Hybrid water heater and side arm?

[Mike Fromme]

anyone using a hybrid (geospring) water heater with a side arm?

I currently have a leaking indirect water heater. I use my wood boiler exclusively for ~8 months and an oil boiler for the rest of the year to heat hot water.

I need to replace the indirect sooner or later and have been looking at options... I can get a GE geospring for about $200 after state and federal rebates. Add another $150 for a sidearm... And then I'd be able to heat hot water with wood, oil or electricity.

Currently paying ~$2 for oil and 12 cents/kWh... So back of the envelope math says would be slightly cheaper to run the heat pump in summer... Anyone got a link to an online calculator?

So what am I missing? Seems like a no brainier vs spending $1200 on another indirect.

 

[maple1]

It should be a whole lot cheaper than oil, operating wise. Our ordinary resistance tank only runs us about $25/mo at 0.18/kWh.

Did you know GE has discontinued the Geospring? Or will? There's a thread in the Green Room about it.

 

[Mike Fromme]

I found a good calculator for water heaters

http://www.efficiencymaine.com/at-home/home-energy-savings-program/water-heating-cost-comparison/

At 12 cents and $2 I'd save about $75 annually over an oil with an indirect. (At 50 gallons a day)

I know the geospring is discontinued and hasn't had the greatest reliability. Warranty and parts are a concern... Not sure how GE would handle future problems. I've dealt with their customer service for other appliances and never been impressed.

BUT Lowes has them for $1000. There is a federal tax credit of 30% and a state rebate of $500 is available. And if I can find a 10% off coupon I would be out under $200 and another $100 for a sidearm) Payback would take a while since I'd be using wood via the side arm at least half the year...lots of variable...maybe five years. But my indirect needs to be replaced anyways which wouldn't save me anything.

Worst case is the heat pump stops working and I just use the tank with the oil/wood and side arm.

 

[STIHLY DAN]

I have the ge hpwh that replaced my oil boiler. You will save way more than $75 a year. I am saving over a grand a year. I use a tempering tank off my wood furnace to preheat the water then send to the water heater. used electric heaters are good for that. Works very well for me. Also the bad rap was the 1st gen heaters, 2nd gen made in the US have been fantastic.

 

[sloeffle]

Our HPHW saves us about $40 a month vs a conventional resistance type electric hot water heater. Our electric rate is 12 cents/kWh also. I also don't need to run the dehumidifier in the summer either. I paid $900 ( no rebate in backwards OH ) for an AOSmith HPHW and expect my payback to be around 18 months.

 

[maple1]

Worst case is the heat pump stops working and I just use the tank with the oil/wood and side arm.


Does the GE also have conventional element(s) too as a backup? Thought I read that. If so, another worst case thought would be if the pump stops working you'd still have a conventional heater (might be getting mixed up with another heater) which should still be less expensive to operate than oil.

 

[Mike Fromme]

Worst case is the heat pump stops working and I just use the tank with the oil/wood and side arm.


Does the GE also have conventional element(s) too as a backup? Thought I read that. If so, another worst case thought would be if the pump stops working you'd still have a conventional heater (might be getting mixed up with another heater) which should still be less expensive to operate than oil.

It does have 4500 watt back up elements. You can set it to run in hybrid mode or heat pump only or resistance elements only.

Though according to the calculator I linked to running in resistance mode only would be over two times the cost of oil with an indirect.

 

[Mike Fromme]

I have the ge hpwh that replaced my oil boiler. You will save way more than $75 a year. I am saving over a grand a year. I use a tempering tank off my wood furnace to preheat the water then send to the water heater. used electric heaters are good for that. Works very well for me. Also the bad rap was the 1st gen heaters, 2nd gen made in the US have been fantastic.

I'd have to use some government level math to save $1000...I only buy a 100 gallons of oil a year. Last time I got hit with a delivery fee because the tanks wouldn't fit a 100 gallons.

 

[STIHLY DAN]

So when you use your boiler for hot h2o you are using a hair less than a gallon of oil a day. Thats close to what I was using, except I did it all year.

 

[Mike Fromme]

So when you use your boiler for hot h2o you are using a hair less than a gallon of oil a day. Thats close to what I was using, except I did it all year.

Yeah, that sounds about right.


I found a 10% off coupon so I went ahead and bought one. Too good of a deal to pass up with the rebates.


The weak point of my system has been making hot water; I have my system set so if the 1000 gallons gets to 110 the oil will kick on. I like the setpoint to switch over kept low so that oil doesn't kick on unless it's really needed. Downside of that is at 110 supply temps I don't get much hot water... And to make matters worse if the indirect calls for heat when the 1000 gallons is below the indirect temp then heat comes out of the DHW.

It's more of a problem in the shoulder seasons when I try to stretch out the time before firings. I know the house will warm up during the day so I don't want oil coming on in the early morning... End result I've been manually turning the indirect aquastat on and off to manage hot water. I've forgotten about it a few times and the wife is not happy when she takes a shower in the morning.

Now I'll be able to run it off wood in the winter and have the heat pump kick on if the system storage temps get low. And then oil will kick in if the heatpump can't keep up.

In summer I can run heat pump first with oil back up.

 

[maple1]

That calculator is out to lunch.

 

[Mike Fromme]

How so?

 

[maple1]

My real life experience says so.

Which is $25/mo of $0.18/kWh electricity in a conventional resistance water heater. Family of 5, over 4 summers.

And between 3/4 and 1 gallon of oil per day for a tankless coil setup for same demand. Over 17 summers.

 

[STIHLY DAN]

How so?

Doesn't work in your scenario either. If you used oil for hot h2o all year , at your almost a gal a day, although in winter this would be more. (350 gal @ $2.00) would be $700 a year. Compared to the charts $184. 350% off.

 

[Mike Fromme]

Doesn't work in your scenario either. If you used oil for hot h2o all year , at your almost a gal a day, although in winter this would be more. (350 gal @ $2.00) would be $700 a year. Compared to the charts $184. 350% off.

Ive been using right around 75-100 gallons for about four months of hot water... Best guess. So less than .75 gallons a day which would equate to about $550 annually.

The calculator I linked to assumes 50 gallons use daily of hot water and let's you caclulate various fuel prices and methods. It would be nice to be able to adjust daily use in the calculations.

Obviously I'm using more than 50 gallons daily.

As long as it's cheaper to make a gallon of hot water with a hpwhh then oil I'll be happy. The more I use the more I save... Time to remove some more flow restrictors.