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  1. #1
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    Apr 2013
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    Default oil to gas conversion - heating question

    I'm in the process of buying a 2100 sqft house in MA built in 1928. It has an oil fired steam boiler that feeds radiators and baseboards for heat. I'd like to convert to a gas system, any suggestions for what I should into? Ideally, I'd like a 3 zone system, a thermostat on the first and second floors, and one more for when the basement is eventually finished.

  2. #2
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    Nov 2012
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    central pa
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    98

    Default Re: oil to gas conversion - heating question

    as far a zoning that depends entirly uppon how the radiators are plumbed now could be easy could be very difficult and expensive

  3. #3
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    Default Re: oil to gas conversion - heating question

    As far as I know, you're probably stuck with the steam heat system the way it is; there is no way I know to convert a steam system to zoned valves; of course, you can still control the heat to each room with the radiator/baseboard shutoff valves.

    If you're thinking of converting to a gas-fired forced hot water system, you would have to scrap the entire steam system, install new baseboard & distribution piping and a gas-fired boiler with 3 zone valves---the zone valves themselves are easy to do & very widely done, but in your case it would be expensive, perhaps $10k or more to scrap the steam system & go with hot water; the steam systems in these older homes tend to be very old, noisy, and most of all, very inefficient and burn a lot of oil---if it's a very old steam system, it probably should be scrapped; a new system would burn 1/2 the oil or gas as the old steam relics.

    I favor gas-fired boilers by Triangle Tube, Buderus, Burnham, Crown, Dunkirk, Peerless and Weil-Mclain with a companion 40 gallon indirect hot water heater for the domestic tap hot water needs.

    What about AC for the summer heat?? If you decide to scrap the steam think about a forced hot air heating system where the heating vents would double as an AC system in the summer; if you want to go with forced hot water heat you could install ductless mini-split AC units to cool the house in the summer.

    There is also a Unico system that combines high velocity forced hot air & forced cool air for heating & cooling seasons at http://www.unicosystem.com
    Last edited by Dobbs; 04-14-2013 at 09:41 PM.

  4. #4
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    Default Re: oil to gas conversion - heating question

    Thanks for that info! I'm definitely considering scrapping all of the current steam heating system. Most of it is very old. Plus, I grew up with a natural gas steam radiator system in my parent's house and would prefer something quiet and much more efficient.

    I'm thinking of choosing a tankless water heater. I'd like to finish the basement at some point, and want to minimize the space needed by utilities.

    I'd like to do AC as well, I'll be looking into those options. The mini-split AC looks easier to install vs putting in ducts.

  5. #5
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    Feb 2008
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    Default Re: oil to gas conversion - heating question

    Rekonn,

    It sounds like you've done your research & are headed in the right direction; I would recommend a gas-fired forced hot water heating system with 3 or even 4 zone valves, but instead of a tankless hwh, I would recommend a 30 gal or 40 gal indirect hwh; I've included a site below that explains how an ihwh works---they are actually a HEAT EXCHANGER---they efficiently use the boiler's hot water to heat a 30 or 40 gal tank of fresh water via piping (and yes,) using a zone valve & the boiler's circulator (pump)----many studies have shown that this is the most efficient & cost-effective way to heat domestic hot water (tap water), and you'll never run out of hot water; these units have no moving parts & no flame burner, so they last for decades---if you happen to have hard water (high calcium & mineral content well water) in your new house, opt for a double-walled stainless steel ihwh.

    I also favor the standard cast-iron gas-fired boilers, as mentioned in a previous post, over the more recently introduced wall-hung "boilers" which have demonstrated lots of operational problems, because the bugs haven't yet been ironed out, and because the standard cast iron boilers operate at 180 degrees water temperature which provides fast & continuous heating comfort for the house occupants, and gives quicker response for the indirect hwh.

    Consult the Yellow Pages under "Heating Contractors" & get written estimates from at least 3 contractors before you decide which one to hire---the quotes usually vary in cost estimates by quite a bit, for what's essentially the same job & equipment---make sure each HC does a HEAT LOSS CALCULATION, which takes into account building square footage, window condition, insulation, attic insulation, etc.; the first thing the HC will ask you is do you have any insulation in the exterior walls of the house. (a HLC is based on the concept that your building is losing a certain # of heat BTUs/hour on a cold day; once the calculation is done & the contractor has a heat loss number (for example 70,000 BTU/hour heat loss) the boiler is sized accordingly, & a 70,000 BTU/hr gas-fired boiler is installed---reject any heating contractor that wants to put in a boiler without doing a HLC).

