View Full Version : Manual J - Part of job estimate?
12-02-2007, 08:36 AM
Looking to replace my existing heat pump system (which is a mismatch) and have received a few estimates...one said he would de the manual J but charge $260.00...the others only go off the existing sizing...I really don't know who to trust around here...received all sorts of prices...ugh!! I live in Northern Va around Quantico...I feel that the Manual J should be done because my upstairs heat and cool stinks...oh, on a wicked budget also...should I just pony up for the Manula J?
12-02-2007, 08:58 AM
A lot of hours can be spent doing the Manual J. Some contractors will credit this charge if they get the job. The ones that won’t do the calculations or size by existing equipment I’d walk away from.
On the top of this page you’ll see HVAC Calc Click on it, Pay the $50 and use it to compare the results.
Remember you get what you pay for.
12-02-2007, 09:06 AM
Replacing the system will probably not fix the upper floor not working properly. This sounds more like a ducting issue, however the coil could be packed with dirt, replacement would correct that issue.
What a good room by room load calculation will do for you, is give you the answer to the problem rooms. If a room needs say 4000 btu's to cool it and the duct supplies 50 cfm then the duct size is too small. A new unit will not correct that problem, but at least you will have the answer.
BTW if you are on a tight budget, and I would assume the outside unit was replaced, last time around. You could just have a matching indoor blower installed on the existing outside unit.
12-02-2007, 10:26 AM
Hmmm, if a dealer cuts corners on the selling end of the job, what corners will he cut on the installing end?
I almost always did a quick whole house calc. Also was usually quoting smaller equipment (more comfy, more efficient) than the rest who were guessing or basing it on what was there.
dan sw fl
12-02-2007, 06:45 PM
.. and have received a few estimates...one said he would de the manual J but charge $260.00...
...I really don't know who to trust around here ...
Trust Me! Manual J is OBViou$ly NOT a part of quote.
Are you buying from this contractor or just bidding?
12-02-2007, 06:54 PM
there are customers that just wants to know what size of unit they need to purchase and install themselves so they wont a manual j performed for free.
no i will not do the manual j for free unless i get the contract
12-02-2007, 10:15 PM
All of the contractors that I just got estimates from would do load calc after signing a contract.
Makes sense, why spend all of the extra time on it? The price differences between an 80k and 100k unit were relative rounding errors in the end, with much more of the job being install and other things that are indentical.
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