HVAC questions for installers

[Showkey]

Well, I'd choose the load calc contractor over the let's guess contractor...

I thought there were a bunch of hoops to jump through over in California for this type of job. I thought that would have weeded out the hacks... unless it's a no permit job.

One big assumption........the load calc guy did it right.

Or both guys “pencil whipped” the paper work as they jump through the hoops.

Kinda like the 100 Point checks In the car business.............easier to check all the boxEs than actually do the work.

 

[lilcuda]

Not an installer, but recently we replaced our 17 year old HVAC system. Have you considered a variable speed system versus a single speed? Does noise matter? How about energy efficiency?

Also, keep in mind, once you get the system replaced, since your in California, it will have to be HERS tested afterwards

https://www.wegreeninc.com/blog/why...,residential and non-residential construction.

Noise matters. I want the system to be as quiet as is practical. Thinking about a variable speed system, depending on cost.

We are aware that it needs to HERS tested afterwards. It's only $300. In a project of this scope, it's small additional cost.

 

[lilcuda]

Hold on here did he measure each room (wxdxh) and the windows all this is required to do a proper Manual J calculation or did he measure the size of the duct work? I would ask to visually see a room by room calculation. Good old boy rule of thumb is not the proper way seen it before and competed for bids a few times where they did it the good old boy way.

If the guy is wanting to install a 5 ton and the existing duct work was designed for a 31/2 ton the registers and the duct work wouldn't be the right size.

Depending on where you are in the SF bay area you Humidity may not be that bad I was there (South SF) all last summer and other then a hand full of days I was very comfortable most of the summer inside or out.



when the duct system is designed correctly the variable speed fan motors are nice and quiet as well as a saving on electrical. I would look into a Heat pump depending on your area they are cheaper to operate in the heating mode.

I don't know that contractor #1 (3.5 ton bid) has done the calculation yet. It is included in the cost of the project. I need to ask him if he has done it yet or if he will do it if we award them the job.

Contractor #2 (5 ton bid) did not mention anything about a load calc, so I emailed him. He does not usually do them, but will do it for an extra cost.

We are replacing all of the ducting as a part of this project because the ducts are original and leaking like crazy and virtually no insulation on them. So whoever does the project should be designing the system as a whole. We are also going to have the attic air-sealed and have more insulation added (R13 to R44).

Also, we are about 40 miles southeast of South SF. Very different climates, believe it or not. The bay area micro-climates are pretty incredible in their differences. 6 years ago, we moved 5 miles east and the temperature is about 3 degrees warmer at our new house on average.

 

[Git]

Noise matters. I want the system to be as quiet as is practical. Thinking about a variable speed system, depending on cost.

We are aware that it needs to HERS tested afterwards. It's only $300. In a project of this scope, it's small additional cost.

We went with a contractor from Costco and one of the reasons I decided to go for the Lennox top of the line unit was the decibel rating. When the outdoor condenser runs, it is barely noticeable. (HERS testing was included in the price since it is mandatory)

 

[lilcuda]

Met with an insulation/HVAC contractor today. He was much more focused on the insulation than the HVAC aspect. he was telling me that blown-in cellulose insulation is better than batts and that it acts as an air sealer. My research says otherwise. He also told me they install Carrier. I mentioned Bryant and he told me they see a lot of problems with Bryant. After he left, I did a little searching online and found out that Bryant is owned by Carrier and that they are essentially the same.

Can't these guys just be honest?

 

[lilcuda]

We went with a contractor from Costco and one of the reasons I decided to go for the Lennox top of the line unit was the decibel rating. When the outdoor condenser runs, it is barely noticeable. (HERS testing was included in the price since it is mandatory)

Having a quiet condenser is good, but the big thing I want to avoid is a bunch of noise from the registers.

 

[danski0224]

One big assumption........the load calc guy did it right.

Or both guys “pencil whipped” the paper work as they jump through the hoops.

Kinda like the 100 Point checks In the car business.............easier to check all the boxEs than actually do the work.

That's correct.

I never do a load calculation before getting awarded the job. The initial quote is always based upon "what's there".

If I see issues, they get written up, along with an estimate to correct. Or explained right then and there if the client is involved.

The wholesale price spread between adjacent sizes of equipment within a model series is pretty close.

 

[Innovate1]

Met with an insulation/HVAC contractor today. He was much more focused on the insulation than the HVAC aspect. he was telling me that blown-in cellulose insulation is better than batts and that it acts as an air sealer. My research says otherwise. He also told me they install Carrier. I mentioned Bryant and he told me they see a lot of problems with Bryant. After he left, I did a little searching online and found out that Bryant is owned by Carrier and that they are essentially the same.

