Converting from oil to gas Eastern PA

The very first thing you should do is to get someone (possibly us) to do is a heat loss calculation to size your new boiler properly. If you can tell us:

1. the date of your recent $1000 oil fill

2. How many gallons it was

3. The date of the previous fill (so we know how long it took to burn that quantity of oil)

4. Nearest city (so we can look up climate data)

Knowing that, we can calculate how many BTU/hr your new boiler will need to supply on a "design day," which represents the 99% coldest day of the year in your area.

Having said that, your current boiler is probably in the right ballpark for an 1890's farmhouse which is likely poorly insulated with leaky windows. But if the house envelope has been insulated and air sealed, with improved windows, then it's possible your existing boiler is oversized.

But if your $1000 oil delivery was, say, 285 gallons @ $3.50/gallon, and that was roughly one month's worth of heat/hot water, I'm guessing your house is fairly leaky and poorly insulated, which could mean your existing boiler may be in the right ballpark size-wise.

Also, given your current setup in which the boiler is heating domestic hot water through a tankless coil, that is typically a very inefficient setup in which drastic efficiency gains are possible, particularly by installing a highly efficient boiler like one made by Energy Kinetics (EK). Energy Kinetics boilers are extremely well engineered and extremely efficient. They're also pricey, but if you can afford one, I would highly recommend it in your situation. Depending on how inefficient your current boiler is, it's entirely possible you may cut your energy use by 35% or more (on a total BTU basis).

Here's the Energy Kinetics website. Their president @Roger occasionally posts on this forum and can direct you to a local rep who can answer questions and perhaps recommend a local installer who's familiar with EK boilers.

https://energykinetics.com/

I am not a heating pro, just a homeowner/mechanical engineer with two oil boilers that I maintain for our 4-unit condo building. I have no agenda, just trying to help homeowners like myself. But if I were in your situation, looking to stay in a "forever home" and looking for a very efficient, reliable, long lasting boiler, an Energy Kinetics boiler would be number one on my wish list.

So if you can start by answering the questions I posted up top, we can help you get an idea of what size boiler you'd need.

Get a blower door test done. Then you will know where the leaks are and can deal with them.

Tightening the envelope has the greatest return on investment. Now you can go with a smaller boiler and burn less money.

Did that boiler run 24/7 in cold weather or cycle on / off?

It's the end of the season, concentrate on improvements 1st.

Energy costs like those you are dealing with really put a damper on living in an old house. (I own a 1700s farmhouse with 1800s addition…I get it).

The replacement windows will be helpful. The rest is part of the journey to bring the energy bills down to a far less painful point.

Would you post a picture of the exterior of the house (to better see what you’re dealing with)?

There's not much you can do about the lack of insulation in your walls without spending a lot of money and often not getting the results you hoped for, but fixing drafts can do a lot to lower heating costs and improving comfort. But, to fix 'em, first you gotta find 'em. I have a low-cost, low-tech method for doing this.

Close all your windows and outside doors, get some insense sticks, light one and walk around the house trying to detect air currents. You don't need to do this in the winter. You can wait until it's warm enough to do whatever work you might need to do on the outside. For best results, do it when no one else it walking around the house disturbing the air. Patience is key. If you try to hurry, it's easy to get frustrated and confused.

When you detect moving air, keep moving towards the source where the air is either coming into the house or exiting, so be aware of which way the wind is blowing outside. Since it's usually easier to find where air is leaking into the house, you may need to repeat the processs over several days where the prevailing wind direction is different.

When you locate the source, you just need to figure out how to address it. Sometimes it's just a matter of some caulking; sometimes you need to replace or install some weather stripping; sometimes you need a new window or door. Do the easy/cheap stuff first, then prioritize what's left.

Please… before you spend close to a grand on each "new modern window" (if you're spending less that that, you aren't getting a product as good as what's there), listen to @Hap_Hazzard and make sure you are fixing a problem. Those double hungs, with a small amount of work, can be made quite tight, and replacing the outside storm sashes (I think that's what I'm seeing?) (which, I agree, are a first class pain) with quality interior storm windows (I use this outfit:

Interior Storm Windows For Older Homes, Churches & Buildings

but there are others) will do the job — and last.

Speaking of new windows, one of my neighbors discovered that it is possible to purchase Pella windows without going through an installer. I'm not sure who he had to talk to (but it definitely wasn't the installer) or if it's possible to get Andersen or other brands this way, but if you end up needing new windows, and you're capable of doing the work yourself, look into it.

We had our 100-year-old double-hung windows professionally weatherstripped with spring bronze seals on the sides of the sashes, and silicone rubber bulb seals at the top, bottom, and middle parting rail. With new sash ropes, the windows are better than new, and with conventional storm windows they seal just as well as new replacement windows.

So I am also an advocate for restoring and air sealing old windows. I can prove they seal just as well as replacement windows, because we live in a 4-unit building with two heating systems. One boiler heats the half of the house with the original, weatherstripped windows with storms. The other boiler heats the other half of the house where the owners replaced their old windows with new vinyl replacement windows. I track fuel usage of both boilers with ecobee smart thermostats, and both sides of the house use almost exactly the same amount of oil.

Yes, and that's common, because the boiler installers don't want to take the time to do the calculations, and they don't want to be blamed for insufficient heat. So they commonly oversize by a factor of 2, even 3.

The New Yorker CG50F has a DOE output of 117,000 BTU/hr, which is about 2x what you need.

