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Subject Author Date
Load Calculation Dick Adams 06-15-2008
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Posted by Noon-Air on June 16, 2008, 10:07 pm

> Noon-Air wrote:
>>
>>>> Dick Adams wrote:
>>>
>>>>> When I needed a new roof, it took me over a year
>>>>> to find a rep who knew roofing. One rep told me
>>>>> the job would be a roof over and would need 24
>>>>> squares. I knew the roof already had two layer
>>>>> and would be a tear-off - plus the roof was only
>>>>> 24 squares. Needless to say I am leery of home
>>>>> improvement reps.
>>>>>
>>>>> But now every one with whom I have spoken about
>>>>> a new AC unit has a Master License (I checked).
>>>>> But not one of them has done a load calculation.
>>>>> And the lowest bid for a 2.5 ton, Seer-15 is
>>>>> $5,400.
>>>>>
>>>>> Where can I find the math for a load calculation?
>>>
>>>> I don't show my load calculations on estimates.. You buy the job
>>>> you get to see about $300 worth of load calculations. This isn't a
>>>> hobby. A good computerized Load calc costs upwards to a $thousand and
>>>> up
>>>> to $5 thousand with all of the duct, material, etc addons. Plus it
>>>> takes
>>>> a few hours to input and get it right. Inspection department has to OK
>>>> it along with the work plan. I don't do the paper hob for my
>>>> competitors. When they worked for me I taught them right and let them
>>>> do
>>>> their own work. If you want to pay for the load calc..That is
>>>> business..
>>>> Free.. no way!
>>>
>>> Since you won't show me your load calculation, why should
>>> I believe you did one?
>>>
>>> For all I know you're just looking at my existing unit
>>> and making a bid to see how much I'm willing to pay.
>>>
>>> Dick
>>
>> The correct answer is this.....
>>
>> You will get a printed copy of the load calc report and an ARI
>> certificate of performance when we install the system.
>
> Nope.. First it is filed with the building officials along with an outline
> of the work. When the Inspectors approve the job, You pay the tab..Then
> and only then do you get everything that goes with it including the
> warrantee paperwork. There is no insurance to pull. You own that policy or
> you don't have a license. And a Bond. If you do Government work, it is
> even more complex. By the way the Feds pay for
> all necessary calculations before reviewing your bid. Most states require
> all of this in advance or you don't get your license. and you have to
> update your education each year. The client can of course go to Community
> development and peruse the Marshall-Swift for typical costs of such a job
> in his/her exact area and date. I have no problem with the customer
> getting several competitive bids either. As for price books, I have no
> intention of allowing my competition to get a look at that. It is a bid
> with all services and equipment listed with a bottom line price. This bid
> is good for 30 days and gives the period of time for the job. If we are
> financing the Job, then there is a whole other paperwork to be included.
> We like it that way, the customer likes it that way and both yours and our
> bankers like it like that. Even the Lawyers understand that. My job is to
> do your job with as least pain to you as possible.

Ummm... Don, here we don't have to get approval from the inspectors *before*
doing the job, and I don't have a problem with the customer seeing it, as my
book only shows *INSTALLED* prices.....Its all flat rate. I offer a
certificate of insurance for every install that I do, and thats as a
courtesy only. The only place here where licensing et all is an issue, is
inside of the city limits. Outside the city limits is where the scarey stuff
happens and I get called to fix it. FWIW, I don't do "estimates" I only do
written quotes, and yes they are only good for 30 days.

>> Here is the installed price from my price book, there is no guesswork,
>> and no surprises. Would you like me to pull a certificate of insurance
>> for this job??
>>


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Posted by Don Ocean on June 16, 2008, 9:47 pm
Dick Adams wrote:
>> Dick Adams wrote:
>
>>> When I needed a new roof, it took me over a year
>>> to find a rep who knew roofing. One rep told me
>>> the job would be a roof over and would need 24
>>> squares. I knew the roof already had two layer
>>> and would be a tear-off - plus the roof was only
>>> 24 squares. Needless to say I am leery of home
>>> improvement reps.
>>>
>>> But now every one with whom I have spoken about
>>> a new AC unit has a Master License (I checked).
>>> But not one of them has done a load calculation.
>>> And the lowest bid for a 2.5 ton, Seer-15 is
>>> $5,400.
>>>
>>> Where can I find the math for a load calculation?
>
>> I don't show my load calculations on estimates.. You buy the job
>> you get to see about $300 worth of load calculations. This isn't a
>> hobby. A good computerized Load calc costs upwards to a $thousand and up
>> to $5 thousand with all of the duct, material, etc addons. Plus it takes
>> a few hours to input and get it right. Inspection department has to OK
>> it along with the work plan. I don't do the paper hob for my
>> competitors. When they worked for me I taught them right and let them do
>> their own work. If you want to pay for the load calc..That is business..
>> Free.. no way!
>
> Since you won't show me your load calculation, why should
> I believe you did one?
>
> For all I know you're just looking at my existing unit
> and making a bid to see how much I'm willing to pay.

