Getting a price to replace my 21 year old WaterFurnace GeoHP

[Jerry_NJ]

I'll talk with my Water Furnace dealer to see if also installs HPWH. He does go some on his "own" as the proposal includes an 80 gallon A.O. Smith electric water heater which he sources outside Water Furnace.

An interesting item I think I picked up on this thread is more control of the blower. I currently have a 3 speed fan which is dedicated as follows: low = demand circulation (under my control to turn on/off ) medium = Stage I operation and high = Stage II and Emergency operation. If the variable speed and the new thermostat makes it possible for me to pick a higher than low speed for circulation it would help a lot in my battle to distribute wood heat.

 

[moey]

I wasn't trying to dissuade you from a DSH they do work well when setup up properly two tanks etc. You just really need to get the maximum out of them to recoup your costs. They probably have a longer life then a HPWH too.

 

[Jerry_NJ]

Checking Geospring on Amazon I see it runs about $1K and it has very poor customer evaluations... never mind the second part for now, wouldn't the fact that the HPWH is dumping cold air into (my case) the basement, does it have a drain for removing condensation? Wouldn't that help dehumidify the basement in the summer, as well as help to cool it? Looks to me we have a couple of wins beside sufficient hot water with a COP of , what? better than 2?

 

[woodgeek]

yes, HPWH's provide cooling and dehumidification of a basement for 'free', and do require a condensate pump/drain. COP in warm basements is prob ~2.5 heating water to 120°F. The Geosprings have terrible reviews online, but we can't find anyone on Hearth.com who has had a problem, just many satisfied customers. Idea seems to be to buy the extended labor warranty (part warranty is included), and cross your fingers. Are you running a dehumidifier in the basement, or tying it into your AC?

 

[moey]

There are several generations of GeoSprings the first generations had bad reviews. They newer generations have much better reviews or far less negative reviews.

 

[Jerry_NJ]

Thanks, I run a dehumidifier part time in the summer, I prefer to run an exhaust fan. I have a good quality fan that sits on the floor and vents through a basement window. If I remember I turn it on when the outside temperatures are dry - a dew point below 50 degrees. I will let it run over night and try to provide air from upstairs rather than draw from around my floating slab.

I did consider that the hybrid water heater would not hold up like my existing Water Furnace, which has the DSH, but I quit using it when the aux pump failed. This failure also brought an end to the dealer I called for repair. He misdiagnosed the problem and replaced both of my loop pumps - there was some common fuse, don't recall the details any more. This was then "covered up" by sticking me with new pumps running 24/7 I heard them running is how I discovered the "error". When I got the schematics and diagnosed and tested my theory I called him back, we as very willing to make things "right" but I then looked for a new dealer and may have never purchased a WF again, but I found a dealer I believe is very competent as was the dealer (since retired) who installed my WF 21 years ago.

Can anyone point me at a good thread on the Hybrid Water Heater (heat pump)? Yes, I know how to use search, but someone active here may have a favorite thread. I'm not sure how the HPWH develops such a high (150 degrees?) temperature. But given it can it is easy to see that it could also produce considerable BTU. If a COP of 2.5, that would be only 1,800 watts and should be well within the existing circuit capacity delivered to a WH using 4,500 watts. What's the strategy on the HPWH, does it still call in resistive heat when it can't keep up with demand?

I left a message with my dealer asking if he also installs HPWH, and if so I "have" about $2,200 I could transfer from the current plan taking away the new 80 water heater and the DSH. I understand I would be able to seek the same US Gov rebate of 30% for the HPWH.

 

[sloeffle]

If you do a search in the top right hand corner for geospring. You should find the various threads.

I personally am not a big GE fan. Their are plenty of other companies ( Stiebel Eltron, Rheem, A.O. Smith ) that make HPHW and would be worth looking into.

 

[Jerry_NJ]

My Water Furnace dealer likes A.O. Smith for regular electric water heaters so if he installed HPWH they may be Smith.

 

[woodgeek]

I have the 80 gal AOSmith HPWH, 2.5 years in, 100% Chinese made, no problems. I have two teen girls...the Smith runs the shower for 90 minutes or so straight in HP only! Ask me how I know. It would be overkill for you, as would the 60 gallon I suppose. The 50 gal Geospring costs almost half as much after rebate, IIRC

The COP is ~2.5 heating water to 120°F from a 70°F air source. Higher water temps are not recommended (scalding or tempering valve required). Lower temps could allow pathogens, hypothetically. 120°F is perfect. It achieves the higher temps by using a different refrigerant, HCFC-134a, if I recall, rather than R-22 (now phased out) or R-401a (for newer ASHPs and geos) aka 'Puron'.

