This post is very confusing. What is your real question - why your propane bill is so high because your usage is up? Why your water bill is so high?

You are heating a 75-gallon hot water tank with propane and using some of the hot water for forced air heating and the rest for hot water usage. The hot water used for heating is returned to the hot water tank. Do I have this right?

Did you have the same set-up in the south as you do now in Virginia?

Do you think you are losing propane or hot water?

What are your propane costs? Propane, along with electric resistance, is one of the most expensive heating sources.

Sorry for the confusion! Yes, you have it right about the use. No, we did not thave this in the south. We had just straight gas furnace. As I said, our builder has this very same system and a large family and has 1/2- 2/3 our usage. After all these years, I only discovered the huge difference in our usage compared to his upon doing copious research about a separate repair and discovering the seemingly much less costs for electric water heating compared to propane here where we are. I am not addressing cost for propane but rather gallons used. Costs are indeed rising but that is a separate issue.
I am trying to find others who may have this system of heating to see what kind of usage they have. Two people should not have the gas usagae that we seemingly hav hade. There are obviously no leaks inside our basement becasue there is absolutley none of the noxious smaell, so whatever may be causing the usage has to be underground and inherent since the whole thing was set up.
Please shed any light you can for similar situations. Thanks!

It is very difficult to compare your propane usage against another home's usage. There are too many variables to consider including house type, size, age, insulation, thermo-stat settings, roof type, roof color, air infiltration, doors, windows, house orientation, etc.

Have you asked your propane supply company to check your tank and pipeline for leaks?

I am confused.

Did you say that you are using more gallons of propane now than you were one or two years ago?

Up here in the northlands, people don't use water heaters for space heating, because water heaters are substantially less efficient than space heating boilers, and don't last nearly as long.

Perahaps your water heater is becomeing less efficient due to sediment build-up. Do you flush the sediment out of the water heater periodically?

I said that we (just two) have been using consistently the same huge number from day one 15 years ago, and that our builder, with an equal or larger house and 4 children and who knows how many loads of clothes etc. I of course know that things vary because of many things. What I have been sayng all along is that the variables ALL point to his using much more than us and in reality we use much more than him. Or SEEMINGLY use;it may be leakage. The water heater is no worse than when it was brand new and yes we have flushed it. We are in VA so it is not the same as MN or somewhere. Using the same water that is already hot is a very efficient way to do it. And the water heater is going strong! They will be coming to check for leaks now that I know that my comparison family uses 1/2 as much as us. Keep the thoughts coming! At this point at electricity at a yearly average of 6.36 cents a KWH and propane at 2.50 a gallon, propane is so far bad that it is amazing....

IMO, you have potentially the most efficient type of heat, so if it is overpriced, I would look at the propane usage vs the cold days vs where you set your thermostat. A typical coil uses between 8-15 gallons per minute for a 40,000 btu coil. Figure out the amount of time the pump is running per hour on an average. Do this over a 24 hour period and note the temp glide for the day. Average the temp and the on time. This should be done for a mild heating day, an average heating day and a cold day. From this you can estimate yearly costs.

IMO, radiant heat is more efficient, but forced air can be acceptable. Consider using a couple of solar panels for assist in heating hot water. This would eliminate summer propane usage. If the water heater is adjusted proper, you will be at he best usage.

How large is your propane tank?

There is a gauge on the tank that reads %full (I think). Check the gauge and write down the reading and the date. This is a starting point. You can check it weekly to see if the gauge reading is dropping.

900 gallons over a 4 month heating season is 225 gallons/month. That gauge should be dropping like a rock if you really have a leak.

Another thought: Do you really know that you are getting the propane delivered to your tank that you are paying for? Do you check the gauge reading after delivery?

A propane water heater is typically 65% efficient at turning fuel into hot water. For a 15 year old water heater, I would expect lower than 65%

A propane fired boiler is typically 85% efficient at turning fuel into hot water.

From an operating cost perspective, making hot water with a boiler is cheaper than doing so with a water heater.

From a capital perspective, a propane fired water heater heating system is probably on the order of 1-2 K. A propane fired boiler with indirect hot water tank (to supply domestic consumptive hot water) is probably 4-6 K.

I don't think you can reasonably compare your house to the builder's without additional info. For all we know, he might keep the heat at 58 degrees, use a wood stove to supplement, have awesome state-of-the art insulation, great southern exposure/solar gain, or he might be inflating the truth.

We keep our house at 68, have a huge southern expsoure which roasts us in summer, run the dishwaher every other day, use only warm water for clothes washing, and the builder does not have a wood stove. Our tank is 500 gallons, I do check after delivery sometimes but not much, the water heater is 75 gallons, which is a lot of hot water. Running the water through the coils supposedly only cools it at most 15 degrees. Keep thinking! Thanks!