I don't care what your willing to pay. The cost is what it is.
If your an astute purchaser. You will list all oranges and apples
and get realistic competitive bids. I would expect nothing less.

>
> Dick

Posted by Zyp on June 15, 2008, 8:06 pm
Dick Adams wrote:
> When I needed a new roof, it took me over a year
> to find a rep who knew roofing. One rep told me
> the job would be a roof over and would need 24
> squares. I knew the roof already had two layer
> and would be a tear-off - plus the roof was only
> 24 squares. Needless to say I am leery of home
> improvement reps.
>
> But now every one with whom I have spoken about
> a new AC unit has a Master License (I checked).
> But not one of them has done a load calculation.
> And the lowest bid for a 2.5 ton, Seer-15 is
> $5,400.
>
> Where can I find the math for a load calculation?
>
> Dick

Sorry Dick;

Load calc's [Manual J & Manual D] come when the contract's signed.


--
Zyp



Posted by Noon-Air on June 15, 2008, 9:19 pm

> When I needed a new roof, it took me over a year
> to find a rep who knew roofing. One rep told me
> the job would be a roof over and would need 24
> squares. I knew the roof already had two layer
> and would be a tear-off - plus the roof was only
> 24 squares. Needless to say I am leery of home
> improvement reps.
>
> But now every one with whom I have spoken about
> a new AC unit has a Master License (I checked).
> But not one of them has done a load calculation.
> And the lowest bid for a 2.5 ton, Seer-15 is
> $5,400.
>
> Where can I find the math for a load calculation?
>
> Dick

Load calc is part of the paid job.... and FWIW, $5400 for a 2 1/2 ton heat
pump and air handler is a steal. I just did a change-out for the going rate
of $7,000...had it been with a gas furnace, it would have been $8,000.

BTW, did anybody give you a copy of the ARI certificate for the specific
equipment??


--

Steve @ Noon-Air Heating & A/C

"Stop calling me for freebies Satan,
I'll fix your air conditioner when you pay me, Cheapskate!"



Posted by Andy Energy on June 16, 2008, 12:08 pm
On Jun 15, 3:04=A0pm, rdad...@panix.com (Dick Adams) wrote:
> When I needed a new roof, it took me over a year
> to find a rep who knew roofing. =A0One rep told me
> the job would be a roof over and would need 24
> squares. =A0I knew the roof already had two layer
> and would be a tear-off - plus the roof was only
> 24 squares. =A0Needless to say I am leery of home
> improvement reps.
>
> But now every one with whom I have spoken about
> a new AC unit has a Master License (I checked).
> But not one of them has done a load calculation.
> And the lowest bid for a 2.5 ton, Seer-15 is
> $5,400.
>
> Where can I find the math for a load calculation?
>
> Dick

Here is the organization some application are modeled after http://www.acca=
.org/

You can get the books from them on how to do a Manual J (load calc), D
(duct sizing), T (Air distribution basics), S (system sizing).

I have done most of the design through the manuals and my advice is to
hire a contractor that has the software to do the calcs. Be sure they
do a complete assessment of the thermal envelope, a blower door test
pressure balancing and a duct test and possible an infrared camera.
Doing a heat loss/gain calc is worthless without knowing what you
really have. I do not know anyone that can guess at the natural Air
Changes per House of a house or the CFM duct leakage.

If your contractor only installs the AC unit without testing out it is
a second rate job.
1)        Superheat or Subcooling depending on a TXV or not
2)        Duct test for leakage
3)        Static pressure in the ducts
4)        Flows from each grill to balance the system
5)        Pressure balance room to room
a.        To be sure there is no back drafting of natural draft
chimneys if you have any
b.        To reduce forced infiltration/ exfiltration by the fan
blower
6)        Measure the system flow to be sure your getting what is rated (this
normally requires new ducts and a larger return)
7)        Install dampers in each duct to do balancing
8)        High efficiency filter in the return grill
a.        Grill must be large enough to reduce static
b.        Filter is at the return to keep the whole duct system clean

A properly sized system will be nearly silent, draft free comfortable
and low utility bills.

Does the contractor subscribe to Building Science, if not find another
that does. May things in a house are connected and fixing one can
upset another.

By the way it is unlikely the bid for $5,400 will get you any of this,
buyer beware...

Hope this helps

Andy
Whole House Performance is the right thing to do

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