, are not. There are no natural barriers to make competition difficult.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • ChrisJ
    ChrisJ Member Posts: 12,657
    Natural gas spot prices are going up, too. Unless artificial controls are established, I believe that you will see the various fuel prices per BTU even out again, but at a much higher level than before. Fuel oil prices are more volatile, as the level of government control is less.
    So. That's a bad thing, no?
    That is a political question... not going there.

    Less stable fuel prices seems like a bad thing to me.   Not to mention you basically already went there my friend.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • Erin Holohan Haskell
    Erin Holohan Haskell Member, Moderator, Administrator Posts: 1,839
    No politics here. Thanks!
    President
    HeatingHelp.com
  • fentonc
    fentonc Member Posts: 76
    Oil has basically always been a globally-traded commodity, so the price has historically been much more sensitive to world events / markets than gas. Gas has mostly been supplied via long-term contracts, and was difficult to ship around the world, so there have been big long-term price discrepancies in NG prices between different parts of the world (Europe is ~10x the USA right now, for instance). In the last few years, the US has built a lot of LNG export capacity, and with the current Ukraine/Russia situation (and thus sky-high prices for LNG in Europe and Asia), NG prices in the US have been increasingly volatile because more of it can be exported when someone else is willing to pay a higher price. Prices have basically doubled since March, for instance. Anytime you're directly exposing yourself to volatile commodity prices, you're kind of making an investment decision/bet about the future price of those commodities.