    Before you even THINK of changing the heating system, by all means think exterior wall INSULATION---ask the previous owner if there is any insulation in the exterior walls of the house---there are several ways to check, or call in an insulation contractor to check it out---it's amazing how many new homeowners completely ignore exterior wall insulation (which costs only a few hundred $$$ to have cellulose insulation blown in & done completely from the outside of the house in one day)---this will save you thousands of $$$ over the years of your occupancy at the new house in both heating & cooling costs---this usually allows the heating contractor to install a smaller capacity boiler, & thus allows considerable savings in annual heating costs; insulation & a new heating system (and new vinyl double-pane windows on any windows that are old & single pane) all qualify for the $500 credit you can qualify for in your annual Federal tax return.


    I also concur on your comments about the mini-split ACs---great cooling systems without any indoor noise, easy installation.


    http://homeenergysaver.lbl.gov/consu...eater-combined
    http://www.consumerreports.org/cro/a...heaters-ov.htm
    Last edited by Dobbs; 04-15-2013 at 12:25 PM.

  6. #6
    Join Date
    Apr 2013
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    Massachusetts
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    Default Re: oil to gas conversion - heating question

    I'm glad I found this forum, thanks for the advice!

    Yes, I'll be looking into the insulation for sure. MA has this masssave program where you can schedule a home energy assessment. LINK A special_ist comes over and analyzes your house and comes up with a custom list of recommendations that include insulation and heating/cooling system options.

    The attic floor has this crushed styrofoam looking stuff the sellers say they added in the 1980's. They couldn't remember what it was, but my inspector believes it's Perlite. No idea if anything is in the exterior walls, I suspect not, but I'll ask.

    The house already has a 32g indirect hwh (Amtrol I think); it's in much better shape than the oil boiler. Can I reuse that with a new gas boiler?

    I found this calculator LINK, and put in my location and 2950sqft (this includes the currently unfinished basement). It says my estimated BTU requirement is 146,000 BTUs. If a contractor comes up with the same number from their HLC, would this boiler work LINK? Is $2636 a good price for that?

  7. #7
    Join Date
    Feb 2008
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    175

    Default Re: oil to gas conversion - heating question

    Rekonn,


    Yes, "mass save" looks like a good resource.
    Yes, you can use the existing Amtrol Boilermate indirect with the new boiler---this should save you $1K to 1.5K on the installation of a new indirect; sometimes the new installer may refuse to install an existing indirect with a new boiler due to transfer of warranty issues, as well as being unable to determine the inner condition of the Amtrol.

    The Weil-McLain CGA-7 looks like a good boiler, but unfortunately, WM has had a lot of problems with the cracking of the cast-iron sections of this particular unit, so it should be avoided.

    The heat loss calculation (HLC) (Manual J) from Pex Supply is well-intended, but is essentially useless in determining a particular building's heat loss; it simply takes the building square footage and the geographical area of the residence & ignores the extremely important factors as the amount of a building's glass (glass window area), exterior wall & attic insulation, ceiling heights, foundation structure, double pane/single pane glass, prevailing winds & surrounding building structures (if any), building materials used in exterior & interior walls/ceilings, etc.,etc.; for these calculations heating contractors rely on a professional computer-driven HLC such as the one by Slant/Fin that takes several hours to complete; you might find this HLC on-line via Google; there is usually a usage charge; or you can Google "heat loss calculator" & find one that includes most of the above listed factors & probably get a reasonably accurate HLC for your new building.

    I would recommend you look at the Crown Cabo II, or the Dunkirk EV series, or Peerless PSC II, Slant/Fin Victory, Utica USC series, or the Buderus G124 for floor model cast-iron gas-fired boilers in the 85% AFUE efficiency range; Pex Supply does make an important distinction in their BTU calculator between "low-temp heat" (radiant/90 degree hot water) and "hi-temp heat" (baseboard/radiators/180 degree hot water) boilers---I suggest you concentrate, as previously noted, on the 2nd category, "hi-temp heat" boilers, gas-fired at approx 85% AFUE---these are much less expensive than so-called condensing boilers, and usually can be vented into an existing chimney (sometimes requiring installation of an aluminum chimney liner); they're cast iron boilers, made to last decades.

    As a separate issue aside from the above, I wonder if this is your first house purchase & if the sale of this house has been finalized & if you've hired a residential building inspector to go thru this 85 yr old house to try to find any major repair issues with the condition of the roof (leaky, old shingles), poor siding, old leaky single-pane windows, old cast-iron steel plumbing/water supply piping, foundation issues (cracks/sagging), cellar water leaking problems, etc.----many prospective house buyers are simply not experienced (understandable) in picking up defects in a building they are about to buy & live to regret not having an experienced building inspector checking things out before the sale is finalized---there is almost ALWAYS a few thing wrong with any house on the market----the residential bi will help you to size up if the level of defects reaches the point where you should turn down the sale & look elsewhere for a new home.