A co-worker has come up with another scenario. The hot water tank has a plastic cold water inlet pipe that goes down to the bottom of the tank. If this inlet pipe is broken near the top or in the middle, the flow path in the tank will be compromised. The water will not mix as designed, and there will be large temperature variations in the tank (especially a large 75-gallon tank). The propane burner may have to cycle much more frequently to maintain the temperature setpoint, resulting in significantly higher propane bills.

This last point by garyg is very interesting and I might really think that it has merit (and it might anyway) BUT the thing has been using this much gas since day one. Could that be at all possible???
The use of water that is already hot anyway has to be the best thing going but when I look at all the averages that I find, and granted every home is different, the "average for an LP water heater is light years less than our costs, as in a third or so. The builder says that the application we haev should yield the same effieciency as a high efficiency gas furnace, and when I check those "averages" and add them to the "averages" for a gas water heater, they still come up a whole lot less than our costs.
So, either the thing has been bad since day one (but it makes great hot water and no shortage of it) or we have had some kind of gas leak since day one. Whatever "it" is has been since the beginning. Logic says that a 5 year old water heater should be a lot worse at its job than the same one new....Half the proble is that this method of heating is so unusal to the average person and therefore there is not a lot of common knowledge.
IF one of the claim to fame SUPER gas water heater could actually be as energy effficient as they claim, they would be worth the monumental investment just to not be paying th gas company that much a year.
Please keep the thoughts coming. Someone is going to be the key to all knowledge about this.

"The builder says that the application we haev should yield the same effieciency as a high efficiency gas furnace,"

Could you tell us the make, model and year of your water heater, and describe how the flue gasses are vented? This will help us figure out how efficient the unit actually is.

State Censible 510E, model PRV75PRRTV6F, 1992.

It is vented up through our roof (2 stories). The air handler is First Company Aqua Therm.

Is it the brand of heater?? The company that makes State also makes the super pooper- scooper, Polaris, oddly enough.

We love the gas and have been told that an electric water heater cannot provide enough hot water for a dual application like this. Is this true? If it isn't then with our electricity costs so much less, it would be a no-brainer..... after buying a new heater of course.

Thanks so much for this info!

Have them install a flow meter - recorder on the tank's
supply line. This will tell you when, how much, and how
often you are using gas. This system can be left on for as
long as it takes. Up here the system you are using for heat is not permitted and illegal for the very same reason
you complain about. It also violates and cancels the U.L.
approval and all warranties. The tank is being used for other than what it was intended for. When the tank was connected did they remove the restrictors before soldering
the lines or leave them in and burn them off ? What is the
temp of your supply water to the tank ? Is it coming from a well at 36 degs. ? Was the gas valve on the tank checked
with a manometer to insure proper gas pressure to the burners ? If you have your tank water temp turned down to
140 or lower you have no reserve heat and your burner will
kick in immediatly when you turn on the hot water tap. When they installed the by-pass to service the pump, and there better be one, did they leave the valve open ? And it goes on. good luck

Can you here the burner firing frequently or for a long period of time?

900 gallons of propane per year x $2.50/gallon = $2250/year for propane = $188/month. Ouch.

Do you have central air or window units for a/c?

how hot is the water heater set? maybe you have a large standby loss.

75 gallons is not that big. we have an 80 gall heater at home and after my wife and i each get a shower and my daughter gets a bath in a tub only filled partway, there is little to no hot water.

maybe the hot water used is not returning to the heater, but instead is going else where, then the heater must reheat 1 gallon for every gallon circulated.

how much LP do you use during the summer? it should be less than the winter, if it is close then i would assume there is a leak. if the winter usage is drastically higher than the summer usage, i would assume that everything is fine.

as to comparing to the builders larger house, unless you run a manual J for both houses, there is no way to tell if his requires less to heat than yours. my parents house requires less to heat and cool than mine, even though theirs is 3-400 sq ft larger. the main reason is that their house has the long sides facing east-west and mine is north-south. their house requires a total of a little under 4 tons of HVAC, mine requires over 6 tons. that makes a HUGE difference in the amount of energy required.

have an energy audit done to determine if your have any air leaks and also have someone check your system for problems.

lastly, try turnign off the heater for a day. check your guage onteh tank, then check it again the next day to see if it moved. if it did, then you likely have a leak. my TANK leaks at times, the pressure relief valve on it started leaking and it occassionally will let off gas, but not enough to move the guage. i am waiting on the new tank to be delivered now, since they cannot repair this int eh field.

also, we have only a gas dryer at home. we have a 150g tank and have used only 180 gallons in 3 years, so i don't doubt that you saw little change after removign the dryer. and with only 2 of you, unless you cook alot, i doubt you would see much change after the removal of the stove either.

you say the gallons used has never changed, but what about the interval between fill ups? if you always call them when it gets to 10%, then you will always use the same amount of gas to fill it, but maybe instead of it being every 90 days it is every 120 days?

most folks i know with a forced air propane heater use around 200 galls a month during our winter. that means 600 gallons and we do not get that cold here.

