One month comparison: steam radiators to underfloor radiant

SteamtoHotWater

A little over a month ago, I finished installing my mod/con combi boiler. I also ran PEX through my first and second floor joists that connected to aluminum plates. My previous heating was a 1972 steam boiler to cast iron rads. I also had a gas 40 gallon water heater.
The day of reckoning has arrived - my energy bill came in! There’s a huge difference in cost and efficiency. In fifteen or twenty years I might even make up what I spent in savings ; )

Now, my old system was in serious need of a tuning. My neighbor has nearly the exact same house and heating system and they were spending about 15% less per year. But I really wanted to move on from steam and radiators.
More than anything, the house is just so much more comfortable than before. We’re walking around barefoot. And, the heating is just so even. With the radiators, the upstairs was always five degree warmer than the downstairs. Now, we keep the bedroom much cooler and the downstairs nice and toasty.
One unforeseen consequence - the basement is really cold now. I never realized just how much heat the old steam boiler was putting out down there. It's not a big deal, it's an unfinished basement and we don't hang out down there. Just something I had not anticipated.
I was in way over my head and in plenty of despair at times. Huge relief now that it’s done. Though, I still have a ton of cosmetic things that need to be done.
Could not have done it without this forum. I’d been lurking for a couple years and finally started asking questions and planning over the summer. You guys really helped out a clueless homeowner. I’d buy everyone a round if I could. Thanks again.

EdTheHeaterMan

I’d buy everyone a round if I could. Thanks again.

We are all visiting this winter for that drink, @Erin Holohan Haskell can use your IP address to find your location.

JMWHVAC

Nothing beats in floor radiant for comfort except the good old woodstove!!

Steamhead

The question we need to ask is, since you say "my old system was in serious need of a tuning" is, how much money could you have saved by fixing the steam? Your 15% is certainly possible, since some of our customers have saved over twice that when we fixed their steam systems. And the ROI would have been much better.

SteamtoHotWater

EdTheHeaterMan said:

We are all visiting this winter for that drink

Lemme know where.

Steamhead said:

The question we need to ask is, since you say "my old system was in serious need of a tuning" is, how much money could you have saved by fixing the steam? Your 15% is certainly possible, since some of our customers have saved over twice that when we fixed their steam systems. And the ROI would have been much better.

I definitely considered it. My neighbor (the one with the near identical house) got a new steam boiler this past spring. Both our boilers were over fifty years old. He was doing 15% better than me before the new boiler, and he might eke out a little bit better performance this year. His installer was going to knock off several hundred on the installs if we went in together. And the installer had an idea or two to improve performance and the upstairs/downstairs disparity. My neighbor's install cost a nearly 30% less than what I spent. And it was done in four days by real professionals. And his boiler might last another five decades. He's really pleased.
But, like I wrote earlier, I'm was done with steam and radiators. It's a small house and the rads took up a lot of space. Now I can move both my desk and the couch where they logically belong ; ) The heat never felt all that even - warm near the radiators, colder farther away. And I was fairly confident that a new mod/con and underfloor radiant would be much more efficient than a new steam radiator.
Problem was, I couldn't afford to have pros do all the work for an entirely new system. At first, I thought I'd just do the grunt work, i.e. demolition, running PEX and screwing in plates. But the forum gave me the confidence that I could do all the work. Well, confidence isn't quite the right word - gave me the "hope" that I could all the work.
It definitely would have been significantly less expensive to stick with a new steam boiler. And much, much less work. I would never, ever, do it again. The extra money was well worth it. I don't know if I can say the extra time and my labor was "worth" it. It's hard to make that calculation. Regardless, especially now that it's mostly done, I'm glad I went with underfloor radiant.

hot_rod

Reducing the temperature of the medium used to carry the heat is where fuel costs get reduced. But not much you can do with steam. If you are running condensing mode you get the extra energy recovered from that mode.
If you can heat with 120 or less you are in an ideal temperature range. It's the return temperature to the boiler that allows the condensation.

GroundUp

My last bill was also close to half of last year's and I changed nothing. So there's that.

Hot_water_fan

@GroundUp yeah you have to compare therms/HDD. $ change constantly so can mislead. I remember someone complaining here that their new modcon was only saving them 30% because they got lied to about their heat loss and their therm price increased. 

SteamtoHotWater

GroundUp said:

My last bill was also close to half of last year's and I changed nothing. So there's that.

Shockingly, in my area, natural gas is cheaper this year. That's why I wrote, "There’s a huge difference in cost and efficiency." Had the price of natural gas remained the same as last year it would have been $133 vs $218.

GroundUp

My point was that it's much warmer outside this year than last year. Fewer BTU required = less fuel and therefore lower cost. Unless you're actually metering your BTU usage, the gain in efficiency is a guess at best.

JUGHNE

When you put the HDD and therms used in the equation, that should cover any outside temp factors.
Price of gas is not one of the factors in this analysis.

It's like MPG, you may have a new car but you still do the math with the gallons used for miles driven.

Seems like one of the times where "You have to follow the science"

Hot_water_fan

My point was that it's much warmer outside this year than last year. Fewer BTU required = less fuel and therefore lower cost. Unless you're actually metering your BTU usage, the gain in efficiency is a guess at best.

It is where you live? It's colder this year vs. the previous 3 years, but...slightly. '23 is only 9% colder than the warmest year, 2020. I find my memory of which year was colder always wrong. Thankfully the data exists.

SteamtoHotWater

GroundUp said:

My point was that it's much warmer outside this year than last year. Fewer BTU required = less fuel and therefore lower cost. Unless you're actually metering your BTU usage, the gain in efficiency is a guess at best.

I don't understand your logic, but perhaps I'm missing something.
For my area, the temperature has pretty much been the same - 970 vs 950. And then my billing shows you the therms over degree days. Seems like pretty good evidence of improved efficiency.
I guess it doesn't show you what I set my thermostat to. Perhaps last year I had it at 80º and this year it's at 60º.

SteamtoHotWater

Another month, another bill.

Still pretty happy with the results. I promise this will be my last update. At this becomes the norm, I'll be less giddy. And the results in May won't be as interesting.