Propane usage - sticker shock

[DHT]Osiris

Lifer
Dec 15, 2015
14,004
12,069
146
Just moved into a new place in Oct (owned by the in-laws), and got our first post-initial fill bill for our Propane (so normalized usage throughout the month) 453 gallons for $1,300 or so. I've been running some numbers and I'm not quite sure if this is supposed to be reasonable or not, hoping someone in here can shed some light for me.

House is ~3100 sq ft, most is single floor with an upstairs area (outside entrance) consisting of about 1100 sq ft. We kept the heat off up there (baseboard radiant heating). Downstairs uses radiant in-floor heating (not in-slab I don't think, it seems to be one of the misc 'concrete-on-joists' configurations... could be wrong). 3 zones, the one we spend the least amount of time in was set to 60, other two zones to 65. Outside temps were generally in the 10's-30's all month, giving me an average delta of around 45F.

Boiler is a Weil-McLane Ultra 105, rated at 105k BTUs, at 92% efficiency.

If I've done my math right:
435/30=14.5 gal/day...
14.5*91,000 BTUs=1,319,500 BTUs/day...
/24=~55,000 BTUs/hr...
*92% efficiency=50,580 BTUs output...
/3300 sq ft = 15.3 BTUs/sq ft. average.
/2000 sq ft = 25.3 BTUs/sq ft average

I have no idea if that is considered to be efficient for either number, the closest I could find is this page stating that .1 BTUs/hr/sqft/degreeF is great, .3 is good, .6 is fair, and 2 is bad.
https://www.radiantec.com/wp-conten...diant_Heat_Design_and_Construction_Manual.pdf (page 3)

Per the above values, with an average delta of 45F, I have the following rough numbers:
.34 BTUs/HR/sqft/degree delta for 3300sq ft
.56 BTUs/HR/sqft/degree delta for 2000sq ft

Note that the above is a bit higher than reality due to us having a hot water heater eating a little gas, as well as incidentals from a gas stove, and dryer. I'm assuming that the vast percentage (>90%) of the fuel is being used by the boiler however.

The reason I keep separating out the sq footage is that although we have the heat off in the upstairs 'apartment', there's a few air pass-throughs (presumably for heating assistance and cooling upstairs) so I'm assuming I'm heating that space as much as I am downstairs. Place also has very high ceilings in the living/kitchen area, so there's a lot of cubic footage of air to heat. Energy company confirmed there's no leaks in the system.

Note that since the above sticker shock, I turned the radiant heating down to 50 on all zones and we've started leaning very heavily on our pellet stove instead (I assumed it would be less efficient, it's apparently far more for what we're trying to accomplish).

Does this all seem out of bounds? Should I be looking at upgrading insulation/doors and windows to improve efficiency? Or am I just stuck with a second mortgage now? Thanks!
 

herm0016

Diamond Member
Feb 26, 2005
8,385
1,011
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my parents have a similar house with forced air and they used propane, until NG was run down there street a couple years ago. built in the 90s, ~3000 sq feet with mostly unfinished basement, high ceilings and very exposed to wind. they only had to fill their tank 2x per year at 1500 gallons. in michigan. propane cook top, water heater and fireplace. 400 gallons for a month seems like a lot to me. should be closer to 100 i think. but i'm not an expert. i would see if your electric utility or city offer home energy audits at reduced cost. there are a lot of ways to increase your homes efficiency.
 

[DHT]Osiris

Lifer
Dec 15, 2015
14,004
12,069
146
my parents have a similar house with forced air and they used propane, until NG was run down there street a couple years ago. built in the 90s, ~3000 sq feet with mostly unfinished basement, high ceilings and very exposed to wind. they only had to fill their tank 2x per year at 1500 gallons. in michigan. propane cook top, water heater and fireplace. 400 gallons for a month seems like a lot to me. should be closer to 100 i think. but i'm not an expert. i would see if your electric utility or city offer home energy audits at reduced cost. there are a lot of ways to increase your homes efficiency.
Yep, we've got a heating/plumbing company coming out to take a look at things, to give me a better understanding of the system and ensure I'm grokking all this correctly, as well as ensure it's actually functioning correctly. All my co-workers (technically inclined) think it's completely out of control, and ensure me they're using a quarter or less of my propane a month for roughly equivalently sized homes.

