Return to the Heating & Air Conditioning Forum | Post a Follow-Up

 o
Heat Pump.....will it really save me money?

Posted by Jinx_1832 (My Page) on
Wed, Apr 18, 12 at 20:27

I recently moves into a new house in Mass, a 1650 sq ft house built in 1998. We have a 1 zone central AC - Rheem 10 seer 3 ton and a 2 zone heating system - Burnham Boiler (tankless water heater) that has 80% efficiency but is oversized for the house.

The 1st investment we made was to install a solar PV system as in MA the incentives are great and payback is about 4 years. We have no option for natural gas, so heat pumps seems like a great option to curb heating costs and utilize the cheap electricity.

I received the following quote:

Option #1
Bryant Evolution Extreme Cold Climate Hybrid Heat Pump
20 SEER 13 HSPF
3 ton 280ANV036 and FE4003
1 Bryant Evolution thermostat control
Electromagnetic HEPA filter
$9,000

Is this system any different than other heat pumps, what makes it perform better in cold temps? I am struggling to quantify the cost to operate this system in cold temps and when you would use oil to back-up.

What other systems should i investigate for competitive quotes?

Thanks for your help!


Follow-Up Postings:

 o
RE: Heat Pump.....will it really save me money?

Will it save money - sure. How much - hard to say.

The issue is what are your electric rates and do you have to use them. PV generates less in the winter so I suspect you will be buying a lot of your electricity to run a heat pump but I don't know.

In NC, we are always just buying our KWs even if we generate more than me use. For us, it is $.10 a kwh. The savings of that heat pump vs oil would be something like 80%. If you pay $.20 a kwh, you would still save money but it wouldn't be 80%. I guess it would be 60%.

That assumes $4.50 for oil and an average COP of 3.2 (this is the biggest variable). The published HPSF actually puts the COP at 3.8 which makes the heat pump even cheaper, I deducted 20% to give a worst case scenario.

In a/c season, your savings will be roughly 50%.

Assuming your incentives are similar to NCs, then solar hot water should payback under 5 years. Here we pay about $2500 after incentives for solar hot water. At $.10 a kwh, it pays back under 10 years easily and some might see payback at 5 years. But I'm guessing, you pay a lot more for electricity and I know you pay even more for oil, so your payback will be much less. Interesting - if people install solar hot water, they are on average lower uses of hot water (at least from a study here compared to DOE average use). Kind of like people with hybrid cars driving in the slow lane.


 o
RE: Heat Pump.....will it really save me money?

Jinx

Post your cost/gal on oil and your full KWH electric rate.

The main benefit of the Bryant cold climate HP is that it holds it's BTUs numbers below freezing before significantly dropping off. Since I expect you will be using your boiler at or below freezing, then the benefit of the cold climate HP becomes marginal

I would get a price on a Trane/AmStd heat pump mdl XL15i or XR15 and AS Heritage 15. Then weigh the cost difference.

BTW, your Bryant dealer has not given you the best choice on the air handler. And yes it makes a big difference. You want the FE004AN(B,F)005.

Post back.

IMO


 o
RE: Heat Pump.....will it really save me money?

David, thanks for your input. My PV runs on net metering, so i should have surplus of electricity from the summer to support the heat pump in the winter. My system output exceeds my usage even with my 10 seer A/C system.

Can you help me with the math behind your calculations? I am concerned that the COP will drop dramatically in the cold weather 20-30F, so I want to model the potential financial impacts.

I have also looked at a heat pump water heater and solar thermal. I am concerned about the performance of heat pump hot water systems, seems to be some issues with consistent hot water and the equipment quality across brands. I really like solar thermal, but it is closer to $5K in Mass (after incentives) and there is an increased maintanence profile over PV.

Any additional insight would be appreciated.


 o
RE: Heat Pump.....will it really save me money?

Oil is a very expensive way to heat in the last 5 years because of the high cost of oil. It all depends ofcourse on your cost of electricity. If your electricity rate is very expensive and oil gets cheap, you may not save much. I think that expensive oil is here to stay though. I would try go get off he oil and go with a heatpump. Even if its not the super-duper carrier, the highest efficiency single stage heatpump will handle alot of your heating needs efficiently. Just make sure it has demand defrost.


 o
RE: Heat Pump.....what size heat strip?

