Fed up with Manual J!

[enb54]

Perhaps you folks in California can enlighten me, just curious.

I looked over that pdf the OP posted, and noted a basement and wall construction insulated with R19 and ceiling of R30, some double and some single glazed windows, solid core exterior doors and "tight" construction for a total home area of 13,945 sq. ft. The load calculation for this area with a design temperature of 38F (rise to 70F) is 60,385 BTU/hr, so that means the average new home in California only requires about 4.33 BTU/hr per sq. ft. on the coldest day?

The carrier furnace appears to be oversized based on the figures published, but man, that is one big area for only one furnace...

Just thinking out loud...

[Mr Bill]

And I for one am not about to stake my reputation on someone elses determination of what is a proper load calculation..

O God! I may as well with that kind of thinking, fire my install crew. Heck! I for one am not about to stake my reputation on someone elses installation..... Heck, give me some credit, at least I have heard of a LC... You should be out promoting it to folks that have not heard of one...you can start in California.

[ga-hvac-tech]

Looking at the load calc provided I can easily believe that the load is only 60K especially with a 38* outdoor design temp. My house in Houston was built in 1971 has minimal wall insulation and old single pane windows, the indoor temp does not drop below 50* on days in the mid thirties if we do not run the heater. I also agree that one furnace of any size will be inadequate for the airflow requirements.

I also wonder at the lack of A/C for a large tight home, in the long run this is going to come back to haunt you.

I would not use a manual J I would run a manual N commercial load calc and have a commercial company design and install the system. From the drawings I would look at hydronic hating and going with a Unico SDHV (small diameter high velocity) system using their unchiller for A/C and heat.

If you contact UNICO directly they will connect you with a trained and certified UNICO installer and help with the design and sizing of the system.

While I do not have much UNICO experience, I think the idea of hydronic (or elec baseboard) heat might be good. With the size of the home and the small heat requirement... elec baseboards will not be that much cost to operate... vs the cost of ducting a house of that size.

And yes, I think you WILL need AC sooner or later... so not installing it would IMO be a mistake.

[enb54]

While I do not have much UNICO experience, I think the idea of hydronic (or elec baseboard) heat might be good. With the size of the home and the small heat requirement... elec baseboards will not be that much cost to operate... vs the cost of ducting a house of that size.

And yes, I think you WILL need AC sooner or later... so not installing it would IMO be a mistake.

I don't live in California, but visited many times our relatives in Anaheim, and tend to agree with your assessment...

[udarrell]

IMO, One furnace & air handler with that amount of duct run would not begin to pass a Manual D check on it.

It appears to be way too much duct system for a small CFM furnace air handler to begin to deal with.

It makes sense to me to divide the rooms served to two furnace & duct system setups. That is the only way I'd ever begin to tackle this gigantic situation, & then, not without the aid of a zoning expert.
Am I off base on this...?

Guess they're trying to zone it so somehow it could work.

I am not a zoning expert; you experts on zoning, can they make it pass a manual D checkup, by using zoning techniques?

[classical]

I remember a quote by Samuel Clemmens (Mark Twain) "The coldest winter I ever saw was summer in San Francisco" so A/C may not be necessary for most or older homes. However a tight home is going to breed humidity and that will need to be dealt with.

[Mr Bill]

Hey Bill,

My approach is to explain load calcs to the HO... and give them a hard $$$ Proposal that states we will do the load calc AFTER the sale is made. Most of the folks I talk to are agreeable to that.....

John, what do you base you price on, existing equipment price? I don't care what anyone says here, the only person I personally know of in Houston and "I know a ton of my competitors", that can sale a smaller tonnage A/C system in Houston is Al "classical". You come down here and do all your LC's and present it to the customer, and tell them we can reduce you a/c size from 5 ton to 3.5 ton. Yea right! 99% of the time, especially if they have been in Houston all their life, they will tell you to hit the road Jack. Everyone seems to be living in the dream world that think LC's are the silver bullet to the correct system, well I have news for you, you can chunk that LC, unless your doing duct work also for just one example, and most all duct work everywhere is incorrect. Man we sure have some dreamers here, I really wished they would come open up a business in Houston, they would sink like the Titanic the first year doing a LC on every job. O once again for the record, I do condone the LC for all you that think I don't, my opinion is someone else should be doing them, not me, man the dreamers should seize the moment, start you LC and energy audit business, if your in Houston, I will give you all my business.

[ga-hvac-tech]

IMO, One furnace & air handler with that amount of duct run would not begin to pass a Manual D check on it.

It appears to be way too much duct system for a small CFM furnace air handler to begin to deal with.

It makes sense to me to divide the rooms served to two or three furnace & duct system setups. That is the only way I'd ever begin to tackle this gigantic situation, & then, not without the aid of a zoning expert.
Am I off base on this...?

Guess they're trying to zone it so somehow it could work.

I am not a zoning expert; you experts on zoning, can they make it pass a manual D checkup, by using zoning techniques?

