First, there is no way you should need a 5-Ton heat pump/A/C in MA.

You do not size heat pumps by the heating requirements; they should only be sized by cooling requirements.

You are spending a fortune on a system that will end up being costly to operate. The duct system is unlikely to support five ton, 2000-CFM of airflow.

Do your own Free whole house load calc

Here is a link that might be useful: Free Whole House load-calc

Do have central AC now and if so what is the size?

Your heating demand may be higher than that of cooling, but the heat pump still needs to be sized for the cooling load. If you do not then you run the risk of short cycling and high humidity in the summer. I would also would be concerned the duct work would not be big enough to handle the 2000 CFM needed for 5 tons of cooling.

My advice is have the contractor do the manual J calculation, pick the correct cooling size and make up the difference for the heating load with the heat strip.

Ductwork is existing or will be new?

Getting off oil should see some good savings plus an actual measurable payback.

This is good equipment, Bryant's top of line var speed low temp HP condenser. You should request that the heat strip be staged in increments.

5158972 Active Systems EVOLUTION EXTREME PURON HP BRYANT HEATING AND COOLING SYSTEMS 280ANV060****A FE4ANB006+UI 1500 1100 875 56000 12.70 18.00 55500 12.00 52500 1 HRCU-A-CB 386 993 Yes

With one system and the size of your home, I would look into the feasibility of zoning controls and if not that then two separate systems. Ductwork system should be reviewed for size, adequate return, leaks, insulation properties, etc. I would want a filter box cabinet.

IMO

For other posters, I see now that OP says he is replacing oil furnace and a 5 ton AC. I agree that a Man J is necessary and ductwork should be thoroughly evaluated. But I don't see a problem with the 5 ton Extreme HP condenser since it is variable. I am more concerned about the comfort level with zoning control or two separate systems. The feasibility and cost will need to be weighed by the homeowner{{gwi:9241}}.

IMO

This post was edited by tigerdunes on Sat, Jun 21, 14 at 8:06

Thank you everyone for your comments.

More background information was in my previous posting, http://ths.gardenweb.com/forums/load/hvac/msg06150038548.html.

We already have 5 ton AC and about 110,000BTU ~80% efficiency oil furnace. Our existing duct supply and returns are quite big, 21"x16". Many people have noted it. Everything goes from the basement to the first and second floors. Nothing in the attic.

udarrel, yes, I discussed this with the installer and he gave the following logic, that because we need BTUh that requires a 5 ton heat pump and because the heat pump is a variable speed it will adjust accordingly for the cooling/AC. Tigerdunes also mentioned this.

Tigerdunes, yes, I showed my calculations in the previous post (http://ths.gardenweb.com/forums/load/hvac/msg06150038548.html). It shows that going to Heat Pump will save lot and additionally, electric auxiliary/backup heat is slightly lower than oil.

Also, the proposed 20KW heat strip (62800BTUh) is staged at 5,20. I am wanting to use KFCEH3401F240 24KW heat strip (75300BTU) because I wanted to make sure we had sufficient heat and that also better staged at 8,16,24. Only confusion was that he could not get any information from Bryant on this heat strip yet.

Mike_home, another vendor had given us Manual J calculation for heating at 72769BTUh, and I did do my own calculations using loadcalc.net and I attached the graphics. But I seemed to end up with low numbers so I am not sure if I did it correctly. (I udpated the graphics after noticing some errors in input.)

Tigerdunes, we discussed zoning, the installer's response was that the payback was not worth it so he would not recommend it. He said installing baffles for all the first floor branches(?) and the second floor would add quite a bit of cost for 2-3% savings at the most. He said most of my payback would come from the heat pump.

Tigerdunes, what is advantage of "a filter box cabinet"? Isn't that covered with the "5" pleated merv 8 filter"?

Tigerdunes, what about the issue of "electronic demand defrost" that you say is very important. This system does not do that. That has sent me back into a tail spin in the decision.

And what about the noise issues with this system?

Also, if we assume that the system is correctly configured, is the price high?

