heat pump setups

[doogan123]

hi guys - I have been looking for some posts that i came across a while back explaining SEER, EER and HSPF. I am unable to locate them.

I seem to recall somewhere that the best bang for the buck was not a really high seer system but a lower seer setup with 2 stages :confused: . Where does EER and HSPF come into play? What do I gain/loose by going with higher/lower seer?. There seems to be a significant cost difference as you go higher

Would anyone care to post a quick blurb on this - or any clarification questions needed to understand my question further.

I pay .19/KWH


thanks folks again

[BaldLoonie]

SEER is cooling BTUs per watt over the whole cooling season. In a cooler climate like yours, look for the highest SEER.

EER is BTUs per watt at 95 out, 80db/67wb inside. In a hot climate, a higher EER is important.

HSPF is heating BTUs per watt over the heating season. For a cold climate this is another important number to look at.

Also look at heating outout and look for the higher numbers.

I'd question whether the big bucks for 2 stage units would be worth it. I'd look for a good single stage if I were you.

[gary_g]

I seem to recall somewhere that the best bang for the buck was not a really high seer system but a lower seer setup with 2 stages :confused:

That's somewhat contradictory.

13 to 15 SEER are typically single stage compressors.

16 SEER is typically a dual-stage compressor (low and high stage).

19+ SEER is typically a dual compressor system (one compressor for low and another for high).

Note that not all systems are the SEER value as advertised. The famous "up to" XX SEER is typically used in advertising and marketing.

With your 19 cent per kw-hr electric rate (very high) and location in Upstate NY, I would go for a heat pump with the following:

15 SEER
12 EER
9 HSPF
Full heating btu's at the 47F rating temp.

Good luck.

[dac122]

With your 19 cent per kw-hr electric rate (very high) and location in Upstate NY, I would go for a heat pump with the following:

15 SEER
12 EER
9 HSPF
Full heating btu's at the 47F rating temp.

Good luck.

The real upstate and central NY secessionists might take offense at calling Westchester part of that area. :D Just kidding...

This may be as close as you get to a sweet spot. Get some quotes for systems along these lines and repost the results. The pros here can help weed out the best quote.

[doogan123]

Garry - as you can see i was confused. Thanks for the clarity. Is there any real benefit to a dual stage heat pump. ?

Can you also clarify - the variable speed air handler impact. Am correct in understanding that this is a separate piece of technology after the heat pump ( Can you have a single stage heat pump with a variable speed Handler?) From what i read this is suppose to add comfort - correct? Is a variable speed handler something that i should have included

dac122 - I like your comment on a westchester person being upstate ..funny - When i am working in manhatten - i am referred to as upstate - when i am home - i am in the 'burbs :)

thanks for the input

[skippedover]

When trying to understand the bells and whistles, it's important to separate the efficiencies from the comforts. For example, a 2-stage gas furnace uses just as many Btu's to heat your home on a given day as a 1-stage furnace but the 1st stage heating cycle will be much longer on a 2-stage, thus giving greater comfort. Often but not always, the multi-stage furnace comes with a variable speed air handler, which is an energy efficiency improvment in electrical usage.

The same holds true with AC and HP units with a small exception. 1st Stage on a 2-stage unit is really more energy efficient because the compressor is a pump and does less work on 1st stage, thereby consuming less electricity. But overall, 1st stage is more of a comfort issue than an efficiency issue, IMO. Longer heating or cooling cycles means greater comfort, slower blower speeds and happier occupants. As for efficiencies, the higher the SEER/EER and HSPF, the more efficient. You can only make a statement on which is a better deal (higher efficiency = higher price) based on what you're willing to gamble on. If greater comfort doesn't do it for you, then you have to wrestle with what the system costs today and what the energy costs in your area are. As to what todays investment will be worth 2, 4 or 10-years down the road when compared to the energy costs of those future years is anyones guess. My personal recommendation is to buy all the efficiency you can afford at todays prices because I believe the cost of energy is going no place but UP. So today's 18-SEER HP with 9.5 HSPF will probably be considered relatively inefficient in 10-years. So just imagine what a 14 or 15-SEER/EER unit will be!! We're already recommending replacing 10-SEER units in our area (the electric companies actually give a bonus to the clients to replace them) and some are only a couple or three years old! So forecast away and make your best decision. Good luck. :)

[gary_g]

Garry - as you can see i was confused. Thanks for the clarity. Is there any real benefit to a dual stage heat pump. ?

