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Complete HVAC Replacement Project

Posted by CigarLover (My Page) on
Mon, Jul 18, 11 at 5:40

Hello All,
I have been around the construction industry all my life (36 years) as well as making it my career, however my knowledge of HVAC until a few months ago was very limited. It has been a challenging experience but fun & very worthwhile. I have taken on the task of researching new systems for my mother�s home. Her home was built 25 years ago & the Central HVAC system was installed at that time using a builder�s grade (Carrier) system. The system has worked well all these years however it�s now time to do a complete replacement. I have learned a few things over the years in construction, the most important being: You get what you pay for, every time! That being said I have scoured the HVAC industry recently to find the Best equipment available at the best value for our money. I have located a very good contractor to sell us the equipment & perform the install but I want to insure that I am getting a fair deal as well as getting the right system for our application. I would really appreciate your opinions/expertise or any suggestions as we would like to do the complete replacement in the next 3-4 weeks. Thank you in advance, this site is really great!

Home Details:

�2 Story Home in Northern California (Pretty mild Climate that we have)
�1500 Square Feet of living space built on slab
�The home gets sun in the Summer months most of the day
�Insulation in the home is decent, Doors are Air-tight
�Windows have all been replaced 3 years ago with very high quality efficient ones
�Tile Roof
�14.5" Cabinet 64,000 Btu Upflow Gas Furnace installed in Garage (Current System)
�2.5 Ton A/C coil indoor & outdoor (Current System)
�Return air duct only downstairs
�Line-set built into the house so we can�t change them. Is flushing the lines Ok/acceptable?????

Our System Requirements/Wants:

�Need some additional cooling Tonnage for those really hot days. (105+Few days a year)
�Variable Speed drive for added comfort for both summer & winter seasons
�17.5" Cabinet for added CFM throughout the home compared to the current furnace
�We don�t feel that a 90+ efficiency is needed due to our short, mild winter season so I think the 80 will work great & still be much more efficient that the current furnace
�Want a good whole-house filtration system that I can clean a few times a year but don�t want to buy filters. Contractor recommended the Honeywell F300 because you never have to buy filters again. Just clean the unit in the dishwasher.
�New system must be very quiet & Quality built in the USA
�Want the system to last for 20-25 years with regular maintence done
�High quality install of the complete system

New American Standard HVAC System Design:
2011 American Standard 3-Ton Cased Indoor Coil:
Platinum Series High Efficiency Coil 4TXCB036BC3HCA (INCLUDED) 2011 American Standard 3-Ton Air Conditioner Coil:
Gold XI Allegiance 15 "SEER" Air Conditioner 4A7A5036E (INCLUDED)
2011 Honeywell Electrostatic Filtration System:
Model F300 ($980 Installed)
2011 American Standard 17.5" Furnace 64,000 BTU Model Options:
Platinum SV Furnace 80% "AFUE" Efficiency Variable Speed Model AUD2B080ACV32A with Vision Pro 8000 Thermostat - $8,636.00 Installed

Follow-Up Postings:

RE: Complete HVAC Replacement Project

How much do you pay per KW for electricity? I hear that california has expensive electric but sometimes they give discounts for heating with a heatpump. You might want to explore this idea since heatpumps cost just a little more than the same model A/C.

I mention this because you say the climate is mild. Heatpumps produce comfy warm (not hot) heat when above 30 degrees. They don't dry out the air like gas furnaces.

This might not be a good solution because of your electric rates but maybe worth exploring. I like having the upgrade done in many situations since it gives extra flexibility incase gas prices go up.

RE: Complete HVAC Replacement Project


first about previous post on heat pumps. As I've said many times, heat pumps are not for everyone or every application. Generally for California, heat pumps are not used except in all electric situations where nat gas service is not available. Main reason is California's ridiculous electric rates. Plus this will be a new system for a homeowner that appears to be a senior citizen most likely use to nat gas heat.

Now to the original post and the system quoted. These are my observations and I will say from the start that I like AmStd systems.