Thank you for all you inputs.

This post was edited by sgw-ma on Sat, Jun 21, 14 at 10:04

If you like to keep a constant temperature in the summer then the AC will stay in the low stage most of the time. A set back in temperature will usually cause the AC to go into the high stage if it can't reach the desired temperature in a reasonable amount of time in the low stage.

How big is the temperature difference between the first and second floor in the summer? If it several degrees then you would benefit from zoning. The primary purpose of zoning is to keep the temperature even. It may save some money depending how you set the first and second floor temperatures.

The main supply and return ducts may be adequate, but what about the filter size? I would want to know the static pressure when the AC is running in high stage. The Evolution Controller will measure this for you. Ask the contractor to show you the measurement.

I still think a 4 ton AC would be adequate for your location. Review the contractor's load calculation carefully when it is done.

I also think the price is high. You should get additional quotes.

Zoning and two systems are not about payback, it is all about comfort. I think you would be making a terrible mistake not to thoroughly investigate the feasibility and cost. Yes both will be an added cost but if you intend to make this switchover from oil to electric, then do it right. You will be happier and better satisfied in the long run.

There is an old adage that goes like this. Satisfaction and comfort are long remembered while cost is forgotten very quickly.

IMO

Thank you, mike_home and tigerdunes.

mike_home, Currently the filter size is 16x25x1.

Here we use AC only for 2 months or so, max 3 months, and we keep it 74F for night and 75F rest of the day. For heating we keep 70F for day and 66F/67F for night.

I have not kept track of the temperature difference between downstairs and upstairs, but there is difference. We currently only have one zone and the thermostat is in the dining room on the first floor. It does gets warmer upstairs in summer and colder downstairs in winter. So we just adjust the vents to balance it little better for different seasons. No major issues.

Heating is more important to us. So everything is designed with heating in mind. The 4 ton will give max 48,000BTUh, while the 5 ton will give max 60,000BTUh. The configuration proposed will give 55500 BTUh (High) and 52500 BTUh (Low). Which will be closer to the required heating BTU and will then use less of the auxiliary/backup electrical heat.

Tigerdunes, okay will have to follow up on what you said which will take time. Will have to get addition quotes and see what this installer quotes for two zones with central system.

For two zone, one method is to have central system and two zones using baffles, and another to have two zones and two systems which will complicate things because might need different duct works (in the attic?). What should we do here? Wont all this being the price up even more?

No one has responded to the "demand defrost" and "noisy" questions.

Thank you.

Your filter is very undersized. You would need at a minimum two 16x25 inch filters for a 5 ton system.

I realize your primary concern is heating. You set back the thermostat at night so you not operating under the design conditions of the load calculation which is typically a 72 degree indoor setting. So you have extra margin there.

Please keep us updated if you go ahead with this system. The information you provide would be very informative.

I also realize your electric rates are high and you want to minimize the amount of time the heat strips are on. People on this forum have posted excellent low temperature performance with the Carrier Greenspeed equivalent. I think some people have locked out their heat strips to zero degrees. Do a search and look for these posts. You may get a little more heating BTUs out of the 5 ton, but I think the savings will be minimal if any. The heat pump experts will have to weigh in on this.

There have been reports about noise issues with the Carrier Greenspeed so I assume the Bryant Extreme will have similar noise levels. The installer is supposed to install a muffler as part of the installation. Is this contractor a Bryant authorized dealer? If he is he should have access to the training and installation manuals. I would not feel comfortable if this were his first installation.

I have no opinion on whether a conventional heat pump with demand defrost will operate more economically than a inverter heat pump without it. Again leave this up to the heat pump experts.

If you go ahead with this system, then keep us informed on the results. I would like to know how well it is performing.

The more return, the better airflow and comfort. I believe I mentioned adequate return in earlier post.

TD

Thank you again mike_home you last response was also helpful. Thank you to tigerdunes too. I have read several of your post during the research and they have been the basis of my research.

mike_home, for heating I did use 70F which is our daytime setting.