Can you also clarify - the variable speed air handler impact. Am correct in understanding that this is a separate piece of technology after the heat pump ( Can you have a single stage heat pump with a variable speed Handler?) From what i read this is suppose to add comfort - correct? Is a variable speed handler something that i should have included


In general, dual-stage compressors are a benefit in cooling mode in hot, humid climates. Running on first stage allows for better humidity removal because of reduced on/off cycling, and it saves operating $$ because the EER (Energy Efficiency Ratio) is higher on first stage than second stage. Dual stage condensers must have a variable speed fan in the air handler (indoor unit) to obtain the maximum benefit of a 2-stage condenser.

Yes, you can have a v-s motor in the air handler with a single speed condenser. Most pros recommend it. The v-s motor aids in better humidity control in the summer and can also change speed for consistant air flow. Note that these motors are very expensive to replace if they should fail out of warranty.

My personal opinion is that dual stage condensers are overkill for many homes, especially for heat pumps in climates where heating is as important as cooling. If you can afford it, go ahead and get it, but it is more for comfort than operating cost savings.

Remember also that SEER is a fictituous "seasonal" representation of summer usage. No one I know runs their central a/c at 67F and 72F ambient. These 2 low temps make up over 40% of the value of the SEER calculation for a variable speed motor in the air handler. It's just not realistic. You want as high EER and HSPF as you can get, regardless of your SEER choice.

You also want a syatem that has full heating btu's at the 47F rating temperature. Anotherwords, a 4 ton system should be 48,000 heating btu's and not 44,000 btu's. Some system combinations are weak on heating btu's.

Take care.

[doogan123]

gary - thanks

I am seeing that even tho i would be going with a deul feul (boiler backup) that there is still some type of strip heat for the defrost cycle. what is this for and its purpose. Is this something that is needed?

[air2spare]

at 19 cents per KWH I would seriously look at geothermal. I believe there are some excellent tax encentives for homeowners coming from all of this federal bailout program

[gary_g]

gary - thanks

I am seeing that even tho i would be going with a deul feul (boiler backup) that there is still some type of strip heat for the defrost cycle. what is this for and its purpose. Is this something that is needed?

Dual fuel implies that there is another fuel source located in the air handler (indoor unit) like a gas/propane furnace or a hot water coil from the boil. If this is the case, the furnace or boiler will run while the heat pump is in a defrost cycle and no electric strips are required.

If the boiler is not part of the forced air system, like hot water radiators or hot water baseboard heat, then you will need electric strips to temper the cold air from the air handler while the heat pump is in defrost.

Will the bolier back-up be part of the forced air system, or separate from it?

[beenthere]

19+ SEER is typically a dual compressor system (one compressor for low and another for high).

Note that not all systems are the SEER value as advertised. The famous "up to" XX SEER is typically used in advertising and marketing.



There are at least 3 manufacturers of 19+ SEER equipment.
Only 1 uses a 2 compressor set up.

So 19 SEER would not typically have 2 compressors.

[doogan123]

Dual fuel implies that there is another fuel source located in the air handler (indoor unit) like a gas/propane furnace or a hot water coil from the boil. If this is the case, the furnace or boiler will run while the heat pump is in a defrost cycle and no electric strips are required.

If the boiler is not part of the forced air system, like hot water radiators or hot water baseboard heat, then you will need electric strips to temper the cold air from the air handler while the heat pump is in defrost.

Will the bolier back-up be part of the forced air system, or separate from it?

Gary - i am planning a boiler backup as part of the system assuming it comes in at a reasonable cost.

So i get the strip heat - but what is the defrost cycle about? and how does it work

Air2spare - I looking into geo - its great and i am a beliverer in it, however its too $$$ in my area at this time

thanks for everyones comments..

[gary_g]

Gary - i am planning a boiler backup as part of the system assuming it comes in at a reasonable cost.

So i get the strip heat - but what is the defrost cycle about? and how does it work


Still not sure if you are saying that the boiler is part of the forced air heat (with the heat pump) or separate from the heat pump like baseboard or radiators.

The heat pump condenser defrosts based on outdoor temps and temp of the coil to remove frost build-up on the coil surface which decreases efficiency and heat transfer. In defrost mode, the heat pump runs in a/c mode: hot refrigerant flows to the condenser to melt any frost while the indoor coil blows cold air. The electric strips (or hydronic coil from a boiler) provide heat to temper the 50F air from the air handler to 90F or so.

[doogan123]

[QUOTE=gary_g;2012663]Still not sure if you are saying that the boiler is part of the forced air heat (with the heat pump) or separate from the heat pump like baseboard or radiators.

