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DSL417 · 01-03-2020, 08:57 PM

I have seen this discussed several times, but thought I might offer some analytics on the amount of diesel burned by the aquahot in typical cold weather conditions. Being a meteorologist in a past life, I can tell you that the weather piece of this, as it relates to diesel usage is accurate as well, and not an estimate.

Location Bend OR
Tank filled Thanksgiving Day, 28 Nov.
Drove six miles to park.
From 28 Nov - 3 Jan (36 nights)
Temps: highest 53 (today and only two days over 50 for high)
Average high temp: 41
Average low temp: 24
Lowest temp: 12
Avg humidity levels around 60-70% in morning and 20% in Afternoons
Settings in coach: Zone 1 67. Zone 3 66. Zone 2 (floor): 84

Tank filled today 3 Jan: 114 gallons

Moral of the story: Just under 3 gallons of fuel a day. If it is cold and you are using AH for heat only, plane on filling that tank every 35-40 days. Note, with these temps, use of the overheads really wasn’t feasible, and our fireplace fan wa squeaking, so we didn’t use it.

Hope this helps for those of you planning on cool weather ops.

LWBAZ · 01-03-2020, 10:23 PM

Good info Dave - thanks for posting.

Obviously you're bolder than a friend of mine who lives by what he calls the 40/90 Rule of RV'ing:

If it gets down to 40, he leaves.

If it gets up to 90, he leaves.

DebbieMH · 01-04-2020, 05:41 AM

Great information, Dave! Hopefully y'all are ready to head back to LVMC now ... enough of that cold, cold weather!

brobox · 01-04-2020, 05:48 AM

Great detail info Dave. Thanks for posting that.

**Spdracr39** · 01-04-2020, 05:50 AM

That makes it very real world thank you !

bsaldeen · 01-04-2020, 05:57 AM

Super helpful, especially so since it was sort of worst-case scenario conditions (for me, anyway). I love the 40/90 rule too.

As an aside, it seems like it would be helpful if these rigs had a GPH meter on the tank. Seeing as there are two diesel-guzzling devices and no real way of knowing how much they are using. On the downside, one more thing to break. ;-)

KennyGolub · 01-04-2020, 06:19 AM

Let me pass on my thanks for that report.
Something I always wondered about.

.

Butte64 · 01-04-2020, 06:25 AM

Great information, thanks. Did you have the electric turned on the entire time? If you did not I think the fuel use would be significantly higher.

lwmcguire · 01-04-2020, 06:38 AM

I have found that the Tuscany 42GX Aquahot fuel burn to be very similar

When temperatures are above 30 and electric is included I switch to the heat pumps and the electric Aquahot is on continuous

It is expensive to camp in the cold temperatures

Gary.Jones · 01-04-2020, 06:53 AM

Most heat pumps do very little under about 42 degrees ambient. At 30 degrees, they are doing very very little to warm you. I have two 5 ton Trane heat pumps at my S&B and their external units are programmed to simply turn off the heat pumps and switch to nothing but strip heat at temperatures below 42 degrees. Our units in our coaches often work the same way. Now, I think that my VegaTouch is programmed to do the same thing if it sees an external temperature below the efficient heat pump temperatures.... it simply turns off the heat pumps and turns on the AquaHot blowers and system if the AquaHot is not already in the line (but it doesn't turn on the diesel burner if it is not already on, at least in my coach).

Of course, if I know the temps are going to go below ~ 40 degrees, then I try to always have the diesel fired burner "on" so that system is ready to provide heat.

Oh, and that is great data Dave. You probably know that I published similar data on AquaHot usage of diesel, but did it the opposite direction.... I timed each burn cycle, calculated the time the burner was actually fired and burning diesel, and what percentage of the hour the burner was burning fuel, and then multiplied that to get 24 hours. Your data is the opposite way to calculate it, but a very easy and clear way to look at diesel use per day. Thanks for the information.

Gary

Busskipper · 01-04-2020, 07:17 AM

Quote:

Originally Posted by DSL417

I have seen this discussed several times, but thought I might offer some analytics on the amount of diesel burned by the aquahot in typical cold weather conditions. Being a meteorologist in a past life, I can tell you that the weather piece of this, as it relates to diesel usage is accurate as well, and not an estimate.