I do recommend a load calculation for both heating and cooling. For a mild climate, it is difficult for me to understand why you would need an 80K 80% eff furnace even a two stg VS model. Plus it appears you want to go up in size on AC condenser from a 2 1/2 ton to a 3 ton mdl. Why?

I would ask dealer for the Matching AHRI Directory matching number. I did not see it although I may have overlooked it. For me a matching number is important. You are aware that the furnace quoted is a communicating mdl? I suggest you go to AmStd website and read the features on this furnace if you haven't already.

I am not a fan of electronic air cleaners because of the regular maintenance required. I prefer a good 4-5" pleated media cabinet that has to be changed out once a year like the HW 200 model. Zero maintenance/cleaning. You need a good understanding of what routine maintenance is expected on the EAC.

Any hot/cold spots in home? Has ductwork been thoroughly inspected? Does home have adequate return? If you only have one return, I would add another for upstairs living area.

Flushing refrigerant line is an acceptable practice. However, line set must be correct size for new condenser. This is important! And. I regret to tell you many dealers are not as candid and truthful about this issue as they
should be.


Here is a link that might be useful: Platinum SV Furnace

RE: Complete HVAC Replacement Project

Hello Neohioheatpump,
Thank you for your creative thoughts on a heatpump system, however here in California Gas is less expensive than electric. So for that reason we don't use heatpump systems very often unless you don't have access to Gas (Rural areas.) Thank you & Take care......

Thank you TigerDunes

Hello TigerDunes,
I have seen & read your postings before on this site & I must say you are very knowledgeable on HVAC applications. Are you in the Business? I really appreciate all your thoughts & suggestions. We are doing load calcs & duct tests tomorrow on the house but the Contractor that I have been working with on the quote says load calcs can be misleading & he believes going with knowledge of living habits of the people living in the home in some cases. My mother has lived in the home for 20 years this August so we asked her several questions about likes & dislikes of the current HVAC system & then designed the new system with those thoughts in mind. I don't understand your question about the furnace selection? We went up a 1/2 ton in cooling because the current system works really hard on hot days to make temp. Matching AHRI Directory matching number? Please educate me on this, not familar it? I'm aware that the furnace has the comunicating option, not a big selling feature for us but we wanted the top-of-the-line 80% furnace & I have been told you can't order it without that option? There are no hot or cold spots in the home since we replaced all the windows with high efficent ones. What a difference that made. The return is good however one upstairs would be even better. I will post again later today, I want to pick your brain about your recommendation of the 4-5" fiter system & line size suggestions. Thank you again for your time.

RE: Complete HVAC Replacement Project


I like your forum name.

Just giving you a few ideas. There are three equal components of a successful new install; good quality HVAC, a competent dealer with attention to detail, and probably the most disregarded and overlooked is a good ductwork system.

Correct sizing is important. A Manual J is the professional method for sizing. One has to input the average summer high for cooling and the average winter low for heating. I always like to use a fudge factor of at least 10% on degrees. I looked up the climate for SanFran as a guide and found about 75 degrees for cooling and about 50 degrees for heating.Then of course there is the inside thermostat setting for cooling/heating for the occupants. Number of occupants is important as well as how home is used for entertaining, etc.

On the furnace sizing , it is difficult for me to believe that this home would require anything higher than a 60K 80% eff furnace. A manual j report would be the tell of the tape so to speak.

AHRI is the authority on matching systems. This stands for American Refrigeration Institute. They have a directory on matching systems. In your case, a matching system would be the furnace, outside condenser, and evaporator coil. In my opinion, any system that is not a match is not acceptable. The directory has it's own website. The match would list both BTUs produced and their efficiency.

I will tell you up front I am biased against EACs-electronic air cleaners. It has been my finding that most of the problems relating to a EACs is not performing the maintenance/cleaning schedule. Most homeowners will not or can't do it. That's why I prefer the 5" pleated filter cabinets with once a year change out that is easy.

Refrigerant line set size is a big deal. If it's not right, you are hurting yourself in performance/eff and can do damage to the system. Sorry but this is true.