    In regards to the boilers I've listed above, you should Google each one of the boiler models using phrasing such as "Crown Cabo II problems", or "Dunkirk EV problems" to read thru the responses to see if this particular model is currently experiencing any major problems with the cast iron combustion chamber, or multiple issues that would merit rejecting that particular boiler model.


    http://energybible.com/saving_energy/boilers.html
    Last edited by Dobbs; 04-16-2013 at 02:49 PM.

  8. #8
    Join Date
    Apr 2013
    Location
    Massachusetts
    Posts
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    Default Re: oil to gas conversion - heating question

    Again, thanks for the recommendations! I owned one house before for 4 years in AZ, but it was built in the late 80's, so it really didn't need any work. The house I'm buying now has one hurdle left until the sale is finalized, the appraisal. We did have an inspection, and you're right, several things were found that I never would have noticed. Based on the result of the inspection, we were able to negotiate an additional $7k off the sale price.

    You mentioned earlier getting quotes from at least 3 contractors, and having each of them do a heat loss calculation. If the HLC takes a couple hours, I'd imagine that doesn't come free with a quote, does it?

  9. #9
    Join Date
    Apr 2013
    Location
    Massachusetts
    Posts
    28

    Default Re: oil to gas conversion - heating question

    Also, anything bad with a condensing boiler besides cost? MA offers these rebates, which according to the prices I see on pexsupply, evens things out between the 85% AFUE vs condensing models.

    $1,000 Rebate Forced Hot Water Boilers ≥90% AFUE rating
    $1,500 Rebate Forced Hot Water Boilers ≥95% AFUE rating

  10. #10
    Join Date
    Feb 2008
    Posts
    175

    Default Re: oil to gas conversion - heating question

    Rekonn,

    Condensing boilers & heating systems , as noted in my previous post fall into the category of "lo temp heat", as opposed to "hi temp heat", as mentioned in the Pex Supply heat loss calculation; these are technically advanced systems that operate at 90 to 110 degrees water temp as opposed to 170-180 degrees HW in the more traditional "tried & true" "hi-temp" cast iron boiler technology; "lo temp" systems have their strongest application in new housing, often where plastic tubing (PEX) can be extensively embedded in newly-poured concrete slabs during house construction throughout the new house; low-temp HW does a good job of heating the concrete mass & the heat "radiates" throughout the house (radiant heat); a number of people have problems adjusting to this system because control of house temps is usually very slow & "automatic"; there is almost always an outdoor temperature reset combined with a computer-driven heat-monitoring system, both of which further isolate the occupant from control; the emphasis is on minimizing fuel usage, often at the expense of occupant comfort; this is quite unlike a "hi-temp" system where one simply turns up the t-stat to get more heat; there have also been higher incidences of functional problems with this new high tech equipment, causing frustration for the homeowner, who expects the heating system to be reliable & trouble-free, especially in freezing-cold climates; only recently have the mfgrs of condensing radiant systems begun to think of including "override" capability to these computerized systems to give the building occupant more control over the call for heat.

    Retrofit radiant systems in existing older wood frame houses can be done along similar lines, often at high expense; one option you MAY have is to get an opinion from a local radiant heat installer regarding the existing cast iron radiators from the old steam system; sometimes if they are in good shape & don't leak they can be used to install a retrofit radiant system; this would depend on you finding an installer who would take on the project; again, like the Amtrol issue, heating equipment installers want to avoid "call-backs"---many of them can't afford to be called back on a weekly basis to tweak the bugs out of cutting edge technology equipment, so many techs will turn down an offer to install retrofit lo-temp radiant heat; on the other hand, there's a LOT OF MASS in the cast iron rads that could make an excellent radiant heat system & you could qualify for the deeper rebates on the boiler---it's always a shame to see cast iron rads relegated to the junk yard, but sometimes it's for the best; consult the Yellow Pages under "Heating Equipment-Parts" to get the location of heating parts supply houses in your area; go down & talk to the counterman (in the afternoon when it's not so busy) to ask for a referral for a tech who specializes installing radiant retrofits.

    Charging for a HLC by the installer is usually not done; you can help the process by having most of the vital info at hand beforehand, such as the total square footage of all windows, doors, total sq.footage of the building, ceiling heights, exterior wall & attic insulation thickness, etc.
    Last edited by Dobbs; 04-20-2013 at 08:47 AM.

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