Can't these guys just be honest?

I would say blown in IS better than batts as it fills the spaces better but it is not an air sealer - no way.

Sounds like they want to sell the top of the line for more profit. Most of the big names have another brand name they sell under. It's sometimes last years model or not quite top of the line. Sometimes exactly the same.

 

[danski0224]

I don't know that contractor #1 (3.5 ton bid) has done the calculation yet. It is included in the cost of the project. I need to ask him if he has done it yet or if he will do it if we award them the job.

Contractor #2 (5 ton bid) did not mention anything about a load calc, so I emailed him. He does not usually do them, but will do it for an extra cost.

We are replacing all of the ducting as a part of this project because the ducts are original and leaking like crazy and virtually no insulation on them. So whoever does the project should be designing the system as a whole. We are also going to have the attic air-sealed and have more insulation added (R13 to R44).

Also, we are about 40 miles southeast of South SF. Very different climates, believe it or not. The bay area micro-climates are pretty incredible in their differences. 6 years ago, we moved 5 miles east and the temperature is about 3 degrees warmer at our new house on average.

You can buy a single license for HVAC-Calc, which is a fairly easy to use load calculation program, for less than $100.00.

It will also give duct sizes.

The software has not seen any updates in a while, and it has issues with displays over 1920x1080. The monitor resolution will have to be reduced or else the program errors out. The programmer apparently has zero desire to fix this problem.

There are avenues to get a load calculation/duct design/equipment schedule through an independent 3rd party. Then you can provide the "specs" for the job and have something meaningful to compare bids against. I had this done for a permit and the cost at the time was $300.00. I had to provide a drawing for the house and construction specs.

You can also try searching out an NCI certified contractor (National Comfort Institute).

I'd suggest looking into spray foaming the roof deck if it's possible. Having the attic as "conditioned space" will eliminate the need for duct insulation, and that could save some money if access is bad.

Your insulation changes will alter the load calculation.

I have yet to see an existing residential HVAC system with a 5 ton condenser with enough ductwork for the required airflow, not to mention air filtration... unless I have altered it.

 

[danski0224]

Met with an insulation/HVAC contractor today. He was much more focused on the insulation than the HVAC aspect. he was telling me that blown-in cellulose insulation is better than batts and that it acts as an air sealer. My research says otherwise. He also told me they install Carrier. I mentioned Bryant and he told me they see a lot of problems with Bryant. After he left, I did a little searching online and found out that Bryant is owned by Carrier and that they are essentially the same.

Can't these guys just be honest?

Insulation/building science: Sometimes, they don't know.

Carrier is part of ICP, which has a lot of brands under the umbrella. They aren't all "the same". The equipment is generally well designed and reliable, so most issues can be traced to faulty installation.

 

[brewchief]

Carrier and Bryant are like a Chevrolet and a GMC, Carrier's top of the line unit might be different or have more features but everything below it is the same, warranty may not be the same.

I agree with danski on possibly having a third party company do a proper load calculation taking into account the insulation changes and spec equipment size and to a complete duct design.

FWIW some multi stage and modulating equipment doesn't come in half ton sizes so if you need a 3.5 ton you end up with either a slightly undersized 3 ton or a slightly oversized 4 ton.

I also agree with the suggestion to see if there is a NCI trained company, that doesn't guarantee anything but if they were willing to pay for the higher level of training then they probably won't be the worst choice.

Sent from my SM-T510 using Tapatalk

 

[Rusty Fords]

He also told me they install Carrier. I mentioned Bryant and he told me they see a lot of problems with Bryant. After he left, I did a little searching online and found out that Bryant is owned by Carrier and that they are essentially the same.

Most Carrier and Bryant are the exactly the same! I sold Carrier for 8 years in my own business only difference is paint and sticker. Carrier is the preferred contractor models brand the Bryant equipment they will sell to other companies. So if you own 2 different brands named X & Y, You only sale brand X to certified companies that go through a certified installation training and brand Y companies don't have to go through training. Which brand will you most likely have more problems with???

That's correct.

I never do a load calculation before getting awarded the job. The initial quote is always based upon "what's there".
.

Sorry Dan but if you don't do a heat load up front then figure out the system isn't right you will go back with a change order to install the correct sized unit? I always took the time and did it before giving a cost to the customers. Off course maybe that is why I was working 6-7 days/week and 12-16/day

I would say blown in IS better than batts as it fills the spaces better but it is not an air sealer - no way.

