Cigar

Several questions.

What is zip code for gmother's location? Describe typical winter climate.

What size is system you are considering replacing?

It is difficult to believe that a 5 ton is correct size if home has reasonable insulation qualities.

I have never particularly liked the Heritage 16 (Trane XL16i). Note the relatively poor BTU output in both cooling and heating for system you listed.

If money is no object, you might look at Carrier's new Greenspeed HP system. I am not advocating it, just informing you. It has high HSPF for an air source HP.

There are three reasons for needing a properly sized heat strip.
1. To temper supply air when HP is in defrost mode
2. To add supplemental heat on cold days where HP by itself can not maintain indoor thermostat setting
3. To provide emergency heat in case of mechanical breakdown of outside condenser.

What size is existing heat strip?

Here is my general spec sheet for new system.

both outside and inside units should be replaced to have a properly matched system.

15 SEER, 12.5+ EER, 9 HSPF
best matching VS air handler
full BTUs in both cooling and heating for your rated size
R-410a refrigerant(same as Puron)
scroll compressor preferred
electronic demand defrost preferred
thermostat with "dehumidify on demand" feature
staged backup heat strips
new and correctly sized refrigerant lineset
10 yr warranty on parts and compressor

you want a thorough inspection of your ductwork system. size, overall condition, supply and return lines, insulation qualities, leak test, etc.

any hot/cold spot issues in your home should be addressed.

My personal recommendation is Trane/AmStd, Rudd/Rheem, and Carrier/Bryant.

Depending on your location, I would not purchase a new system that did not have electronic demand defrost.

Post back.

IMO

FYI - if you have an air source heatpump, you really shouldn't setback the t-stat. Heatpumps work best at maintaining temperatures. They are not good at bringing temperatures back up. When you do that the backup electric element is used which is 3 or 4X as expensive typically.

Get new highest efficiency single speed heatpumps and your electric bill should drop dramatically.

Hey Tiger,
Thank you for the quick response buddy. You have brought to light several issues. First off the zip is 95141. The typical winters get down into the high 20's at night & 40's during the day however because of her health issues she's always cold. She likes to keep the house about 80 degrees in the winter. I can't even go into the house when it's that hot. No cold spots, just large rooms. The room that she watches Tv & spends most of her time is 600sqft. I don't know for sure what the size of the current system is yet cause we can't find the nameplate with the serial#? I think it may be on the backside of the unit & we can't get back there without disconnecting the airhandler & moving it out of the way. I don't want to do that until install time of the new HP. Do you think the outside unit will have the info we need? She lives about an hour away from me. Regarding the 5-ton question: I would love to go down to a 3 or 4-ton but I want to be positive it's going to provide enough heat you know. Interesting that you mentioned the new Carrier GreenSpeed HP, I looked at it in depth a few days ago however I'm pretty sure it requires gas as well. Not totally electric? I think that's how they get 13 HSPF? I'm going to call them as soon as get done posting this back-up for you. I'm familar with Carrier, have a system in my own home. I have to admit I love American Standard though, but have no experience with their HP's? Thank you for the education about heat-strips, all of that makes good sense. Do you think we need the "Demand Defrost" Option? What HP system Mfg. would you buy for your home if HP was your only option? Thank you again for all your help...

Cigar

Here is a snapshot of your location's climate. Keep in mind they are averages, not extremes either summer or winter days.

Climate averages for:� SAN JOSE, CA, 95141
Hot weather Cold weather
��Average days per year above 75: 0 ��Average days per year below 40: 0
��Average high temperature: 72.7 ��Average low
temperature: 49.4

Really there are two things that need to be accomplished before you make an equipment selection/purchase.

1. You need to find out size of existing system for downstairs

2. You need a load calculation performed by either a professional dealer or you could do it yourself.

Just for the record, Carrier's new GreenSpeed system is an all electric HP system.

I personally would not purchase a new HP system that did not have electronic demand defrost feature. This feature eliminates unnecessary, nuisance, and expensive defrost calls. San Jose though appears to have a moderate climate so demand defrost is less of a big deal than a location in a colder climate.

If you go back to my check sheet, you will see my recommendation on brands. And BTW, I do have a Trane DF system for my home. Not always the best numbers but certainly one of the best and reliable on the residential market.

IMO

Hey Tiger,
OK sounds like we are on the right path. I will dig for the the info on the current HP to see what the size of it is. I have a call into my Hvac guy to see if he can buy Carrier Products(He's a American Standard Dealer)so he can work up a firm quote on the GreenSpeed HP system. I'm going to take your advice & have him do a load Calculation, however I'm going to check his numbers against mine. I already have done the measurements in each room for total sq feet. Please teach me how to do the Load Calculation the way that you do it? Just so I know how much additional cost is the "Demand Defrost" option typically run on HP's? It makes sense to have it on a really cold morning for her.

Hey Tiger,
OK sounds like we are on the right path. I will dig for the the info on the current HP to see what the size of it is. I have a call into my Hvac guy to see if he can buy Carrier Products(He's a American Standard Dealer)so he can work up a firm quote on the GreenSpeed HP system. I'm going to take your advice & have him do a load Calculation, however I'm going to check his numbers against mine. I already have done the measurements in each room for total sq feet. Please teach me how to do the Load Calculation the way that you do it? Just so I know how much additional cost is the "Demand Defrost" option typically run on HP's? It makes sense to have it on a really cold morning for her.

DD is not so much an option as something a particular manufacturer has included or not. I think.

Also, the manualJ needs to be done with 80F as the desired heating temperature, not 68F like some might do.

weedmeister is correct.

Demand defrost feature on heat pumps really is not an option.

It is available on only a few brands. Those include Trane/AmdStd, Rheem/Rudd, York.

I have heard about an aftermarket DD kiit that is on the market but know
nothing about it's use, reliability, and effectiveness.

Why so few demand defrost HP condensers? Because time defrost is so cheap and most homeowners are not really educated about the difference.

IMO