When you say two 16x25x1 filters, do you mean side by side or back to back?

BTW, zoning can be a modular task and can be done separately later too?

Actually, relative to Massachusetts, our electrical rates are low hence this suggestion and solution to use electric by the installer. As mentioned in the other post our electric is 11.39 cents.

Following is the calculations again from the other post.
1. For Oil at $4.00 per gallon $36.09 per Million BTU.
2. For Electric furnace/backup heat at $0.1139 per KWH $34.06 per Million BTU.
3. For Heat Pump with HSPF 12 (Bryant Extreme) at $0.1139 per KWH $9.49 per Million BTU.

As you can see the more we stay on the heat pump for heating the better we do cost wise.

The cost difference for heat pump between say 5 ton ($4,389) and 4 ton ($4,096) is not much. Similarly, for air handler 5 ton ($1,989) versus 4 ton ($1,829) is not much. These numbers I found on another website.

The installer, as far as I can tell is quite knowledgeable. He has definitely installed these heat pumps at other places. He gave me two references and one more might be possible. I will check how many he has done.

I did research many posts about the "demand defrost:" topic and would have preferred to have it to, unfortunately as noted by others too, for some reason Bryant/Carrier did not implement it in their systems. I am nervous because tigerdunes recommended it very strongly for new installs.

I read that one post by one person who fine tuned it to basically eliminate the use of heat strips and defrost cycle practically from his run time, but he lives somewhere where south (FL?) he rarely sees low temperature nights/days. I will though try his techniques to fine the system too, if we go this route. Because I don't want to have unnecessary defrost cycles going.

I will try to get more quotes and get back here with the information. Also if I do go this route, I will try to remember to update this after at least one winter.

Tigerdunes, great, it is relief to know the ducts are okay.

If there are any other heat pumps experts who are willing to give their input, I would appreciate it a lot.

Does anybody know if it is possible for this heat pump to be configured to disable the blower during defrost cycle such that it will not blow cold air into the house?

Thank you all very much for all the help.

I know on a furnace you can install a filter on each side. I am not sure how it would be done on an air handler. Ask the contractor what he proposes. Don't let him convince you a 16X25 filter is sufficient.

Don't misunderstand, I did not say the ducts were sized correctly nor I did I say you have enough return or they are sized correctly. It does seem though without a visual that you could easily add zoning controls for one system or add a separate system for upstairs.

TD

Just wanted to update.

We got more quotes for similar configurations and all of them were comparable or more.

TD, okay, noted correction.

Thank you.

Just wanted to update everyone because of all the help we got and thank everyone for the help they gave us.

We got a slightly higher quote with zones and we decided to opt for it (partly based on recommendation from here too).

We got the same setup as the original post and the system is up for a week so far and every thing looks good.

So far our experience/observations are.

The heating is working good, and the zoning is really good too. The heat is more even and steady due to variable heat pump, The zoning is helping out lot too because we have better control over first and second levels.

We have to see in peak winter how often and how good the heating is with backup heat strips.

No oil any more.

We had discussed with one reference and he mentioned that if you use heat strips for defrosting then you don't have problem with cooling first in the house while the heat pump takes heat from the house for defrosting. Will have to see the noise issue. Although here also we moved to away from the original window position.

As recommended we had requested a air filter cabinet/box and they installed Air Bear (had choice of Aprilaire, but preferred Air Bear because of the fixed filter seemed easier to install).

So thank you all very much for all your help.

Here is a link that might be useful: http://ths.gardenweb.com/forums/load/hvac/msg0718001325969.html?23228

This post was edited by sgw-ma on Sun, Nov 2, 14 at 10:23

This should be Bryant Evolution zoning controls, nothing else.

No more than 20 KW heat strip and should be staged in increments of say 10 KW and 5 KW increments.

IMO

Of course you want to do this right but if running your oil furnace, you are burning money.

TD

Have the heat pump for the whole calendar year and so am able to share the following numbers. Use view image to see the charts.