Blow in is better then batts for sure, Spray i can't say I have heard of some night mares on spray foam off gassing for years, I would make sure to check with multiple insulation contractors on this.

 

[danski0224]

I can usually guesstimate proper equipment and duct sizing, and what issues are economical to correct, as most people will not pay for a complete duct tear out.

Equipment pricing for 2.5/3/3.5 ton AC is close enough to shoot for the middle. It is highly unusual to run into an existing "3 ton system" that really needs "5 tons".

Running a load calculation before getting the job takes too much time. Taking final measurements for fabrication before getting the job takes too much time.

If they say "go" then and there, that's different.

Customers don't want to pay for a load calculation because too many "contractors" give it away for free, even if the charge is taken off the job later.

And yes, the earlier pencil whipping comments, hinting that the calculation may not even be done right, are valid. Pencil whipping certainly happens in commercial air balancing and duct pressure (leakage) testing during construction.

A true independent contractor should be used for any testing or verification. Not a "independent contractor" that is really tied to another sheet metal shop.

 

[Jackfre]

It is really very difficult to install new duct work in an old building. Assuming this job will be permitted it will have to have the duct pressure test to pass. Do not overlook this. It is hard enough to seal duct work in open spaces. Once you get into an attic or crawl space, maybe...maybe not.
Did you get a quote on a mini-split? I bet you dollars to donuts they will be much quieter than a retro-fit duct install. Also, having spent to much time in attics in CA in the summer, your timing is off here.

 

[nadogail]

IMHO, you should seek the contractor with the best local reputation. Basically the equipment does not vary from one contractor to another, but Customer Care does.

 

[lilcuda]

I would say blown in IS better than batts as it fills the spaces better but it is not an air sealer - no way.

Did some reading about this yesterday. Apparently that's the case. I guess I was thinking that blown-in was the quick and dirty way of doing things. I'll have to reconsider it.

 

[lilcuda]

You can buy a single license for HVAC-Calc, which is a fairly easy to use load calculation program, for less than $100.00.

It will also give duct sizes.

The software has not seen any updates in a while, and it has issues with displays over 1920x1080. The monitor resolution will have to be reduced or else the program errors out. The programmer apparently has zero desire to fix this problem.

There are avenues to get a load calculation/duct design/equipment schedule through an independent 3rd party. Then you can provide the "specs" for the job and have something meaningful to compare bids against. I had this done for a permit and the cost at the time was $300.00. I had to provide a drawing for the house and construction specs.

You can also try searching out an NCI certified contractor (National Comfort Institute).

I'd suggest looking into spray foaming the roof deck if it's possible. Having the attic as "conditioned space" will eliminate the need for duct insulation, and that could save some money if access is bad.

Your insulation changes will alter the load calculation.

I have yet to see an existing residential HVAC system with a 5 ton condenser with enough ductwork for the required airflow, not to mention air filtration... unless I have altered it.

I don't have the time to try to learn how to do the calculations myself. Maybe if I was retired. I had an energy audit done in January and have given that info to all of the contractors I have talked to. So far, only one has really taken the time to read and understand it. He happens to be the "3.5 ton guy". I'm leaning towards going with him, but I'm waiting o=for one more bid to come in.

 

[lilcuda]

It is really very difficult to install new duct work in an old building. Assuming this job will be permitted it will have to have the duct pressure test to pass. Do not overlook this. It is hard enough to seal duct work in open spaces. Once you get into an attic or crawl space, maybe...maybe not.
Did you get a quote on a mini-split? I bet you dollars to donuts they will be much quieter than a retro-fit duct install. Also, having spent to much time in attics in CA in the summer, your timing is off here.

Already budgeting for the tests after the install. The independent energy auditor alerted me to that cost back in January.

Our attic & crawl spaces are pretty accessible.

Forgive me for my timing being off here. I'm sorry my timeline doesn't fit into your expectations for when an HVAC install should take place. We had a couple of little things like income taxes to pay, then there has been this thing called Covid19 you may have heard of.

 

[danski0224]

I don't have the time to try to learn how to do the calculations myself. Maybe if I was retired. I had an energy audit done in January and have given that info to all of the contractors I have talked to. So far, only one has really taken the time to read and understand it. He happens to be the "3.5 ton guy". I'm leaning towards going with him, but I'm waiting o=for one more bid to come in.

All you have to do is take measurements and plug them in.

The software is easy to use and learn. There is a demo on the site, iirc.