Who provided the Man J indicating a 3.5 ton HP system was the correct size? You have the load calculation in writing, on the software letterhead, and have reviewed it including the design temps both inside and outside for both cooling and heating?

Since you have had so much trouble, I would want a new and correctly sized refrigerant lineset. Save the old, strip it, and take to scrap yard to redeem.

I think the quote is high. I assume the FV005 or FV006 var speed air handler was quoted.Confirm back.

What size heat strip? If more than 10 KW, I would want it staged.

Edge Thermidistat would be the best choice since this is not an Infinity system.

This is nice HP system but it does not offer electronic demand defrost like Trane/ AmStd.

As far as ductwork for a 3 1/2 ton system, it should be sized 1400 CFMs min supply, same on returns. How many returns do you have now? I suggest a filter cabinet on return side of air handler.

IMO

Thanks for the response. I'll try to address each point (let me know if I skip anything).

A local business (Lexington, KY) provided the quote. Monthie Mechanical. I do have the load calculation on-hand. It was designed around:

Summer: 72F Indoor / 95F Outdoor
Winter: 68F Indoor / 8F Outdoor
RH%: 30 Grains

The Heat Pump model is: 25HNH542A003
The Air Handler model is: FV4CNF005T00

Technically the Manual J math came out to 3.69 tons. They recommended dropping to 3.5 tons vs going oversized with 4 tons.

The quote is for a 20 KW strip model: WKFCEH3301C20

The thermostat in the quote is "TP-PHP". It looks like that's the "Edge" you're referring to?

The quote also includes a new drip pan (30x60), 30AMP circuit panel addition, and new concrete Condenser pads for the Heat Pump.

The current supply is capable of 1500 CFM, but the current two return are only capable of 1200 CFM. The plan is to either enlarge one of the two current returns or add an additional third return to bring the return CFM up to 1500 CFM.

Let me know if you need any more info. :)

I would add an additional return strategically located. Another return will give you better airflow which should increase comfort. Three better than two. Add filter box at return of air handler.

I disagree about the 20 KW heat strip. A 15 KW yields about 51 KBTUs which should be fine. It should be staged. Keep in mind at 17 degrees, you will be getting around 26 KBTUs in heat from the condenser. See below.

7021410 Active Systems CARRIER AIR CONDITIONING PERFORMANCE SERIES PURON HP CARRIER AIR CONDITIONING 25HCC542A**30 FV4CNB006L 1225 42000 13.00 16.00 42000 9.00 26200 1 HRCU-A-CB 326 883 Yes

You want the FV006 L suffix air handler for the better heating efficiency. Pay attention here. The L suffix gives you the aluminum coil which is a plus.

IMO

I agree with the heat strips. I currently have 15W (10W + 5W) and they upped it to 20 due to my complaints of the unit not keeping up in the winter, but I believe that was due to the Heat Pump being completely dead (and only having the strips heating), not that the strips weren't capable (if the Heat Pump was helping).

I've did some searching but I can't find anything with the L? Is that because the aluminum coil is standard now?

http://catalog.dcne.com/catalog/WebCatPageServer.exe?PROD_FULL&ProdInfo=00007000488

Lists the aluminum coil in the description. The L was replaced with a T representing their tin coating "ArmorCoat" from what I can tell.

One difference I noticed is that your model number is a Modular cabinet (vs a singular cabinet). It also has a higher BTU range (30 --- 60,000 vs my quoted unit's 30 --- 48,000). Is that the extra heating efficiency you were referring to?

Indoor summer temperature for the load calculation is usually 75 degrees. Did you ask for it be done at 72 degrees?

You stated summer temperatures are typically 90 degrees, yet the outdoor temperature used was 95 degrees. The typical high should be used, not the record highs.

I am skeptical that an 8 year old 2200 sq. foot house would require 3.69 tons of cooling. I think part of the problem is the indoor and outdoor temperatures. This is making the calculated load larger.

It sounds like you duct work was undersized even for the old 3 ton unit. are you going to get more quotes and see if you can get a load calculation from another contractor?

Hi Maconi.. Not sure if what I say will be helpful but we have Infinity air handlers with Performance series condensers. My understanding was that the Performance Series 17 which is what I have was originally the early Infinity condensers. From a cooling standpoint (we have 5 zones in 3800 sq ft Massachusetts home) the system has been flawless but we hope to upgrade the Condensers to Carrier Greenspeed Heat Pumps 25VNA and hope to sell off our 3 ton performance series condensers which are barely used. Heating is more of a need in our world than cooling so the heat pump option makes sense potentially to us.

We were quoted $13,575 for the replacement of our 2 Performance Series Condensers and the setup of the (2) 3 Ton Greenspeed Heat Pumps.

Sorry for the delay. I've also decided to go with Greenspeed. Since they are supposed to be sized to heat rather than cool (since it's so variable and will self-adjust the cooling to match the needs of the home) it will be okay to go up to 4 tons I was told (although my ductwork can really only handle 3.75 tons so I might upgrade that to take full advantage of the 4 tons of heating).

It sure is expensive though. $12,000 (after rebates) for one set of new Infinity 20 Greenspeed Heat Pump/Air Handler (wi-fi thermostat). Hopefully the savings in heating will pay off the difference between it and the $9000 Performance (after rebates) I was quoted.

Overkill for your location but you are paying the bill...

You need a load calc performed...

Good Luck...