Jinx

What size heat strip was quoted for the Bryant system?

IMO


 o
RE: Heat Pump.....will it really save me money?

Tiger,
I asked about the heat strip yesterday and he said the system uses inverter technology similiar to a ductless system, does this make sense? Should their be an additional heat strip?
Thanks.


 o
RE: Heat Pump.....will it really save me money?

Jinx

There are three reasons for a correctly sized heat strip.

1. Supplemental heat at low temps
2. To temper the supply air when in defrost mode
3. Emergency heat when there is a malfunction of the outside condenser.

Now granted, these reasons are less important with your baseboard boiler system.

However, I would want a heat strip.

Has this dealer ever installed one of these systems? His reply about the heat strip leads me to question his competence. I would want a customer reference that you can call.

I believe Bryant has just recently introduced this model that basically is identical to sister company's Carrier Greenspeed that came out summer 2011.

Refer back to my first post.

Post back.

IMO


 o
RE: Heat Pump.....will it really save me money?

Tiger, I am on the case. What heat strip would you recommend considering we already have oil back-up? Also, can you provide more info on why the air handler is not a good fit for the greenspeed type system?

Also, can anybody provide a good reference for the math calculations related to HSPF/COP for comparison between oil and HP (electric). I can then pull the COP date from the mfg and run some numbers.

Thanks.


 o
RE: Heat Pump.....will it really save me money?

Jinx

The air handler quoted is a match according to the AHRI HP directory. However, it is not the best match based on performance/efficiency numbers.

You can look it up yourself at the link I am providing below.

As to size, no less than a 10 KW heat strip. Dealer should know this and already checked your breaker box for a free circuit to handle this size.

Dealer should also provide you the HSPF/COP numbers you are looking for. The AHRI directory will give you the HSPF at 45 degrees fah.

IMO

Here is a link that might be useful: AHRI HP Directory


 o
RE: Heat Pump.....will it really save me money?

"What heat strip would you recommend considering we already have oil back-up?"

I'm in the suburbs of DC. I have a two year old Carrier Heatpump and a Carrier ~80% Oil Furnace. I do not have heat strips.

Works fine.

In an existing home with oil heat I see a lot of recommendations that I don't understand to replace the oil heat with gas or other systems. I think that usually every case can be made to steer away from oil in new construction, but in existing oil heated homes maybe not so much.

As expensive as oil is per gallon or per BTU, if you use very little of it that absolute cost may not be so terrible - when compared to the cost to convert versus pay back.

This past winter was the mildest winter in DC recorded history. My heat pump is set up to heat when the outside temperature at or above 30 degrees. With outside temperatures below 30 degrees my oil furnace is the heat source.

I used about 70 gallons of heating oil this winter - presumably less than $350 worth. I can't tell you exactly because my tank level is 3/4 Full and I have not had an oil delivery since March 2011!! :-)

My electric usage for 2011 was $2446 compared to $3251 in 2009. (In 2010 the usage is in between because during that year I had my new heat pump and heat pump hot water heater installed mid-year.

You mentioned a heat pump hot water heater. I have the GE model that Lowes carries. My electric here is quite high... I save about $50 per month in electricity for my family of two adults and only the occasional granddaughter.

Additionally, my basement located heat pump dehumidifies my basement. The heat pump makes no measurable change in basement room temperature.

The only downside I see with the heat pump hot water heater is it is noisy ... probably louder than the heat pump. Not a problem in my case because we don't spend much time down there. (Additionally, like your heat pump, you'll need to dispose of the condensate from the heater.

I had promised the forum a detailed accounting of my energy costs/savings after this winter ended. The reason I have not done so is that the winter was so mild that using straight oil would likely have looked great compared to past years of oil heating. lol


 o
RE: Heat Pump.....will it really save me money?

For Salti

Your situation is entirely different as you have a full forced air system, oil furnace and heat pump.

OP has a boiler for baseboard heat. He wants to add a HP with air handler to minimize oil heat. Yes, he needs a heat strip.

IMO


 o
RE: Heat Pump.....will it really save me money?

tigerdunes,

Thanks! (Once again, I've added confusion to the mix.)

Sorry...


 o
RE: Heat Pump.....will it really save me money?

