Boiler with a Geo Thermal setup in the house

[jimmyjon]

I'm actually thinking of getting a waste oil boiler and using it for heat and water heat in the house. The thing I'm not sure of and also not really sure how to determine is will this save enough on my electric bill to be worth the time and money? I will most likely build one out of an old fuel oil boiler I found listed near by but I dont even want to start this until I either get some testimonials maybe from some of you guys with wood boilers and Geo which maybe similar or better yet if there are people here doing just what I'm thinking about.

With Geo theres no gas bill to save on so I suspect it may be harder to justify something like this because of that. But at the same time when it gets in the single digits Geo alone will no keep up and it has to kick on its emergency heat which is just a big electric heat grid. If I could knock a $100 off my electric bill Id definitely do this. But again thats why I'm here.

 

[sloeffle]

A buddy of mine heats his house and barn ( keeps it at 55 when it is not occupied ) with a waste oil burner. He burns around 3k gallon a year of oil. He gets it all for free from local businesses.

We have geothermal heat / AC and you are correct that when it gets really cold it cannot keep up. I got home from work one time when it was really cold ( 5F if I remember right ) out and didn't want to mess with making a fire and woke up to the house being 55F with the red heat strip light on. I don't have the heat strips wired up. Typically I use the wood burner when it gets really cold. I did some math one time and I think the heat strips would cost around $2 - $3 per hour to run. IMHO geothermal shines for cooling and not heating.

 

[TCaldwell]

Short story, about 12 years ago my boss built a 22ksqft house on a windy hillside. The hvac engineer specified geothermal, 15 wells worth, the monthly elec bill averages 7k $ per month and dwh is covered by a dedicated fossil boiler.
Good thing they can afford it!

 

[jimmyjon]

A buddy of mine heats his house and barn ( keeps it at 55 when it is not occupied ) with a waste oil burner. He burns around 3k gallon a year of oil. He gets it all for free from local businesses.

We have geothermal heat / AC and you are correct that when it gets really cold it cannot keep up. I got home from work one time when it was really cold ( 5F if I remember right ) out and didn't want to mess with making a fire and woke up to the house being 55F with the red heat strip light on. I don't have the heat strips wired up. Typically I use the wood burner when it gets really cold. I did some math one time and I think the heat strips would cost around $2 - $3 per hour to run. IMHO geothermal shines for cooling and not heating.

I agree A/C cooling nothing beats Geo. Do you have a 2nd water tank tied to your water heater as a buffer?

 

[jimmyjon]

Short story, about 12 years ago my boss built a 22ksqft house on a windy hillside. The hvac engineer specified geothermal, 15 wells worth, the monthly elec bill averages 7k $ per month and dwh is covered by a dedicated fossil boiler.
Good thing they can afford it!

Holy crap! cant even imagine that... but I guess its all relative to whatever hes got in to his 22k sq ft house... geesh

 

[Bad LP]

Short story, about 12 years ago my boss built a 22ksqft house on a windy hillside. The hvac engineer specified geothermal, 15 wells worth, the monthly elec bill averages 7k $ per month and dwh is covered by a dedicated fossil boiler.
Good thing they can afford it!

I would have shot the engineer.

 

[sloeffle]

I agree A/C cooling nothing beats Geo. Do you have a 2nd water tank tied to your water heater as a buffer?

We did not at first but we do now. I realized how much it was costing me ( $ 50 - $60 ) to heat hot water a month. So now I use the 50 gallon Marathon as my buffer tank and an A.O. Smith 50 gallon HPHW ( $5 - $10 per month ) as our "primary" hot water heater. When we installed the geo, HPHW's were just coming onto the market.

If I were buying a geo right now with a de-super heater. I would get the cheapest 80 gallon hot water tank I could buy for my buffer tank and the get the highest COP HPHW that I could afford.

 

[maple1]

We did not at first but we do now. I realized how much it was costing me ( $ 50 - $60 ) to heat hot water a month. So new I use the 50 gallon Marathon as my buffer tank and an A.O. Smith 50 gallon HPHW ( $5 - $10 per month ) as our "primary" hot water heater. When we installed the geo, HPHW's were just coming onto the market.