RE: Complete HVAC Replacement Project

Hello Again TigerDunes,
You have made a great point that we may have overlooked regarding the line set size? I'm on my way over to mom's house to measure the lines right now to confirm. I will update you later with my findings. You made some other great suggestions that i would like to revisit with you, but first want ot measure those lines to make sure I don't have an issue with them. Thanks a bunch you have been very helpful on this project!!!

RE: Complete HVAC Replacement Project

Hey TigerDunes,
We are good on the existing line-set. The large line is 3/4"OD & the small line is 3/8"OD. The total length of the lines is 24 feet. I feel better now! LoL.

Your suggetion about the weather temps, I think i need to explain futher. Her home is located about 40 miles inland fron San Fran so the temps are much lower in the winter (high 20's) & in the summer somtimes it will be 105 degrees. San Fran is on the water so it doesn't get as cold or hot as we do. I hope that makes more sense with the system sizing as we have it. There's only 2 people living in the home but they like it 72 in the summer & 70 in the winter months.

With regards to the furnace that I have listed unless I'm confused the specs on American Standards website are as follows: AUD2B080ACV32A - 41,600 Btu's stage one & 64,000 Btu's stage two. The current system in the home is a 64,000 Btu's single stage furnace. Did my contractor not spec it out right? Next your suggestion about a matched system is intriguing to me but it doesn't seem important to these contractors out here, not sure why that is? I tried to match a system on the AHRI web-site as you instructed but was unsuccessful in doing so. Suggestions?

Lastly, I looked up the HW F200 & it's $300 less than the EAC that runns about $500. I like how the F200 doesn't need any power source to run it. I like that, but don't like the fact of buying $40 5" pleated filters twice a year. The maintenance issue you mentioned on the EAC makes perfect sense for most people but I am very maintenance driven & I accually enjoy it. The selling feature for me on the EAC is no more filter costs, it pays for itself over time (3-5 years.) I'm not ruling out the HW F200, much faster to change out the filters for sure...

What are your thoughts on RX-11 Line flush to switch over from R-22 to R410? Is it the best stuff out there? They say it is?????

RE: Complete HVAC Replacement Project


First, I just used SanFran as a guide as I had no idea of your location or how far inland you were.

I would rely on your dealer's load calculation for best and correct sizing both heating and cooling. Get this in writing on the software's letterhead,
Review carefully for any mistakes or false assumptions from the person who performed the Man J. Remember the result is only as good as the person who inputted the info such as insulation qualities of the home, size, and design temps for cooling and heating both inside and outside.

AHRI match is important. I will review again today when time is available.

On the line set size, I would ask dealer the size of your existing as a means to verify what you found. Then ask him what AmStd's spec for the line set is for the both Allegiance 15 in 21/2 and 3 ton size.

On the filter cabinet, I have Trane's Perfect Fit media cabinet and changeout once a year. Generics are available from Internet filter stores. $40 is about right for a MERV 10-12. I like the idea of zero cleaning/zero maintenance and no parts to fail,no power used. Your choice. I will say again though you need a thorough understanding of what's involved for cleaning/maintenance, the frequency, and who will perform this chore. I am a big believer in the KISS principle.

Line flushes are done everyday so I don't think that's an issue compared to the correct size.


RE: Complete HVAC Replacement Project

Tigerdunes is giving you excellent well thought out information. I really like that he says the following:
"Plus this will be a new system for a homeowner that appears to be a senior citizen most likely use to nat gas heat."
comfort is a huge issue, your Mother would likely be cold in the winter with a switch to heat pump heat.
temp difference between gas and heat pump heat is 10 to 15 degrees.

Tigerdunes and I are also on the same page with the filters.

Aside from that...all I can add is that checking the ducts and returns for air leakage..I'm sure you have duct leakage everyone does..
mastic sealing ducts, return air, plenum connections to to system and supply boxes will make a big difference.
She will get more conditioned air into the house, and the sealing will eliminate some of the dirt drawn in from these leakage sites.
better comfort, improved indoor air quality.

its commendable that you are researching this so well for your Mother, kudos to you.
will you be there for the install?

best of luck.

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