Question about Heat Load Calc....

STEVEusaPA

I just started toying around with 2 computer programs--Taco's Load Pro (trial version), and Hydronic Design Studio 2 (full version).

My question, in HDS2, when calculating for a row home, do you use only the 'exposed wall' area of the front and back walls of the house(say 10 degrees outside, 70 degrees inside), or do you also consider the party walls as exposed areas?

My thinking is, if I don't consider the party walls, and the customer's neighbors move out, will the unit now be undersized, if one or both neighbors homes are now vacant, unheated?

If you do count the party walls, do I go for a different outdoor temp (say 50 degree outside, just to add some more BTUH?

Or, is the row home so small, that the smallest boiler will probably be fine/ possible a little oversized anyway.

2 story, 13ft wide row home.

Second question, and probably better for TACO, it seems like the Taco software really leaves alot out, but is that because it's only the trial version? Seems hard to draw with it.

 What do the wallies think about either one/both.

My goal isn't to design all my own systems, I'm just looking for a tool to use to help diagnose, general purpose info etc.

All comments welcomed :)

Jason_13

Party Wall

I don't use either one so I cannot comment on either.

As far as the party wall do not include it. Even if the homes are empty most likely they will be heated to sell. If not it will not make a huge difference because the heat loss is usually about 20% heavy.

meplumber

I prefer HVAC Calc

I have used most of the Heat loss/gain programs.  I like HVAC Calc the most.  It has customizable reports.  Easier to use in my opinion.



I never really caught on to the Taco Load Pro.  It left a little to be desired in my opinion. 



As to your question about party walls, I would treat it as you would an unheated basement.  With say a 45-50 deg temp, just in case.  Yes you might over heat the adjoining rooms a little if the adjacent is occupied, but might save you if it sat empty for an entire winter.



Just my opinion.  Good Luck.

STEVEusaPA

Thanks you both

Thanks to both of you, Jason, and meplumber, for your responses. 

Robert O'Brien

Fudge factor

Keep the fudge factor built in to all  heat loss software in mind

MIke_Jonas

Two thumbs up

...for HVAC-Calc. There is no "fudge factor" built into HVAC-Calc.

Jason_13

load calc

They all have fudge built into them due to Manual J having fudge built into it. They calculate wind against all four walls at the same time. I have been using hvac-calc for about 15 years and have compared to others and they are all about the same. I have a few complaints with it but that is another story. It is usually 20%. That is why I suggested not to add for the party wall. Out of the operating time of the boiler over it's life how often will the party wall be cold? Remember the other party wall is also heated.

STEVEusaPA

thanks jason

for your suggestions.

NRT_Rob

I use HVAC calc as well on occasion

and I hate it. If you do anything outside the norm you have to hack it to get results, and it doesn't seem to take time of day into account very well on the cooling side so I am deeply suspicious that the cooling loads are VERY conservative as it appears to be totalling up the max load for each space. but maybe I'm missing something there.



HDS is really good. too bad it's windows only.



don't include party walls UNLESS they are separated by an airspace. I've seen some shared walls like that, which actually have a space that is open to the top. In those cases you need to include the wall. but including party walls will drastically oversize your heat plant and there is no real credible situation where the adjacent area would not be heated unless it were abandoned. If you're doing this kind of work in that part of town, well then maybe take that into account.

STEVEusaPA

NRT Rob

Thanks to Rob and everyone for their responses.  I'm going out Sunday to take a look. Yeah, it's in a bad part of town where unoccupancy is  the norm.  It was reffered to me by a friend.  It's for a single parent family, 3 kids, (isn't always 3 kids, or 2 kids and a grandparent?  lol) unit crapped out last March, and they eked by with some plug in electrics.  They really need some help.  So at worst they'll get it at cost and my free labor, and maybe I can twist a few arms and get them some more help.  But I still don't want to oversize, and was concerned about abandoned neighbors.  These houses are stone fronts, brick party walls, well built beauties from the 1930's, and probably no insulation.

  Thanks again for all the input.