If I were buying a geo right now with a de-super heater. I would get the cheapest 80 gallon hot water tank I could buy for my buffer tank and the get the highest COP HPHW that I could afford.

Wouldn't that make it pointless to have a de-super heater? (I don't know a lot about Geo...)

 

[sloeffle]

Wouldn't that make it pointless to have a de-super heater? (I don't know a lot about Geo...)

Having a HPHW ?

 

[jimmyjon]

We did not at first but we do now. I realized how much it was costing me ( $ 50 - $60 ) to heat hot water a month. So now I use the 50 gallon Marathon as my buffer tank and an A.O. Smith 50 gallon HPHW ( $5 - $10 per month ) as our "primary" hot water heater. When we installed the geo, HPHW's were just coming onto the market.

If I were buying a geo right now with a de-super heater. I would get the cheapest 80 gallon hot water tank I could buy for my buffer tank and the get the highest COP HPHW that I could afford.

Now with that setup the desuperheater actually only heats the buffer tank during cooling operation right? Or am I way off?

 

[moey]

Do you have any type of electrical monitoring from your power company? For us we can log into our account and it shows a hourly breakdown. The reason I ask is when you have electric supplemental heat with a geothermal heating system it does not run much.

Say its 5F at 1AM outside and your thermostat is set to 68F. Your geo system can not keep up so the temperature drops to 67 it will stay at 67F for a hour or two depending on how your thermostat is setup. At that point after several hours the electric heat will cycle for 20-30 minutes then the temperature will go up to 68F. The electric heat will shut off and the cycle will repeat if needed. In actuality your not running heat strips for very long. The temperature outside goes up towards morning and the heat strips will not come on again because the thermostat senses the geothermal system is keeping up.

When we first got our geothermal system I more or less said Ill run our pellet stove when it gets super cold. I did for the that first year. The second year I let the electric heat come on. I never noticed a difference in my bill. It was like $5-10 a month when I looked at my hourly billing for the coldest months. Electric heat does not run much and when it does its in short bursts until the outside temperature goes. You might want to read your thermostat manual and see how the electric heat is setup sometimes the settings are aggressive. Ours is setup for not being able to maintain a setpoint for 3 hours I think.

 

[moey]

Wouldn't that make it pointless to have a de-super heater? (I don't know a lot about Geo...)

In colder climates de-super heaters work great in the winter but in the summer they dont do much. Its either not warm enough outside to run the geo or when it does run the pressures in the system never really get high enough to generate heat for the desuperheater because the cycles are too short and incoming water temps are low because your in a cold climate. So having a HPWH helps greatly in the summer.

 

[maple1]

Having a HPHW ?

Yes. Seems I have read a lot that making DHW with a geothermal setup (via desuperheater) doesn't really work that great. I have had some people tell me that personally who have them also. Might be a situational thing.

 

[jimmyjon]

Do you have any type of electrical monitoring from your power company? For us we can log into our account and it shows a hourly breakdown. The reason I ask is when you have electric supplemental heat with a geothermal heating system it does not run much.

Say its 5F at 1AM outside and your thermostat is set to 68F. Your geo system can not keep up so the temperature drops to 67 it will stay at 67F for a hour or two depending on how your thermostat is setup. At that point after several hours the electric heat will cycle for 20-30 minutes then the temperature will go up to 68F. The electric heat will shut off and the cycle will repeat if needed. In actuality your not running heat strips for very long. The temperature outside goes up towards morning and the heat strips will not come on again because the thermostat senses the geothermal system is keeping up.

When we first got our geothermal system I more or less said Ill run our pellet stove when it gets super cold. I did for the that first year. The second year I let the electric heat come on. I never noticed a difference in my bill. It was like $5-10 a month when I looked at my hourly billing for the coldest months. Electric heat does not run much and when it does its in short bursts until the outside temperature goes. You might want to read your thermostat manual and see how the electric heat is setup sometimes the settings are aggressive. Ours is setup for not being able to maintain a setpoint for 3 hours I think.

