A 5 ton condenser seems over sized for a 2800 sq. foot house. What are the average high temperatures in San Jose.

Did any of the contractor verify the duct work is large enough to handle the required air flow?

I recommend staying away from big box stores and look for a HVAC contractor who will do a load calculation. You should not require 5 tons of cooling.

Hi Mike,
Thanks for your reply. The weather is San Jose high might be in 90s and some extreme around 100.
None of the three went to check the duct work. They all said that since the furnace is 5 ton, it's better to match.
Usually, what's the load calculation should be like?
One of the guys from costco, came and counted the number of intake and return.
Thanks.

j1stealth

You intend to keep your existing furnace?

Post Mdl number, size, brand, etc.

Does it have conventional blower single stage or perhaps two stage var speed model?

Post back with info.

IMO

Hi tigerdune,
I am planning to keep existing furnace. I will go back to check the Mdl number, size, brand.. but from the previous contractors, they said it's 5 ton and single stage.
I will go home, check and post some more info.
thanks.

The next questions is why do you have a big furnace? Do you know the BTU rating?

A 5 ton furnace means the blower fan can produce enough air flow to work with a 5 ton condenser. It does not mean you have to buy a 5 ton condenser. Usually the blower speed can be adjusted to work with a small condenser. A good HVAC contractor will advise you of your options. So far I don't think you have met a good HVAC contractor.

j1stealth

I agree with Mike. It appears you are oversized on heating especially considering size of your home and your climate/location.

The fact is though you can not pair high efficient AC condensers and matching evap coils with a conventional furnace. Complete waste of money. You will be just as better off with a quality 13 SEER condenser and matching coil. Of course correctly sized and definitely not a 5 ton based on information you have provided.

Be careful here. Surprised about the quotes you have received and it speaks volumes about their ethics and professionalism.

IMO

Hi Mike and Tiger,
The furnace was originally installed by the builder in 2003. house is 2 story. I think the brand is Bryant.
Typically, what should a load calculation look like?
Also, Typically, what's the expected price?
Some people said not to go through big store bc they charge more.. how much more?

Here is a link to someone who recently posted their load calculation. The calculation should show items such as design temperature, sizes of all rooms, and insulation values. The key output is the total heating and cooling load.

The big box has to make a profit above a he HVAC contractor's profit. It must be at least 10%, perhaps more.

More importantly is the type of HVAC contractor who works with big box store. You have a better chance of finding a good HVAC You on your own.

Here is a link that might be useful: Load calculation example

Hi all,
So I had another very well reviewed on angies list HVAC contractor. Guess what? He showed up 30mins; didn't bring a ladder.. didn't go into the house. Spent outside with me for 10min and quote a 15 seer 5ton unit for $6400.

Hi all,
So I had another very well reviewed on angies list HVAC contractor. Guess what? He showed up 30mins; didn't bring a ladder.. didn't go into the house. Spent outside with me for 10min and quote a 15 seer 5ton unit for $6400.

j1stealth

You are not listening.

The fact is though you can not pair high efficient AC condensers and matching evap coils with a conventional furnace. Complete waste of money. You will be just as better off with a quality 13 SEER condenser and matching coil. Of course correctly sized and definitely not a 5 ton based on information you have provided. Is your furnace var speed or even has a high eff blower motor?

Pst model number, brand, size of existing furnace.

IMO

.

Everybody is saying 5-Ton but am betting your duct system & Return-Air filter area might not even support 4-Ton!

Your 2.5% summer design is 81ðF dry bulb & 65ðF wet bulb or only around 41% RH.

With 2800-sf & those DESIGN Conditions & age of your home, it should not take more than 4-Ton of heat removal.

Do your own Free online load-calc
Print the instructions & follow them; when think U have it RIGHT, PRINT the results; U can't save the results!

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

Hi all,
My current furnace is the following:
Brand = Bryant
Model = 310JAV066110AAJA 5 ton unit
INPUT UPFLOW BTU/HR = 110,000
INPUT DNFL/HORIZ BTU/HR = 105,000
OUTPUT UPFLOW BTU/HR = 89,000
OUTPUT DNFL/HORIZ BTU/HR = 85,000

I had another contract came today. He also quoted me for 5 ton. He said that I have a 5 ton blower and that my duct should be able to handle 5 ton. He quoted me for bryant 15 seer 5 ton model 186 for about $5000.

Any thoughts on bryant brand? he said he also carry american standard but it will cost more since he gets better pricing for bryant.

Thanks.

This post was edited by j1stealth on Fri, Sep 13, 13 at 19:49

With the MILD design conditions you have, there is No Way you need 5-Ton of heat removal from your home!
Doubt you even need a 4-Ton!

Listen to the EXPERTS on this Thread, or you'll be sorry later...your electric bill will be very high for the heat removal you get...

Demand a load-calc for both heating & cooling; it does both at once. Experiment with doing your own load-calc...

Keep looking for another contractor and don't settle on the lowest bid. Cost is what you pay, value is what you get