The house is pretty new (one section built in ~2004, other half in ~2009), with mostly absurdly good materials. Owner was VP of a construction company, basically everything is top notch (all wiring for home + garage is inside stainless conduit, crazy expensive appliances, etc). Based on that I feel like I should trust that the home is insulated properly, but if I don't get good results from the heating/plumbing company, I'm buying a FLIR and turning that house into a bubble.
 

highland145

Lifer
Oct 12, 2009
43,242
5,685
136
Wonder if the tank has a leak. Soapy water...



Side story, friends came home to no heat. After a bit, they saw that someone had stolen their tank. The tank that had just been filled. Inside job, anyone?
 

[DHT]Osiris

Lifer
Dec 15, 2015
14,004
12,069
146
Wonder if the tank has a leak. Soapy water...



Side story, friends came home to no heat. After a bit, they saw that someone had stolen their tank. The tank that had just been filled. Inside job, anyone?
I'd be surprised if someone ran off with a full 1kgal tank, though if they wait a month it'll be half empty :p

I could check for a tank leak in the spring I guess (or a warm day coming up) but that'd surprise me, those things are built pretty solid aren't they? Not a bad idea regardless.
 

snoopy7548

Diamond Member
Jan 1, 2005
8,048
5,043
146
That seems excessive. I have a 1560 sq. ft. two story home with an unfinished basement and attached garage, built in 2012, with a 500 gallon underground tank in the Northeast. I use propane for heating, water heater, cooking, and the clothes dryer, and I've been averaging roughly 1.5 fills per year (a fill is only ~300 gallons). I keep my heat at 69F, but turn it down to 63F when I'm sleeping and at work. The house has pretty decent insulation, and I live alone.

You're paying a lot. I just paid ~$2/gal. for a fill, and the price has fluctuated between $1.6 and $2.3 since 2012, but my neighborhood gets a group discount.
 

Greenman

Lifer
Oct 15, 1999
20,281
5,054
136
That bill seems insane to me. At half of that I'd burn my house down and start over. Note that where I live it rarely get's into the 30's, so I might not understand the actual cost of keeping warm.
 

[DHT]Osiris

Lifer
Dec 15, 2015
14,004
12,069
146
The fittings.
Worth looking at. We've got some non-freezing days coming up so I might just do that.

That bill seems insane to me. At half of that I'd burn my house down and start over. Note that where I live it rarely get's into the 30's, so I might not understand the actual cost of keeping warm.
The trouble is most of the days during the 30 days that this was covering, it was fairly warm, highs in the 30's-50's, lows in the 20's mostly. We've got a lot of really cold days coming up in the next week or few which has me nervous, but I guess we'll just bundle up instead.

You're paying a lot. I just paid ~$2/gal. for a fill, and the price has fluctuated between $1.6 and $2.3 since 2012, but my neighborhood gets a group discount.
2.84/gal, not thrilled about it but the company also does some fuel cost discounts which help (nice filling up the truck for $20). I'll probably start shopping around and see if it's comparable. We're in the boonies so there's nobody to group discount with.
 

bbhaag

Diamond Member
Jul 2, 2011
6,604
1,990
146
That usage seems insane. Granted I'm not familiar with boilers but it seems something is not right if you are going through 453 gallons a month.

Just to give you an idea I have a 3000 sq. ft. greenhouse that is heated using propane with two traditional forced air furnaces. Each one outputs around 260K btu. I have a 1000 gallon tank that feeds them fuel and on average I fill it up once a season which is about two and a half months. I'm located in Central Illinois so my temps are very similar to yours. My greenhouses roof consist of two sheets of 6mil plastic filled with air and the side walls are polycarbonate. I believe the R factor rating for them is between 3 and 5.
My propane bill for that 2 and a half months(from late February to the end of April) is only around $800.

Hell man our 4100 sq. ft. home built in '08 has two HVAC units and is only averaging around $220/month on NG with forced air and that includes electricity.

Like others have mentioned you might have a leak somewhere along the line. When you walk around the area where the tank is buried do you smell anything funny? Something that smells similar to rotten eggs?
 
