Replacement Steam Boiler- Gas vs. Oil, Power Vent vs. Chimney

apaul1018

Hi! Our home is currently heated with one pipe steam radiators using oil and a chimney that needs cleaned and lined. It's a 1920's colonial at around 1300 SF in MA- two large radiators in the main living space, one in each of the three beds, and a small one in the bathroom. We have a tankless gas hot water heater vented through the side-wall. In the last week, our Burnham boiler kicked the can officially and we need to replace the system. I've had oil people through, gas people through, and mini-split/ducted heat pump people through. The existing chimney is non-structural but runs through the center of the home and attic. We'd love to be able to eventually remove the chimney from the attic and use the space as a home office/bonus room (currently unfinished). We expect to be in the home 5-10+ years.

As I understand, our options are to replace with a chimney vented oil boiler, chimney vented gas boiler, or power vented gas boiler. We like the idea of using a power vented gas boiler as it would allow us to remove the existing oil tank and chimney, but are hesitant based on noise and safety, as it would vent basically directly outside our main living space. Cost is essentially all the same excluding the mini splits/ducted heat pump option, which was exorbitant even with rebates and likely need some sort of back-up heat option for cold snaps (for context, our neighbors home is the exact same structurally, and they had issues using heat pumps only this past winter). Is there anything that I've missed and/or any other options we could consider? Are our concerns over safety of the power venting option overwrought? I also feel with so many people turning to heat pumps, the technology in a few years will be cheaper and better, so would just kicking the can and replacing with another oil boiler potentially make sense? Thanks in advance for the help!

ethicalpaul

Homeowner perspective here.

First, what kind of gas? If it's propane, just keep the oil (as much as it pains me to say it). If it's natural gas, switch to that, no question.

If you end up keeping the oil, you'll have a power burner like you do today I assume.

If you go with natural gas, I greatly prefer the quiet and simplicity and efficiency of an atmospheric boiler, but as you say, you'll have to keep the chimney and line it I think if you go that route.

My favorite personal solution would be to install a ground-source water-to-air heat pump and get nearly free A/C and year-around efficiency and comfort (after you install ducts of course, that is some money). You'll be able to get rid of the chimney and the operating cost will be less than or equal to natural gas (I've done it).

Yes you'll have to pay for a well about 500 feet deep, but your house it so small it will only be about 3 tons or less. I used a 3.5 ton to heat and cool my 2000 sq ft expanded cape that had air in the walls.

Seriously consider it. Ground source equipment in a closed loop is completely safe for you, the environment, and it lasts 20+ years with no maintenance. Try that with oil.

apaul1018

It would be natural gas. As much as I'd love a ground source solution, a ground source/geothermal contractor told us we don't have the yard space to drill a well (we live in an inner suburban area). The cost of fixing and lining the chimney essentially equates the two gas options, which is why we're leaning towards the power vent. It would be a Burnham PV system if that helps at all.

TonKa

If you already have a gas fueled tankless hot water heater "vented through the side-wall", what would cause you look at a power vented boiler differently and become hesitant about safety now?

ethicalpaul

OK but here's mine going in my driveway in Norwalk, CT city limits

After they covered it up you'd never know it was there (there's no wellhead)

Jamie Hall

There's one major problem with that heat pump option: you will either have many minisplit heads, which I'm not sure is an option with a ground source unit, or you are going to have to have all new ductwork or low temperature radiation installed (the steam radiators would be hopelessly inadequate). That doesn't come cheap.

In principle I like ground source heat pumps as well as the next guy -- but not for replacing a steam heating system in an existing structure.

ethicalpaul

Yep I mentioned that in my post

Steamhead

@apaul1018 , I'd strongly recommend simply lining the chimney and keeping it. Reason is that power-venting adds moving parts, which always seem to break down on the coldest day of the year. Why ask for trouble?

I'd also recommend natural gas over oil, since this reduces (but does NOT eliminate) the maintenance factor. We like to install Weil-McLain SGO boilers with Carlin power gas burners, for their better thermal efficiency when compared to the usual atmospheric gas boiler.

random12345

@apaul1018 I'm just outside Boston. Have you calculated the EDR of your installed radiators? With only 6 of them, that may place an additional constraint on what boiler you can choose.

Gas is almost certainly the way to go. Out of curiosity, I was looking at our rates: electricity from Eversource is currently $0.40398/kwh, gas from National Grid Boston is $2.0194/therm, and the least expensive heating oil from a full-service company that I've found is $3.64/gallon but average is $3.96 statewide, which comes out to $2.65-2.88/therm compared to gas. In addition to its higher price, oil is less and less popular. According to ACS Census data in 2015, 29.3% of MA households used it (746,949), and in 2021 that number had dropped to 24.4% (662,896). Our oil company told me we had to wait a month for non-emergency service recently. Heat pumps would need an average COP of 4.8 to achieve cost parity with an 82% efficient gas boiler at these prices. I don't think current air source heat pumps can come close to delivering that. I've heard some people recommend replacing a broken or worn out A/C with a heat pump, the idea being that it can provide cooling in Summer and heating in the shoulder seasons, but with these prices it's actually cheaper to just use the gas boiler.

apaul1018

Thank you all for the comments. Strong math from @random12345. There are a total of 8 radiators I believe including some small ones tucked into corners on the main level. Not sure of the EDR. We are going to move forward on the natural gas conversion as it leaves us with the most flexibility moving forward with the house and seems to be the best option overall. Will look into a ducted heat pump (air or ground source) maybe in a few years when hopefully the technology may be better and/or cheaper. I always viewed it as a supplement to the steam/gas vs. full replacement. The cost quoted to us by a contractor for both the gas boiler and heat pumps was just staggering ($K-$K, before rebates), so taking it in steps. Having National Grid out to resize the gas meter next week and hopefully will have heat again soon!

Steamhead

@apaul1018 We do NOT discuss pricing on this forum. You need to edit the prices out of your post.

random12345

@apaul1018 Calculating the EDR of your radiators is necessary to properly size your boiler. Happy to help with that. I'm sure I'm not the only on here who would be either. Digging through old radiator trade catalogs is fun! The more of a challenge it is to identify what you have, the better.

ethicalpaul

There's no need. It will be the smallest boiler they can find.