Manual J calculations for my address available online?

[triode]

I am having someone install a new system tommorrow.The contractor gave me my BTU reqirements for my house.He didn't take any measurements of my house.Is there a database contractors can subscribe to to get these numbers on each and every residence?

[beenthere]

No.

But, he may have gone to the city and got the prints, or load calc from when your house was built.

Or, he's just guessing.

[triode]

I really doubt he went to the city for specs.It was built in 1991.Do you think it's really necessary to get it checked? How oftenl is it that it is done for a good quality install? Am I getting too worried?

[beenthere]

Many home owners find out the hard way. Weather one should have been done or not.

[sktn77a]

Unfortunately 99% of HVAC contractors don't do a Manual J calculation. I think most of them get lucky but I imagine there are many oversized (and maybe a few undersized) systems out there.

[merlin73]

Maybe he is just guessing or maybe he has done a few house that is on your street that is the style house as yours.
i would go with guessing..
why not call and ask, I am sure they have a oncall service that you can call and ask the sales guy. If they dont have an on call service stay away.. LOL,

[catmanacman]

you can have 2 exact houses if one faces north and one faces west it very likely be a different size air conditioner and different duct layout

[Phasewolf]

Why not spend a bit of money and download the program from here to do a load calc yourself? Does not cost a lot and that way you can see if it is even close to what he (thinks) should be installed. If the is way off then you know he is not telling the truth and and look else where. Or you can show him the load calc and ask him why his is so far off. http://hvaccomputer.com/talkref.asp
There is the link to the program if you need it. At $49 dollars it is well worth it to make sure you are not going to be unhappy with a system that does not work correct.