Thanks for the info. I didn’t realize that I’ll have to find my thermostat manual and look in to that.

So you really only noticed a $5-$10 difference from not running the furnace at all or are you just comparing the electric heat part of it?

 

[Bob Rohr]

Geo with loops in a well, trench or pond? It should be able to heat and cool if properly designed and installed. My pond was froze over yesterday and the HP is still heating the home, no strip heat installed?

$50- 60 to heat DHW? That sounds pretty high, how much DHW do you consume?

Be aware there is a lot of service and maintenance involved with waste oil burning, even with top quality drain oil. most is contaminated and hard on the burners.

 

[moey]

Thanks for the info. I didn’t realize that I’ll have to find my thermostat manual and look in to that.

So you really only noticed a $5-$10 difference from not running the furnace at all or are you just comparing the electric heat part of it?

The $5 - $10 was for running pure electric resistance heat to supplement the geo system.

Its tough to accept running pure electric heat after getting a geothermal system. But its actually part of the design. If you designed a system to accommodate the very cold days that means on the warmer days when its in the 20s, 30s your system is not performing on the optimal curve as its cycling a lot and will actually cost more to run per year then a smaller system that uses more supplemental heat. Although now they are coming out with variable speed compressors to try and get closer to the optimal curve on warmer days.

 

[sloeffle]

Do you have any type of electrical monitoring from your power company? For us we can log into our account and it shows a hourly breakdown. The reason I ask is when you have electric supplemental heat with a geothermal heating system it does not run much.

Say its 5F at 1AM outside and your thermostat is set to 68F. Your geo system can not keep up so the temperature drops to 67 it will stay at 67F for a hour or two depending on how your thermostat is setup. At that point after several hours the electric heat will cycle for 20-30 minutes then the temperature will go up to 68F. The electric heat will shut off and the cycle will repeat if needed. In actuality your not running heat strips for very long. The temperature outside goes up towards morning and the heat strips will not come on again because the thermostat senses the geothermal system is keeping up.

When we first got our geothermal system I more or less said Ill run our pellet stove when it gets super cold. I did for the that first year. The second year I let the electric heat come on. I never noticed a difference in my bill. It was like $5-10 a month when I looked at my hourly billing for the coldest months. Electric heat does not run much and when it does its in short bursts until the outside temperature goes. You might want to read your thermostat manual and see how the electric heat is setup sometimes the settings are aggressive. Ours is setup for not being able to maintain a setpoint for 3 hours I think.

I have an Efergy monitoring my geothermal system. It uses around 2.4 kilowatts when running. We have a three stage thermostat that was designed for heat pump systems. Our system is a Waterfurnace 5 series, it was called something else when we bought it. It is 4 tons. I believe the manual J they did came up to 3.5 tons. So they jumped to the next biggest size vs going to a smaller unit. We have 600' of pipe in the ground per ton. So we have a total of 2,400 feet of pipe in the ground. Our house is around 2,220 sqt feet and insulated pretty well. We do have an open pasture next to our house that really hurts us when it is windy.

I am too cheap and never hooked the heat strips up. I never realized that is how they worked. I figured once they were on, they were on until the set point was reached. I'll check the manual and see how the electric heat is setup.

 

[sloeffle]

Geo with loops in a well, trench or pond? It should be able to heat and cool if properly designed and installed. My pond was froze over yesterday and the HP is still heating the home, no strip heat installed?

$50- 60 to heat DHW? That sounds pretty high, how much DHW do you consume?

Be aware there is a lot of service and maintenance involved with waste oil burning, even with top quality drain oil. most is contaminated and hard on the burners.

Geo loops are in a 6 foot deep trench. We have 2,400 feet of pipe in the ground. 600 feet per ton.

Unfortunately our water company doesn't have a website that graphs our usage out. As rough guess from looking at my bills we use around 3500 gallons a month. We do water livestock with that water, and I live with two women who love their hot showers.