The Bradford White combi at 199,000 BTU/hr is about 3x what you need, but it can modulate, so the oversizing isn't as bad. I'm not a boiler expert, so don't take my word for it, but I think most pros here will advise against installing a combi boiler.

One other factor to be aware of. Boiler sizing is typically done for a 99% low temperature condition, meaning 99% of the time, the temperature will be higher than what you're sizing for. But 1% of the time, the weather will be colder. And in extraordinary conditions, like a polar vortex day with high winds, the high winds can add 40% to your heat loss. We had a brutal polar vortex 3-day event here in Boston in Feb 2023 (?) during which I monitored our boiler run times. Normally our building has a design heat loss of about 100,000 BTU/hr at zero degrees outside air temp. During that polar vortex, with near-zero temps and high winds, we lost almost 140,000 BTU/hr. That was a one-in-50-year record cold.

So, you need to be aware that, 99% of the time, sizing your boiler per my math above will match or exceed your house's loss at design temps, which is 11 degrees F for your area. But there will be some rare extraordinary cold events which will temporarily exceed the demands on a boiler sized per the above method.

Check the Philly area for old window restoration specialists. We have three or four such specialists in the Boston area. Make sure to ask if they use spring bronze air seals. If they don't, don't bother with them. The pros who do it right use spring bronze; the pretenders don't even know what spring bronze is.

This is expensive, possibly as expensive as cheap replacement windows, but after you do this, your original windows will last another 100 years, while cheap vinyl replacement windows will fail in 20 years.

Here's a video from one of the pros who does it right with spring bronze side seals and silicone rubber bulb seals at top, middle and bottom. You want someone who uses these materials, installed properly like this guy.

https://www.youtube.com/watch?v=TYAYnp4M_lM

Back on boiler sizing, I would look at the Weil-McLain CGa-3 or CGa-4.

https://www.weil-mclain.com/products/cga-gas-boiler-series-3

The CGa-3 is rated at 67,000 BTU/hr input, 48,000 BTU/hr net output. That would probably cover you for 99+% of the time, but on a rare design day with high winds, it will struggle to keep up.

The CGa-4 is rated at 100,000 BTU/hr input, 73,000 BTU/hr net output. 99.95% of the time that will be overkill, but on the once-in-50-years polar vortex with high winds, it will have the extra margin for that.

So a CGa-4 with an indirect hot water tank might be a good setup for you, or a CGa-3 if you don't mind the rare day when the house loses a few degrees because the boiler can't keep up with the high winds at single-digit temps.

The boiler cycling when at design conditions says oversized. The on time off time can give you a good idea by how much.

You can certainly go the high-efficiency modulating-condensing route. But you should be aware of the tradeoffs. You will get somewhat higher efficiency, but only if your mod-con is piped and programmed correctly with outdoor reset to run as low water temps as possible in order for the boiler to condense. And mod-cons are less reliable, fail more often, and will probably need replacing sooner than a plain cast iron boiler.

You can read hundreds of threads here about the potential pitfalls of mod-con boilers here and decide for yourself whether they're worth the additional cost and headache of maybe 10-20% better efficiency, assuming they're set up correctly, which they often are not.

After reading all the tales of mod-con woe from homeowners, my own personal conclusion is that I'd rather lose the maybe 15% efficiency gain in exchange for a plain, dumb cast iron boiler that will last maybe 30-40 years with minimal maintenance.

Or an Energy Kinetics non-condensing which will be higher efficiency than a conventional cast iron boiler, but doesn't have the headaches that come with condensing.

That's just my 2 cents. You'll have to make your own judgment on the tradeoffs. Just keep in mind that with your envelope upgrades, most of the time your heat loss will be under 40,000 BTU/hr, so you're not going to be using a lot of gas anyway, and the less you need, the less you save from higher efficiency, so you get diminishing returns.

Yes, gas should be cheap in PA, so you won't save much on a 10% efficiency gain.

No, mine's natural gas. At least have someone take a look at it. I thought my boiler was on its last legs the first time I blew down the LWCO and saw all the rust and junk that came out. That was 25 years ago.

Based on what you have said so far, it looks like:

• you have your forever house;
• you’re leaning towards natural gas (over the existing fuel oil);
• you are committed to significantly reducing the energy load of your house;
• your existing boiler is keeping you comfortable, but the cost of operating the boiler with fuel oil is what is causing the pain;
• you have concerns about the existing boiler’s longevity.

I strongly suggest that you consider moving forward with scheduling the energy audit, as well as establishing a relationship with an HVAC contractor whom you can trust and work with over the years.

I have learned (as a tradesman & as a homeowner) that the relationship with and the quality of the installing contractor is second in importance only to having clear goals to communicate to your contractor. This is especially true with the goals that relate to the HVAC system(s) for your forever house.

The energy audit should be a powerful tool for both you and your HVAC contractor. Choose the auditor well, leave plenty of time for him\her to perform the audit, and be sure to tell them what it is that you want to get from the audit.

@Ghynes440 Watch the fine print on that calculator - those are July prices conveniently, which are misleading. Obviously Peco built the calculator and know what they charge, so they consciously picked a summer month with outdated delivery costs instead of keeping it updated. Current peco rates are, at least from an online search is:

$15.70/month

+ $.68/ccf delivery

+$.59/ccf commodity cost.

+ whatever other fees they tack on. So they’ve misstated the savings by several hundred.

The issue with a gas utility (and I have a gas connection, no oil) is that they keep raising the delivery costs. You can have dirt cheap gas molecules but they’ll get ya with the shipping and handling. So conversion might look like a ten year payback, but as those flat fees are tacked in future years on it becomes a trap.