When you decomission your geo, have them recycle the R-22 rather than vent it, the earth will be grateful.

 

[DBoon]

You can realistically get a COP of 2.25 heating water to 120 degrees F with a 60 degree basement temperature. If you try to heat to 130 degrees F, I would estimate that COP is a little below 2, and at 140 degrees F maybe only 1.5.

I was much more satisfied with my Nyle HPWH once I 1) superinsulated the supply and return lines from the HPWH to the tank, and 2) lowered the water temperature to 120 degrees F. Run time decreased by about half with the reduction in temperature.

If you get an all-in-one HPWH, you don't have the issue with superinsulation of supply and return lines.

 

[Jerry_NJ]

I haven't gotten any response yet to my telephone message with my dealer asking about a HPWH in place of my DSH and 80 Gal electric/buffer tank combined. But I got some interesting numbers from his "Geolink Project Report" for the two size GeoHPs I am considering.. and I think I may be the most happy with the smaller. This run assumes a DSH and functioning buffer and hot water tank. For the 3.5 Ton and 4 Ton the DSH is rated at a mere 1,300 BTU/H or about 380 watts (roughly)... so the recovery is very slow when the resistive HW heater element is not running.

The run is for the temperature range 2 degrees to 97 degrees external with 70 degrees and 75 degrees, respectively for inside temperature. Of course at for the 038 HP (3.5 ton) resistive auxiliary heat is required. The model expects to see 2 degrees for only 5 hours total and requires 13 KWH of aux heat... this is only 2.6 KW average. This says to me I want the two stage resistive heat to be one 2 KW and one 8 KW. Moving up the temperature scale the model expects to see 30 hours at 7 degrees and a use of 48 KWH of resistive heat. That's only 1.6KW average which means only the 2 KW or Aux heating element will see use, and not full-time. The 8 KW will see very little use unless there is a need for emergency heat (loss of the HP).

This is the area I was most concerned about for the smaller unit, the 049 uses no aux heat, zero. Given I'm a "Minister of Fire" on this family of forums it is obvious I have not problem using some wood heat. I have about 2 cords covered and ready to burn right now.

In total the estimated operating cost including Hot Water for the 3.5 Ton is $1,423 and for the 4 Ton $1,549, or I save about $100 per year with the smaller unit and dryer air in the during the hot/humid NJ weather. Both units have enough to handle the 97 degrees and there is no aux cooling to call in, so good thing. Interestingly the smaller unit at 87 degrees (for the model time at that temperature) uses 302 KWH while the larger unit uses 331 KWH or almost 10% more energy, because the smaller unit is running almost 100% of the time in Stage I with an EER of 30.

Many other interesting numbers, and I don't know what my price is with the smaller unit, but I assume less.

I remain undecided on the DSH/80gal Buffer/Heater. I've gotten a lot of negatives on that operational mode, but I still feel running the 80 gal with the lower unit off or set as low as it will go will provide me much the same as a 40 gal buffer and a 40 gal hot water heater in series. As said somewhere, when I'm home and the HP is running anywhere over 50% of the time I'll switch the HW Heater Braker off. I'm of the opinion from the above that the DSH should be able to bring the the tank (or maintain) to 120 degrees with no resistive heat used in the tank. With only two senior age adults most days the tank will not see any one hour draw above 40 gallons. Wild guess, I think my shower is more like 5 gallons of hot water, my wife's maybe 10 gallons. The dishwasher is a newer high efficient unit and it takes over a hour to wash the dishes in "darn" little hot water.

Hope not too many typos - I appreciate communicating clearly is the only way to get the usual great help. But, it is now 11:25 PM and I'm tired.

 

[woodgeek]

OK, if I recall, we had a whole discussion last year re whether you would downsize to a 3 ton unit, and I think we concluded that the step to 3 tons was just too much, and you would call too much aux. Just based solely on that memory, I could believe the 3.5 tons is 'ok'. You have extensive experience with the 4 ton, and know it always or nearly always kept up (right) so dropping 12% is not going to be a world of difference (versus dropping 25% to 3 ton).

Suppose that the balance point was previously 10°F for the 4 ton, heating the inside to 70°F, or 60° Delta. The 3.5 tone will only heat 60° *(3.5/4) = 52.5°, so you new balance point will be 7.5° higher, or 17.5°F. Now, there is a lot of lag and thermal inertia in BTU loads, so if you drop to below balance point for only a few hours, you may never even call aux at all.