Location Bend OR
Tank filled Thanksgiving Day, 28 Nov.
Drove six miles to park.
From 28 Nov - 3 Jan (36 nights)
Temps: highest 53 (today and only two days over 50 for high)
Average high temp: 41
Average low temp: 24
Lowest temp: 12
Avg humidity levels around 60-70% in morning and 20% in Afternoons
Settings in coach: Zone 1 67. Zone 3 66. Zone 2 (floor): 84

Tank filled today 3 Jan: 114 gallons

Moral of the story: Just under 3 gallons of fuel a day. If it is cold and you are using AH for heat only, plane on filling that tank every 35-40 days. Note, with these temps, use of the overheads really wasn’t feasible, and our fireplace fan wa squeaking, so we didn’t use it.

Hope this helps for those of you planning on cool weather ops.

Great post - a follow up would help - did you think about supplementing with small electric heaters? IMHO they really help. Using electric should help. We did 60 plus days one winter in Colorado (Low of -17 10 nights) with electric and Diesel only burning 25 gallons..........makes your $10 a day feel expensive, JMHO.

Quote:

Originally Posted by LWBAZ

Good info Dave - thanks for posting.

Obviously you're bolder than a friend of mine who lives by what he calls the 40/90 Rule of RV'ing:

If it gets down to 40, he leaves.

If it gets up to 90, he leaves.

Being from the Annapolis area that is very Boat Oriented its called Socks and Pants - If you ever need Socks or have to change from Shorts to Pants, it's time to get under way!

Most of the Captains (Yes in the Boating World they Hire a Captain to Pilot the Boat) use this rule as the time to start heading South, actually think many do not own Socks or Pants.

Again good info, Thanks for Sharing,

Gary.Jones · 01-04-2020, 07:25 AM

Sadly, the calendar date that one first feels the need to add socks and long warm pants (or long sleeve "golf" shirts rather than real "golf shirts"or flannel shirts), gets progressively earlier each year that I have lived, once past ~ 60.... The need for warm clothes is much earlier at my current age than it was at 60....

(guess I'm still breathing, so really can't complain.... that was not a certainty a couple of years ago. I just buy warmer clothes)

Gary

46490 · 01-04-2020, 08:07 AM

Quote:

Originally Posted by DSL417

I have seen this discussed several times, but thought I might offer some analytics on the amount of diesel burned by the aquahot in typical cold weather conditions. Being a meteorologist in a past life, I can tell you that the weather piece of this, as it relates to diesel usage is accurate as well, and not an estimate.

Location Bend OR
Tank filled Thanksgiving Day, 28 Nov.
Drove six miles to park.
From 28 Nov - 3 Jan (36 nights)
Temps: highest 53 (today and only two days over 50 for high)
Average high temp: 41
Average low temp: 24
Lowest temp: 12
Avg humidity levels around 60-70% in morning and 20% in Afternoons
Settings in coach: Zone 1 67. Zone 3 66. Zone 2 (floor): 84

Tank filled today 3 Jan: 114 gallons

Moral of the story: Just under 3 gallons of fuel a day. If it is cold and you are using AH for heat only, plane on filling that tank every 35-40 days. Note, with these temps, use of the overheads really wasn’t feasible, and our fireplace fan wa squeaking, so we didn’t use it.

Hope this helps for those of you planning on cool weather ops.

I have experienced the same type of fuel usage here in Utah. I called Aquahot and was told if I turned off floor heat and just used the Aquahot zone heaters the fuel usage would be less due to the fact whenever a door is opened the floor cools down enough to cause the burner to turn on. So I turned the floor heat off. I will update the difference if there is any in fuel usage.

DSL417 · 01-13-2020, 10:07 PM

In answer to one question, yes the electric was turned on.

Another point, didn’t use overheads because the amount of time above 40 where the heat pumps might be effective was relatively short each day, if at all.

Third point, yes we have electric space heaters, but we were renting by the month and had to pay electric...BTW, electric costs for that time period we’re just short of $150.

Finally, not using zone 2 for floor heat may save fuel, but the floor tile also heats up and radiates heat longer. My guess is using floor heat is a net positive.