Can't a hydronic coil be used instead of electric heat strips? I understand that reaction time might be too slow for that unless the circulator can anticipate the defrost. Alternatively, can the blower be coupled to the temp of the theoretical hydronic coil and not run until the coil is warm when in defrost mode?

How does the OP heat water, in the same oil boiler? In Mass., won't evacuated tubes be needed for DHW? That would add a big expense compared to warmer climes.


 o
RE: Heat Pump.....will it really save me money?

Hey Ion, it seems like just switching to the oil furnace may make sense during defrost. I assume the Evolution control can easily make the transition. The aux heat can't be cheap, close to using oil heat?

I have tankless hot water with my boiler, looking at options for splitting it out (Sch�co Solar Thermal or heat pump water heater).


 o
RE: Heat Pump.....will it really save me money?

In my area, electric heat strips cost 40% less than oil. Very

I'm still confused by your electric rates. If you always have surplus, then what do they pay you for surplus? If they don't pay you anything, then obviously a heat pump would save you a lot of money.

COP numbers are hard to get but they do give an average based on region and you should be mid 3's.


 o
RE: Heat Pump.....will it really save me money?

I am just a dumb amateur so there are probably some pitfalls that prevent using oil instead of electricity in the ducts during defrost. I am sure that the pros know how to make me look ignorant, and I welcome that. OTOH, it could be reasonable. I ask because the last time I checked, the cost of heating with oil in a relatively low efficiency boiler much lower than electricity in cold, upstate NY. IIRC, it was at least 5x less expensive a year or two ago.

Since you are using your boiler for DHW, it is going all the time so it would be available for defrost heating in a HP. YOu need back up DHW with solar DHW so why not keep the oil for that? HPWH will not pay as well as in my area, Gulf coast LA.


 o
RE: Heat Pump.....will it really save me money?

Net metering on solar up here works in a annual cycle, so if you have a surplus over 1 year, they will pay you the wholesale rate ($0.10ish). You can also send your surplus electricity credit to another account (family/friends). I figured the best bang for the buck is to use it for the heat pump and decrease my oil usage.

I left a nice space on my roof for solar hot water, may just focus on the heat pump hthen look at DHW options.


 o
RE: Heat Pump.....will it really save me money?

Jinx

Follow up on the air handler mdl and the 10KW heat strip.

IMO


 o
RE: Heat Pump.....will it really save me money?

I have met with a few additional authorized dealers, how does this Carrier Greenspeed system look, is this the ideal air handler?

Carrier 25VNA036A003
3 Ton 20 SEER Infinity Series Modulating Heat Pump Condenser
Carrier FE4ANF003
Infinity Series Variable Speed Air Handler (Fan Coil)

*9KW staged heat strip
Carrier
SYSTXCCUID01-V Infinity Series Thermostat

The pricing in MASS is still pretty high even after rebates ($10K). The pricing for the 16 SEER systems is about $1,500 lower. Any additional guidance would bee appreciated.

Thanks!


 o
RE: Heat Pump.....will it really save me money?

This is Carrier's top of the line heat pump. It is expensive, but it is supposed to give very good performance at low temperatures.

The the FE4ANF005 provides better performance numbers over the coil you listed. Not enough to justify a big price increase.

You don't need a 20 SEER air conditioner in Mass. You could move down to a lower model Carrier Infinity heat pump. You will be giving up some performance in the heat pump mode. You have to weigh the heating and cooling performance in order calculate the return on investment in order to justify the additional $1500.


 o
RE: Heat Pump.....will it really save me money?

Jinx

As previous poster points out, the 003 air handler size is wrong;don't think it is even a match. You want the 005.

Glad to see the info about the heat strip. It is needed. Not certain that it is correct size, especially for tempering air on a defrost call.

However, I would weigh the cost of this system versus a three ton Trane XL15i or XR15 and AmStd Heritage 15 HP systems. The Greenspeed may be overkill considering you have boiler heat for the low temps.

IMO


 o
RE: Heat Pump.....will it really save me money?

Hi Jinx 1382, Over a year has passed since your original post and questions. I too am in Mass. What did you decide to do? What did you ultimately do? What have your results been? Many thanks!!


 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!


Return to the Heating & Air Conditioning Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Please review our Rules of Play before posting.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.


Learn more about in-text links on this page here