Where is the air handler?
Do you have any ductwork up in the attic or in an unconditioned crawlspace?

The air handler is right next to the water heater and although the ductwork does go through the unheated attic, it is insulated.

So what do any of you know about using a super effiecient electric heater for this purpose? Is our plumber correct that this will not work? I would think that a large electric super high efficiency should be able to do it, but then I think something is very wrong here!

The house is new enough to have adequate insulation to put it in a different catagory thatn the ancient, drafty kind of house.

As I am researching, I have found the before mentioned Polaris- very expensive, the Apollo, and the Bock that claim to be hugly cost effective. Has anyone any experience with any of these? LP is not likely to go down in price and our electric kwh price is less thn many places, hence my question about switching to electric. There again, with only two people, a large tank should be bale to serve???

Thanks everyone!

I bet the problem is the attic ductwork.

I had "insulated" duct work running through my attic for my forced air heating system. There was a big trunk line that ran up into the attic through a closet. In the attic, the trunk line branched off into the various rooms with ceiling vents. It was leaky and in efficient, and there were no air return registers up there. IMO, trying to heat a room with a ceiling register is very inefficient. After I eliminated it, and increased the insulation up there, my gas (NG) consumption dropped by half. The insulation on my ducting (flex ducts) was a joke.

Might be a thought to check into, but we do have big return air vents upstairs, that also go through the attic, three of them.
That being said, ceiling registers are what we have, so does one just beef up the insulation covering the duct work???

I don't know the relative cost of electricity in VA, but there is a company in VA named Southern Refridgeration that installs electric boilers.

They are 100% efficient, will do you job you want, and are trouble-free with a long, long, lifespan.

I don't really understand the concept of heating water then using the hot water to heat air which is then distributed through the house with a fan and ducts. IMO, if one is using a boiler (water heater) to heat the house, one should circulate that warm water through radiators (or even better, radiant floors) to heat the rooms directly, and just leave the fan and ductwork for summer air conditioning.

If electricity is cheap, then electrical heating would be the lowest cost option. But using the electric boiler won't solve the problem of heat losses via the ductwork.
The ductwork running through the unconditioned space is prolly most of the problem. If it is possible to eliminate the heat ducting through the unconditioned space, that is the best option.

The ductwork is connected via the vents in the ceiling to the indoor air. The ducts should be totaly sealed in the undconditioned space to make them leak-free, and they should have the same level of insulation as is up in the attic. In my area, R-49 is recommended, which translates to about 25 inches of fiberglass batting.

I only offered another option for her to heat water for the coil, which is her desired way to heat.

The electric boiler is a good idea and may very well be cheaper than propane.

Greengirl, can you post your cost of electricity and what you are paying for propane?

Electricity is average of .0636/kwh and propane is 2.499/gallon..... :(

I listed another post asking for input on several high effieciency gas water heaters, in an effort to research something better- Polaris,Vertex, Apollo, and Bock. any opinions here?? By every calculation that I can come up with from every souce that I can find, electric would be MUCH cheaper. The issue would be if a large (and how large) electric water heater could replace our 75 gallon propane one. Plumber says electric won't work, but one thing I have discovered in this search is that people never all agree on anything. So opinions here too, please!

http://www.efmheating.com/electthermboilers.html

The largest model should heat a whole house.

So what was the diagnosis of the initial problem - high propane usage?

Nice price on electricity. I pay at least twice that.

Here are some numbers for you, based on your figures:

A kilowatt of electricity is about 3,413 BTUs, and is $0.0636, which works out to be 53,660 BTUs per dollar. Electricity is 100% efficient, meaning that there are no combustion losses that go up the chimney at your house.

Propane has about 92,000 BTUs per gallon, and is $2.50 gallon, which works out to be about 36,800 BTUs per dollar. Your existing water heater is prolly on the order of 60% efficient, which means that 40% of the BTUs out of a gallon of propane end up going up the chimney, and not in your house. As such, you are getting about 22,000 BTUs per dollar out of it.

If you went with a new water heater, such as the Polaris which is 95% efficient, you would be getting about 34,900 BTUs per dollar after combustion losses.

