New AC and furnace help in Southern California

[Cosmonaut]

Hello all. Have been lurking here for a little bit and thought I would make a post about my current situation and seek some of your advise.

I live in Orange County, California which is about 15 or 20 miles from the beach. My furnace and AC are both original from the house which was built in 86. Insulation is fairly good although I don't know the material type, just what I have been told. Double pane windows all throughout downstairs only. Currently havea4 ton Lennox AC and a 75000btu Lennox furnace.

The problem I have is that I am not getting any ventilation to my 2nd story house. Total sqft is 2350. I have had 6 people come bid. Why 6 you ask. Well the first one was from a company I called to do a service which ended up being worthless and they "discovered" a crack in my heat exchanger which no one else could find. The scare tactic worked but after the other quotes came in i realized that is all it was. We have been in a heat wave for about two month here, by Southern California standards

The next two guys spent a total of 10 or 15 minutes total here. Both went in attic. Told me I need 5 ton, gave me a cheap quote and left. Then I came here, read a little, checked yelp and Angie list and called three more guys.

First one was very thorough and spent about 2.5 hours here, said that there is space to increase my duct from 12inches to maybe 14 for the run upstairs or that I can add another 12 since my plummen sits right on top of the heater and it is a straight shot up. I have 5 runs in the attic now. Doing the second one I can run two into my master and master bath which has vaulted ceilings and 3 into guest rooms and bathroom, one with a y split. New runs also since they are original from 86.

Downstairs is about 1300sqft and the dining area and formal room is all vaulted ceilings as well. The recommendation so far is a 80% eff variable motor furnace and likely a 5 ton AC 13 or 14 seer, one Stage. Second and third guy also said the same thing but said the extra duct may not be needed as they believe I just have a dirty evaporator coil which is causing the low air flow and the runs are not efficient, ie a few extra bends versus straight shots. They spent auto an hour each here.

All recommended I go with bar types vents instead of my current ones and basic thermostats. I can upgrade to ecobee or nest if I want. Not sure it is worth the money.

Now that you have context, and thank you for reading, I think all three contractors would do a good job. First one uses Amana. Second one uses Lennox. Third one uses tempstar.

Amana guy also said he would do a manual j if he got the job. Rest would not do it. Don't have a quote yet from Amana. Coming today. He also said I spicule go 4 ton AC and 5 ton furnace?

Lennox is merit 14acx AC with a merit ml180u furnace or a elite xc14 and a sl280 furnace for another 40% increase. I do get some money back in a Costco gift card.

Tempstar is the n4a3 AC and the v80 furnace. His job was about 15% less before the gift card is factored in. Only thing that gave me pause is he said if we increase to a 14 duct and they have it make it oval that is ok, wouldn't that change the cfm etc?

My questions are ( finally)

1. Are the brands and models good?
2. Is 4 ton or 5 ton ok? I don't want to short cycle. Can I mismatch a 4 ton AC and a 5 ton furnace?
3. Is a increase to a 14 vent or running an extra 12 a better solution to increase airflow upstairs?
4. Are bar types needed?
5. Is a nest or ecobee good or just a nice fancy thing to have?

Thank you all for the help. Once I get the Amana quote I can provide those furnace and AC.

[isuredo]

A Manual J is required BEFORE the quote!!, you cannot size anything correctly without a properly done load calc. Insist this is done 1st, then you can address airflow concerns, and if its a seperate trunkline to upstairs, Carrier has a very nice Infinity zoning that may be the answer to all your problems airflow wise by allowing seperate conditioning for both spaces, good luck!

[CraziFuzzy]

I concur on zoning upstairs and down separately. Even if you are able to get the summer air balance just right to have the single system cool the entire house evenly, then It is unlikely that it will be even in the winter. Adding a zoning system to an existing house CAN be complicated, depending on the duct arrangement, but it sounds like since the ductwork is already segregated between the upstairs and down, most the work is already done.

[Cosmonaut]

Yes zoning would be ideal but that would require moving the furnace upstairs and increasing my cost twofold. Not sure the incremental comfort would be worth the the additional cost.