One analysis is to look at heating done right at the 4 ton balance point, so your aux btu demand goes from 0 with the 4 ton to 12% with the 3.5 ton. Your new COP is rather than 3 (for the geo), actually 3 for 88% of BTUs and 1 for 12%, my math gets you an effective COP of 1/(0.33*0.88 +1*0.12) = 2.43, or you are using 23% more power at that temp. So, at whatever balance temp you had before....you will now use 23% more energy at that same temp with a 3.5 ton. IF your balance point previously was close to your ave January temp (say 28°F), the 3.5 ton would boost your energy bill 23%. If your balance point was -10°F, and now it is closer to 0°F with the 3.5 ton, you will use no extra energy with the 3.5 ton. The truth for you is certainly between these limits. 0% more to 20% more. IF it was 10% more, (maybe $100/yr) does the lower up front price make sense? Maybe the AC dehumidification is worth $100/year in comfort (not energy), but it still seems the right answer might be a 4 ton two speed (like you have now).

I really think certainty on this point is going to be elusive....that would require some empirical knowledge re 'balance point', at what sustained outdoor temp the 4 ton could just keep up. Any estimate I or your installer comes up with will be very uncertain relative to that datum. Do you have a number in your head, where you noticed aux coming on??

And those demand hour tables that the installer generates are decadal averages. That 5 hours at 2°F...that means 50 hours one year, and then 0 hours in the next 9, on average. They are not useful without balance point info....any calcs he makes are assuming some balance point....and it could be garbage in garbage out.

Phew....DSH/HPWH will have to wait...

 

[sloeffle]

My math skills are no where near woodgeek's so I will give you the philosophy on why I went with a 4 ton unit over a smaller unit.

I debated the same thing with my HVAC until he brought up a interesting point. Yes, the cost of a 4 ton unit is more expensive than a 3.5 ton unit. But by going to a bigger unit you will run first stage ( 2 tons / 22 amps ) heating and cooling more vs running in second stage ( 4 tons / 35 amps ) or aux heat ( 3.40$ and hour in my case ) . My GSHP has never hit second stage in cooling mode and I only hear it kick into second stage heating generally when we wake up in the morning and the thermostat ups the temperature.

In Ohio we do a lot more heating than cooling so the dehumidification effect of going to a smaller furnace IMHO is not worth it. I would assume that New Jersey would be the same.

 

[Jerry_NJ]

Hum, I don't recall discussing this last year, but I am sure I was considering a voluntary replacement that far back. The not too expensive, $450, repair last December and the news a new compressor would not be an option got me more serious on the replacement subject.

The computer program (factory/Waterfurnace) didn't give cums on Stage I and Stage II, but the data can be harvested out of the time for each external temperature. My estimate is the 3.5 Ton (38KBTU Cooling max, closer to a 3 Ton it seems, even less heating at 28KBTU Stage II) runs a lot in Stage I also. Yes, the weather is similar to OH, we lived in Granville for a number of years in the 70s (near Columbus), but there we did see some 25 degree below zero and the natural gas furnace had trouble keeping up. Yes, that was unusual.

Interesting, perhaps, the program provides total run times for the given model of 695 cooling and 2648 heating for the 3T and 528 cooling and 1942 heating for the 4T. But, the COP of the 3T is higher - and that doesn't take into account my ground loop was designed to support a 4T which says to me the loop temperature will be more moderate (efficient) with the 3T. My/our plan is to reuse my recently rebuilt loop pumping station but run its two pumps for both Stage I and II, currently the system runs only one pump for Stage I. It may be possible to run just 1 pump for both stages with the 3T unit.

Some of the design numbers: Delta T, 70 degrees heating, 20 degrees cooling (max), Hot water Temp setting 130 degrees (this one needs some explanation), Internal gains 8,400 BTU/H, this too needs some explanation - what cooking? Maybe real geothermal, we're on a ground fault : (

I have been looking at the 3T for heating/cooling cost/benefits not initial cost. If the 3T is $1,000 less that would be another big advantage for me. I can not see any way I will live in this house even 5 years more. A $200 a year average spending of the savings would cover any aux heating needs. Here, did I say, I am thinking for the two stages of resistive heating: 2 KW aux, 8KW emergency, with either 3 or 4T. And, I will not feel I am pulling any dirty tricks on the next owner who will have a geothermal (gs) hp that is near new and much more economical than an oil furnace and air to air AC unit. Of course, if we get the promised "electric rates will necessarily sky rocket" the economics could shift the other way. Then too there seems to be an effort to make the cost of oil/gas sky rocket too. Of course oil has already. When I put in my first Geo in 1993, heating oil was about $1 a gallon and electric in NJ was about 10 cent KWH. Now heating oil is $3.50 or more and electricity is 15 cents. That's what made my decision to go Geo a wise one. Then too, I had to depreciate a heating system that cost 3 or 4 times as much. I'm still depreciating the ground loop, and put the HP with installation and maintenance/repair at about $600 to $700 per year depending on when the ground loop fails. Whats maintenance on an oil furnace? Must be $200 a year just for cleaning and adjusting... bur I digress, yet all these factors play in the economic modeling. Iin fact Just Like Geo (GS) HPs.