Based on your posted information, electricity would be about 65% the cost of propane for heating with a 95% efficiency water heater, and 41% of the cost of propane using your existing water heater.

An electric water heater won't work because they donÂt produce enough BTUs to keep up with the demand on the house. But an electric boiler might, depending on the model and how manu BTUs your house requires to keep it warm on the coldest day of the year. An electric boiler will require a lot of electricity, though, prolly on the order of 100 amps. A 200 amp electric service to your house would be the minimum needed to run the electric boiler.

You still need to address the ducting losses through your attic. If yours are anything like mine were, that is half the problem right there.

The largest electric boiler has a gross/net output of 102/89K BTUH, more than enough to heat a house in PA. Total amps, if all elements are working, is 125amps.

If that wouldn't be enough heating, 2 smaller units could be used and zoned.

Yes, the propane issue is the real crux of it. Too much money for too long!

The gas compnay came tody to check and the good news id there is no minute leak in the underground line. The bad news is there's no....... so the cost of gas witht his heater will be as high as it ever was.
I had a consversation with the original installer of this hot water heating system and was asking his recommendations about water heaters. he also says electric won't do as the do not put out enough hot water fast enough. (We are talking just WH here, not boilers.) So I asked his opinion of the several new high efficiency heaters and he said to avoid Polaris and Vertex because, while they are great effieciency wise, they are very bad reliability wise and parts(here) are hard to get. He did not know much about Apollo and had not used Bock. He strongly recommends Bradford White, which is what our plumber did as well, just as strongly. Seems they have a high effieciency 75 gallon one too, although thier efficiency is only 80%, but they are supposedly extremely reliable and part are readily available.....
Don't know what to do here short of replacing everythign to the tune of thousands- which is not what we'd like to have to do, since the AC is functioning well at this point. If we do have to do this, both the plumber and the original guy today said Trane heat pump, but we did not get inot models etc.
So more thoughts?? Replacement thoughts?? Thoughts for spells to fix this to a good end?? What kind of energy use do the electric boilers have??

Properly sized electric boilers are made to serve your need. See the attached link provided by baymee. This manufacturer makes electric boilers in 5 different sizes.

A heat loss caculation on your house will tell you how big of a boiler you need. You could also size the boiler to the net output of your water heater (i.e., input in BTUs/hr times efficiency rating).

Water heating could be zoned off the electric boiler, or you could install a separate electric water heater.

Another option is to install electric baseboard heat. The advantage of electric baseboard heat is that you can control each room individually, and heat only the rooms you need, to and to the degree required in each. That would eliminate the heating losses from having the heating ducts in the attic. The ducts would still serve the role of air conditioning in the summer.

Here is a link that might be useful: Link to an electric boiler manufacturer information sheet

Keep in mind that an electric boiler is NOT meant to produce domestic hot water, unless you use a flat-plate heat exchanger. But they will heat your house through the coil and produce hot air. You can also zone them and use traditional baseboard heat or in-floor radiant heat; the most comfortable type of heat.

The one thing about all this with regard to an electric bioler rather than a water heater is that we have turned left from the original purpose, which was to accomplish both with one appliance. I realize that so far we have come up empty, but putting in new equipment takes us to the "get a heat pump place".....

The ductwork in the attic including the return ducts should have 12" of fiberglass or equivelant on them.

Do you have ceiling fans to move the warm air down? Try putting a thermometer close to the ceiling and see how warm it is up there.

I thought the original purpose was how do you save money on fuel costs?

If your primary goal is save money on fuel costs for heat and hot water, then the one appliance approach won't do the trick.

Any way you slice it, heating with propane vs. heating with electricity is gonna be approximately twice as expensive in fuel costs.

I don't know much about heat pumps, because around me, they aren't used at all, as it is too cold in the winter. By for your location, the heat pump may very well be better than an electric boiler.

"we have turned left from the original purpose, which was to accomplish both with one appliance."

- I thought that the original purpose was to figure out why you, with 2 people in your home, have a propane bill that is 50% - 66% higher than the builder of your home, who has a wife and 4 kids and uses the same heating system?

Other than the builder, are there any other homes in your area that use this type of heating system?

Do you truly believe that the builder's propane usage costs are 1/2 to 2/3 of your cost? Maybe the builder is lying thru his teeth and this set-up stinks for heating which is why it isn't used by anyone but you and the builder?

Have you looked at the tank to see if the cold water fill line is in place? Probably not as this requires some disassembly of the tank.

A heat pump will be provide the lowest cost heat for your home in Virginia. You have low electric rates, and heat pumps are 300% efficient even at 30 degrees F outside air temperatures.