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[DHT]Osiris

Lifer
Dec 15, 2015
14,004
12,069
146
Like others have mentioned you might have a leak somewhere along the line. When you walk around the area where the tank is buried do you smell anything funny? Something that smells similar to rotten eggs?
Negative, and the energy company came out and did a leak test as well. It's possible the tank is leaking (I don't spend much time around that area), I'm planning on going out with some soapy water and checking today.

Your energy usage is what I was expecting to see, maybe a bit less since it's radiant. Glad to hear I'm not out of my mind.
 

dphantom

Diamond Member
Jan 14, 2005
4,763
326
126
That usage does seem high. I would expect usage to be around 100-150 gallons per month, perhaps a bit higher depending on weather, insulation, etc. But 450+ gallons in a month is definitely an outlier.
 

[DHT]Osiris

Lifer
Dec 15, 2015
14,004
12,069
146
30 days in, OP's house blew up.
I can confirm that I did not, in fact, blow up.

In fact, I think I'll make this my new 'Adventures in home efficiency' thread.

Had tank and lines checked, no leaks. Had boiler checked, it's fine as expected. Bought a FLIR attachment for my phone (FLIR ONE, highly recommended, about $300 on amazon), and went to town with the house. Found several 'cold spots' that were obvious to me, so went playing in the attic finding all the places where mice had dug away/jacked up my insulation and fixed it, got some benefits out of that. Bought caulk, caulked up tons of places inside the house where there was air leaking in, as well as outside. Caulked all windows to seal the top half (I'd rather wash them externally than have air blowing in the house). Did some additional weather stripping of doors, as well as placing some blankets and whatnot in front of extremely leaky ones (buying some door snakes to make that more permanent).

Those steps got me from ~10gal of propane a day to ~8gal, not bad.

Got a free home efficiency audit done yesterday. He identified a few more things. For one, we've got ~12" of fiberglass insulation in the attic, he said realistically that should be replaced with cellulose blow-in or spray foam (upstate NY). I'm opting for cellulose since apparently rodents can't handle it, and historically the house has had mice. The cats have found two since we moved in, I haven't seen/heard anything since then though. He also identified via a FLIR one entire wall, probably a good 30-40' with a ~8' wide fireplace in the middle that's just *not insulated*. Said that's surprisingly more common than you'd expect. I didn't realize what I was looking at via my FLIR, but now I know what to look for regarding that specifically.

Finally, and this I think is the big one, the slab itself isn't insulated in any way. He said it's normal procedure, when installing radiant heating or building a home with the intent of installing radiant heating, to create some kind of insulation barrier around the slab, or at least insulate the air gap below the floor where the radiant heat pipes are installed (that gets you ~4" down). That was never done with this house, which he was able to conveniently point out yesterday as we had just gotten a fresh snow. Snow was not only receding back from the house, and dirt was very soft. Also evident by the blue line you can trace around the outside walls/floor barrier of the house/ Basically all the heat is being leached out of the house into the ground. He suggested that they have a method of fixing that, via trenching a gap around the slab, and dropping in an insulation barrier (some kind of layered mix of plastics, foam, metal, and concrete or something).

Getting a quote for both of the above, as well as one or two other obvious issues (one ~8" strip of one side of house has no siding, leaching warmth out, and a stove pipe not attached to anything in an uninsulated joist gap in our second floor apartment).

EDIT: Forgot to say, we're also leaning very heavily now on our pellet stove. Got a ton from our local Agway, burning around 1-1.5 bags a day. I was under the impression originally that the flooring would be much more efficient than wood pellets, but apparently not (at least not yet).
 
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highland145

Lifer
Oct 12, 2009
43,242
5,685
136
Go home, boys, no stuff to be had.

;)

The FLIR looks really interesting but I might stroke out with how leaky my 80 y.o. house is.
 

[DHT]Osiris

Lifer
Dec 15, 2015
14,004
12,069
146
The FLIR looks really interesting but I might stroke out with how leaky my 80 y.o. house is.
You would, I promise. I was losing my shit about this house and it's only a decade old.

Having said that, I'm really glad I bought it. Really shows how obvious some stuff is. Examples included.
 

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highland145

Lifer
Oct 12, 2009
43,242
5,685
136
:oops:

I'd better wait. The new HVAC is going in ATM and my ass can't take much more reaming.