 

[moey]

Folks curse at electric heat coming on to much. But the thing to remember is if its coming on when its 10F outside that means you saved money earlier in the year when it was 35F and you were not running such a oversize unit for that temp and short cycling. You only realize the COP of 4+ on long runs so if a unit is cycling for 5 minutes when its 35F out your losing out on savings.

One of the biggest arguments for smaller vs larger units is the cost to drill/dig you already have that part paid for.

Theres a writeup somewhere on this house http://welserver.com/WEL0478/ online at geoexchange.org I cant find. It basically a house with 50K btu heat loss that has a 3ton unit installed in it. The ductwork would have needed upgrading and more digging so they opted for a small unit. The yearly cost difference was in the $10-$20 range a difference that would never be made up.

 

[woodgeek]

Hum, I don't recall discussing this last year, but I am sure I was considering a voluntary replacement that far back. The not too expensive, $450, repair last December and the news a new compressor would not be an option got me more serious on the replacement subject.

I was thinking of these threads...
https://www.hearth.com/talk/threads/i-am-thinking-about-replacing-my-20-yo-waterfurnace.124456/
https://www.hearth.com/talk/threads...ier-at-compressor-out-time-to-replace.119434/

To wrap it up, the downsizing calc is doable IF you knew or otherwise estimated a balance point for the existing system, not otherwise. If you really think the aux comes on very rarely, then the existing unit IS oversized from an economic point of view (mainly meaning the loop cost more than it had to 20 years ago). With the 4-ton loop as a sunk cost, however, it seems the marginal cost of a new 4-ton is small. Downsizing will not be likely to increase your (small) elec bill more than 10-20%. And the smaller unit will like the bigger loop, re loop temps.

The next owner can/will improve the insulation and airsealing of the house, IF he/she cares about the heating bill, and the balance point will drop back down to eliminate aux. Not your job on a 5 year horizon. If you went 4 ton single speed, when the next guy airseals and insulates (hypothetically) the new unit gets even more oversized. E.g. based on BTU loads I should have gotten a >5-ton ASHP when I installed 6 years ago, and I ran a lot of aux while I improved my house envelope. Now my 4-ton is perfectly sized for heating.

That said, I agree that you DO want two-speed for comfort and dehumidification...and heating in stage 1 is prob nice and quiet....has good balance too, etc. I think comfort, summer and winter, should drive the final decision and don't worry about downsizing a bit.

Re the DSH....I am no expert, but I think it is a complex, expensive white elephant. I would listen to sloeffle that a 1-tank solution will not be happy....your effective HW 'capacity' will be much less than 1/2 the tank volume. You and the DW might 'get by', but the next family with kids will curse the lousy hot water when they want 5x as much DHW as you do. Going to 2 tanks is both expensive, takes up a lot of space and provides more points of failure. And then at the end of the day, its not efficient. DSH can't lift to high temps efficiently by itself, and using an element to 'finish' heating the water seems wasteful.

In the 1990s, 'free hot water' must've sounded great. Guess what...when I switched from oil DHW to my HPWH, my annual elec bill actually fell. Scrapping my boiler saved me a ton of AC, and I eliminated a dehumidifier....so even with 2 teens I still have 'free' hot water. HPWHs are the wave of the future, in a couple years all elec units bigger than 50 gal will be required by existing law to be HPWHs (like the light bulb ban). From an engineering POV, get a system designed (with a different refrigerant) to efficiently heat DHW, rather than get a complex kludge that tries to do it with a system optimized for other HVAC purposes...and then dump the whole thing on the next owner.

 

[woodgeek]

And, I will not feel I am pulling any dirty tricks on the next owner who will have a geothermal (gs) hp that is near new and much more economical than an oil furnace and air to air AC unit. Of course, if we get the promised "electric rates will necessarily sky rocket" the economics could shift the other way. Then too there seems to be an effort to make the cost of oil/gas sky rocket too. Of course oil has already. When I put in my first Geo in 1993, heating oil was about $1 a gallon and electric in NJ was about 10 cent KWH. Now heating oil is $3.50 or more and electricity is 15 cents. That's what made my decision to go Geo a wise one. Then too, I had to depreciate a heating system that cost 3 or 4 times as much. I'm still depreciating the ground loop, and put the HP with installation and maintenance/repair at about $600 to $700 per year depending on when the ground loop fails. Whats maintenance on an oil furnace? Must be $200 a year just for cleaning and adjusting... bur I digress, yet all these factors play in the economic modeling. Iin fact Just Like Geo (GS) HPs.