A few mos back, there was a thread by a guy that found a VERY VERY VERY (did I say VERY) complicated zone system that literally could move the heat from one room to the next, and move the cool from one room to the next with the next cycle. The programming alone made my head swim when I read the website.

I think the name of the system was 'My Temp'... but I am not sure on that.

This may be an option... however I can ASSURE the prospective HO this will be a VERY (did I say VERY) expensive and VERY service intensive gadget you are about to embark on... and after all that $$$ to install, tweak, tune, and maintain it... IMO you probably would have saved $$$ with elec baseboards; without all the hassle.

[ga-hvac-tech]

John, what do you base you price on, existing equipment price? I don't care what anyone says here, the only person I personally know of in Houston and "I know a ton of my competitors", that can sale a smaller tonnage A/C system in Houston is Al "classical". You come down here and do all your LC's and present it to the customer, and tell them we can reduce you a/c size from 5 ton to 3.5 ton. Yea right! 99% of the time, especially if they have been in Houston all their life, they will tell you to hit the road Jack. Everyone seems to be living in the dream world that think LC's are the silver bullet to the correct system, well I have news for you, you can chunk that LC, unless your doing duct work also for just one example, and most all duct work everywhere is incorrect. Man we sure have some dreamers here, I really wished they would come open up a business in Houston, they would sink like the Titanic the first year doing a LC on every job. O once again for the record, I do condone the LC for all you that think I don't, my opinion is someone else should be doing them, not me, man the dreamers should seize the moment, start you LC and energy audit business, if your in Houston, I will give you all my business.

Hey Bill,

Sounds like you are busier than a one-armed paper-hanger... GOOD for you! BTW: I will be at the Goodman dog and pony show next Mon-Wed (26-28)... And will be free Tuesday evening the 27th if you want to get dinner.

This is a public forum... I will send you a PM.

John

[beenthere]

I know I would NEVER install a system and guarantee it based on someone else's load calc... that is just spitting into the wind IMO.

Very common in commercial. An engineer does the load calc, duct design, and register specifications.

[ga-hvac-tech]

Very common in commercial. An engineer does the load calc, duct design, and register specifications.

Not singling you out Been... however that may be one of the reasons I do not like commercial. There is always the issue of who is responsible if it does not work? And we all know an incompetent engineer will just voluntarily step forward... NOT. Personally; I can avoid that mess BOTH for the homeowner and myself by not relying on non-verifiable numbers.

I think most residential folks will agree: We do not do work off someone else's load calc, and we do not guarantee from someone else's load calc.

[tipsrfine]

Good link to article that sums up much of what has been discussed here:
http://www.greenbuildingadvisor.com/...j-and-manual-d

I personally think there should be some regulation/inspection and enforcement of ensuring things are being done correctly. Before anyone starts with the old "Since when has government intervention solved anything" argument, all I ask you to consider is that too many studies, and more and more articles, are pointing to the fact that the majority of residential hvac installations are just being done wrong. I personally saw it during my time working for a few different hvac companies, and I see it now as an energy auditor working with hvac companies. The only way forward is acknowledging that something is broke, and that it needs fixing. No blame, just forward thinking. Some of the reasons responsible for the problem, I think is:

1. Too many hvac companies out there that are not doing things correctly because they have to compete against too many other companies out there that are also doing things incorrectly. (Self perpetuating).
2. Too easy to become a hvac contractor in too many places.
3. No real standards. No independant inspections of installations to prompt contractors to do things correctly.
4. Until somebody steps in to force everyone to play by the same rules, nobody can afford to be the first one to do so because they get out-bid by all the others still doing things the incorrect way.

More & more contractors are finding ways to be successful in doing things right, but it would be a lot quicker & easier if they got rid of the ones that say "Heck, I'm too busy running around doing things the wrong way to possibly start trying to do things the right way! I'd go out of business!"

[Mr Bill]

it would be a lot quicker & easier if they got rid of the ones that say "Heck, I'm too busy running around doing things the wrong way to possibly start trying to do things the right way! I'd go out of business!"

Who is they? would that be the same folks that created the:

'Free Enterprise System'
An economic system where few restrictions are placed on business activities and ownership. In this system, governments generally have minimal ownership of enterprises in the market place. This system aims for limited restrictions on trade and minimal government intervention.

Again, I have not seen one post here were anyone has commended the Load Calculation. Here is what I have read, small businesses don't have the money to send a $25.00 per hr. service tech out to do a LC, I will do one when the customer signs on the dotted line, I refuse to do a free LC. "AND" there is no Government "regulation" to perform one and there never will be under a "Free Enterprise System" so keep dreaming. What I do support as a small business, is a separation of the a/c company and the folks that do energy audits and LC's. For someone that is so gung ho about something, you would think they would support any ideas on getting this service performed, and quit being a baby and singling out folks because they don't as a small business have the resources in this terrible economy to do things that don't put $$$$ in the bank. There is nothing worse that someone trying to tell someone how they should operate their business, this is why most of us work for ourselves so "we can" operate as we wish, I guess next, someone will suggest we should wear our blue boxers on all calls.