I put an Efergy on the electric line that feeds the Marathon and that is what it averaged out to over a 3 month period. The Marathon is a 4,500 watt unit. Our electric at that time was .12kWh.

 

[moey]

A simple way to look at it. Say you need 40000 btu to heat your house to 68F when its 5F outside your heat pump delivers 40000 btu so that is the balance point. At 0F you may need 45000 btu so the 5000 btu comes from somewhere usually the electric heating elements. The electric heating elements would cycle because they probably deliver 30000 btu so they dont stay active for very long. As soon as the temperature starts going up the electric heating elements shut off.

The reason a geo system has about a 10000 watt heating element is in case your heat pump quits so you dont freeze yourself or pipes. The cost of heating elements is nearly the same for 2000 watts vs 10000 watts so they just put a big one in to protect you in case your system dies.

 

[Bob Rohr]

Yikes, it must be the cattle, a typical family uses 10- 15 gallons per day of DHW. $300- 400 per year is an average DHW bill.

Those cows must take long showers also

Actually my neighbor has a bunch of horses, he claims they eat less hay in the winter when he waters them with warm instead of ice cold water. Any truth to that, is warm water better for digesting the hay and feed?

He was asking me about a solar assist to water the horses, it must be a large load.

 

[moey]

Different parts of the country pay different electric rates it makes a big difference. We pay north of .15 a kw/hr. During the summer I would estimate our hot water usage for a family of four costs us $50-$60 a month.

 

[maple1]

Our rate is $0.18/kwh. Heating our DHW via resistance tank heater in the summer runs us about $25/mo. Same sized family.

 

[sloeffle]

Yikes, it must be the cattle, a typical family uses 10- 15 gallons per day of DHW. $300- 400 per year is an average DHW bill.

Those cows must take long showers also

Hmmmmm. According to what I am reading, we are in the norm for water usage. Our family of three uses around 100 gallons a day. It doesn't seem horrendous IMHO. Our water bill is about $30 a month.

The chickens get watered with "city water" and I'd say it averages to about 100 gallons a month. Our bigger livestock is watered via a water well. In the summertime our three cows can easily drink 60 - 100 gallons of water a day. The sheep might drink 20 gallons a day.

Actually my neighbor has a bunch of horses, he claims they eat less hay in the winter when he waters them with warm instead of ice cold water. Any truth to that, is warm water better for digesting the hay and feed?

He was asking me about a solar assist to water the horses, it must be a large load.

I know that is true for ruminants. I don't know a lick about horses. Cold water actually decreases the temperature of the rumen ( 1st stomach ) which causes the microbes in the gut to slow down. It takes about an hour or so after they drink for the temperature of their gut to come back up to temperature. By giving animals warm water you are decreasing the time it takes for their stomach to come back up to temperature. Ruminants can actually somewhat regulate their body temperature by eating.

 

[moey]

Just to give a idea on electric heat usage. Today it got up to about 10F. The electric heat came on around 6PM ( its was about -1F outside ) it ran for about 20 minutes temperature went from 67->68F and then the electric heat shut off. Its now ran for several hours maintaining 68F with just the heat pump. It should slip down a degree and the electric heat will come on for another brief period to move the temperature back to 68F at some point. I have mine setup to come on if it cant reach the setpoint in 120 minutes. Although Im not sure how exactly that is calculated because if it were 40F outside and I adjusted the temperature on the thermostat from 60F to 70F the electric heat wont come on it must sense the temperature is rising rather then falling and not allow the electric heat to come on.

A 20 minute burst of electric heat costs me $.50 ( fifty cents) ( at .15kw/hr)

 

[sloeffle]

A 20 minute burst of electric heat costs me $.50 ( fifty cents) ( at .15kw/hr)

I looked mine yesterday coincidentally when I was checking on something inside of the geo furnace. Each unit is 60 amps and we have two of them.

((60*2)*240) = 28,800 watts at full draw

28,800/1000 = 28.8kW * .14ish kW/hr ( we buy some solar electric from our coop up and how much is produced depends on the time of the year ) = $4.03 per hour