The average cost of electricity in the US has been flat or falling, corrected for inflation, for 30 years, (as your numbers show). Current projections from the EIA and many market analysts are for that to continue into the foreseeable future. Cheap wind, cheap (for now) natural gas and flat or falling demand are putting a ceiling on the price generators can get for power, and the falling price of solar PV will apply even more pressure in the future. A highly efficient, electrically-powered HVAC system will be 'future-proof' for the next owner, and will likely be running on mostly or 100% renewable energy well before it wears out in 2035.

 

[Jerry_NJ]

Okay, guilty as charged, yes I was thinking this subject immediately following my last December repair and the news that a new compressor is not available for my current unit.

I had just about decided to give the DSH another try.. now again I wonder.

I looked at the tax rebate form (one contributor gave a link) and I didn't see a line for HP WH, but somewhere I saw there is a $300 rebate/credit - need to verify that as that would be another plus for the HP WH.

 

[woodgeek]

I think we the fed rebate for HPWH was part of the big package several years ago that had a cumulative cap....I exhausted the rebate with other things, and now its gone?? I did get $300 from my utility, and I think most utilities are providing a rebate these days. Note that I was not replacing an electric tank either.

 

[woodgeek]

OK, after a little Google fu, I found:

http://www.njcleanenergy.com/residential/programs/warmadvantage/gas-water-heaters

that seems to say a HPWH is eligible for a $500 rebate from the state of NJ if installed before June 30, 2015.

It seems that rather than have the utilities pay this out individually, it is out of a central, state office.

 

[Jerry_NJ]

Thanks, I see a connection to what my dealer said, something about I get $500 from some fund associated with the power companies, not government. He didn't explain and I didn't ask. Looks like it is for the DSH hot water. He said he'd apply for that "refund".

 

[woodgeek]

Thanks, I see a connection to what my dealer said, something about I get $500 from some fund associated with the power companies, not government. He didn't explain and I didn't ask. Looks like it is for the DSH hot water. He said he'd apply for that "refund".

I did not see any DSH on that link, but I did see HPWHs. ??

I would think you would apply for the rebate yourself, not your installer.

 

[Jerry_NJ]

Thanks, I'll give it a closer look. You may have introduced me to a new "pay off" to encourage being more "green" : 0 ) As already noted, I've been using a Geo (ground source) HP for over 20 years. Unfortunately, my past experience with DSH wasn't good.

 

[woodgeek]

I think the new geo w/o DSH and separate HPWH should work better and could be more efficient than your sol'n 20 years ago. The geospring all in one will be cheap to install, not complex or 'weird' to techs that will work on them in the future (i.e. they are sold off the shelf in Home Despot), and will score a $500 rebate from NJ. At 50 gallons, it will provide plenty of nice DHW for two older folks in pure HP mode. If more water is ever needed (e.g. by subsequent owners) they can press a button to go to hybrid mode, in which the unit will switch to an element when faster recovery is needed.

 

[sloeffle]

Folks curse at electric heat coming on to much. But the thing to remember is if its coming on when its 10F outside that means you saved money earlier in the year when it was 35F and you were not running such a oversize unit for that temp and short cycling. You only realize the COP of 4+ on long runs so if a unit is cycling for 5 minutes when its 35F out your losing out on savings.

One of the biggest arguments for smaller vs larger units is the cost to drill/dig you already have that part paid for.

Theres a writeup somewhere on this house http://welserver.com/WEL0478/ online at geoexchange.org I cant find. It basically a house with 50K btu heat loss that has a 3ton unit installed in it. The ductwork would have needed upgrading and more digging so they opted for a small unit. The yearly cost difference was in the $10-$20 range a difference that would never be made up.

I am not advocating buying a grossly over sized unit. Was just stating my conversation that I had with more than one HVAC guy about my situation. I did have the numbers ran from the waterfurnace program and my load came up in between 3.5 and 4 tons. So going to 4 tons is not a big deal IMHO. It is not like I told the OP to get a 6 ton furnace.

I got my furnace when the HPWH's were first coming out. I didn't buy a HPHW then because I am not a fan of first generation technology. If was getting a GSHP today I would forgo the DSH and get a HPWH.

If they made a HPHW with a plastic tank, I probably would get rid of my Marathon and buy that. I plan on tying a Geyser into my system one of these days when I have some extra $$$ to throw around.

Scott