The heat pump condenser defrosts based on outdoor temps and temp of the coil to remove frost build-up on the coil surface which decreases efficiency and heat transfer. In defrost mode, the heat pump runs in a/c mode: hot refrigerant flows to the condenser to melt any frost while the indoor coil blows cold air. The electric strips (or hydronic coil from a boiler) provide heat to temper the 50F air from the air handler to 90F or so.[/QUOTE

Sorry - I am planning on a coil from the boiler into the air handler - so part of the forced air system.

so I understand - the heatpump needs to be defrosted - right? and this is achieved by hot refridgerent? How often does this need to happen and is it below a certain outside temperature?

Does this also mean that every time its needs to defrost - the boiler needs to kick in? Is this eficient?

Just trying to understand - not question

thanks

[beenthere]

How efficient it is to use the boiler for defrost tempering. Varies with what your gas/oil rate is compared to your electric rate.

At 19 cents per KWH, oil at 5 dollars a gallon and 80* efficiency, and LP at 4 dollars a gallon and 80% efficiency are cheaper to operate then electric strip heaters.

How often the HP goes into defrost depends on what type of defort control it has. Time and temp, or on demand. On demand is much more efficient.

Are you also going to use the boiler for heating your hot water?

If the only thing your going to use your boiler for is for the hydro coil.
It may be more cost effective to use a hot air furnace then a boiler.

Neither a cold start boiler, or a hot air furnace will warm up quick enough to eliminate a cool air discharge when your HP first switches over to defrost.

That may be another reason why your contractor is listing a strip heater with his estimate.

[doogan123]

How efficient it is to use the boiler for defrost tempering. Varies with what your gas/oil rate is compared to your electric rate.

At 19 cents per KWH, oil at 5 dollars a gallon and 80* efficiency, and LP at 4 dollars a gallon and 80% efficiency are cheaper to operate then electric strip heaters.

How often the HP goes into defrost depends on what type of defort control it has. Time and temp, or on demand. On demand is much more efficient.

Are you also going to use the boiler for heating your hot water?

If the only thing your going to use your boiler for is for the hydro coil.
It may be more cost effective to use a hot air furnace then a boiler.

Neither a cold start boiler, or a hot air furnace will warm up quick enough to eliminate a cool air discharge when your HP first switches over to defrost.

That may be another reason why your contractor is listing a strip heater with his estimate.


Ok .... so one of my proposals will be with a HP, boiler, a coil in the air handler, indirect DHW ( With solar). THe second is a Bryant evoulation system with furnace. In the second solution i am trying to figure out a tankless propane DHW that works with solar - thats for another day tho

So, is there a trigger for defrost? Or should i assume its constant during the heating season?

How do others engineer it with the boiler setup listed and without electric heat. My rates are high

thanks

[beenthere]

Can't tell you how they do it everywhere.

I use a 5 KW strip heat to temper the air. So on 3 and higher ton HPs, the air isn't warm, but its not coming out cold either.

In your case, your electric is almost double of ours.

I would suggest a gas furnace, instead of boiler. There will be a slight lag in warm air during defrost. But your electric rate makes strip heat a bit too expensive.

Defrost can occur above 40°F, but seldom does. For the most part, it only happens under 40°F. With the evolution system. It uses a on demand defrost board. So it doesn't do needless defrost cycles. The defrost board will monitor the frost conditions of the coil by checking coil temp, and liquid line temp.
Under 40°F, If it hasn't gone into a defrost in six hours of accumilated compressor run time. It will go into defrost to make sure the outdoor coil is not getting oil logged.

So under some conditions. A neighbor that has a HP with standard time and temp defrost, could go into defrost 6 or more times, to your 1 time.

Tankless heaters can be hooked to tanks. So using a furnace would still allow you to use a tankless heater, with a tank, and solar system. And be close to the same cost range as a boiler system.

[doogan123]

Been - thanks . I just spent last night understanding my electricity charges in more detail and reliased that i am on some sort of a variable pricing structure which is why my bills all summer showed up ~19 cents /kwh. I just calculated sept. and its back to ~10 cents . So either i am missing something drastic or this is just the way variable works. I will be calling them tomorrow to try understand the variations.

