Data Analysis Needed (Insulated heat pipes in basement)

I'm not sure you'll be able to gain much info from this to conclude difference between before and after insulating pipes.

If you could measure how much fuel you burned before and after….on exact weather days, that could tell you something. In general, I see about 8 thermostat cycles in 12 hrs (blue line) when is 5F outside. What is the 99% design temp? It looks like you could turn the supply water temperature down to smoooth out some of the peaks/valleys in red and blue lines.

I'm doubtful that insulating the basement pipes is helping much. In our 100-year-old 4-unit condo building in the Boston area, we have two oil boilers in the unheated basement, along with the original uninsulated gravity conversion hot water piping.

The basement ceiling is not insulated, so the exposed subfloor planks in the basement and the oak strip flooring in the first floor are basically at the basement temperature, which hovers around 60 degrees. This means that all the flooring on the first floor is losing a lot of heat into the basement. And the colder the basement, the higher the heat loss through the floor.

So if your building has similar construction (ie no insulation in basement ceiling, and wood subfloor/floor above), you're in the same boat. The colder the basement, the more heat you lose to it through the flooring.

So for every BTU you save by insulating the pipes, you'll lose some fraction of that BTU through the first floor back into the basement that's now slightly colder. I don't know what that fraction is, but it could be large enough to make the juice not worth the squeeze.

@josephny I don't think you're interpreting your data correctly. Before insulating, your boiler was running about once per hour. After insulating, your boiler was running…once per hour. Look at the actual room temperature lines (blue and red). They follow the same 1-hour periods before and after.

Trust me, I've done the same kind of temperature monitoring/graphing/boiler run time analysis on our building, and it's easy to fool yourself into thinking some tweak you made is suddenly saving you a lot of energy.

The best possible data "collector" you can get is an ecobee smart thermostat that records boiler run times. Using the beestat.io interface on the web, you can collect detailed stats on daily, weekly, and monthly boiler run times. Because your oil-fired boilers run at a fixed input rate, you can calculate exactly how many gallons of oil you burned based on the ecobee's run time data. In our case, each boiler burns 1.2 gallons per hour of run time. I check our ecobee data from the beestat.io website at the end of each week, and I log the weekly run time totals. I now have 1.5 years of weekly run time data, plus 10+ years of oil consumption records.

Things I've learned the hard way:

(1) the effect of changing weather will overwhelm your ability to parse out minor energy savings from, say, insulating basement pipes. Wind effects alone can increase our building's heat loss by up to 40% on any given day. So even when you try to compare boiler run times from days with the same outdoor air temperature, a 10 mph difference in wind speed will have a major effect on boiler run time. So you'll imagine you just found a 20% energy savings. No, it was just less windy that day, sorry.

(2) you only really know you saved energy at the end of the year when you add up the total run time. Our total run time is about 30,000 minutes per boiler per year, or 60,000 minutes total for two boilers. That's 1,000 hours, or 1200 gallons burned at 1.2 gal/hr. But then you have to adjust for the number of heating degree days (HDD), which will vary annually. There will also be some variability due to wind effects, which are impossible to quantify because the HDD data does not account for wind effects. So even after you correct for annual HDD's, there will still be a difference from wind effects that you cannot quantify.

(3) the net result is that, even after you have 2 years of ecobee run time data, you will still not know how much of the annual difference was due to your building envelope improvements and how much was due to variable wind effects. In our case, I have 10+ years of oil consumption data because we kept records even before I installed the ecobees 2 years ago. So I can see that our combined attic insulation and window upgrades several years ago did produce an average of about 10-15% savings in oil consumption averaged over several years. But any smaller improvements in the building envelope are basically invisible in the data.

So, my best advice is: (1) get an ecobee thermostat and use the beestat.io website to log weekly boiler run time totals, (2) you will not be able to see any real (vs imagined) energy savings without having years of data logging or oil consumption records for baseline comparison and without subsequent major improvements to your building envelope like large-scale air sealing, insulation, window upgrades, and (3) any minor energy savings you think you see without doing the above will be mostly or entirely imaginary.

Great, you have all the data you need. But you still need to interpret it correctly. The boiler is still firing about once per hour, according to the boiler temp sensor. So insulating the basement pipes didn't change anything measurable in that data set, and I wouldn't expect it to. At most you might see a few percent savings at the end of the year, and then you'll have to decide how much of that percent change was due to HDD's variation, how much was due to wind variation, and how much (if any) was due to whatever insulation/airsealing/etc you did before or during the heating season.

Yeah this casual comment about insulating a door really concerned me too.

Is that double wall (B vent) or is that single wall vent?

That's single wall.

In the earlier picture you can see where the foam melted.

Get that foam board further away also.

To determine air leakage you can have a blower door test performed. It would be good to know what the air leakage number is in the home.

Also the test can usually identify where the leaks are, around doors and windows, framing to foundation, etc. Then you can seal areas increase comfort and lower heating and cooling costs.

There are mechanical ways to direct air to the boiler if the basement gets sealed tightly.

foam is give 12” above.

You could use concrete board or any other fireproof material. Is it worth the expense? Personally I don’t think so. That opening is peanuts compared with all the other leaks you gave.
As said by @hot_rod

Blower door test to know how much and where.

The way that vent pipe looks, it may be corroded to the thickness of paper. I've seen it happen. Might be wise to check it for soft spots and replace if you find any.

The ripples that you reference, I believe this is the boiler cycling on and off.

The thermostat cycles about once every hour. But the boiler firing on and off is more frequent. When thermostat calls, Boiler fires ~15 minutes, off 6 minutes, on 7 minutes, off 6 minutes, on 4 minutes (Thermostat call met), boiler off ~30 minutes, thermostat calls again. This is with outside temp 23F. @josephny mentioned this sensor was near boiler exhaust.

@hot_rod mentioned concern for short cycling based on exhaust vent corrosion. Could these ripples be a sign of short cycling, one could argue it is. @josephny would have to confirm with onsite eval.

I'm not suggesting that a failing exhaust is causing the variations in the black line.

In the new graph you sent, it looks like the red thermostat is calling for heat constantly between midnight and 0900. And (if i'm interpreting the black line correctly) it looks like the boiler is firing about 50% of the time when the outside temperature is 0F. If 0F is the design temp, your boiler is roughly ~50% oversized.

At 0F outside, your boiler firing is going through its usual cycles ~ 6 min on, ~6 min off. It reaches the high limit on the aquastat and stops firing for ~6 minutes. AFter a few minutes (4-7 minutes in your case) the boiler temperature drops enough to meet the differential temperature setting of the aquastat and the boiler fires again. Some aqua stats have an adjustable differential, and setting the differential larger will increase the boiler cycle times. @fentonc had an interesting, very detailed post about it recently. I'm not suggesting you follow all of those steps.

Here's my analysis: the temperature of the basement doesn't seem to have changed much after the pipe insulation was put on, it seems to still be in the high 50's. As such, there's no reason to believe that the whole house heat loss has changed at all, so I wouldn't expect any impact on comfort or fuel usage.

burner on, since that is what is using the gas or oil.

A data logger on the electric supply would show electrical consumption, which is some of the cost of heating.