As for manual j one company said they would perform to confirm their initial suggestion calcs out. No one else would do it and I have looked into all reputable companies locally that have good reviews on angies list or yelp. This is why I'm leaving towards moving forward with the Amanda group but I need to see their bid and equipment.

Any thoughts on the other questions I posted. Thank you both for the initial feedback.

[motoguy128]

I concur on zoning upstairs and down separately. Even if you are able to get the summer air balance just right to have the single system cool the entire house evenly, then It is unlikely that it will be even in the winter. Adding a zoning system to an existing house CAN be complicated, depending on the duct arrangement, but it sounds like since the ductwork is already segregated between the upstairs and down, most the work is already done.

This is Socal.. so the biggest challenge will be sizing. Very ,very easy to oversize since it's a very moderate climate, low humidity and warm winter. At 2300sqft you probably don't even need a 60k BTU furnace.... and you won't need a lot of AC either, a load calc probably won't call for more than 4 tons. Oversized unit make temerpature imbalances between floor worse because the equipment short cycles. THe longer the cycle, the more even the temrpature will be.

Remeber, there's always 2 sides to everything. If the upstairs is "short" on airflow... that means the downstiars has too much airflow. FOrtunately a lot of 60k BTU furnaces do come with 4 ton blowers, so if hte load cal calls for a 3, 3.5 tr 4 ton system, you're covered if hte ductwork is sized adequately. The larger the AC, the more airflow and more ductwork you need.

[jtrammel]

Get a blower door test done on your house, then a manual j. That's the only way to properly size hvac equipment. Go to the contractor locator on these sites www.comfortinstitute.org or www.bpi.org and find a good contractor. I thought testing was code in California?

[Cosmonaut]

Jtrammel. Comfort did not have one within a 100 mile radius of my zip code. That is their max query setting. Bpi had a few up in los anegels so like 35 to 60 miles away which may be too far to get them to come down. I can look into them but most looked like contractors not actual HVAC techs. Also I believe manual j or dis only a rrequirement for new construction not necessarily a change out. Or if it is them it is definitely not enforced so no one offers it or thinks it is necessary. Perhaps due to the more mild climate as mentioned by motoguy.

[CraziFuzzy]

Yes zoning would be ideal but that would require moving the furnace upstairs and increasing my cost twofold. Not sure the incremental comfort would be worth the the additional cost.

As for manual j one company said they would perform to confirm their initial suggestion calcs out. No one else would do it and I have looked into all reputable companies locally that have good reviews on angies list or yelp. This is why I'm leaving towards moving forward with the Amanda group but I need to see their bid and equipment.

Any thoughts on the other questions I posted. Thank you both for the initial feedback.

I was going on the impression that you had a separate trunk running from the furnace to the upstairs areas. If that is not the case, then yes, zoning would add a bit to the cost (though I don't think you'd need to move the furnace from it's current location). If, though, you actually have a single large trunk going from furnace, up to the inter-floor space, where it branches out to the 1st floor ceiling registers, and then continues up to the attic where it feeds the upstairs ceiling registers, than zoning would simply require the dampers to be installed where they split between the floors (and obviously a furnace/air handler that is compatible with zoning).

As for the load calc, the others are correct - there is no point in even looking at equipment until the demands of the structure are assessed. A proper load calc needs to be done. One of the critical numbers in that calc is the amount of outside air infiltration, which can only be determined via a blower door test. If the contractor is sizing a system for you, THEN telling you he will do a load calc after you choose his system, he's missing the point of the load calc completely.

[Cosmonaut]

Thanks all. Maybe others in socal had success getting an HVAC person to do a load calc for free but I haven't. So maybe finding one is possible but no luck so far.

Yes one trunk that gets split is my understanding.


Amana quote came in. Best Price. 4 ton 13 seer model gsx130481. Furnace is 5 ton 80% gmvc80805

This group was very good and while I understand the manual j should be done first if it is really about the installer they were the only one willing and capable to do a manual j. And we xcan adjust equipment at that point. Or I can likely okay them to it but again free doesn't happen in socal at least not for me

[Cosmonaut]

Having called around more and checked various contractor and energy websites I will have to go to a non installer for a manual j unless I do it with the group that provides Amanda products.

Based on the post above where I listed the models does anyone have any comments, good or bad, on Amana?