I feel i have spent longer on my HVAC systemt than designing the house - but you guys have really pointed me in great directions. I am big fan of the lowest operating cot possible going forward balanced with a reasonable installation price. with the 2 systems i am down to - I am just trying to finalse pricing. I think that they are both effective good solutions. (Bryant Evolution w/ furnace/tankless DHW/solar or Tempstar HP/Budarus boiler heating coil in air handler/indirect DHW/solar)

Thanks!

[beenthere]

Some areas have one rate for summer, and another for winter rate.

We're switching to optional variable rates here soon.

[Sonicview]

Neither a cold start boiler, or a hot air furnace will warm up quick enough to eliminate a cool air discharge when your HP first switches over to defrost.

You could install an aquastat on your aux. heat coil, and control the fan with the aquastat switch. this will prevent cold air blowing in defrost mode and between HP and aux. heat mode, this gives the coil a chance to warm up and cool down... just another option if going with the boiler. I have the Tempstar T4H7 2 stage with Burnham boiler .. works great!

[beenthere]

You can do that, on a PSC motor.
It can add time to the defrost cycle. And at low outdoor temps, it could trip the low pressure safety switch.

On a VS blower(or most VS blowers), there is more then one control circuit that will bring the fan on.
You would have to interupt all 3.

[Sonicview]

With my system using a VS blower I disconnected the w1 wires (Aux heat/defrost) from the fan coil board and brought them to the boiler's hydronic 4 wire zone valve yellow wire and the other hydronic zone valve yellow to Common on the fan coil board. only when w1(defrost/aux oil heat) calls for heat will this circuit engage..opening the zone valve and turning on the boiler circulator,.. once the aux heat coil heats up the aquastat engages causing R and W2 to make its connection and fan comes on (W2 being aux heat fan speed).. all other fan controls remain connected for y1 and y2. Since oil is also used for hot water and another baseboard loop in the house I believe it shouldnt take that long for the fan to kick on and create issues for the defrost cycle... hopefully... lol

[doogan123]

Sonicview - I take it you are happy with tempstar - its hard to find people that have it, alto one of my potiential installers whom i feel very confident in, is a strong believer in tempstar.

On the defrost issue - I am calling Nyseg tomorrow, - Something is funny with my electrical rate. Are you on NYSEG in duchess?

[beenthere]

As long as the Y1 and Y2 terminals have voltage to them, the blower won't stop.

So you could still get a cool air from it before the coil warms up.

It also sounds like your system is not a cold start boiler.

[Sonicview]

Sonicview - I take it you are happy with tempstar - its hard to find people that have it, alto one of my potiential installers whom i feel very confident in, is a strong believer in tempstar.

On the defrost issue - I am calling Nyseg tomorrow, - Something is funny with my electrical rate. Are you on NYSEG in duchess?

yes, I am on NYSEG and currently I am paying $0.08/kwh but that is not the delivered rate...if i take my bill and divide it by the actual kwh I used it comes out to like $0.11/kwh.... but it does fluctuate on the market. I am happy with the Tempstar unit, it seems to be a Carrier in a different shell. I had some problems with the installer so I had to find someone else to service it and assist with warranty work. since Tempstar dealers are hard to find I found a dealer that sells Heil and Carrier that was willing to work with me. Heil is the same as Tempstar as you probably already know.... I like the fact that it is so quiet because I have a small yard it isnt over powering when I am outside. So who did you find in your area that deals with Tempstar? ... I work in Katonah and was wondering if they are someone I know of.

Been... I believe when defrost is energized with this particular defrost board y1 and y2 drop out... I'll have to really check it out when defrost kicks in... it is hard to catch it in action lately...
and no it's not a cold start boiler so I guess it could take 3 or 4 minutes to warm up if there wasnt any demand for it in a while....

[beenthere]

The W terminal's fan speed over rides the Y1 and Y2 speed(as in slow down or speed up). But only when it is energized.

Since your boiler isn't a cold start. You won't have cool air for as long as a cold start. But you will have some.

[doogan123]

Sonic - the guy I am working with is from danbury. I have not been able to get anyone in westchester to even give me a quote.. i guess they are all too busy with the high end westchester clientele to bother with a low end job...

[Sonicview]

Sonic - the guy I am working with is from danbury. I have not been able to get anyone in westchester to even give me a quote.. i guess they are all too busy with the high end westchester clientele to bother with a low end job...

Doogan ok Danbury... thats still not far from me. I'd still like to know who it is...if you dont mind send me an email with the guys name... So far I would recommend the Tempstar unit I have the 2 stage T4H7 outdoor and the FVM4X indoor fan coil... what unit were you quoted?

Been... thats good to know.. I would have been wondering that eventually..